Ecological genetics of larval and metamorphic traits

1
Ecological genetics of larval and metamorphic
traits
Predicting responses to fluctuating selection
Allison Welch
Department of Biology University of North
Carolina, Chapel Hill
2
Many organisms inhabit variable environments
3
Evolutionary consequences ofvariable environments
fitness
environment 1
4
Evolutionary consequences ofvariable environments
positive genetic correlation
fitness
environment 1
environment 2
5
Evolutionary consequences ofvariable environments
negative genetic correlation
fitness
environment 1
environment 2
6
Amphibian larvae often facevariable environments
7
Amphibian larvae often facevariable environments
Predation
Access to resources
Hydroperiod
Competition
Time of oviposition
8
Do amphibian populations have thegenetic
potential to respond adaptivelyto fluctuating
selection in the larval environment?
9
Measuring genetic correlation between environments
1
4
3
2
1
2
3
environment 1
4
environment 2
10
Experimental design
1
4
3
2
1
2
3
4
(N790)
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Measures of offspring performance
larval period mass at metamorphosis larval
growth rate
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Larval period was genetically correlated across
environments
rg 0.69 p lt 0.01
13
but the relative LP of some genotypes varied
across environments
rg 0.69 p lt 0.01
G x E p lt 0.005
14
Cross-environment genetic correlations for mass
at metamorphosis and larval growth
15
Cross-environment genetic correlations for mass
at metamorphosis and larval growth
0.5
rg 0.68 p lt 0.01
0.45
0.4
Metamorphic mass (g)
0.35
0.015
rg 0.46 p lt 0.01
0.014
0.3
0.013
0.012
0.25
0.011
0.2
Growth rate (g/day)
0.01
high
low
0.009
0.008
Food level
0.007
0.006
0.005
high
low
Food level
and genotype-by-environment interactions
16
Conclusions

• Larval performance traits are genetically
  correlated across environments.
• This population may be able to respond adaptively
  to fluctuating selection in the larval
  environment.
• Selection on these metamorphic traits may deplete
  genetic variation, even in a variable
  environment.

17
Acknowledgements

• Jenny Webber
• Danica Gomes
• David Pfennig
• Bob Podolsky
• SPIRE postdoctoral program NIH