Consequences of morph formation in the wing polyphenic sand cricket, Gryllus firmus

Wing polyphenisms in field crickets (Gryllus sp) represent a classic life history trade-off between investment in reproduction or dispersal. Despite a body of research assessing trade-offs in the adults, little work has been done assessing how these trade-offs play out across adult lifespan; often focusing just on a subcomponent of adulthood. We assessed consequences of morph formation (i.e. trade-offs between wing length and other metrics of adult fitness such as fecundity and longevity) over a long-term experiment in two highly selected lines of Gryllus firmus. Interestingly we found a significant difference in total fecundity between the two morphs but did not in total longevity. Additionally, we found strong evidence the early adult period is the most biologically relevant part of adulthood for both morphs, with female crickets reaching a point in adulthood where they become so bloated with ovary mass that they are no longer able to effectively fly or crawl. This indicates that in natural settings they would likely be preyed upon or otherwise be removed from the breeding population. Through dissection experiments we found that the eggs start to decay within the late-stage female's ovaries indicating even if an individual were able to evade predation, it's contribution to the population's gene pool would be limited. The differences we found between early and late adult traits are best communicated by visual media demonstrating the importance of how we choose to communicate results regarding phenotypic plasticity as entomologists – sometimes a picture really is worth a thousand words.