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Genotype × environment interaction, environmental heterogeneity and the lek paradox
Michael D Greenfield1, R G Danka, J M Gleason
1Institut de recherche sur la biologie de l'insecte, CNRS UMR 7126, Université François Rabelais de Tours, Tours, France. michael.greenfield@univ-tours.fr
Journal of Evolutionary Biology
|January 25, 2012
Summary
Temporal environmental changes, not spatial differences, may resolve the lek paradox in Achroia grisella moths. Genotype by environment interactions create crossover in male song traits, maintaining genetic variance despite female choice.
Area of Science:
- Evolutionary Biology
- Behavioral Ecology
- Genetics
Background:
- The lek paradox describes how male signalling traits persist despite strong female preference, which should reduce genetic variation.
- Genotype by environment interaction (GEI) and reaction norm crossover are proposed solutions, where no single genotype is superior across all conditions.
- Theoretical models suggest spatial or temporal environmental heterogeneity is necessary for crossover to maintain additive genetic variance (V(A)).
Purpose of the Study:
- To investigate the role of GEI and reaction norm crossover in maintaining V(A) for male acoustic traits in the moth Achroia grisella.
- To determine if spatial or temporal environmental heterogeneity drives GEI and crossover in natural populations.
- To test whether crossover incidence differs between populations and across years.
Main Methods:
- Studied Achroia grisella, a species known to exhibit GEI in male song traits.
- Measured male song reaction norms across different environmental conditions in four isolated populations over one year.
- Extended measurements to one population across consecutive years to assess temporal heterogeneity effects.
Main Results:
- Observed reaction norm crossover for male song parameters, confirming GEI.
- Found no increased crossover incidence between genotypes from different spatial populations compared to the same population.
- Detected significantly higher crossover incidence for key song parameters between genotypes from different years than from the same year.
Conclusions:
- Temporal environmental heterogeneity, specifically varying selection pressures across years, may be a key factor in conserving additive genetic variance (V(A)) in Achroia grisella.
- While spatial heterogeneity's role was not strongly supported, temporal variation offers a potential resolution to the lek paradox in this species.
- Further research is needed to explore other contributing factors to the maintenance of genetic variance in male signalling traits.
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