An animal’s phenotype may be shaped by its genes, but also reflects its own environmentand often that of its parents. Nongenetic parental effects are often mediated by steroidhormones, and operate between parents and offspring through mechanisms that are welldescribed in vertebrate and non-vertebrate model systems. However, less is understoodabout the strength and frequency of hormone mediated nongenetic parental effects acrossmore than one generation of descendants, and in nonmodel systems.In Chapter 2, I report that variation in the ecdysteroid hormones (ESH) provided byfemale house crickets (Acheta domesticus) to their eggs can be robustly, replicablymeasured using an Enzyme Immunoassay technique.In Chapter 3, I show that variation in the ESH that female A. domesticus deposit into theireggs determines the early development rates of their offspring. I also show that variationin the active forms of ESH provided by a female house cricket to her eggs derivesprimarily from the quality of nutrition available to her mother and maternal grandmother,regardless of genetic background, age at oviposition, or any contribution of ESH by hermate.In Chapter 4, I uncover a potential mechanism of generating delayed density dependenceby showing that female A. domesticus alter their ESH provisioning strategy in response tosocial density.In Chapter 5, I demonstrate that these effects are not limited to lab-raised species, but arerelevant to and present in at least two species of wild Gryllid (Gryllus veletis and G.pennsylvanicus).In sum, work reported here demonstrates the power of variable hormone provisioning bymothers to their offspring. These findings highlight the importance of distinguishingbetween phenotypic plasticity and genetic effects in observing field and laboratoryorganisms across time and space.
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The Past Is Never Dead, It Isn't Even Past: Maternal Environment Affects Multiple Generations of Offspring via Hormone Provisioning
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