DISCUSSION
Tho r e s u l t s p r e s e n t e d i n t h e f o r e g o i n g chnpteru b r i n g
o u t s e v e r a l i n t e r e s t i n g a s p e c t s w i t h r e g a r d t o t h e food
and w a t e r u t i l i z a t i o n and e x p e n d i t u r e i n t h r e e rtlcea of
Bombyx m o r i namely Pure Mysore r a c e , NB D
4 2
and i n P h i l o s a m i a r i c i n i .
and KA r a c e s
F u r t h e r , t h e e f f e c t of i n s e c t i c i d e
p e r m e t h r i n on food and w a t e r u t i l i z a t i o n and e x p e n d i t u r e
during f i n a l 2 i n s t a r s are a l s o revealed i n
g.
(Pure Mysore r a c e ) and i n P h i l o s a m i ~r i c i n i .
Food u t i l i z a t i o n budaet:
Foregoing a c c o w t on silkworm Bombyx mori h a s
brought many i n t e r e s t i n g r e s u l t s
t h e b a s i c d a t a on
E. mori ( J a p a n
(1920) a r e r e c a l c u l a t e d ,
d i f f e r e n t races of
.
g.
m
For comparative purpose
r a c e ) r e p o r t e d by H i r a t s u k a
The food u t i l i z a t i o n budget i n
a i s more o r l e s s s i m i l a r .
The
most s t r i k i n g d i f f e r e n c e s c a n be summarised a s follows:
1) L a r v a l p e r i o d a v e r a g e s 30.5 days i n NB4D2 and KA
races.
The japaneee r a c e and P u r e Mysore r a c e o f
g. mori
t o o k a s many a s 33,O and 34.5 days r e s p e c t i v e l y . . The
d i f f e r e n c e i n t h e l a r v a l p e r i o d among t h e d i f f e r e n t r a c e s
i s not s t a t i s t i c a l l y s i g n i f i c a n t ,
on d i f f e r e n t r a c e s of B_. m
A v a i l a b l e informat i o n
a range from a minimum of 19.2
days i n Afagen X J a p a n e s e r a c e t o 26,2 days i n Vietnam r a c e
Fig. 13:
Bombyx mori
P u r e Mysore r a c e
Food consumption
(+)
assirnilat ion
c o n v e r s i o n (..-**.)
(.-,-a.-*)
(me; d r y
d e f e c a t e d (-+-)
a g e / l i f e stage.
and m e t a b o l i s e d
w e i g h t ) and f a e c e s
as f u n c t i o n o f
FOOD UTILIZATION BUDGET
-+Food intake
Food assimilated
Faces defacated
Dry matter converted
..-..o.-.~.Metabolized
-+a
- +-
+.+.a
Bombyx
mori
Pure Mysore race
/
/
/
/
/
/
/
/
/
4
p'
/I
/
* * ,
,,/"
/I,
dl
/
d"
0.11
1
I
I
I1
I
m
Life stages
I
m
1
1
(Refer: Text book of t r o p i c a l s e r i c u l t u r e , 1 9 7 5 ) .
The
l o n g e s t l a r v a l p e r i o d i n Pure Mysore r a c e h a s r e s u l t e d
i n l o w e s t c o n v e r s i o n of 248.3 mg d r y weight ( F i g . 1 3 )
.
However, t h e J a p a n e s e rRce c o n v e r t e d a s much a s 610.9 mg
d r y weight d u r i n g 33 dpye
of l ~ r v a pl e r i o d .
Though NB4D2
and KA r a c e s t o o k 30.5 days t o complete t h e l a r v a l p e r i o d ,
t h e c o n v e r s i o n amounts t o 458.4 and 535.0 mg dry weight
r e s p e c t i v e l y ( F i g . 14 & 1 5 ) .
It i s n o t c l e a r whether t h e
amount of food c o n v e r t e d t o body t i s s u e s depends on l a r v a l
period o r n o t ,
Longer l a r v a l p e r i o d s i n v o l v e s h i g h e r
e x p e n d i t u r e of energy f o r t h e body maintenance ( S c h r o e d a r , 1976)
2 ) The food consumption i n Pure Mysore r a c e i s comparable
t o t h a t o f t h e Japanese r a c e and is not s i g n i f i c a n t l y
different.
The consumption i n NB4D2 and I(A r a c e i s about
2 t i m e s more t h a n t h e consumption i n Pure Mysore r a c e / o r
i n Japanese race.
The KA r a c e consumes about 51.2% more
t h a n t h e consumption i n Pure Mysore and J a p a n e s e r a c e .
S i m i l a r l y t h e consumption i n NB4D2 i s 47.3% more t h a n t h e
consumption i n t h e endogenous r a c e s .
Similar differences
a r e r e p o r t e d i n food consumption o f d i f f e r e n t r a c e s o f
-B e mori
- (Periasamy
e t a l , 1984),
The Pure Mysore X KA r a c e
consumed 3323 mg d r y weight d u r i n g t h e f i n a l i n s t a r .
Much
h i g h e r consumption i s r e p o r t e d by Periasamy e t a 1 (1984)
i n b i v o l t i n e h y b r i d s (NB18X
amounting t o 3510 mg
Pig. 14: Bombyx m o r i
NB4DZ race
Food consumpt i o n (---X----)
assirnilat ion
conversion
(a
*.)
c.-+.p)
(.... . p" .. .)
and
metabolised /Jag dry weight) and
faeces d e f e c a t e d (-
-0- -)
as
function of age/life stage.
b
1
1
I
I
1D
1
5
15
Days
20
25
Fig, 15:
Bombyx rnori
KA r a c e
Food consumption
assirnilat i o n
conversion
(..-+..)
(-+)
*.)
and
metabolised (..*-tZ\--.-*) (mg dry w e i g h t )
and f a e c e s d e f e c a t e d (-+-)
f u n c t i o n o f age/life stage.
as
FOOD
UTILIZATION
BUDGET
Food i n t a k e
Faeces defaecated
.--6-Food assimilated
Dry m a t t e r converted
.....b--..
Metabolized
--it-
- +-
.+-.a
Bornbyx
mori
K A race
/
?'
/
/
/
/
/
/
'4
'
'
/d".+
I
0.11
I
I
n
b
1
I
5
10
I
I
m
1P
L i f e stages
I
I
I
15
Days
20
25
36
Fig. 16: P h i l o s a m i a ricini
Food consumption
(e)
(-9
a s s i m i l a t ion
and m e t a b o l i s e d
(...'~'*.o)
(mg dry w e i g h t ) a n d f a e c e s
defecated
-
-
o f a g e / l i . f e stage.
as function
FOOD UTlLAZATlON BUDGET
+ Food
- -
intako
faeces defaecated
Food assimilated
4
. -o- n
Dry matter converted
Metabolized
,....o. ,...
Philosamia ricini
/
I
I
I
I
.
,' /
I
I
J
uI
m
n
Y
Lito stages
I
0
1
5
I
10
I
It,
Days
I
20
I
20
2k
S i g n i f i c a n t decrease i n consumption i s found
dry weight.
i n Guang Nong-3 which consumed 1872 mg dry weight.
Where-
as t h i s r a c e crossed with NB4D2 consumes a s much a s 2750 mg
dry weight during t h e f i n 8 1 i n s t a r ( ~ e r i a s a m ye t 81, 1984 ).
Philosamia r i c i n i t a k e s 24.5 aays t o complete t h e
l a r v a l period.
During t h i s p e r i o d it consumea 6398.1 mg
(Fig. 1 6 ) dry weight of food which i s comparable t o t h e
consumption i n KA r a c e of j. x
i
. Although t h e consumption
v a l u e s a r e s i m i l a r i n KA race of silkworm and i n e r i silkworm,
t h e a s s i m i l a t i o n s i g n i f i c a n t l y changes and t h e conversion
of t h e a s s i m i l a t e d food i s more t h a n two t i m e s i n P_. r i c i n i
g. m a .
t h a n i n KA race o f
Food a s s i m i l a t e d v a r i e s not
only i n d i f f e r e n t i n s e c t s (Delvi and Pandian, 1972) but
even amongst t h e d i f f e r e n t r a c e s of
g.
e.Higher
consumption has r e s u l t e d i n increased a s s i m i l a t i o n .
i n s t a n c e t h e Pure Mysore race o f
g. mori consumes
For
lesser
amount o f food t o t a l l i n g 3081,8 mg and a s s i m i l a t e s 1597.5 mg,
Similarly i n
z,
r i c i n i t h e consumption and a s s i m i l a t i o n i s
h i g h e s t amounting t o 6398.1 mg and 3324.6 mg r e s p e c t i v e l y .
~ o n s u m ~ t i oand
n a s s i m i l a t i o n changes even among t h e d i f f e r e n t
races of
&.
A
h i g h e r consumption of 5872.7 mg i n
NB4D2 and 6472.6 mg i n KA r a c e r e s u l t e d i n h i g h e r a s s i m i l a t i o n
of 2263.0 mg and 2582,l mg r e s p e c t i v e l y .
However, t h e
consumption o f food i n Pure Mysore race and Japanese r a c e
of
E,
a i s s i m i l a r amounting t o 3081.8 m g and 3111,4 mg
m
r e s p e c t i v e l y but t h e a s s i m i l a t i o n is 1597.5 mg i n Pure
Mysore race and 1952.7 mg i n J a p a n e 6 ~race which i s about
20% more than t h e Pure Mysore race.
'
The r e s u l t s presented above are i n t o t a l agreement
with t h e r e s u l t s found by o t h e r workers f o r o t h e r races
g. G.
Periasamy et &
f i n a l i n s t a r l a r v a e of g.
of
(1984) have shown t h a t t h e
consumed and assimilated
d i f f e r e n t amounts of food depending on t h e race.
Guang
Nong-3 consumes 1872 mg dry weight of food and a s s i m i l a t e s
685
me. Crossing of Guang Nong-3 with
NB4D2 ha6 r e e u l t e d
i n increased consumption and a s s i m i l a t i o n amounting t o
2750 and 770 mg r e s p e c t i v e l y ,
Higher consumption i s found
i n hybrid races l i k e the Pure Mysore X
KA race which
consumes 3323 mg of food and a s s i m i l a t e s 853 mg.
consumption of 3510 m g i n b i v o l t i n e hybrids
Higher
increased
a s s i m i l a t i o n of 1361 mg (Periasamy ~t al, 1984).
Working on
g. 9 l a r v a e
(N124 X C124) Horie e t a l ,
(1976) have found t h a t t h e male and female l a r v a e belonging
t o f o u r t h and f i f t h i n s t a r consumed 4114,7 mg and 4718.3 mg
respectively.
Likewise t h e i r a s s i m i l a t i o n a l s o increased
depending on the amount of food consumed.
The a s s i m i l a t i o n
amounts t o 1663.2 mg i n male and 1867.4 mg i n female.
The a s s i m i l a t i o n i s r e l a t e d t o t h e amount of food consumed
n o t o n l y i n d i f f e r e n t r a c e s o f g.
@
but a l s o i n
i n d i v i d u a l s belonging t o d i f f e r e n t sex.
In
ce r i c i n i
t h e food a s s i m i l a t e d i n c r e a s e s from
f i r s t i n s t a r a l o n g w i t h t h e food consumption t o t h e maximum
i n the f i n a l instar.
I n any one s t a d i a t h e amount o f food
a s s i m i l a t e d i s r e l a t e d t o t h e amount of food consumed.
In
an o r t h o p t e r o n i n s e c t s l i k e P o e c i l o c e r u s p i c t u s ( ~ e l v i ,1972)
t h e food a s s i m i l a t e d i s r e l a t e d t o t h e amount o f food
consumed.
Delvi (1985) h a s demonstrated t h a t t h e maximum
amount o f f a e c e s i s produced d u r i n g h i g h e r f e e d i n g s t a g e s
i n the populations of
g. p i c t u e ,
It h a s become d i f f i c u l t t o compare t h e value o f f e e d i n g
r a t e a v a i l a b l e f o r d i f f e r e n t i n s e c t s due t o d i f f e r e n t
methods used i n c a l c u l a t i o n s .
While few workers have
considered wet weight o f i n s e c t i n g (Waldbauer, 1968)
o t h e r s have expressed i n mg/mg/day
1981) o r mg/g/day
( S c r i b e r and Slansky,
(Delvi and P a n d i m , 1972).
Consideration
of t h e weight of i n s e c t e i t h e r i n wet weight o r dry weight
as suggested by Waldbauer (1968) l e a d s t o c o n s i d e r a b l e
d i f f e r e n c e i n t h e f e e d i n g r a t e because t h e water content o f
t h e i n s e c t d i f f e r enormously depending on t h e type of food,
s p e c i e s , age and o t h e r environmental f a c t o r s ( s e e a l s o
D e l v i , 1983).
The f e e d i n g r a t e expressed i n mg d r y weight o f f o o d
p e r mg l i v e weight o f i n s e c t p e r day i s t h e h i g h e s t f o r
Pure l y s o r e race of
g.
amounting t o 1,6477 mg/mg/day
,
though t h i s r a c e consumes t h e l e a s t food when compared
t o other races.
The f e e d i n g r a t e d e c r e a s e s w i t h t h e
i n c r e a s e i n t h e amount o f food consumption.
NB4D2 r a c e
consumes 5872.7 mg o f food a t t h e r a t e o f 0.7111 mg/mg/day,
where as KA r a c e consumes as much a s 6472.6 mg of food a t
t h e r a t e o f 0.8157 rng/mg/day,
Further
g.
r i c i n i which
h
consumes 6398.1 mg o f food e 5 i b i t s a poor f e e d i n g r a t e o f
o n l y 0,4872 mg/mg/day.
However, i n J a p a n e s e r a c e of
B. mori
t h e f e e d i n g r a t e i s t h e l e a s t amounting t o 0.1810 mdmg/day
though t h e t o t a l amount o f food consumed i s a l s o l e s s
(3111.4 mg).
T h i s may be due t o t h e f a c t t h a t t h e J a p a n e s e
r a c e l a r v a e were r e a r e d a t 2 2 ' ~ where a s o t h e r r a c e s were
reared a t 26'~.
Most of t h e n v a i l a b l e i n f o r m a t i o n on f o o d i r ~ t n k eof
i n s e c t s h a s been e x p r e s s e d i n t e r m s of mass o f food consumed
p e r i n s t a r o r p e r day d u r i n g t h e s u c c e s s i v e i n s t a r s .
In
o r d e r t o compare t h e d a t a o f v a r i o u s i n s e c t s Slansky arid
S c r i b e r (1982) have c a l c u l a t e d t h e food consumpt i o n f i g u r e s
a v a i l a b l e f o r i n s e c t s i n terms o f r e l a t i v e consumption r a t e
(RCR) e x p r e s s e d i n mg d r y weight p e r mg mean l a r v a l d r y
weight p e r day.
Across a l l f e e d i n g c a t e g o r i e s Slansky and
S c r i b e r (1982) found f e e d i n g r a t e r a n g i n g from 0.04 t o 2.3
mg/mg/day and have c l n s s i f i e d t h e d i f f e r e n c e s depanding
on t h e t y p e o f food i n g e s t e d l i k e t h e h e r b i v o r e s , c o r n i v o r s ,
The a s s i m i l a t i o n r a t e i n ( F o l i a g e Chewing)
detrivors etc.
L e p i d o p t e r a n i n s e c t s r~lngud from 0.27-1010.70
m~r/mg/d~~y.
The h i g h v a l u e o f f e e d i n g r a t e (10.7 mg/mG/day) f o r f i r s t
i n s t a r l a r v a e of P i e r i s rapae may be due t o t h e p o s s i b l e
e r r o r i n e s t i m a t i n g s m a l l q u a n t i t y of food consumed
( ~ l a n s k y ,1974
l hat
and B h a t t a c h a r y a ( 1 9 7 8 ) , S l m s k y (1974 )
S l a n s k y and Feeny ( 1 9 7 7 ) ,
S r i h a r i (1970) have a l s o r e p o r t e d
h i g h f e e d i n g r a t e r a n g i n g u p t o 6 mg/mg/day
f o r other
lepidopteran insects.
The body weight o f d i f f e r e n t l i f e s t a g e s o f
and
P.
r i c i n i d i f f e r e d considerably.
B. & m
Hence, t h e body weight
food consumption i s r e l a t e d t o u n i t weight o f t h e t e s t
insects.
The i n v e r s e r e l a t i o n between f e e d i n g r a t e erid body
weight i s l i n e a r f o r t h e i n d i v i d u a l s b e l o n g i n g t o t h e second
i n s t a r from about 1 3 mg i n NB4D2 and KA r a c e .
l i n e r e l a t i o n i s a l t e r e d below 1 3 mg.
This s t r a i g h t
The a l t e r a t i o n
below 1 3 mg i s n o t due t o i n a c c u r a t e e s t i m a t e s of food
consumption ( ~ a v e y ,1954; Knst i n g and McGinnis, 1959).
r e g r e s s i o n l i n e f o r t h e f e e d i n g rate-weight
The
relationship
h a s been c a l c u l a t e d f o r t h e weight range 1 3 t o 1447 mg f o r
NB 4 D2 r a c e and from 1 3 t o 1671 mg f o r t h e U r a c e .
formula Y = a
+
bx h a s been a p p l i e d ( B a i l e y , 1 9 5 9 ) .
The
The
corresponding i n v e r s e r e l a t i o n s h i p obtained f o r Pure
Mysore r a c e of
E. * m
i s c u r v i l i n e r thm
'Linear.
While
t h e s t r a i g h t l i n e r e l a t i o n i s a t t a i n e d below t h e second
i n s t a r (13 mg) i n NB4D2 and KA r a c e , i t i s a l t e r e d below
t h e t h i r d i n s t a r (34.4 mg) i n Pure Mysore r a c e .
I n order
t o f i n d weight exponents, t h e r e g r e s s i o n l i n e f o r t h e Pure
Mysore r a c e i s a l s o computed o v e r t h e weight r m g e of t h e
second i n s t a r t o t h e f i n a l i n s t ~ r( 7 mg t o 795.3 mg).
In
P, r i c i n i
t h e i n v e r s e r e l a t i o n between f e e d i n g r a t e
and body weight i s l i r i e a r f o r i n d i v i d u a l s weighing 24.5 mCI;
(2nd i n s t a r ) and 3617.1 mg ( f i n a l i n s t a r ) .
l i n e r e l a t i o n i s a l t e r e d below 24.5 mg.
This s t r a i g h t
The r e g r e s s i o n
e q u a t i o n s are:
NB4D2 race
KA
i c i i
- 0.000064X
- 0.000093X
r a c e Y = 0,6695 - 0,00055X
Y = 0.3769 - 0.000053X.
Y = 0.4829
race
Pure Mysore
.
Y = 0.4403
i e e e 1 mg i n c r e m e i n body weight t h e decrease i n f e e d i n g
r a t e i s 0.000064 mg/mg/day
f o r KA r a c e ,
f o r NB4D2,
0.000093 mg/mg/day
0.00055 rndmdday f o r Pure l y s o r e race and
0.000053 mg/rng/day f o r
z.
ricini.
The i d e a t h a t t h e magnitude of weight exponents obtained
f o r t h e f e e d i n g rate-body weight r e l a t i o n i s i n d i c a t i v e of
t h e p o s s i b l e maximum body weight a t t a i n a b l e by a n i n s e c t
s p e c i e s i s n o t e worthy; i n p a r t i c u l a r t h e f a c t t h a t t h e
v a r i a t i o n s e e n i n t h e weight exponent w i t h r e f e r e n c e t o
d i f f e r e n t r a c e s can l i m i t t h e mwirnum body w e i a t o f
d i f f e r e n t s i z e l e v e l s f o r t h e same s p e c i e s o f f e r s a
p h y s i o l o g i c a l b a s i s f o r t h e occurencc of s p e c i f i c e c o t y p e
i n a n i n s e c t s p e c i e s , each w i t h i t ' s own maximum body w e i g h t ,
B e s i d e s t h e s e i n s e c t s , a d i r e c t C o - r e l a t i o n between t h e
weight exponents and t h e p o s s i b l e maximum body s i z e a t t a i n e d
e x i s i s t s i n other insects.
D o l v i and Pundian (1972) hove
r e p o r t e d t h e weight exponents f o r t h e f e e d i n g r a t e ,
a s s i m i l a t i o n r a t e body weight r e l a t i o n s h i p f o r s e v e r a l
i n s e c t s ; t h e y found t h a t t h e r e i s a pood r e l a t i o n between
weight exponents and t h e maximwn body weight a t t a i n e d i n
the insect.
The ' X I p r e f e r a b l y c a l l e d t h e "weight exponentbb
(Paloheimo and D i c k i e , 1966) i n d i c a t e s t h e measure o f
d e c r e a s e i n f e e d i n g r a t e f o r e v e r y m e i n c r e a s e i n body
weight.
The rnaximun wet body wei6;h.t a t t a i n i l b l e f o r t h e
s p e c i e s concerned o r f o r d i f f e r e n t r a c e s may be c u l c u l a t e d
from t h e weight exponents.
Most o f t h e a v a i l a b l e i n f o r m a t i o n on food i n t a k e o f
i n s e c t s h a s been e x p r e s s e d i n t e r m s of mass o f food consurned
p e r i n s t a r o r p e r day d u r i n g s u c c e s s i v e l a r v a l p e r i o d .
o r d e r t o compare t h e d a t a D e l v i and P a n d i ~ n(1972) and
In
Slansky and S c r i b e r (1982 ) have r e c a l c u l a t e d food
consump-
t i o n f i m r e s a v a i l a b l e f o r i n s e c t s i n t e r u ~ sof feeding r a t e
and r e l a t ive consumption r a t e r e s p e c t i v e l y .
Food i n t a k e a s
f u n c t i o n of l i f e s t a g e from h a t c h i n g t o death i s knowri f o r
few grasshoppers l i k e Oxya velox (Delvi & Pandiiu?, 1971)
P o e c i l o c e r u s g i c t u s (Delvi, 1972) and f o r few l e p i d o p t e r a n
from h a t c h i n g t o pupation l i k e
B, mori (Japano
race)
( H i r a t s u k a , 1920)., Spodopter~jl i t u r - t i , P e r i c a l i t i r i c i n i ,
and Eprotus fraterni.1 ( P r e a ~ a l e e l aand Delvi, Unpublished d a t a ) .
Not only t h e silkwonas but u l s o t h e grasshopper l i k e . 2 , velox
and
z,
p i c t u s and Schistocercya gregarie. (Hussain e t a1 ,
1946) showed a s t r a i g h t l i n e i n c r e a s e r e l a t i o n s h i p f o r
t h e f e e d i n g rate-body weight.
The feeding r a t e i n the v a r i o u s r a c e s of
g, mori
decrease from t h e second i n s t a r t o t h e f i n a l i n s t a r d e p e n d i w
on t h e body weight.
Highest f e e d i n g r a t e i s seen i n t h e
f i r s t i n s t a r of
E.
&
o
y
f i r s t i n s t a r of
P.
ricini.
-0, -velox
et al,
-
( a l l t h e t h r e e r a c e s ) and i n t h e
I n o t h e r i n a c c t s l i k e the
(Delvi r u ~ dP m d i a n , 1 9 7 1 ) ,
1946),
P, ~ i c t u s(Delvi,
2.
~w
(Hussain
1972) f e e d i n g r a t e was
highest during t h e second i n s t a r and decrease a s the
weight i n c r e a s e s .
--
Nayak e t a1 (1985) working on Antheraea m y l i t t a fed
on Terminalia tomentosa have found t h a t t h e food consumption
i s d i r e c t l y p r o p o r t i o n a l t o age and shows e x t r a o r d i n a r y
i n c r e a s e during t h e l a s t s t a g e of t h e l a r v a , i.e,
instar larva,
fifth
These authors have confused t h e feeding r a t e
a s expressed by Delvi & Pandifin (1972) with t h e mass of
food consumed.
I f t h e t o t a l amount of food consumed i s
considered it appears t h a t t h e l a s t s t n e e of t h e l a r v a e
a r e most a c t i v e a s pointed out by Nayak e t a 1 (1985) but
it i s c l e a r l y i n d i c a t e d by t h e d a t a presented i n t h i s t h e s i s
and by o t h e r a u t h o r s on d i f f e r e n t i n s e c t s ( ~ v a n s ,1939;
Mishra, 1972; Carne, 1966; Delvi and Pandicm, 1972) t h a t
an i n v e r s e r e l a t i o n s h i p of f e e d i n g r a t e with age e x i s t s
i , e , e a r l y devolopmentol stagen consume h i e h mount of food
per u n i t body weight per day* Nayak e t a1 (1985) have not
c a l c u l a t e d t h e f e e d i n g r a t e but have concluded depending
on t h e t o t a l amount of food consumed per i n s t a r .
It i s well
known t h a t 97-987'0 of t h e t o t a l amount of food i s consmed
during t h e f i n a l two i n s t a r n i n the l e p i d o p t e r a n i n n e c t s
( ~ a l d b a u e r ,1968).
However, Delvi and Pandian (1972) have
presented the r e c a l c u l a t e d d a t a of Hiratsuka (1920) on
E, mori (Japanese
r a c e ) ; they found t h a t the values obtained
f o r feeding and a s s i m i l a t i o n r a t e of f i f t h i n s t a r i n d i v i d u a l s
- -
of B. mori (Japanese r a c e ) were very high and were not
included i n t h e r e g r e s s i o n .
B.
( ~ a p a n e s ur a c e ) f e e d s
n e a r l y 1 9 times f a s t e r during the f i f t h i n s t a r period than
t h e expected value ( ~ e l v iand Pandian, 1972).
The food energy
obtained through t h i s h i g h e r f e e d i n g r a t e , savel through
b e t t e r a s s i m i l a t i o n and conversion e f f i c i e n c y i s spent
p e r t i a l l y on cocoon ( s i l k ) production and p a r t i a l l y on
metabolism d u r i n g non-feeding pupal and ~ d u l ts t a g e s
(Delvi and P a n d i m , 1972),
d i f f e r e n t races of
E. & m
I n t h e present s t u d y of t h r e e
m d a l s o eri-silkworm
g.
ricini
it i s found t h a t f e e d i n g r a t e continuously reduces as t h e
It i s not
body weight i n c r e a s e s even i n t h e l a s t i n s t a r .
c l e a ' r a s t o why such h i g h e r f e e d i n g r a t e was obtained by
H i r a t s u k a (1920) d u r i n g t h e l a s t i n s t a r of
race).
E,
mori
(Japanese
Although t h e t o t a l food consumption i s h i g h e r
d u r i n g l a s t i n s t a r t h e f e e d i n g r a t e p e r u n i t body weight per
u n i t time of e a r l y i n s t a r i s n e a r l y 4 t o 5 times g r e a t e r .
The f e e d i n g r a t e of f i r s t i n s t a r silk won^^ o f
Pure
Mysore r a c e i s a l s o n e a r l y 6 times a s high a s t h a t of f o u r t h
and f i f t h i n s t a r ,
Thie i s an important c o n s i d e r a t i o n from
t h e p o i n t of e s t i m a t i n g t h e l e a f consumed p e r u n i t weight
of t h e i n s e c t ,
of
B, mori
mg/mg/day
Since t h e f e e d i n g r a t e of f i r s t i n s t a r l a r v a
i s 6.1064 mg/mg/day
and it i s o n l y 0.2986
during t h e f i f t h i n s t a r , i t r e q u i r e s n e a r l y 6 mg
of f i f t h i n s t a r l a r v a t o consume equal amount of l e a f of
Morus a l b a p l a n t a s 1 mg of f i r s t i n s t a r l a r v a .
While f e e d i n g r ~ t eg i v e s a n i d e a of amount of l e a f
u t i l i z e d t h e a s s i m i l a t i o n r a t e i n d i c a t e s t h e metabolic l e v e l ,
and product ion r a t e
of i n s e c t s .
The r e g r e s s i o n s obtained
f o r r s s i m i l a t ion r a t e-body weight r e l a t i o n s h i p a r e l i n e u r
from t h e second i n s t a r t o t h e f i f t h i n s t a r .
Pure Mysore race of
g.
However, i n
t h e l i n e a r r e l a t i o n i s from t h e
t h i r d i n s t a r t o f i n a l i n s t a r and hence r e g r e s s i o n 3 a r e
c a l c u l a t e d f o r drawing t h e l i n e from 34.4 mg t o 795.3 mg.
I f t h e v a l u e s obtained f o r f i r s t and second i n s t a r s a r e
included f o r the Pure Mysore race of
g. mori t h e
would be c u r v i l i n e r r a t h e r t h a n l i n e a r .
relutionship
However, f o r
comparative purposes t h e r e l a t i o n s h i p of n s s i m i l a t i o n r a t e body weight has been ccilculated from t h e second i n s t a r t o
final instar in
g.
(Pure Mysore r a c e ) .
The e q u a t i o n s are:
f o r Pure Mysore race
NB4D2 r a c e
Y = 0.5475
Y = 0,2037
I(A
race
Y = 0.2634
P.
ricini
Y = 0,2177
- 0.00059X
- 0.000054X
- 0,000089X
- 0.000035X
S i m i l a r r e l a t i o n s h i p i s found i n o t h e r i n s e c t s l i k e
Oxya velox (Delvi and Yandian, 1971)
Pandiiin, 1 9 7 2 ) ,
and
9.
z.
p i c t u s (Delvi and
€ r e p a r i n ( ~ u s s a i ne t a l , 1946) and
B. mori (Japanees
r a c e , H i r a t s u k a , 1920).
However, i n
- -
B. mori, t h e a s s i m i l a t i o n r a t e l i k e t h e feeding r a t e of the
f i n a l i n s t a r i n c r e a s e s about 1 9 times h i g h e r than the expected
values.
Although t h e food i s consumed a t much higher r a t e
in
!&.(Japanese r a c e ) i t i s digested and a s s i m i l a t e d
with t h e same e f f i c i e n c y (3896).
This should have been
tx
radicnb adoptive change i n d i g e s t i o n through chmgeo i n
enzyme s e c r e t i o n and/or enzyme k i n e t i c s arid n s ~ i m i l aito n
through changes i n conduction of food and/or a c t i v e a b s o r p t i o n
i n t h e f i f t h i n s t ~ ri n d i v i d u a l of Japanese r a c e of
a.
g.
It i s s u r p r i s i n g t o note t h a t such changes a r e not found
i n t h e f i f t h i n s t a r i n d i v i d ~ l a l sof t h e 3 t e s t e d r a c e s of
g. mori but
a r e r e s t r i c t e d only t o the f i r s t i n s t a r a s i n
o t h e r i n s e c t s ( s e e a l s o Delvi and Pandiim, 1972).
The average a s s i m i l a t i o n e f f i c i e n c y as well a s t r e n d s
obtained f o r the e f f i c i e n c y a s f u n c t i o n of age a r e temperature
dependent i n
g.
p i c t u s (Delvi, 1972).
Working on
2.
6rep;ar-i~
(Hussain e t a l , 1946) and Davey (1954) showed t h a t t h e
e f f i c i e n c y decreased from h i g h e s t l e v e l i n t h e f i r s t l n s t a r
t o about jj$ i n t h e f i f t h i n s t a r ,
t o e+bit
a s i m i l a r trend.
(Delvi and Pandian, 1971).
2.
velox has been shown
I t s e f f i c i e n c y averaged 27%
Based on s h o r t t e r n l ~ ~ l o r a t o r - y
experiments Smalley (1960) r e p o r t e d an e f f i c i e n c y of 27$
for
SP5,
2,
f i l i c i n i u m and Wiegert (1965) 37S f o r Melar~oplus
Slansky and S c r i b e r (1982) have r e p o r t e d a range of
9 t o 88% e f f i c i e n c y f o r various i n s e c t s ,
The t r a d i t i o n a l
view t h a t carnivorus have h i g h e r e f f i c i e n c y values t h a n
herbivorus ( ~ a l o w ,1977) has been supported by Slanshy and
S c r i b e r (1982).
They have s u g g e s t e d a m e m v a l u e o f 805
f o r c a r n i v o f s and 35 t o 53$ f o r F o l i a ~ echewers.
However,
s e v e r a l s p e c i e s o f h e r b i v t r s m a n l f e s t c o m p l e t e l y high
a s s i m i l a t i o n e f f i c i e n c y v a l u e s r a n g i n g from 72 t o 88$
( S l a n s k y and S c r i b e r , 1981).
The e f f i c i e n c y v a l u e s change among t h e i n s e c t s
b e l o n g i n g t o same g r o u p s and a l s o among t h o s e occupying
t h e same t r o p h i c l e v e l .
I t r z n g e s from 12% i n t e r m i t e
C r y p t o t e r m i s b r e v i s a t 21°c ( W o l c o t t , 1924) t o 70% i n
P r e d o n i a e r i d a n i a a t 2 7 ' ~ ($00 Hoo and, P r a e n k e l , 1 9 6 6 ) .
With t h e d a t a a v a i l a b l e on e f f e c t s of t e m p e r a t u r e und r a t i o n
l e v e l of few h e r b i v o r u s i n s e c t s it can be s a i d t h a t w i t h t h e
i n c r e a s i n g r a t i o n l e v e l from 25 t o 100% t h e a s s i m i l a t i o n
e f f i c i e n c y i n c r e a s e d from 48 t o 5 4 s i n
P, p i c t u a
(~uthukrishnan
and D e l v i , 1974) and 4 1 t o 4 7 s i n Danaus c h r y s i p ~ g atha ha van
and P a n d i a n , 1975; Mathavan and Muthukrishnan, 1978).
The
e f f i c i e n c y o f P_. p i c t u s i n c r e a s e s from about 33.5% a t 2 6 ' ~
t o 54.5% a t 3 6 ' ~ ( ~ e l v i ,1972).
The r e s p o n s e of
2.
chrysippus
t o i n c r e a s i n e ; t e m p e r a t u r e was s t r i k i n e l y c o n t r a s t i n g i , e ,
e f f i c i e n c y d e c r e a s e d from 516 a t 1 9 ' ~ t o 46% a t 3 0 ' ~
( ~ u t h u k r i s h n a ne t a l , 1976).
In case of
2.
velcx the
e f f e c t of t e m p e r a t u r e on a s s i m i l a t i o n e f f i c i e n c y wae marked
(Muthukrishnan and D e l v i , 1 9 7 3 ) ; t h e e f f i c i e n c y was 37$ a t
2 7 ' ~ and 69.3% a t 3 2 ' ~ .
It i s n o t c l e a r whether t h i s h i g h
a s s i m i l a t i o n e f f i c i e n c y a t h i e h e r t e ~ n p e r s t u r e i s due t o
t h e change i n t h e q u a l i t y of f o o d o r n o t s i n c e i t i s w e l l
known t h a t h i g h e r t e m p e r a t u r e ( w i t h i n t h e b i o k i n e t i c r a n g e )
a c c e l e r a t e s t h e r a t e o f energy t r a n s f o r m u t i o n b u t n o t t h e
e f f i c i e n c y (Kinne, 1 9 6 0 ) .
It may be t h a t i n c r e a s e i n
temperature not only increases
b u t a l s o t h e r a t e s o f enzyme
i n these insects.
r a t e of passage o f food
s e c r e t i o n and i t s a c t i v i t y
From a l i m i t e d number o f d a t a on t h e
e f f i c i e n c y f o r t h e c o c k r o ~ c hB l a t t e l l a germtmica, Woodland
et a1 ( 1 9 6 8 )
-
r e p o r t e d t h a t t h e e f f i c i e n c y was h i g h , a b o u t
84% and v a r i e d l i t t l e w i t h age s u c h h i g h e f f i c i e n c y v a l u e s
have a l s o been r e p o r t e d f o r a n o t h e r cockroach P e r i p l n n n t a
americana (Michael, 1971).
Among t h e o r t h o p t e r t l n s , t h e
cockroaches a r e b e t t e r a s s i m i l a t o r s than t h e grasohoppers.
~ a r n i v o ? i~n s e c t s (88% Pyrrhosorn:i n ~ m p h u l nadonilta
1971a; Melanotus r u f i p e s 90"h C o l e o p t e r a ,
Lnwton
D u t t o n , 1968;
83% A c r o n e u r i a p a c i f i c a p l e c o p t e r a Brocksen e t a l , 19bR;
805 Mantis r e l i g e o s a . Muthukrishnan e t a l , 1 9 7 6 ) u s u a l l y
d i s p l a y h i g h e r a s s i m i l a t i o n e f f i c i e n c y o f RO$ t o 9@1 and
at least in
P. nvmphuln,
t h e e f f i c i e n c y h a s been shown t o
v e r y l i t t l e w i t h c h a n g e s i n q u a l i t y o f food and t e m p e r a t u r e
and a s w e l l a s t h e age o f t h e l a r v a .
On t h e o t h e r h a n d ,
t h e h e r b i v o r o u s i n s e c t s (42$ Bombyx m o r i , L e p i d o p t e r a
H i r a t s u k a , 1920; 44$, 64 Phytophagous i n s e c t s * , Waldbauer,
*
(The mean a s s i m i l a t i o n e f f i c i e n c y o f 64 s p e c i e s o f phytophagous i n s e c t s l i s t e d by Waldbauer ( 1 9 6 8 ) amounts t o Ad$).
1968; 62% Heriodiscus t r u q u i i : D i p t e r ~Stockner, 1971;
32s Leptorpersa d o l ~ b r a t e: Heteroptora, McNeill, 1971;
jO$ a t 2 6 ' ~
P.
h
pictus
Orthoptera, Delvi, 1972) e x i b i t
low e f f i c i e n c y ranging from 30 t o 62$.
I n a l l these
h e r b i v o r e s , t h e e f f i c i e n c y decreases with i n c r e a s i n g age,
S c r i b e r (1981) working on Spodoptera e r i d a n i a ( f i f t h
i n s t a r ) found d i f f e r e n t a s s i m i l a t i o n e f f i c i e n c y depending
-
on t h e type of food.
When fed d i l l S. e r i d n n i n e+bited
e f f i c i e n c y of 49.7$,
when fed on bean i t e x i b i t e d 76.5%
e f f i c i e n c y and when fed on cabbage the e f f i c i e n c y was 78.9$
-S.
e r i d a n i a e x i b i t e d high e f f i c i e n c y ranging from 70 t o
7 8 , s when fed on sequence of bean, cabbage and d i l l l e a v e s .
Schroeder and Malmer (1980) working on 34 s p e c i e s of
hymenoptera and l e p i d o p t e r a fed l e a v e s of Prunus s e r o t i n a ,
found a s s i m i l a t i o n e f f i c i e n c y ranging from 32$ i n g h i n g i d a e
t o 71$ i n Hydria s p a The most i n t e r e s t i n g aspect i s t h a t
i n t h e same genus of Hydria t h e a s s i m i l a t i o n e f f i c i e n c y
ranged from 36$ t o 71$.
h.
Bombyx mori a l s o exabited s i m i l a r
d i f f e r e n c e s i n t h e a s s i m i l a t i o n e f f i c i e n c y depending on t h e
race.
For example i n Japanese race t h e e f f i c i e n c y i s 37$
( H i r a t s u k a , 1 9 2 0 ) , i n Mysore race X C-nich race t h e e f f i c i e n c y
averages 40% (Horie
&,
1976) where a s i n another race
Soo Hoo and Prankel (1966) found t h e e f f i c i e n c y t o be 44$.
Considering the whole l a r v a l s t a g e t h e mean a s s i m i l a t i o n
Table-29:
A S ~ i m i l E i t i ~efficiency
n
i n few i n s e c t s ,
Sex &
Assimil~tion
l i f e stage efficiency($)
Insect and Authority
Bombyx mori
a) Hiratsuka (1920)
Japanees race.
b ) Shyamala e t a1 (1960)
MysoreX C-Nichi race.
c ) Soo Hoo and Frankel
(1966)
--
d ) Horie e t a1 (1976)
N124 X c 124
Morus
alba
-
Whole l a r v a l
stage.
M.alba
--
Final 2
instars.
M.alba
Fourth
instar
--
Yinal 2
instars
M .alba
e ) Naik (Present work)
i) Pure Mysore race
i i ) NB4D2 race
i i i ) KA race
M .alba
Whole l a r v a l
stage
Whole l a r v a l
stage
Whole l a r v a l
s t age
M
_
.
a
M ,alba
Philosamia r i c i n i
Naik (Present work)
Ricinus Whole l a r v a l
communis stage
64 species of Phytophagus insects.
Waldbauer (1968)
34 Species of Hymenopt e r a and Lepidopt e r a ,
Schroeder and
Malmer (1980)
303 s p e ~ i e so f insects.
~ l & s k y and Scriber
(1982)
(Range )
-
- - Pure Mysore
Fig, 17: Bombyx m o r i
race
Hate of feed in^ (mg o f d r y food p e r mg
of l i v e i n s e c t per d a y ) as f u n c t i o n o f
a s s i m i l n t i o n e f f i c i e n c y ($)
.
Regression
l i n e i s i n d i c a t e d in c o n t i n o u s l i n e
w h i l e b a s i c v a l u e s o b t a i n e d are
i n d i c a t e d by p o i n t s ( c i r c l e s ) ,
Bombyxmori
-
Pure Mysore raco
Assimilation efficiency
,
%
e f f i c i e n c y value f o r Pure Mysore race ( P r e s e n t work) i s
51.81 and 38.5$ f o r NB4D2 wd 39-95 f o r Wi r a c e (Present
work).
These v a l u e s a r e i n g e n e r a l agreement with t h e
v a l u e s found by o t h e r workers f o r Bornbyx rnori i n d i f f e r e n t
r a c e s and o t h e r s p e c i e s belonging t o d i f f e r e n t genus
a able-29).
Considering t h e a s s i m i l a t i o n e f f i c i e n c y a t each i n s t a r
l e v e l , i t i s found t h a t t h e e f f i c i e n c y i s i n v e r s l y proport i o n a l t o feeding r a t e .
r a c e s of
mori and
in
It i s found t h a t i n a l l t h e t e s t e d
g.
r i c i n i the assimilation efficiency
i n c r e a s e s with t h e i n c r e a s e i n f e e d i n g r a t e .
i s not r e l a t e d t o body weight o r age.
The e f f i c i e n c y
The decrease i n t h e
e f f i c i e n c y with i n c r e a s i n g l i f e s t a g e s i s not s i g n i f i c a n t .
The r e l a t i o n s h i p between t h e a s s i m i l a t i o n e f f i c i e n c y ~ n d
f e e d i n g r a t e i s l i n e a r from 50.5% t o 97,9$ i n Pure Mysore
r a c e , 36.6$ t o 91.4$ i n
m4D2 and
36.4% t o 92.9$ i n KA r a c e s
i r r e s p e c t i v e of l i f e s t a g e s and age ( ~ i g .1 7 t o 20).
The
r e g r e s s i o n s have been c a l c u l a t e d f o r f e e d i n g r a t e v e r s u s
assimilation efficiency.
A t any one p e r t i c u l a r point t h e
e f f i c i e n c y increases with t h e i n c r e a s e i n t h e f e e d i n g r a t e .
For example t h e h i g h e r feeding r a t e during t h e f i r s t i n s t a r
of d i f f e r e n t r a c e s of
g. mori
assimilation efficiency.
and
P.
r i c i n i r e s u l t e d i n high
It i s i n t e r e s t i n g t o note t h a t
t h e f e e d i n g r a t e dropped suddenly i n t h e second i n s t a r of
o r i NB4D2
-B. m-
and KA r a c e and i n
P.
r i c i n i along with a
sudden d r o p i n t h o assimil[lt i o n e f f i c i e n c y .
i n KA r a c e o f
mg/mg/day
g,
For e x m p l o
t h e f e e d i n g r a t e dropped from 2.3425
i n t h e f i r s t i n s t a r t o 0.5949 r n d m d d n y d u r i n g
t h e second i n s t a r correspondingly t h e a s s i m i l a t i o n e f f i c i e n c y
a l s o dropped from 92.8% i n t h e f i r s t i n s t a r t o 69$ i n t h e
second i n s t a r .
I n P u r e Mysore r a c e o f
r a t e r e d u c e d from 6.1064 mg/mg/day
t o 1.2224 ag/mg/day
9. mari
the feeding
during the f i r s t i n s t a r
d u r i n g t h e second i n s t a r and t h e
e f f i c i e n c y d e c r e a s e d from 97.96 t o 91.9h i n r e s p e c t i v e
instars.
F u r t h e r d e c r e a s e i n t h e f e e d i n g r a t e reduced t h e
e f f i c i e n c y and any i n c r e a s e i n f e e d i n g r a t e i n c r e a s e d t h e
efficiency also.
R e l a t i n g t h e n e t growth ( ~ o n v e r s i o n ) e f f i c i e n c y( K 2 )
t o a s s i m i l a t i o n e f f i c i e n c y v a l u e s r e p o r t e d f o r a number o f
a q u a t i c primary and s e c o n d a r y consumers, Welch (1968)
obtained a l i n e a r relation.
F u r t h e r i t was g e n e r a l i z e d
t h a t t h e ' s e c o n d a r y consumers have h i g h a s s i m i l a t i o n e f f i c i e n c y
and low n e t c o n v e r s i o n e f f i c i e n c y ; h e r b i v o r s / d e t r i v o r e have
l o w e r a s s i m i l a t i o n e f f i c i e n c y and h i e h e r n e t growth e f f i c i e n c y ,
In
g.
e,
the assimilation efficiency
net conversion efficiency.
is not r e l a t e d t o
The a s s i m i l a t i o n e f f i c i e n c y i n
P u r e Mysore r a c e i s 51.8$ and ( K ~ i) s 1 5 . 6 s where a s ipl
NB 4 D2 a s s i m i l a t i o n e f f i c i e n c y i s 38.5$ w i t h h i g h e r c o n v e r s i o n
-
Y i t l . 18: Liornbyx rnori
NU4D2 Race
State of f e e d i n g (mg o f d r y food
p e r mg o f l i v e i n s e c t p e r day) as
f u n c t i o n of a s s i m i l a t i o n e f f i c i e n c y
Regreasion l i n e i s i n d i c a t e d i n c o n t i n o u s
l i n e while b a s i c v a l u e s o b t a i n e d are
i n d i c a t e d by p o i n t s ( c i r c l e s ) .
-
1o
r
1.0
m
'0
B o m b y x n*r
N B 4 D 2 race
.
\
?
D
E
gl
D
OeI7
-
C
,
'0
Q)
9)
IL
.
0~01
0
I
20
I
I
I
LO
60
Assimilation off iciency
80
,
%
I
100
I
A similer a s s i m i l u t i o n e f f i c i e n c y
e f f i c i e n c y o f 20.3$.
v a l u e o f &bout 4 0 s i n KA rHce r e s u l t e d i n convurt;ion
e f f i c i e n c y (K2) o f 20.7%.
In
r.
r i c i n i which h a s a s s i m i l u t i o n
e f f i c i e n c y o f 5 2 s t h e c o n v e r s i o n o f f i c i e r i c y K2 v a l u e is a s
h i g h as 37.86.
In
g.
pictus also the assimilation efficiency
valueo a r e not r e l n t c d t o convergion u f f i c i e ~ i c y(Dolvi,
1972).
Similar r e s u l t s are obtained i n three lepidopteran
i n s e c t s Spodoptera l i t u r a ,
P e r i c n l i a r i c i n i and E u p r o c t u s
f r a t e r n a when t h e a s s i m i l a t i o n e f f i c i e n c y i n c r e a s e s w i t h
i n c r e a s e i n feeding r a t e i r r e s p e c t i v e of l i f e stage8
( P r e m a l e e l a and D e l v i , Unpublished d a t a ) .
Further these
t h r e e l a r v a l g r o u p s were s u b j e c t e d t o d i i ' f e r e n t e n v i r o n m e n t a l
c o n d i t i o n s l i k e t e m p e r a t u r e , p h o t o p e r i o d and d i f f e r e n t food
quality.
e{ibites
F o r example Spodoptero l i t u r t ~f e d on
R.
comunis
a n e f f i c i e n c y o f 7 1 1 a t 2 6 ' ~ and 68.7% a t 3 6 ' ~ .
Whereae P e r i c a l i a r i c i n i f e d
g.
communis i n c r e a s e d t h e
e f f i c i e n c y from 64.4$ t o 71e4$ w i t h i n c r e a s e i n t e m p e r a t u r e
from 2 6 ' ~ t o 3 6 ' ~ r e s p e c t i v e l y ,
In
g. f r ~ t e r n atenlperuture
d i d n o t change t h e a s s i m i l a t i o n e f f i c i e n c y and i t a v e r a g e
about 70%. Though t h e e f f i c i e n c y changes s i e n i f i c a n t l y
w i t h t h e changes i n t h e t e n ~ p e r a t u r ep h o t o p e r i o d and food
p l a n t , t h e r e i s no d e f i n e t e t r e n d i n t h e s e changes.
For
example i n P e r i c a l i a r i c i n i a change i n f o o d p l a n t from
M_.
t o C a l o t r o p i s g i ~ a n t i ar e d u c e s t h e e f f i c i e n c y from
70.8% t o 43.0$.
Where a s i n
E.
f r a t e r n a t h e change i n t h e
Pi(..
19:
h o n ~ t ) y xmarl
M Htice
f t * c . t i l n c ( m l f 01'
I l v c rnsc*ct
rler
-
Hate of
t11.y f o o d p e r m e
d::y)
of
a5 function
o f ~ 1 : . 3 0 1 r n 1 1 f ~ tl o r , e f f l c l e n c y ($).
H e ~ r e u e i o n3 i n c i r ; i n d i c a t e d in
contlnous I i n e w h i l e basic vrilues
o l ~ t r i l n e d fir(' 1 . n d i c n t e d by p o i n t s
(c~rcles).
100~
-
Bombyx mori
10
-
100
-
K A race
r
lu
w
\
e
\
;
Q
C
lu
L
0
,
-
C
v
0)
I."
0-1;
0801
0
I
20
I
1
I
LO
60
80
Assimilation efficiency , %
I
100
I
food from
3,
elba d i s p l a y s
communis t o M_.
the assimilation efficiency.
no change i n
Increase i n temperature
increases the assimilation efficiency i n Pericalia r i c i n i
and d e c r e a s e s i n
2.
a constant trend.
litura.
Even photoperiod d i d n o t show
P e r i c a l i ~r i c i n i when exposed t o 1 2 h o u r s
o f l i g h t and 24 h o u r s of l i g h t and 24 hours of d a r k
s e p a r a t e l y a t 3 6 ' ~ and f e d
R.
h
cornmunis e x > b i t 5 an e f f i c i e n c y
of about 72$ and t h e e f f i c i e n c y d i , d not change w i t h changes
i n t h e photoperiod.
Where a s i n
2.
l i t u r a the efficiency
averaged 68.76 w i t h 1 2 hours and 83.85 w i t h 24 hours l i g h t
and t h e e f f i c i e n c y decreased t o 57.6$ w i t h 24 hours o f d a r k ,
at 3 6 ' ~ f e d
R.
communis.
Considering t h e feeding r a t e s f o r
a l l t h e s e i n s e c t s it i s found t h a t t h e a s s i m i l a t i o n
e f f i c i e n c y depends on f e e d i n g r a t e i r r e s p e c t i v e of environmental c o n d i t i o n s ,
Temperature, l i g h t and food p l ~ m t
i n f l u e n c e s t h e r a t e of f e e d i n g which i n t u r n changes t h e
a s s i m i l a t i o n e f f i c i e n c y ( P r e m a l e e l a and D e l v i , Unpublished
data).
P r e m a l e e l a and Delvi ( P e r s o n a l communications) have
found l i n e a r r e l a t i o n between f e e d i n g r a t e and a s s i m i l a t i o n
efficiency.
The e f f i c i e n c y i n c r e a s e p e r s e e . w i t h t h e
increase i n the feeding rate,
The r e s u l t s preeented i n
t h i s t h e s i s i s i n c o n f i r m i t y w i t h t h e r e o u l t s obtained
f o r t h e s e i n s e c t s ( P r e m a l e e l a and D e l v i , Unpublished d a t a ) ,
The h i g h e r f e e d i n g r a t e i n t h e i n i t i a l i n s t a r of a l l
the t e s t e d larvae influences the aesimilation efficiency
Pig. 20: F h i 1 o ~ : u n i r~i c i n i
(rnc
Hate o f feedine
o'f dry f o o d p e r mg o f l i v e i n s e c t
p e r day) as f u n c t i o n o f assimilation
e f f i c i e n c y ($),
Hecression l i n e is
indicated i n c o n t i n o u s l i n e w h i l e
b a s i c v o l u e s obtained a r e i n d i c a t e d
by points ( c i r c l e s ) ,
Philosamia
ricini
Assimilation efficiency
,
%
which i s h i g h e s t d u r i n g t h e f i r s t i n s t a r ,
The decrense
i n f e e d i n g r a t e i n t h e l n t e r i n s t n r reduceo t h e a s s i m i l ~ ~ t i o n
efficiency.
The mean velue o f 80$ f o r t h e c a r n i v o r u s and
35 t o 53% f o r t h e h e r b i v o r u s given by Slansky and S c r i b e r
(1982) i s not c o n s i s t a n t with t h e d a t a r e p o r t e d f o r s e v e r a l
h
h e r b i v o r u s i n s e c t s , Several spocieo e x i b i t comparatively
high e f f i c i e n c y v a l u e s ranging from 73 t o 8 8 s ( ~ l a n s k yand
S c r i b e r , 1982).
The v a r i a t i o n i n t h e e f f i c i e n c y by a
s i n g l e s p e c i e s f e e d i n g on t h e same food ( P r e s e n t work)
i n d i c a t e t h a t h e r b i v o r u s also d i s p l a y h i g h e r a s s i m i l a t i o n
efficiency l i k e the carnivorus.
Comparisons of a s s i m i l a t i o n
e f f i c i e n c y should be made with extreme care.
Conversion e f f i c i e n c y ( K ~ i) s h i c h e r i n NB4D2 and
KA r a c e s with a mean of 20,596 t h a n i n Pure Mysore r a c e
- -
o f B. mori with mean o f 15,5$,
is h i g h i n
P.
Similarly the efficiency
r i c i n i averaging 37.86.
The b e t t e r e f f i c i e n c y
may be c o - r e l a t e d w i t h i t s g r e a t e r converoion of food i n t o
body substance,
Pure Mysore r a c e of
B.
m r n converts
248.3 mg of dry food i n t o body substance w i t h t h e e f f i c i e n c y
of 15,5$, where a s t h e t o t a l food converted amounts t o 458.4
f o r NB4D2 and 535 f o r KA race o f
e f f i c i e n c y of 2 0 . 5 6
g. &,
The e f f i c i e n c y i n
both with high
g, r i c i n i is 37.8$
and t h e t o t a l food converted amounts t o 1257.5 mg dry weight,
The h i g h e r i s the e f f i c i e n c y t h e g r e a t e r i s t h e t o t a l body
weight a t t a i n e d .
5455.5 mg bnd
P_, r i c i n i a t t a i n s a wet body weight of
g. 9
Pure
Mysore r a c e a t t a i n s a f i n a l
wet body weight o f 1173.4 me, where t h e K2 v a l u e s a r e
maximum 37.8% and minimum 15,5$ r e s p e c t i v e l y .
The c o n v e r s i o n e f f i c i e n c y v a l u e s r e p o r t e d f o r number
o f a n i m a l s i n h a b i t i n g mainly f r e s h w a t e r arid t e r r e s t r i ~ l
environment and f e e d i n g throughout t h e l i f e o r d u r i n g
l a r v a l p e r i o d and o c c u p y i w d i f f e r e n t Ccpphic l e v e l l i k e
kl
primary and secondary c h a r a c t e r s e q i b i t an average v a l u e
o f 40% ( s e e D e l v i , 1972).
On t h e o t h e r hand t h e e f f i c i e n c y
f o r immature i n s e c t s g i v e n by Slansky and S c r i b e r (1982)
v a r i e s from 1 8 t o 896 and i n t h e l e p i d o p t e r a n i n s e c t s
e f f i c i e n c y r a n g e s from 2-876.
Such wide r a n g e s i n t h e
e f f i c i e n c y v a l u e s a r e a l s o found i n t h e Urchins ( ~ c h i n o d e r m s )
r a n g i n g from 12-306 depending on age (Kinne, 1970).
Similar
range o f v a l u e s a r e o b t a i n e d f o r c o n v e r s i o n e f f i c i e n c y a s
f u n c t i o n of body weight/age by number of workers ( D e l v i ,
1972).
I n g e n e r a l t h e e f f i c i e n c y f o r f i s h e s averages 1 0
to 20s.
From t h e a v a i l a b l e d a t a i t i s evident; t h a t t h e
herbivorus lepidopteran are b e t t e r convertors than the
echinoderms, f i s h e s o r o t h e r i n v e r t e b r a t e s and even o t h e r
herbivorus i n s e c t s (Delvi, 1972).
Food u t i l i z a t i o n budgets d i f f e r c o n s i d e r a b l y between
t h e i n d i g e n o u s and e x o t i c r a c e s o f
B. G.
A indigenous
r a c e l i k e Pure Nysore r a c e consumes about 50$ l e s s f o o d
than t h e exotic races.
However, t h i u l e s s e r m o u n t of
food i s consumed a t a h i g h r a t e o f 1,6477 mg/mdday which
i s two t i m e s more t h a n t h e r a t e o f e x o t i c r a c e s .
Moreovrr
t h e l e s s e r food consunled i n P u r e Mysore r a c e i s compensated
by h i g h e r a s s i m i l a t i o n e f f i c i e n c y o f 51,8$,
11 t o 12s more t h a n i n t h e e x o t i c r a c e s .
t o n o t e t h a t t h e P u r e Mysore r a c e o f
Which i s about
It i s i n t e r e s t i n g
2. mori a s s i m i l a t e s
t h e consumed food a t a v e r y h i g h r a t e of 1.5188 mdmg/day
which i s about 3 t i m e s more t h a n t h e r a t e found i n t h e
e x o t i c r a c e s l i k e NBqD2 and
KA.
I n Pure Mysore r a c e b o t h
r a t e and e f f i c i e n c y o f a s s i m i l a t i o n i s h i g h e r ,
However,
t h e t o t a l amount o f food a s s i m i l a t e d i s about 34$ l e s s e r
t h a n t h e food a s s i m i l a t e d i n t h e e x o t i c r a c e s .
The l o w e r
c o n v e r s i o n e f f i c i e n c y i n Pure Mysore r a c e r e s u l t e d i n l e s s e r
conversion than t h e exotic races.
The t o t a l m o u n t o f
food c o n v e r t e d i s about 15% l e s s i n Pure Mysore r a c e t h a n
i n NB D and iCA r a c e s o f
4 2
B.
e.
--
P, r i c i n i which a t t a i n s a body weight o f 5455.5 mg
wet weight h a s food u t i l i z a t i o n budget s i m i l a r t o t h a t o f
U r a c e o f Bombyx mori which a t t a i n s a body weight o f 2325.6 mg
The t o t a l food consumed
wet weight ( F i n a l l i v e w e i g h t ) ,
during e n t i r e l a r v a l period i n
P.
r i c i n i amounts t o 6398.1 mg
d r y weight which c a n be compared t o t h e consumption i n
e x o t i c r a c e of B. mo-a but i t i s two t i m e s more t h a n t h e
Pic. 21: E f f e c t
01' p e r m e t h r l n on f o o d i n t a k e
nip d r y wel::ht
us
s t r t ~ e ~n f i n : ~ l 2
f u n c t i o n of' a g e / l i f e
-
i n s t u r s o f Bornbyx m o r i
( P u r e Mysore r a c e ; u p p e r p r m n e l ) and
I J h i l o o r u n i t t rlcbi n 1 ( l o w e r p a n e l ) .
6Ml
EFFECT OF PERMETHRIN ON FOOD INTAKE
mori
Bombyx
Puro Mysore race
Untreated
-0-
- + - Acotone
.-+-.
treated leaves fed
Pormelhrin treated loaves fed
Larval
L
'0
E"
leaves fod
stages
1OOal~
P
-
Philosamia
ricini
1000-
I
100:
I
rn
I
10
1
IJI
L ~ f o stagles
15
20
Days
h1
25
I
30
I
35
consumption i n Pure Mysore race.
Though l a r g e mount of
food i s ingested t h e r a t e of f e e d i n g i s t h e lowest averaging
0,4872 mg/mg/day i n P.
- -r i c i n i .
This i s about 2 times
l e s s e r t h a n t h e r a t e i n e x o t i c r a c e s and f o u r timeo l e s s e r
than t h e r a t e i n Pure Yysore race.
The high i n g e s t i o n coupled
with h i g h e r a s s i m i l a t i o n e f f i c i e n c y of 5 2 5 i n
P. r i c i n i
r e s u l t e d i n l a r g e amount of food being a s s i m i l a t e d .
has
The
t o t a l amount of food a s s i m i l ~ t e damounts t o 3324.6 mg dry
weight which i s morn than two times thnn t h e food a s s i m i l a t e d
i n Pure Mysore r a c e .
However, t h e l a r g e amount of food
a s s i m i l a t e d i s a t a low r a t e of a s s i m i l a t i o n .
a s s i m i l a t i o n r a t e i s about 5 times l e s s e r i n
The
11.
r i c i n i than
It is about l* t o 2 times l e s s e r
i n pure Mysoro r a c e .
than i n exotic races.
g. r i c i n i coriverte t h e assirnilnted
food with a hi~:h e f f i c i e r ~ c yof 37.8% which i s two and a
h a l f times more t h a n t h e Pure Mysore race and about 2 times
more t h a n t h e e x o t i c races.
The consumed food i n
P, r i c i n i
i s a s s i m i l a t e d and converted with higher e f f i c i e n c i e s t h a n
t h e e x o t i c r a c e s of
and conversion.
2. mori but
a t a poor r a t e of a s s i m i l a t i o n
The h i t ~ ha s s i m i l a t i o n and conversion
e f f i c i e n c y has r e s u l t e d i n g r e a t e r conversion a n d hence
--
P. r i c i n i is able t o a t t a i n a body weight o f 5455.5 mg,wet
weight which i s 4* times more thkn t h e weight a t t a i n e d by
Pure Mysore race and about 24- times more t h a n the weight
a t t a i n e d by e x o t i c races.
It may be suggested t h n t an i n d i v i d u a l a t t a i n s a
h i g h e r body weicht by b e t t e r e f f i c i e n c i e s of a s c i m i l a t i o n
and conversion.
EFFECTS OF INSECTICIDE PBKhil3TlIRIN ON N O D U T I L I Z A T I O N
T o t a l m o r t a l i t y was observed i n t h e e a r l y i n s t a r e of
a l l t h e t h r e e t e s t e d r a c e s of
g.
and
g.
ricini.
In
e x o t i c r a c e s even i n t h e l a t e r i n s t u r s heavy m o r t a l i t y
occured.
However, l a s t two i n s t a r s of Pure lblysore race of
mori and P_.
-B.
r i c i n i survived t h e permethrin t r e a t e d l e a f
feeding w i t h heavy m o r t a l i t y r e s u l t i n g i n s u r v i v a l of few
l a r v a e a t t h e completion of experiments,
To overZcome t h e
e r r o r i n c a l c u l a t i o n of food consumption and u t i l i z a t i o n
the rneasurer~ientswere made d a i l y except f o r conversion.
The d a t a t h u s obtained i s added u$o
r e p r e s e n t each i n s t a r .
Conversion i s c a l c u l a t e d f o r t h e t o t a l i n s t n r g i v i n g
weightage t o t h e number of l a r v a e died.
There i s no change
i n t h e l a r v a l period of f o u r t h and f i f t h i n s t a r s i n
whereas
z.
B.
r i c i n i extended t h e l a r v a l period during t h e
f i n a l two i n s t a r s by 0.5 day due t o t h e presence of
insecticide.
As mentiorled e a r l i e r it was necessary t o
d i s s o l v e p e w e t h r i n i n acetone t o o b t a i n uniform d i s t r i b u t i o n .
However, acetone i t s e l f a f f e c t e d and food u t i l i z a t i o n budget
and hence s e p e r a t e values a r e presented along with t h e values
obtained f o r i n s e c t i c i d e t r e a t e d feeding.
There is very
l i t t l e information a v a i l a b l e on e f f e c t s of i n s e c t i c i d e on food
utilization.
Hence, t h e d a t a o b t a i n e d f o r Bombyx mori i o
compared w i t h t h a t o f P h i l o s m ~ i ar i c i n i .
The t o t e 1 food
u t i l i z a t i o n budgets along with t h e r a t e s of feeding
a s s i r n i l f i t i o n m d c o n v e r s i o n arid e f f i c i e n c i e s o f assimi1ni;ion
and c o n v e r s i o n o b t a i n e d f o r f i n a l 2 i n s t a r s o f
g, & m
and
--
P. r i c i n i a r e p r e s e n t e d i n Table-16 and 1 7 ( s e e a l s o
Pie, 31 t o 2 3 ) .
-P. -r i c i n i
consumes 6189.0 rng o f d r y food d u r i n g f i n a l
two i n s t a r s which i s ~ b o u t2 t i m e s more thu.11 t h e consumption
in
g.
&.
Though
l e n s e r food t h a n
E.
B. & t a k e s
a l o n g e r t i m e t o consume
r i c i n i , t h e f e e d i n g r a t e s o f both t h e
i n s e c t s a r e ~ u r p r i n s i n g l ys i m i l a r .
food a t t h e r a t e o f 0.2866 mg/mg/dily
a t t h e r a t e of 0,2391 mg/rng/day.
H. mori c o n s w e s t h e
whereas 2. r 1 ~ 1 n lconsullies
'
B. mori c o n v e r t 6
I '
'
243.2 mg
d r y food i n t o body which i s 8 - 1 6 of food consumed w h e r e r ~ s
-P. -r i c i n i c o n v e r t e s 1232.1 mg d r y food i n t o body which
about 20% of food consumed.
Acetone r e d u c e s t h e consumption
by about 3 l $ and p e r m e t h r i n by about 50$ i n both
and P_. r i c i n i ( P i g . 2 1 ) .
is
B, &
Compared t o t h e c o n s u n ~ p t i o nd u r i n g
t h e n o n - t r e a t e d f e e d i n e t h e r e d u c t i o n due t o a c e t o n e ( ~ a ~ k 3 0 )
(P
< 0.001)
ficant.
and i n s e c t i c i d e ( P
< 0.001)
is highly signi-
'Tt t e s t i s b p p l i e d between t h e normal f e e d i n g and
a c e t o n e f e e d i n g and between a c e t o n e f e e d i n g and i n s e c t i c i d e
f e e d i n g ( ~ a i l y ,1959).
Proportionate reduction i n the
p r o d u c t i o n o f f a e c e s i s found due t o a c e t o n e a s w e l l a s
- -
i n s e c t i c i d e i n B w mori ~ n d 2 .r i c i n i .
While acetone
reduces t h o f a e c e s p r o d u c t i o n by ?4'$ o r 20$ ( P (
0.001 o r
P < 0 , 0 1 ) permethrin reduces t h e f a e c e s p r o d u c t i o n by 646
o r 536 (P <O,O01 o r
P <0.(301) i n E. mori o r
g,
ricini,
Acetone and i n s e c t i c i d e a f f e c t s t h e t o t a l food a s s i m i l a t e d
by r e d u a i n g t h e a s s i m i l a t i o n by about 37$ i n
g.
B.
In
m a .
r i c i n i t h e r e d u c t i o n i n a s s i m i l a t i o n due t o acetone i s
about 25% (P
< 0.001)
whereas t h e reduct i o n due t o permethrin
i s a s much a s 38% (P (0.05).
The c a u s a t i v e f a c t o r s
i n f l u e n c i n g a h i g h r e d u c t i o n i n t h e food a s s i m i l a t e d i n
P.
r i c i n i f e d p e r m e t h r i n t r e a t e d food a r e n o t know probably
t h e r e d u c t i o n i n a s s i m i l a t i o n by 38$ i n
g.
due t o h i g h e r consumption when compared t o
silkworm
E . mori conaumes
g,
g.
&.
The
2932.5 rng dry food which i s about
50% l e s s t h a n t h e food consumed by
consumption by
r i c i n i may be
g.
ricini.
The h i g h e r
r i c i n i r e s u l t s i n i n g e s t i o n of e x t r a
-
amount of i n s e c t i c i d e which must have accumulatod i n t h e
body and i n f l u e n c e d i n r e d u c t i o n of a s s i m i l a t i o n .
The t o t a l
d r y food converted i n t o body s u b s t a n c e r e d u c e s by about 22$
due t o acetone (P
(P
< 0,001)
in
g.
< 0.001)
and about 52s due t o i n s e c t i c i d e
I n 11,
a.
r i c i n i t h e r e d u c t i o n i s 51$
I
due t o acetone (Y < 0.001) and about 62% due t o i n s o c t i c i d e
(P < 0 , 0 0 1 ) .
in
2.
The h i g h e r r e d u c t i o n i n t h e t o t a l food converted
r i c i n i due t o acetone and permethrin may be due t o
g r a d u a l accumulation of i n s e c t i c i d e along w i t h h i g h e r
i n g e s t i o n of food which i s n o t found i n
g.
m.
The
amount o f food energy used f o r o x i d a t i v e p u r p o s e s
( c a l c u l a t e d a s d i f f e r e n c e s of food a s s i m i l a t e d and
c o n v e r t e d ) reduces by about 406 due t o a c e t o n e and 34$
due t o i n s e c t i c i d e i n
g.
whereas r e d u c t i o n i n P_. r i c i n i
&;
amounts t o o n l y 8$ due t o a c e t o n e and 24$ due t o p e n n e t h r i n .
More food m a t e r i a l i s o x i d i z e d i n P_. r i c i n i a s more energy
i s r e q u i r e d t o m a i n t a i n t h e e x t r a amount o f m a t t e r converted
--
i n t o bod# s u b s t a n c e a s P. r i c i n i a t t a i n s g r e a t e r body
2.
weight t h a n
&.
The r a t e of f e e d i n g and c o n v e r s i o n r e d u c e s c o n s i d e r a b l y
in
B.
mori
and i n
t r e a t e d leaves.
z.
r i c i n i when f e d a c e t o n e o r i n s e c t i c i d e
However, i n
P.
r i c l n i feeding rate increase
Moreover t h e d e c r e a s e found i n f e e d i n g r a t e
by about 1Wh.
- -
i n B, mori a l s o amounts t o 135 and 15$ when f e d acetone
and i n s e c t i c i d e t r e a t e d l e a v e s r e s p e c t i v e l y .
in
P. r i c i n i
d e c r e a s e by about 11$ when f e d permethrin
treated leaves,
-P. -r i c i n i
Feeding r a t e
S l i g h t i n c r e a s e i n t h e f e e d i n g r a t e of
when f e d acetone may be due t o h i g h consumption.
The r e d u c t i o n i n c o n v e r s i o n r a t e i s not marked when f e d
acetone b u t is s i g n i f i c a n t l y d i f f e r e n t when f e d i n s e c t i c i d e
in
g. &
g.
r i c i n i i s s i g n i f i c a n t ++both
(P ( 0,01) whereas t h e r a t e of r e d u c t i o n i n
(P ( 0.01) a n d permethrin (P
< 0,2)
d u r i n g acetone
feeding.
While t h e s e
r a t e s reduce due t o acetone and i n s e c t i c i d e t h e r a t e of
1
.
2 :
Ef'f'cct o f pe n n e t h r i n on a s s i r n i l a t ion
( r n ~d r y wei{:ht) as f u n c t i o n o f age/
l i f e a t a c e in final 2 i n s t n r of
lrornbyx rnori
- Pure
M y ~ o r erace
( u p p e r p : m n e l ) und P h i l o s m i a r i c i n i
( l o w e r prillnel )
.
2000EFFECT OF PERMETHRIN ON F W D ASSIMILATED
1000
--
Bombyx
mori
Pure Mysore race
Untreated
-0-
leaves fed
- + - Acetone troated leaves fed
loor
m
>
L
m
d
\
.L
.c
-0
,8ool
,
P)
3
10
I
5
IY
Larval
4 0L
I
m
I
10
1
I
I
m
P
stages
J
I
TP
Y
Life stagas
1
1
I
I
15
20
25
30
Days
a s s i m i l a t i o n show p o s i t i v e t r e n d b o t h i n
mori and g.
ricini.
Not o n l y t h e a s s i m i l a t i o n r a t e b u t a l s o t h e a s s i m i l a t i o n
e f f i c i e n c y increase during i n s e c t i c i d e feeding.
Assimilation
e f f i c i e n c y a v e r a g e s about 51$ i n b o t h ge mori and
d u r i n g normal f e e d i n g .
8, mori and P, r i c i n i
2. r i c i n i
assimilation
permethrin t r e a t e d l e a v e s with a higher e f f i c i e n c y of 64s
(P ( 0.001) and 58.5% (P ( 0.01) r e s p e c t i v e l y .
Similar
t r e n d with regard t o assimilat ion e f f i c i e n c y i n r e l a t i o n
t o o t h e r e n v i r o n m e n t a l f a c t o r s a r e found i n l e p i d o p t e r a n
and o r t h o p t e r a n i n s e c t s w i t h i n c r e a s i n g r a t i o n l e v e l from
25$ t o 1 0 0 s i n P o e c i l o c e r u s p i c t u s t h e a s s i m i l a t i o n e f f i c i e n c y
i n c r e a s e d from 4 8 t o 5 4 s ( ~ u t h u k r i s h n a nand D e l v i , 1 9 7 4 ) .
I n c r e a s e i n t e n i p e r a t u r e enhances a s s i m i l a t i o n e f f i c i e n c y
-
i n P. p i c t u s from 30$ a t 2 6 ' ~ t o 57$ a t 3 6 ' ~ ( ~ e l v i ,1 9 7 2 ) .
The e f f e c t s of t e m p e r a t u r e on a s s i m i l a t i o n e f f i c i e n c y
Oxya v e l o x i s marked, t h e e f f i c i e n c y is 37h a t 2 7 ' ~ ( D e l v i
and P a n d i a n , 1971) and 6Yh a t 3 2 ' ~ (1VIuthukrishnan and D e l v i ,
1973).
Working on t h e e f f e c t s o f food q u a l i t y on consumption
and u t i l i z a t i o n i n t h e polyphagous i n s e c t P r o d e n i a Soo Hoo
and P r a e n k e l (1966) f o n d t h a t consumption l e v e l may
c o n s i d e r a b l y be a l t e r e d by d i f f e r e n t food p l a n t s .
They
r e c o g n i s e d t h a t i n most c a s e s r e d u c t i o n i n consumption l e v e l
was compensated by i n c r e a s e d a s s i m i l a t i o n e f f i c i e n c y ,
House (1965) r e p o r t e d t h a t when o f f e r e d d i f f e r e n t r a t i o n s
by d i l u t i n g a s y n t h e t i c d i e t t h e l a r v a e o f C e l e r i o euphorbiae
p a r t i a l l y s u c c e s s e d i n compensat i n & f o r t h e d e c r e a s e d
r a t i o n by i n c r e a s i n g food consumption.
The i n c r e a s e i n
t h e r n t e and e f f i c i e n c y of a s s i m i l ~ito n d u r i n g p e r m e t h r i n
treated leaves feeding i n
g.
due t o reduced food consumption.
unlike
P. p i c t u s
g. r i c i n i may be
g. mori and P. r i c i n i
marl and
arc: a b l e t o p a r t l y compensate t h e
r e d u c t i o n i n t o t a l consumption by i n c r e a s i n g t h e a o s i m i l a t i o n
e f f i c i e n c y from 5 1 s d u r i n g normal f e e d i n g t o 6 4 s and 58$
r e s p e c t i v e l y during permethrin t r e a t e d l e a v e s feeding,
The f i n d i n g i s s i g n i f i c a n t i n u n d e r s t a n d i n g t h e a d a p t i v e
p o t e n t i a l of silkwono
g.
and
eri-silkworm P.
ricini
i n t r o p i c a l environment.
S c h r o e d e r (1976) found t h a t t h e food d e p r i v a t i o n
i n c r e a s e t h e r e s i d e n c e time o f food i n t h e g u t o f C ~ l o c a l p e
u n d u l a t a , d i g e s t i o n and a s s i r n i l a t i o n may be enhanced and
e f f i c i e n c y o f growth i n c r e a s e d .
i n c r e a s e maintainnnce c o s t .
A slowed crowth r n t e would
I f t h i s i n c r e a s e i n maintennnce
exceeds t h e b e n e f i t s from enhanced d i g e s t i o n and a s s i m i l a t i o n ,
t h e n e f f i c i e n c i e s would be l o w e r ( S c h r o e d e r , 197bL. The
d e c r e a s e i n t h e a s s i m i l a t i o n e f f i c i e n c y v a l u e of
g. p i c t u s
t o 48$ a t 25% r a t i o n l e v e l from 54$ a t 100% l e v e l
(Muthukrishnan and D e l v i , 1974) may be due t o glow growth
rate.
However i n
B.
mori and g. r i c i n i t h e presence of t h e
i n s e c t i c i d e p e r m e t h r i n has r e s u l t e d i n t h e reduced food
i n t a k e and a s s u c h i n c r e a s e d t h e r e s i d e n c e t i m e o f food
i n t h e l a r v a l gut.
D i g e s t i o n iuid n s s i m i l a t i o n e f f i c i e l i c y
t h u s i n c r e a s e s from 50.8$ d u r i n c t h e normal f e c d i n c t o
E. p&
64$ i n p e r m c t h r i n t r e a t e d feed in^. i n
516 t o 58.5$
and from
d u r i n g p e r m c t h r i n f e e d i n g i n P_. r i c i n i .
However, t h e e f f i c i e n c y o f e r o w t h (K ) d e c r e a s e s .
2
The
increume i n a s s i m i l a t i o n e f f i c i e n c y may a l s o be p e r h a p s
due t o t h e i n c r e a s e i n t h e r a t e o f enzyule s e c r e t i o n and
a c t i v i t y i n these insects.
O t h e r f ~ c t o r s( t e m p e r a t u r e
D e l v i tind P a n d i a n , 1 9 7 1 , 1972; D e l v i , 1 9 7 2 ) c a n a l s o
i n f l u e n c e b o t h t h e r a t e s o f food consumption and a s s i m i l a t i o n
efficiency,
The f a c t t h a t b o t h
B.
mori
and
P.
r i c i n i exibited
h i g h e r a s s i m i l a t i o n e f f i c i e n c y may be r e l a t e d t o t h e f o l l o w i n g
adaptive features,
F i r s t , t h e a v a i l a b i l i t y o f food e n e r g y
p e r u n i t t i m e i s r e l a t i v e l y more f o r normal f e e d i n g i n d i v i d u a l s thun f o r t h o s e undergoing permethrin f e e d i n c because
food consumption i s r e l a t ive1.y l e s s on t h e p e r m c t h r i n - t r e u t ed
leaves,
S e c o n d l y , t h e iricreease i n r a t e and e f f i c i e n c y o f
~ i s s i m i l a t i o ndurirlg p e r m o t h r i n f e e d i n g i s i n agreement w i t h
t h e h o r m o l i g o s i s hypothei:is which p r e d i c t s t h a t sub-hormful
q u a n t i t i e s o f any stress in^? agent may be s t i n ~ u l u t o r yt o t h e
organism by p r o v i d i n g it i n c r e a s e d s e n s i t i v i t y t o respond
t o c h a n g e s i n i t s environment and incretised e f f i c i e n c y f o r
It
ooping w i t h sub-opt imum environment (Luckey, 1 9 6 8 ) ,
i s known t h a t d i e t a r y a n t i b i o t i c s s t i m u l a t e growth i n
--
farm a n i m a l s and i n Chicks (Itloore e t al, 1946; C a r p e n t e r ,
1951; Elam and Couch, 1951) and i n
1956),
Be &
(shyamale
et &,
However, t h e mechanism o f a c t i o n o f i n s e c t i c i d e s
i s s t i l l i n c o m p l e t e l y understood.
It i s n o t c l e a r as t o
whether t h e i n s e c t i c i d e s a c t s a s d e t e r r e n t s f o r f e e d i n g
o r by a f f e c t i n g f a v o u r a b l y physiology and metabolism o f
t h e organism i t s e l f ,
I n t h e l a t t e r c a s e it may i n c r e a s e
t h e food e f f i c i e n c y o r r a t e s by a c t i v a t i o n o f enzymes
o r t h r o u g h hormones which c o n t r o l and r e g u l a t e growth,
It h a s been shown t h a t t h e growth promoting a c t i v i t y
i s e x e r t e d by c h l o r o m y c i t i n and aureomycin i n t h e l a r v a e
o f t h e silkworm
Be
m
a ( ~ h y a m a l ae t a l , 1 9 5 6 ) .
It h a s
a l s o been shown t h a t a n i n c r e a s e y i e l d o f s i l k p r o t e i n
o c c u r s when a n e x t r a n i t r o g e n s o u r c e is provided a l o n g
w i t h t h e a n t i b i o t i c s t o t h e silkworm d i e t (Murthy and
S r e e n i v a s a y a , 1953, 1954; Sharda and Bhat , 1 9 5 6 ) ,
A comparison o f t h e a s s i m i l a t i o n e f f i c i e n c y o f normal
f e e d i n g and c h l o r o m y c i t i n t r e a t e d f e e d i n g i n
Be mori
( ~ h y a m a l ae t a l , 1956) shows t h a t t h e r e i a about 2 5 s
increase i n t h e assimilation e f f i c i e n c y with chloromycitin,
C h l o r o m y c i t i n s u p p l i m e n t a t i o n i n c r e a s e t h e transaminase
a c t i v i t y o f t h e i n t e s t i n e and . t h e htiemolymph o f t h e
silkworm ( ~C3 t hr n t ~ l : ! r i r i t i Ilhtlt , 1 0 5 5 ) .
r
t h a t chloromycitin fed
It; hun b e e n i n d i c a t e d
silk won:^ htive an i n c r e a s e i n t h e
cunylase a c t i v i t y o f t h e i n t e s t i n e .
The i n c r e t ~ s ei n t h e
a s s i m i l a t i o n e f f i c i e n c y mny be due t o a b e t t e r u t i l i z a t i o n
Y
o f food by i n c r e a s e d enzyme a c t i v i t y ( ~ h y u l i i , e t a l , 1956).
E.
h
s
n
rl a r v a e ex>bit a n ~ s s i m i l a t i o ne f f i c i e n c y o f
18.1% when f e d on c o r ~ t r o ll c n v e s , 34.6$ when f e d on l e e f
and w a t e r and 43.7$ when f e d on l e a f m d c h l o r o m y c i t i n
Y
( S h rn 1H e t a 1 , 1 9 5 6 ) . Moreover t h e consumption a l s o
increases with t h e respective feeding.
I n case of
g. mori
and
P.
r i c i n i the increase i n
a s s i m i l a t i o n e f f i c i e n c y when f e d i n s e c t i c i d e may n o t be
e n t i r e l y due t o d e c r e a s e
i n t h e consumption but i t n ~ a y
a l s o be p a r t i a l l y due t o a c t i o n o f p e n r ~ e t h r i nwhich may
enhance t h e d i g e s t i b i l i t y by i n c r e a s e i n t h e r a t e o f enzyme
s e c r e t i o n and ~ i c t i v i t y . However, i n t h e p r e s e n t i n v e s t i g a t i o n o n l y r a t e md e f f i c i t ! r ~ c yo f a s s i m i l a t i o n i n c r e m e s
w h i l e f e e d i n g and c o n v e r s i o n d e c r e a s e s c o n s i t l e r n b l y .
K u r a b a y a s h i , (1980, 1 9 8 1 a , b) h a s r e p o r t e d t h a t when
silkworm l a r v a e f e d organovlercuric con~pounde r e s u l t e d i n
t h e r e t o r d a t i o n o f c r o w t h , l o w e r i n g o f t h e cocoon q u a l i t y
and marked r e p r o d u c t i v e a b n o r m a l i t i e s .
Pant
et
(1982)
have concluded t h a t t h e i n s e c t i c i d e hexachlorobenzene when
fed t o
P.
r i c i n i resulted i n i n h i b i t i o n of a c e t y l choline
esterase activity.
I n h i b i t e d e c t e r u s o , induced t o x i c i t y
i n them r e f l e c t i n g t h e i r l a c k o f a p p e t i t e and undernurishment.
These f u r t h e r l e d t o t h e l y n i u o f a l l n u t r i e n t s
c a r b o h y d r a t e s , g l y c o g e n , p r o t e i n s and l i p i d s a s e v i n c e d by
enhnnced p r o t e o l y t i c l i p o l y t i c p h o s p h o r y l c ~ n e and aminot r a n s f e r a s e s a c t i v i t i e s ( P a n t e t a l , 1982; P a n t and
K a t i y a r , 1 9 8 3 ) , w h i l e f e e d i n g m a l a t h i o n t o P_. r l c l' n l' o b s e r v e d
'
t h e d e p l e t i o n o f p r o t e i n s , c a r b o h y d r a t e s , g l y c o g e n and
l i p i d s and enhanced a c t i v i t y o f c o r r e s p o n d i n g enzymes and
i n c r e a s e d t h e r e l e a s e o f f r e e amino a c i d s .
I n addition
m a l a t h i o n induced w e i g h t l o s s and s t u n t e d growth.
Ross
and Brown (1982) when f e d p e m e t h r i n and F e n v u l e r a t e t o
Spodopt e r a f r u g i p e r d a t h r o u g h c h i n o b e r r y l e a v e s d i e t , t h e
i n s e c t i c i d e s r e d u c e d t h e growth.
Kay
g
a 1 (1979)
studied
e f f e c t o f g o s s y p o l ( P h e n o l i c pigment o f c o t t o n p l a n t ) on
growth and development o f H e l i o t h i s p u n c t i g e r a and H e l i o t h i s
amigera.
I n c r e a s i n g eossypol l e v e l i n t h e d i e t r e s u l t e d
i n r e d u c i n g l a r v a l growth r a t e puphl and a d u l t w e i g h t s .
The mechanism by which i n s e c t i c i d e s i n h i b i t e d growth c o u l d
i n c l u d e r e p e l l e n c y , d i s r u p t i o n o f f e e d i n g p h y s i o l o g y and
other chronic t o x i c i t y possibly related t o i n s e c t i c i d a l
a c t i o n ( R o s s and Brown, 1 9 8 2 ) .
Many chernicaln, p a r t i c u l a r l y
c h e m i c a l c o n s t i t u e n t s o f p l a n t s have been shown t o have
a l l e l o c h e m i c a l e f f e c t s ( w h i t t a k e r and Feany , 1971; Beck and
-
Reese, 1 9 7 6 ) .
and
E.
The c h e n ~ i c a lp e r m e t h r i n when f e d t o
2. mori
r i c i n i a c t s a g a i n s t l a r v a e i n s e v e r a l w~iys,
e s p e c i a l l y as a r e p e l l e n t r e s u l t i n g i n reduced f e e d i n g and
conversion (see a l s o Ilethier
Slansky, 1979)
.
et E&,
1960; Beolc, 1965;
WATER UTILIZATION:
D e f i n ~ t et r e n d s a r e found w i t h r e ~ ~ l rt do w a t e r i n t a k e
and u t i l i z a t i o n i n t h r e e r a c e s o f Bombyx mori and i n
Philosamia r i c i n i .
The t o t a l w a t e r i n t n k e p r o ~ r e s s i v e l y
i n c r e a s e s a s f u n c t i o n o f l a r v a l s t a g e and/or age.
The
i n c r e a s e i n t h e w a t e r i n t a k e and hence t h e p r o g r e s s i v e
i n c r e a s e i n food i n t a k e from t h e f i r s t t o f i n a l i n s t a r
i n d i c a t e t h a t water a c t s a s phagostimulant.
water i n t a k e decreases
RS
The r a t e o f
i n c r e a s e i n age and/or body w e i g h t ,
The r a t e o f w a t e r i n t n k e i s maximum I n t h e f i r s t i n o t n r o f
g. mori and i n P. r i c i n i .
3 t h e r ~ t ei s h i & e r d u r i n g
4 2 and KA r a c e s o f
NB D
Mysore r a c e o f
instar.
I n Pure
second
It i s known t h a t t h e f i r s t few i n s t a r s ( f i r s t and
second i n s t a r s ) a r e t h e most a c t i v e l a r v a l s t a g e s i n i n s e c t s
(Evans, 1939; H i r n t s u k ~ ~1920;
,
Kogen and Cope, 1974; M i s r a ,
1962; D e l v i a d P n n d i s n , 1972; Carne, 1966; Poonia, 1 9 7 8 ) .
Large amount of w a t e r i a r e q u i r e d d u r i n g t h i s a c t i v e p e r i o d
and hence t h e r a t e o f w a t e r i n t e k e i s t h e h i g h e s t d u r i n g
f i r s t few s t a g e s .
The i n i t i d w a t e r c o n t e n t o f t h e l a r v a e
a t each i n s t n r l e v e l ranged from 73% t o 89,1$ and averages
82.3% i n 11.
5 (three
r a c e s ) and
2.
ricini.
A t the
commencement of t h e pupation t h e water content of t h e
t e r r r ~ i n a ll a r v a e belonging t o 3 r a c e s of
d e c r e a s e s t o about 786.
D.
mori t u ~ dEl,
-
ricini
Water content of t h e f r e s h l y
defecated p e l l e t s ranged from 68 t o 75$ i n a l l t h e t e s t e d
insects,
No s t a t i s t i c ! t ! l l y s i g n i f i c a n t c o - r e l n t i o n between
f a e c a l water v i r s u s water i n t n k e throuch food could be
obtained,
Hence, water content of t h e l e a f fed and f u e c e s
egested i s considered almost equal (see a l s o Delvi, 1983).
The t o t a l amount of water absorbed i n c r e a s e s a s f u n c t i o n
of t h e l i f e s t a g e s .
The absorbed water follows a closed
t r e n d t o t h a t of water i n t a k e except i n t h e t h i r d i n s t a r
of
E.
mori Pure
Mysore race where t h e water a b s o r p t i o n
suddenly drops by about 60% ( P i g . 24).
The r a t e of water
a b s o r p t i o n i n c r e a s e s from t h e maximum during the f i r s t
i n s t a r t o t h e minimum i n the f i n a l i n s t u r i n
t h r e e r a c e o ) and i n
ricini.
B. mori ( a l l
There e x i s t a c l o s e r e l a t i o n
between t h e r a t e of w ~ t e ri n t a k e and r a t e o f water a b s o r p t i o n
i n the t e s t e d insects.
The water a b s o r p t i o n e f f i c i e n c y
i n c r e a s e s s u c c e ~ s i v e l yfrom about 95$ (average) during
t h e f i r s t i n s t a r t o around 20% i n NB4D2 and KA r a c e , 47%
i n Pure Mysore r a c e and 75% i n
g.
ricini.
Such wide
v a r i a t i o n s i n t h e water u t i l i z a t i o n have been reported
by previous workers f o r o t h e r t e r r e s t r i a l i n s e c t s ( ~ a n d i a n
--
YIR. 24: i:onltlyx rnorl
P u r e Mysort! Hace
W u t e r lritakct (--*)
f'tiecet; (-
- - -)
retri~r~cgd
(
r - 0 -
,.*a.*,
) (mp)
1i
f t b
st it:^.
,
so)
tit;
l o s t through
absorbed
4b- ')
urid t r a n s p i r e d
f u n c t l o n o f age/
,
WATER UTlL IZATlON BUDGET
-+
Water
--a--
/"
intake
/
Water loss through faeces
Water absorbed
,-+-*.
Water relained in the body
.-a...vo.8...-Water loss through transp~ration
. - - 6 - a
-
Bombyx mori Pure Mysoro race
L i f e stages
I
- .
0
5
10
I
I
20
15
Days
1
25
I
30
J
35
et all
-
1978; D e l v i , 1 9 8 3 ) .
F o r i n s t n n c e , t h e monarch
b u t t e r f l y Danaus c h r y s i p p u s r e t a i n s 240 mg o f wuter d u r i n g t h e
f i f t h i n s t a r w i t h SD v a l u e o f 87 mg ( C V = 36.25$)
and t h e
v a r i t ~ t i o n n f o r water i n t n k c o r ubsorbed o r l o u t v i a f c e c o s
o r t r a n s p i r a t i o n r a n g e d from about 9-155 ( ~ a n d i n ne t a l ,
- -
The f a s t e r r a t e o f t r a n s p i r a t i o n i n B. mori ( P u r e
1978).
Mysore r a c e ) d u r i n p t h e f i r s t i n s t r t r may be due t o h i g h e r
r a t e o f w a t e r i n t a k e (17.55 mg/me/duy)
e f f i c i e n c y o f t h e l a r v a e (98.6$)
and h i g h e r a b s o r p t i o n
observed d u r i n g f i r s t i n s t a r .
T o t a l d i e t a r y water budgets obtained f o r t h r e e r a c e s
- -
of B. mori f e d
for
2.
- -
l i b i , l ; ~ uon~ ~f r e s h l e a v e s o f M . nlbu and
r i c i n i fed
l i b i t u m on f r e s h l e n v e s of
R.
a r e p r e s e n t e d i n Table-26 ( s e e a l o o Fig. 24 t o 27).
d i e t a r y w a t e r i n t n k e m o u n t s t o 6345.7
t o p u p a t i o n i n P u r e Mysore r a c e o f
B.
me
comrnunis
The
from t h e h a t c h i n g
e,
The i n t a k e
is
41$ and 5916 more i n NB4D2 and KA r a c e s r e r p e c t i v e l y t h a n
P u r e Mysore r a c e o f
H. m.
The i n t a k e i n
P.
r i c i n i is
n e a r l y 3 t i m e s more t h a n t h e i n t a k e i n P u r e Mysore r a c e o f
-B , mori.
-
Though t h e t o t e l w a t e r intrike i s minimum i n P u r e
Mysore r a c e , i t s r a t e o f w a t e r i n t a k e i s t h e h i g h e s t wnountirg
t o 4,5203 rng/mg/day.
T h i s i s about 4 t i m e s more t h a n t h e
i n t a k e r a t e found i n NB4D2 and KA r a c e and i n P_. r i c i n i .
P u r e Mysore r a c e o f
g. mori i s
a b l e t o s a v e w a t e r by l o s i n g
l e s s e r amount o f w a t e r throuqh f a e c e s a t a l e s s e r r a t e o f
0.2431 mg/mg/day.
The lower i n t a k e of t o t a l d i e t a r y w a t e r
i n Pure Mysore r a c e i s f u r t h e r compensated p a r t l y by
enhanced a b s o r p t i o n e f f i c i e n c y which is about 2 t i m e s (50.5%)
more t h a n t h e e f lqic!iency found i n NU4D2 (23.7$) and KA
(25.8%) r a c e s .
S i m i l a r t r e n d s a r e found r e g a r d i n g t h e t r e n d s of w a t e r
r e t a i n e d i n t h r e e r a c e s of
B.& m
and
g. r i c i n i .
The
t o t a l amount of w a t e r r e t a i n e d i n t h e body i n c r e a s e s w i t h
i n c r e a s e i n body w e i ~ h tand/or
.(Pig. 24 t o 2 7 ) .
see
i n a l l the t e s t insects
The maximum w a t e r is r e t a i n e d d u r i n g t h e
f i n a l instur i n a l l the tested insects.
P a r t of t h e w a t e r
absorbed i s r e t a i n e d i n t h e body and a p a r t i s t r a n s p i r e d .
T o t a l m o u n t of w a t e r t r a n s p i r e d i n
2. &,
Pure Myaore
r a c e i s g r e a t e r t h a n t h e w a t e r r e t a i n e d i n t h e body d u r i n g
t h e f i r s t two i n s t a r s .
Thoueh t h e t r m u l n l ~ i r n t i o nd u r i n g t h e
f i n a l 2 i n s t a r s i s 2 t i m e s more t h a n t h e w a t e r r e t a i n e d i n
t h e body, t h e t r a n s p i r a t i o n d u r i n g t h i r d i n s t a r p e r i o d
a l o n e i s 50$ l e s s t h a n t h e w a t e r r e t a i n e d i n t h e body
(Pig, 24).
T h i s t r e n d of t r a n s p i r a t i o n changes i n NB 4 D 2
and KA r a c e s of 2. mori a n d i n g. r i c i n i ( F i g . 25 t o 27).
However, i n a l l t h e s e i n s e c t s t h e w a t e r t r a n s p i r e d d u r i n g
first i n s t a r i s e r e a t e r t h ~ nt h e w a t e r r e t a i n e d i n t h e body.
T r a n s p i r a t i o n r a t e decreased a s t h e body weight o r
age i n c r e a s e s .
The r a t e s d e c r e a s e from t h e maximum d u r i n g
pip.
2'5: Ilornt,yx
marl
Water 1 n t ; i k e
f'ilecetj ( -
i q l l q l J 2 Huce
-
(mr; -)
l o s t through
* -)
, absor4t,ed (. e.)
,
r e t f i ~ r i e d f .--0-..) m d t r a n s p i r e d
(. . - . n . . . .~3
. ) i ' u r i c t i o n of' uge/life
u t ti4:e
.
WATER UTILIZATION BUDGET
-+.-+.
Water intake
Water loss through faeces
Water absorbed
..-o-.. Water retained in the body
......0.....
Water loss through transp~ration
mori
Bombyx
NBb D2 race
Life s t a g e s
1
0
I
I
5
10
1
15
Days
I
20
1
25
1
30
t h e f i r s t i n s t a r t o t h e minimum i n f i n a l i n s t n r s t a g e ,
It r a n e e s from 3.5379 me/mg/day t o 0.0347 mg/mg/day
in
a l l t h e t e s t e d i n s e c t s except i n t h e f i r s t i n s t a r of
B,
P u r e Mysore r a c e o f
o f 17.11 rng/mg/day
a.
The
extrtmely high value
found i n t h e f i r s t i n s t a r l a r v a e o f
P u r e Mysore r a c e may n o t be due t o e r r i j a e w e s t i m a t i o n s ,
S l a n s k y and S c r i b e r (1982) a t t r i b u t e d t h e h i g h f e e d i n g
-
r a t e found i n P i e r i s r a p a e (Slanslgr, 1 9 7 4 ) , t o t h e e r r o r
b e c a u s e o f snlall m o u n t s i n v o l v e d .
I n t h e present study,
50 i n d i v i d u a l s were grouped t o g e t h e r and t o t a l w a t e r
u t i l i z e d i s estimated.
More o v e r t h e e x p e r i m e n t s were
r e p e a t e d and s t a n d a r d e r r o r (SD v a l u e ) o b t a i n e d .
The w a t e r
r a n g e o f v a r i a t i o n s found amounts t o 20.8s.
a b s o r p t i o n e f f i c i e n c y amounts t o 75.5$
in
The
P.
r i c i n i which
i s 3 t i m e s more t h a n t h e e f f i c i e n c y found i n NB4D2 and K A
race of
B,.&m
Mysore r a c e o f
As s u c h t h e t o t a l w a t e r a b s o r b e d i n P u r e
3.
Q i s 516 more t h a n t h e a b s o r p t i o n found
i n NB D and 23% more t h a n t h e a b s o r p t i o n found i n KA r a c e .
4 2
The t o t a l w a t e r a b s o r b e d i n P. r i c i n i i s 4 t i m e s more t h a n
t h e a b s o r p t i o n found i n Pure Mysore r a c e and 5 t o 6 t i m e s
more t h a n t h e a b s o r p t i o n found i n NB4D2 and KA r a c e s o f
ori,
-B. m-
However, t h e e x c e s s m o u n t of' w a t e r saved by
P u r e Mysore r a c e and
P.
r i c i n i by b e t t e r a b s o r p t i o n e f f i c i e n c y
is l o s t through h i g h e r t r a n s p i r a t i o n .
of
g. mori t r a n s p i r e s
P u r e Mysore r a c e
about 3 t i m e s more w a t e r i n NB4D2 and
PIC. 26:
Ilorntyx rrrori
Writer
KA ftr-ice
~ n t i i k em
)
(
.-+aa)
lost
+ -)
t h r o u p t i f ' ; l e c c n (absorbed
-
,
(.--.Cr;--.)
retained
tmd t r a n s p i r e d
us f ~ m c t l o no f rq:e/life
c--O-+.)
stage.
1
1
I
1
u
I
m
L i f e stagos
-
-
.-
Days
I
n7
1
P
KA r a c e s , a t t h e h i g h e s t r a t e o f 4.2793 mg/mg/day.
t h e t o t a l m o u n t o f wa.ter tr~.m:spired i n
g.
Thouch
r i c i n i is about
1 0 t i m e s more t h a n t h e t r a n s p i r a t i o n found i n NB4D2 and
KA r a c e s , t h e t r m s p i r ~ ~ t i or na t e i s n o t ~ncirkedly d i f f e r e n t
from t h e P u r e Mysore r a c e s o f
budget f o r t h e silk worn^
eri-3ilkworm
lie
g.
E. mori
The w a t e r u t i l i z a t i o n
e.
( P u r e Mysore r u c e ) and
r i c i n i from h a t c h i n g t o p u p a t i o n is d e e c r i b e d
e l s e w h e r e by t h e a u t h o r (Naik and D e l v i , 1 9 8 4 ; D e l v i and
Naik, 1 9 8 4 ) and i n c l u d e d h e r e f o r compnrat i v e p u r p o s e s as
p e r m i t t e d by t h e U n i v e r s i t y .
The o t h e r p a p e r a v a i l a b l e on
w a t e r u t i l i z a t i o n Danaus c h r y s i p p u s (Yandian e t a l , 1 9 7 8 )
d e a l s w i t h t h e e f f e c t s o f t e m p e r a t u r e and l e a f r a t i o n on
t h e w a t e r budget o f f i n a l i n s t a r l a r v a .
A survey of recent
l i t e r a t u r e reveals t h e paucity of information regarding
w a t e r u t i l i z a t i o n from h a t c h i n g t o d e a t h a n d / o r p u p a t i o n .
The o n l y p a p e r on w a t e r u t i l i z a t i o n i s on P o e c i l o c e r u s pict113
( D e l v i , 1 9 8 3 ) which g i v e s v a l u a b l e d a t a on w a t e r u t i l i z a t i o n
o f a n o r t h o p t e r a n a t two d i f f e r e n t t e m p e r a t u r e l e v e l s .
For
c o m p a r a t i v e p u r p o s e s D e l v i ( 1 9 8 3 ) h a s a l s o g i v e n d a t a on
-D.
c h r y s i p p u s from h a t c h i n g t o p u p a t i o n a t 3 2 ' ~ .
Comparative
water u t i l i z a t i o n budgets of d i f f e r e n t i n s e c t s belonging
t o l e p i d o p t e r a and o r t h o p t e r a , a v a i l a b l e i n t h e l i t e r a t u r e ,
a r e summarised i n Table-30.
A p e r u s a l o f t h e Table-31 where t h e w a t e r u t i l i z a t i o n
b u d g e t s a r e g i v e n f o r t h r e e l e p i d o p t e r ~ ni n s e c t s and one
*
,
c,
\.
--
I-
rU
c
,C\
4
m
b
,
C>
I
I.
-
<,ow\"%m~,.,-.-w~
<* -,, w,- 7 ,a " \ m "3- "w ,. .m4 !%> a,".
$I'
m
C
,
I
I
.
-
C'
"1..
"\
9
I
.-
.t
PIC.
27:
t J h l1 O : ; ~ U I I ~ : L r l c i n l
Writer ( m i : ) I n t a k e (*)
t h r o u c h i'tieces (-+
(.&.)
-),
lost
absorbed
r e t i i l n e d (---0--,,)
and
t r t l n ~ l p l r e d (..
.
a
)
aa
function of
orthopteran i n s e c t , indicate t h a t different proportions
of d i e t a r y w a t e r i s taken.
insects like
g, ,&m
g,
The w a t e r i n t u k e i n l e p i d o p t e r u n
r i c i n i and
2.
chrysippus is
c o n s i d e r a b l y lower t h a n t h a t t h e wnter i n t u k e i n an
o r t h o p t e r a n i n s e c t l i k e P_. p i c t u s .
Though t h e t o t a l w a t e r
i n t a k e d i f f e r s c o n s i d e r a b l y i n both l e p i d o p t e r a n and
o r t h o p t e r a n i n s e c t s depending on t h e s p e c i e s r a c e s , s e x
and t e m p e r a t u r e , t h e p r o p o r t i o n o f water i n t a k e i s f o r
higher i n
g.
p i c t u s t h a n i n any o f t h e l e p i d o p t e r u n i n s e c t s .
On an average t h e w a t e r i n t a k e i s s i x t e e n t i m e s more i n an
o r t h o p t e r a n i n s e c t t h a n t h e averagc i n t a k e i n any of t h e
l e p i d o p t e r a n i n s e c t , p r e s e n t e d i n t h e Table-31.
The w a t e r
a b s o r p t i o n e f f i c i e n c y ranges from about 23$ t o about 57'74
i n a l l t h e i n s e c t s e x c e p t i n eri-nilkworm P_, r i c i n i where
t h e e f f i c i e n c y i s a s h i g h a s 75$.
As mentioned e a r l i e r
t h i s h i g h e r a b s o r p t i o n e f f i c i e n c y r e s u l t s i n h i g h e r amount
of t r a n s p i r a t i o n and hence l o w e r r e t e n t i o n e f f i c i e n c y ,
S i m i l a r r e s u l t s a r e found i n
R, mori Pure
blysore r a c e , where
h i g h e r a b s o r p t i o n e f f i c i e n c y o f 50,5$ r e o u l t e d i n lower
w a t e r r e t e n t i o n e f f i c i e n c y o f 29$.
I f t h e ubsorption efficiency
i s l o w e r t h a n wnter r e t e n t i o n e f f i c i e n c y i n c r e a s e s c o n s i d e r a b l y .
For example i n NBqD2 and KA r a c e t h e a b s o r p t i o n e f f i c i e n c y
i s 23,7$ and 28.5s and a s suoh r e t e n t i o n e f f i c i e n c y i s
66.5% and 76.6% r e s p e c t i v e l y .
Such c o - r e l a t i o n a r e a l s o
found i n o t h e r i n s e c t s r e p o r t e d by p r e v i o u s workers
--
( D e l v i , 1983; P a n d i a n e t a l , 1 9 7 8 ) .
-D.
For example i n female
c h r y s i p p u s ( D e l v i , 1983) a t 3 2 ' ~ t h e a b s o r p t i o n e f f i c i e n c y
is 51.9"h and r e t e n t i o n e f f i c i e n c y 38.1$.
Such l o w e r
a b s o r p t i o n e f f i c i e n c y a r e a l s o found i n t h e f i n a l i n s t u r
l a r v a e o f l o w e r t e m p e r a t u r e o f 20, 25 and 30°c, where t h e
a b s o r p t i o n e f f i c i e n c y i s 306, 23$ and 28% r e s p e c t i v e l y .
The respective r e t e n t i o n e f f i c i e n c y is h i g h e r amounting t o .
A t 3 5 ' ~ the f l r s t i n s t a r larvae of
48$, 41% and 54%.
-D,
c h r y s i p p u s e x i b i t e d an h i g h e r a b s o r p t i o n e f f i c i e n c y o f
51% and a s such t h e r e t e n t i o n e f f i c i e n c y i s l o w e r and i s
o n l y 30% (Table-31).
i n s e c t i s t h e male
The o n l y e x c e p t i o n i n t h e l e p i d o p t e r a n
g. c h r y s i p p u s a t
0
32 C where t h e a b s o r p t i o n
e f f i c i e n c y and r e t e n t i o n e f f i c i e n c y is a l m o s t t h e same.
Taking t h e average o f male and female i n
pictus the
a b s o r p t i o n e f f i c i e n c y a t 2 6 ' ~ i s 31.5$ and r e t e n t i o n e f f i c i e n c y
is 16.8$ where a s a t 3 6 ' ~ t h e a v e r a g e a b s o r p t i o n e f f i c i e n c y
i n c r e a s e s t o 48.7$ and t h e r e t e n t i o n e f f i c i e n c y d e c r e a s e s
t o 9.5$.
While t h e w a t e r i n t a k e i s 1.6 t i m e s more i n o r t h o p t e r m
insect than the lepidopteran insects, the absorption i n
-P,
p i c t u s i s 25 t i m e s more t h a n i n m y o f t h e l i s t e d
lepidopteran.
T h i s h i g h i n t a k e and a b s o r p t i o n h a s r e s u l t e d
i n l o s s o f l a r g e amount of w a t e r through t r a n s p i r a t i o n i n
g.
pictus.
The t r a n s p i r a t i o n i n
P.
p i c t u s i s 22 t i m e s more
t h a n t h e mean t r a n s p i r a t i o n o f w a t e r i n l e p i d o p t e r a n
insects,
The l o w e r w a t e r i n t a k e coupled w i t h l e s s e r
a b s o r p t i o n i n l e p i d o p t e r a n may be t h e c a u s e f o r l o w e r
transpiration.
More o v e r t h e l c p i d o p t e r u n i n s e o t s f e e d
only d u r i n g t h e l a r v a l s t a g e which is f o r s h o r t e r i n
d u r a t i o n ( ~ v e r a g e35 d a y s ) t h a n t h e o r t h o p t e r m i n s e c t ,
which f e e d s t h r o u g h o u t t h e l i f e e x t e n d i n g u p t o about 240
days ( s e e Delvi, 1972).
The r a t e s o f w a t e r i n t a k e , a b s o r p t i o n and t r a n s p i r a t i o n
a r e r e c a l c u l a t e d i n t e r m s o f mg of w a t e r p e r mg l i v e weight
of i n s e c t p e r day f o r t h e a v a i l a b l e i n s e c t s and p r e s e n t e d
in Table-30.
The v a l u e s f o r w a t e r i n t a k e i n
B.
s
n
rand
--
P. r i c i n i i s around 1 , 2 5 w/mg/day e x c e p t f o r Pure Mysore
r a c e of
E.
@ which i s
4 . 5 mg/mg/day.
Such h i g h w a t e r
( i n t a k e r a t e i s a l s o found i n o t h e r i n s e c t s l i k e
where t h e r a t e i s 3.2 rng//mg,/day
2.
chrysippus
a t 3 0 ' ~ and r e d u c e s a s t h e
t e m p e r a t u r e r e d u c e s r e a c h i n g 1 , 3 mg/mg/day
0
a t 20 C ,
A
comparison o f r a t e s of w a t e r i n t a k e , a b s o r p t i o n t r a n s p i r a t i o n
between l e p i d o p t e r a n and o r t h o p t e r a n i n s e c t r e v e a l t h a t i n
lepidopteran i n s e c t s t h e r a t e s nre higher than the r a t e s
found i n
El.
pictus.
These r a t e s a r e 5-10 t i m e s more i n
lepidopteran insects than i n orthopteran insects.
orthopteran l i k e
2,
While a n
p i c t u s f e e d s t h r o u g h o u t t h e l i f e and
m e e t s most o f i t s w a t e r r e q u i r e m e n t s from i t s f o o d ,
I
.
2 :
of
b:i'!'t~c:t
(mi')
f I rl:il
11:;
/ i c * n * ~ t . t . l lIn
r on water i n t a k e
f ' ~ ~ n c t l oonf r l t e / l l f ' e
stage i n
:' lr13ti:r:i o f F o n ~ t ~ ynxl o r i ( u p p e r
p~uin(.I) nr~ci 'I'h i lo:-:,ri~l;l r l c h i n i
( l o v ~ e rr~:ir~ricl
)
.
'OoY
EFFECT O f
PERMETWRIN ON DIETARY WATER INTAKE
Bombyx
mori
-
Puro Mysore race
-0-
Untreated leaves fed
treated leaves fed
-*.
Permethr~ntreated leavos fed
- + - Acetone
(0
>
-:looor
\
F
100
I
I
LO,
m
J
P
D
Larval
stages
2 0 w
1000C~
Philosamia
ricini
a
>
-a
L
\
m
1000-
E
Life stages
I
5
I
10
1
15
20
Days
I
25
I
30
I
35
Pic. 29: E f f e c t o f p e x m e t h r i n on water absorbed
(mg) 3.s fimctior-I o f nce/life stage in
-
f i n x l ? instc1.r:; o f Hombyx m o r i (upper
pannc.1 a n d Philos:i,~iri:c ri c i n i (lower
p t u ~ n u)l
.
EFFECT OF PERMETHRIN ON DIETORY WATER ABSORPTION
Bombyx
m o r i P u r o Mysoro raco
_0_
Untreated leavos fod
Acetone treatod loavos fed
-+-
/
Pormo thr in
a * .
Larval
1001
1
1
m
L
I
5
10
XY
Life stages
I
15
I
20
Days
stages
4
1
1
25
30
J
35
- -
l e p i d o p t e r a n i n s e c t s l i k e B e m o r i and
Ye
ricini store
s u f f i c i e n t water during t h e l a r v a l period t o t i d e o v e r t h e
s u b s e q u e n t non f e e d i n g pupal and a d u l t s t a g e s ,
Available
information indicates higher r a t e s of water intake absorption
and t r a n s p i r a t i o n f o r l e p i d o p t e r a n t h n n t h e h e r b i v o r u s
P, p i c t u s .
orthopteran
C o n s e q u e n t l y t h e w ~ i t e ri n t a k e w d
u t i l i z a t i o n i n t h e s e two i n s e c t p r o u p s ohow c o n s i d e r a b l e
adoptive differences,
E f f e c t s o f i n s e c t i c i d e on w a t e r u t i l i z a t i o n :
The e f f e c t o f p e r m e t h r i n on d i e t a r y w a t e r budget i n
f i n a l two i n s t a r s o f Hombyx m o r i P u r e Klysore r a c e lind
P h i l o s a m i a r i c i n i i s p r e s e n t e d i n Table-27 iind 28.
only acetone t r e a t e d leaves a r e fed t o
2. mori <and c.
t h e w a t e r u t i l i z a t i o n budget a l t e r e d c o n s i d e r n b l y .
r i n g t h e water intake values of
When
ricini
Conside-
B. mori and P, r i c i n i
fed
normal l e a v e s a s 1 0 0 , t h e w a t e r i n t a k e i s 807: f o r a c e t o n e
f e e d i n g and 5 5 % f o r p e r m e t h r i n f e e d i n g i n
o r i it
-B e mfeeding,
ricini.
In
i s 68% f o r tlcetone f e e d i n g and 4 U $ f o r p e n r e t h r i n
While a c e t o n e i t s e l f a f f e c t e d u p t o about 205 on
water intake
01'
a b s o r b e d o r l o s t t11rou~t.rf a e c e s ~ m dt r a n s p i -
rtltion, t h c values for pcrmethrin fed i n
-B.
P.
P.
r i c i n i arid
-
m o r i i t r e i n t h e r:[ni:e o f ntrout 4 0 t o 507b.
T h e r e i s no marked d i f f ' e ~ * e n c oi n t h e l a r v a l p e r i o d i n
t h e f i n a l two i r i s t a r s d u e t o t h e p r e s e n c e o f e i t h e r ~ c e t o n c
o r insecticide i n
B. mori N I ga
~ ricini.
Significlint
d e c r e a s e s i n t h e w n t e r i n t rtke r ~ b s o r pito n t r a n s p i r t l t i o n
and w n t e r r e t n i n e d i n t h e body are found c o n s e q u e n t o f
f e e d i n g a c e t o n e and i n s e c t i c i d e t r e : t t e d l e n v e r ; i n t h e
t e s t i n s e c t s ( F i g . 28 t o 3 1 ) .
When w c t e r i n t a k e i n
g. mori
r e d u c e s by a b o u t 52% due t o i n s e c t i c i d e , t h e r e d u c t i o n i n
-P. -r i c i n i
i s a b o u t 45$.
S i m i l a r r e d u c t i o n a r c found i n
t h e w a t e r l o s t throuch f a e c e s o r trrulsl~il.iltion o r absorbed
o r r e t a i n e d i n t h e body.
t h r o u g h f ~ e c e si s G 4 $ i n
The r e d u c t i o n i n w u t e r l o s s
E,
@ ~ r ohout
~ d
53$ i n
S i m i l a r l y w a t e r a b s o r b e d r e d u c e s by ubout 4 1 % i n
- -
a n d P, r i c i n i .
in
2.
e,t h e
ricini.
E. mori
W a t e r r e t u i n e d i n t h e body r e d u c e s by 56$
--
r e d u c t i o n i n P. ri c j n i i s a b o u t 49$a
R e d u c t i o n i n w a t e r t r w ~ s p i r e damounts t o j2$ i n
a n d 38$ i n
g,
P. r i c i n i .
2,
Such r e d u c t i o n s arc! n l c o fount1 i n
rate:; o f w u t e r i n t o k c o r w a t e r l o s t t h r o u g h f a e c e s o r
t r a n s p i r a t i o n i n both t h e i n s e c t s .
However, t h e wo.ter
absorption rntc i n c r e m e s i n case of
2 .&m
from 0.3136
mg/mg/d~.y d u r i n g n o r m c ~ l f e ~ c l i nt o~ 0,3877 mg/mc/day
i n s e c t i c i d e feeding.
i s found i n
-D,
clur~ing
The r e d u c t i o n i n t h e w a t e r u t i l i z ~ iito n
c h r y s i p p u s due t o r e s t r i c t i o n o f f e e d i n g , b u t
chrysippus l i k e
g.
m o r i , e x i b i t e d hil:hers c ~ b s o r p t i o n
e f f i c i e n c y ( P m d i r i n e t a l , 1978).
T e m p e r a t u r e r!l.co sccrliu
t o i n f l u e n c e t h e p a t t e r n and t h e t o t u l w a t e r u t i l i z a t i o n i n
-Dw
chrysippus and
1978).
c.
p i c t u s ( D e l v i , 1983; Pmdirin e t t ~ l ,
The most i n t e r u n t i n l : f i n d i n g i s that ttlu w u t e r
a b s o r p t i o n e f f i c i e r i c y i n c r e a s s s c o n s i d e r a b l y from about
4 % d u r i n g n o r n ~ n l feedinp; t o 61.61;: d u r i n ~ :t h e p e l i n c t h r i n
f e e d i n g (P
< 0,001)
in
R.
e.
E. r i c i n i
R ~ G Oe x i b i t e s ( ~ o l \ r 3 1 )
i n c r e a s e i n w a t e r t i b s o r p l i o n e f f i c i e n c y from 75$ t o ubout
79% (P
( 0.05
significant).
The i n c r e a s e i n t h e r a t e and
w a t e r a b s o r p t i o n durini; pernlethrin t r e a t e d l e u v c s f e e d i n g
in
g. mori and P,
However,
r i c i n i nlay be due t o reduced w a t e r intnlru,
B. mori a.nd z.
r i c i n i a r c ritrle t o p a r t i a l l y co~npensattl
f o r r e d u c t i o n i n t o t a l w a t e r i n t a k e by i n c r e u o i n g t h e
absorption efficiency.
The c o n c l u s i o n i s s i g n i f i c e n t i n
u n d e r s t a n d i n g t h e ctdoptive p o t e n t i t 1 1 o f
He @ cz~d-P ,
-r i c l . n i
i n tropical environme~~t,
The i n s e c t i c i d e t r e a t e d l e a v e s when f o d t o
-P, -r i c i n i
B. mori r ~ r ~ d
r e s u l t e d i n reduced i n t a k e of food as ouch
r e s t r i c t e d t h e a v a i l r ~ b i l i t yof w a t e r f o r t r : m s p i r a t i o n .
I n s p i t e of t h i s t h e t e s t e d i n d i v i d u a l s t r a n s p i r e d a t a
faster rate.
Such n e g a t i v e i n t e r a c t i o n r e s u l t e d i n reduced
s i z e o f pupae aad cocoon.
A s i p p i f i c a n t decrease i n t h e
r a t e o f w a t e r u t i l i z a t i o n and p r o d u c t i o n o f smaller pupae
and s r a a l l e r a d u l t moth whs observed.
S r i n i v u s m (1977)
r e s u l t 8 f o r h o u s e f l y l a r v a Nlusca d o n ~ c s t i c a
r e p o r t e d sirnil~~r
r e a r e d on m i l k pads soaked i n 0.2$ c a f f e i n e .
Ffolomet:~bolous
Table-32 :
E;'fects o f perrnethrin o n u-ater u t i i t z a t i o n b u d g e t o f B o r n b p m o r i Pure
Philosarnia ricini a t 26OC. T - t e s t to cndica t e sta tistccal signt ficance.
Bombvx
&
Philosarnia
.\l!sore
r a c e and
ricini
T-test
be t w e e n
C o n t m l and
.-Icetone group
T-test
between
.Ace tope and
inselictde g m u p
T-test
between
Con?rol and
.4c e tone g r o w
T-test
between
.Ace t o n e and
Insedicide group
\(a t e r 1or.s
through f a e c e s
PC 0.001
Stgnificant
P T r_).~cll
Significant
P c 0.01
Stgniiican t
P s 0.001
S i p t f ican t
Ira rer absorbed
P < 0.01
S!gnificant
P C il. 1
Stgnifican t
P c 0.01
Sign1 fican l
P < 0.91
Signr f ican t
P < U-ooi
Stgncfrcant
P c O.U~I
Stgncfrcarrt
PC 0.~01
Srgn~frcant
P C O.OOI
Signt fican t
Parameters
It a rer in t a k e
rmn.sp~m tton
It a rer in f a k e
m te
Hare o f w a t e r 1o.w
through f a r c e s
P < 0.01
Stgn! fican t
P < 0.~701
S i g n i f i c a nt
P> d.1
l o t significant
P< 0.01
Significant
P < 0.01
Stgnifican t
P c O.t~cl1
Signc f ; c a n t
P C J.@L>I
Siprfccant
PC !1.001
5tgnc i t can t
P< O.OL11
Srgnc f I can t
P > 0.05
\ot stgnl f z c a n t
P .0-~J1
S o t s~gniiican
t
P < 0. sC
'7 I
Is'zgnificant
P > Q.0.5
V o t .;rgnificant
P< 0.01
Sign! f ican t
P < 9.01
Srgnt f t c a n t
P 0-0.5
Siqni f i c a n t
Pic. 30: E f l ' e c t of' p e r n 1 ~ t h r i . non t r a n s p i r a t i o n
(me) u s f u n c t i o n of a c e / l i f e
stnce in
-
f i n d 2 inst:irr; o f Rosbyx m o r i ( u p p e r
punnel) find I ) h i l o s a m i t i ricini
.
(lower p ~ i n n e l )
EFFECT OF PERMETHRIN ON TRANSPIRATION
Pure Mysore race
Bombyx mori
+ Untreated loaves fed
- + - Acotone lroatod leaves
.-o--
fed
Porrno t hrln treat od loavos fod
10
m
coot
I!
n7
Philosarnia
," 1000-
L
Q
\
F
100
I
5
I
10
I
1
I
m
Life
15
IY
stages
20
Days
P
I
25
1
30
1
35
Fie. 31: G f f e c t o f perrnethrin on w ~ t e rr e t e n t i o n
(mc) a s f u n c t i o n o f a g e / l i f e s t a g e i n
-
f i n a l 2 i n s t n r s of Bombyx mori
( u p p e r p n n n e l ) :utd I J h i l o s u r l i a r i c i n i
(lower punnel) ,
10007
EFFECT OF PERMETHRIN ON WATER RETAINED
--
I0
>
IN THE BODY
Bombyx
mori
Pura Mysoro race
+ Untreated loaves fad
- + - Acotono troated leaves fed
L
m
7
100,
m
E
2 01
I
xu1
Ill
Larval
F
stagos
P h i l o s a m i a ricini
m
>
-;1000\
cn
E
1007
I
I
mI
IP
P
L l f a stagos
1
r
15
H
25
LO,
Pays
i n s e c t s accumulate s u b s t m t i a l n u t r i e n t r e s e r v o i r d u r i n g
t h e f i n a l l u r v e l s t a ~ e ;which Fire c h i e f l y d e p o s i t e d as
f a t and glycogen i n t h e i r f a t body ( G i l b e r t , 1964; Wyatt,
1972).
Ponntltion o f a1111~11
pupne and r.idulto tuid u t i l i e n t i o n
o f l e s s w a t e r by lurvoe f e d on p e n n e t h r i n t r e a t e d l e a v e s
may be due t o t h e e f f e c t of t h e t o x i n not o n l y on t h e
s y n t h e s i s of s t o r e d p r o t l u c t s , b u t i.11.ao on p r o t e i n s , an
e s s e n t i t l l phenomenon i n t h e Crowth of t h e ore;~.fiisri~s. The
mechanism by which i n s e c t i c i . d e s i n h i b i t t h e u t i l i z n t i o n
of w a t e r c o u l d be throueki r e p e l l e n c y , d i s r u p t i o n o f f e e d i n g
p h y s i o l o g y m ~ do t h e r c h r o n i c t o x i c i t y p o s s i b l y r e l n t e d t o
i n s e c t i c i d e a c t i o n ( s e e ~ l s oROSS and Brown, 1982).
P e r m e t h r i n p r e s e n t e v e n i n minute q u a n t i t i e s (0.04 PPM)
not only a l t e r s the water u t i l i z r i t i o n p a t t e r n of the l a r v a e
b u t g r e a t l y r e d u c e s t h e s i z e o f t h e cocoon, hence i t i u
s u g g e s t e d t h a t i n s e c t i c i d e s s h o u l d be used w i t h g r e a t
c a r e , a v o i d i n g contnrninntion i n t h e e c o n o n ~ i c a l l yin~po~*ta.rlt
rearing colonies.