The paradox of wing polyphenism in crickets

Wing polyphenisms represent a classic trade-off between investment in reproduction or dispersal. While the analysis of trade-offs known as life history theory explains why this phenomenon occurs, how it occurs at an evolutionary, developmental, or mechanistic level remains unknown. The wing polyphenic sand cricket, Gryllus firmus, exhibits markedly different developmental trajectories based on environmental signals it receives during development. Upon completing nymphal development this species of cricket ecloses with long functional wings, or small non-functional wings. While life history theory predicts that the long wing morph will be favored in poor conditions when stress is high to lead to dispersal, my dissertation work demonstrates a somewhat paradoxical response wherein under extreme stress, such as severe diet limitation or parasite load, the short wing morph is favored. Additionally, we showed the importance of population on the propensity to form a given morph and propose an evolutionary mechanism to explain these observations.