Variable Success of Biological Control Agents for
Lythrum salicaria in Minnesota Wetlands: Understanding
Landscape Patterns in Plant Evolution and Management Efficacy
Evolution of Increased Competitive
Ability (EICA) Hypothesis
• Specialist
herbivores removed
Introduced
Populations
• Cost but no benefit
of defense
Time
(Blossey & Nötzold 1995; Reviewed by Bossdorf et al., 2005)
Evolution of Increased Competitive
Ability (EICA) Hypothesis
• Specialist
herbivores removed
Introduced
Populations
• Cost but no benefit
of defense
• Plants evolve to
allocate resources
to vigor
(Blossey & Nötzold 1995; Reviewed by Bossdorf et al., 2005)
Evolution of
Increased vigor
from loss of
herbivore defense
Time
L. Salicaria Evidence for
Evolution of Increased Competitive Ability
L. Salicaria Evidence for
Evolution of Increased Competitive Ability
• Enemy Release
– Specialist herbivores
(Hight, 1990)
L. Salicaria Evidence for
Evolution of Increased Competitive Ability
• Enemy Release
– Specialist herbivores
(Hight, 1990)
• Evolution of Increased
Competitive Ability
– Decreased herbivore resistance
(Blossey & Nötzold, 1995; Blossey & Kamil, 1996)
– Increased Vigor
(Willis et al., 1999; Blossey & Nötzold, 1995;
Blossey & Kamil, 1996; Willis & Blossey, 1999;
Bastlova & Květ, 2002; Chun et al., 2007)
Lythrum salicaria Biocontrol
• In 1992 three species were introduced
• 2,150 Beetles were released in Minnesota at two sites
(Malecki, R. et al 1993; MN DNR, 2009)
Lythrum salicaria Biocontrol
• In 1992 three species were introduced
• 2,150 Beetles were released in Minnesota at two sites
• More than 9 million insects released in Minnesota
(Malecki, R. et al 1993; MN DNR, 2009)
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
Evolutionary
increased vigor
from loss of
herbivore defense
Introduction of
biocontrol agents
1992
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
Evolutionary
increased vigor
from loss of
herbivore defense
Introduction of
biocontrol agents
1992
Evolutionary
response to
selective
pressure of
specialist
herbivores?
?
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
?
“Historically Low
Herbivory (LH)”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
“Historically High
Herbivory (HH)”
?
“Historically Low
Herbivory (LH)”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
Evolutionary
divergence in
response to
selective
pressure of
specialist
herbivores?
“Historically High
Herbivory (HH)”
?
Experimental Garden Design
ML 1
ML 2
Wetland 1
Wetland 2
Wetland 3
Wetland 4
Wetland 5
Harvest
1st year
Wetland 6
= LH
= HH
Harvest
2nd year
ML 3
ML 4
ML 5
ML 6
H
e
= LH
C
= HH
W
in
Pi
g'
s
ke
nd
on
a
Ey
e
la
Po
e
y
sh
te
r
M
ar
Ce
n
irc
l
tte
r
al
l's
od
g
Po
D
(g ( 95%CI)
Weight
Total L. salicaria
DryGarden
Data (2009)
Experimental
Lythrum salicaria Vigor 1st Year
Average Total Weight (g)
150
100
50
0
Lythrum salicaria Vigor 1st Year
• Stem Weight
150
<
• Inflorescence Weight
100
<
• Stem Height
50
<
on
a
W
in
Ey
e
Pi
g'
s
ke
e
irc
l
C
y
tte
r
Po
H
al
l's
= LH
la
Po
sh
M
ar
te
r
Ce
n
e
od
g
nd
0
D
(g ( 95%CI)
Weight
Total L. salicaria
DryGarden
Data (2009)
Experimental
Average Total Weight (g)
= HH
(Nested ANOVA Models, p < 0.05)
Lythrum salicaria Vigor 2nd Year
• Litter Weight
<
• Stem Weight
<
• Stem Weight
<
• Inflorescence Weight
<
• Inflorescence Weight
<
• Root Weight
• Stem Height
<
<
• Total Plant Weight
<
= LH
= HH
(Nested ANOVA Models, p < 0.05)
• Stem Height
<
Lythrum salicaria Herbivore Defense
• Tannins- defense against specialist herbivores
(Muller-Scharer 2004)
• L. salicaria
leaf dry weight
24% tannins
(Rauha et al., 2000)
Lythrum salicaria Herbivore Defense
• Tannins- defense against specialist herbivores
(Muller-Scharer 2004)
• L. salicaria
leaf dry weight
24% tannins
(Rauha et al., 2000)
= LH
= HH
Tannins (mg/g ( 95%C)
65
60
55
50
45
40
HLH
Significant effect of population type
(Nested ANOVA F= 4.095 p = 0.044)
HHH
Experimental Garden Design
ML 1
ML 2
Wetland 1
Wetland 2
Wetland 3
Wetland 4
Wetland 5
Harvest
1st year
Wetland 6
= LH
= HH
Harvest
2nd year
ML 3
ML 4
ML 5
ML 6
Experimental Garden Design
ML 1
Wetland 1
Wetland 2
Wetland 3
Wetland 4
Wetland 5
Harvest
1st year
Wetland 6
= LH
= HH
Harvest
2nd year
ML 2
ML 3
ML 4
ML 5
ML 6
Lythrum salicaria Herbivore Tolerance
• HH population exhibited compensatory growth
L. salicaria Total Weight (g)
300
AC
C
C
250
AB
200
B
B
150
100
50
0
HLH Alone
= LH
HLH w/Typha
HLH
w/Biocontrol
= HH
(Nested ANOVA Models Tukey HSD, p < 0.05)
HHH Alone
HHH w/Typha
HHH
w/Biocontrol
Lythrum salicaria Herbivore Tolerance
• Herbivory increased HH population reproduction
9
AC
Inflorescence Weight (g)
8
7
C
C
AB
6
B
B
HLH w/Typha
HLH w/Biocontrol
5
4
3
2
1
0
HLH Alone
= LH
= HH
(Nested ANOVA Models Tukey HSD, p < 0.05)
HHH Alone
HHH w/Typha
HHH w/Biocontrol
“Historically Low
Herbivory”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
Evolutionary
divergence in
response to
selective
pressure of
specialist
herbivores?
“Historically High
Herbivory”
?
“Historically Low
Herbivory”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
Evolutionary
divergence in
response to
selective
pressure of
specialist
herbivores?
“Historically High
Herbivory”
“Historically Low
Herbivory”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
Does this
evolutionary
divergence
in plant traits
affect
Galrecuella
behavior?
“Historically High
Herbivory”
“Historically Low
Herbivory”
Invasion from Europe;
release from specialist
herbivores
~200 Years ago
1992
Introduction of
biocontrol agents
How will the
presence of
biocontrol
agents drive
evolution of
L. salicaria in
the future?
“Historically High
Herbivory”
Acknowledgements
Thank you to:
Funding:
Jeannine Cavender-Bares
Will Menzel
Ruth Shaw
Diane Larson Mia Howard
Neil Anderson Steven Lee
Luke Skinner Jennie Sirota
Alyssa Bernardo
Jan Kvet
Dasa Bastlova
Rodrigo Gonzalez Chauvet
Lukas Johnson
Leon & Naomi Quiram
30 construction volunteers
Dayton Wilkie Fellowship Fund
MN-Department of Natural Resources
Carolyn Crosby Fellowship
University of Minnesota Graduate School
MNCenter for Community Genetics
Plant Traits Seminar Small Grants
Rothman Fellowship Fund
Dept. of Ecology, Evolution and Behavior
Dayton Fellowship Fund
Pletcher Graduate Fellowship
Alexander Dubcek Fund
NSF ISG-IGERT Traineeship
Galerucella spp. Choice Trials
• Grew plants from HH & LH
populations
• Collected Galerucella from HH & LH
populations
• Choice tests
Occupancy and behavior
Feeding preference
Egg laying preference
Galerucella spp. choice
Frequency of Occupation
• No preference in
– feeding
– oviposition
Laying
Eggs
0.1%
Mating
9.3%
Eating
12.0%
Still
67.8%
Other
0.4%
Eating
12.8%
Walking
8.1%
18
16
14
12
10
8
6
4
2
0
LH
Low
HH
High
Walking
10.8%
Still
78.8%
(Paired t-test; p= 0.01570, n= 77)
Site Location/Herbivory History
“Historically
Low Herbivory”
“Historically High
Herbivory”
Site Name
Dodge Nature Center
1998
1999
2000
2001
F
D
D
D
Hall's Marsh
D
Pottery Pond
2002
2003
2004
D
C
C
C
D
C
C
2007
D
C
D
A
Winona
B
A
A
A
A
A
A
A
Circle Lake
A
A
A
A
A
A
A
A
Pig's Eye*
D
F
D
D
A
A= widespread >80-100% defoliation of entire
wetland
B= 50-90% defoliation generally widespread
C= damage from insects near release points
D= No damage, few insects, not established
F= No insects or damage present
* The data was collected on a transect that did not run
thought the area of beetle control.
** Locations for HHH and HLH sites taken from DNR
biological control agent release records.
For native sites location was estimated from a Shocart map 215,
ISBN: 978-80-7224-267-2.
A
Invertebrates on Lythrum salicaria
in the US
http://www.flickr.com/groups/lifeontheloosestrife
Minnesota Biocontrol
Purple loosestrife infestation
in Minnesota
Data from: MN DNR
Insect release sites in Minnesota