7.
Reproduction, an <..:.l,tocatylytic and one of the most
i~.,....,')rt.J.nt
... ~
~
event of 1 ife ,..,rocess ensues in most orgonis"!ls on
accur~ulation
ining the [liqrest lovel of g rowth through
nergy by tle proccs8 ::>f
f
f~ecling .
This process ensures
rt · n' 'tir;n of life and s..-,ccies .
C'
Of all tle for" of
repr~duction
the most
recent and
ulvanta,eou s one is sexual reoroduction. But anparently, tPe
0~nes
c
1
for asexual reproiuction seem to be advantageous over
eting :..llelcs of cexuu.l rco::::-o'iuction as the sexually
rc,..,roducinq
~f
~ni~als
vnuld huvc to ensure the union of
ga~etes
t1 e same soecies 2.nd O'i,..,ositc sex \vhich often requires an
0n'>r"''OUS investment in var:i.nuz forms 1 i 1<e r·drrrat ion, nestsite
zclecti0n, 'Tlale rivalry, etc. ,".ga in after sn
onl~
fifty nercent of
~enes
h~<>avy
investl'T'!Pnt
will lc contributed in each
off sprj ng . HO\vever, sexual rpnr-.juction !,)roduces vari.ant
in tivi-:!uc1ls \-lhich
e:x""Jloit the enviorn.,ent more successfully
r~ay
ut ti es of rapid cru.nge. hlcock (1979) rightly su.id that
'
~exual
reproduction is a gamble, but not a wild one. Bets
...1.re hedged because the 0 ncration of variable offspring is
mtrolleu. Progeny are
l 1o...,t never radically
> o~.;.;Ovb.Lds
quarantees H
·~nts
"nd
':~
iif:erE nt from treir parents, but
iff
t
rent
~·
bec..... use devclon""'ent2.l
ey \vill nosse;.s t1 c key adant..1.ti. ns
i,.. .... cc i
·' ·
nut
Je 1 ng
1
;,., ...... ,.,,.r 1.t va'
78
inevita le und un r
·:ct..t1)le vari<.t:lon in
lVL·r sn...1cc an"'l ti""'e. '
Yticil renroduction is
l
J
but
bc·nef ic ial
'lliCh
-,-e c--nviorn':'ents
Tl~us
in comdri son to asexual rcnroduct jon
~ore
costly (in
te~s
of
invcst~ent)
and
r in terms of. qene contribution to edch off ST)ring)
~hi.:;
ore .,tdble.
"1
t-)
nefit tratie - off of .,exual
ecj • ,;;)
' it1
sPveral altern ... tivc .corns nf hel avioural patterns like
~~noqa~y- polvqa~y ,
- neetnaras ' tism,
ne~ting
itero~arity
-
.-.e"'leloari ty , etc.
Reor,.,duct; on,
ecoloay of renro :luct ion
't ""'G.tured to a
ner~nective .
f
'P.u .. i'Jur
including brePding l"( raviour,
j
s ba3ic
f j rr;t initiated by naturalists soon
'\v<~s
co~rchcn-ivc
:l:la 1 y5i5 including eve>lutionary
Hmvever, to
unler.3~an d
etroloqi~ts
n id ,..,ore attention to the descrintion
tre adantive sirynif'c nee
· 'c:i, • >-sryecif ic LeL..1 'i">ural nat terns .1nd in rrany occasuions
Vd
iati ..,ns to t1.,is patt rns \.;ere simply neglt:.cted or treated
a.,
1~.~
"~
i~~ortant .
But it is
~o
sible for a be avioural
)l r 'rn! is-n to be an e;v')l utj ?naril y stable c-:>ndit ion {IVa.ynard
..., 'lith, lq74; .:Javkin.,, 1 '177). 1'hat is, at a certain !::et of
;·xidl cirn.1nstance5
•,t db:: JieG
•
1
\ t.
,_
r
\olitl~
in a
c.~
-,r
·everal altern..ltive l')e"" virmr l
neci
")ers'i..:;t in t .. c
1n'i cv.l.ntr' r
J.
c
.:ion.
>o
•• 5 ;nr in
-tt i
~
n0cP ;s -
ir tai. s i
r t"1
rrc.-~('c': ;~
79
In this c dpter T ldVe tried to correl ate
'f
r tt
r .... viuur~l p ... ttcrn::. of openbill ::.tork \-itt. vari us E>C lo :i.e 1
i
Urltion s .