Abstract
Social environment profoundly influences the fitness of animals, affecting their probability of survival to adulthood, longevity, and reproductive output. The social conditions experienced by parents at the time of reproduction can predict the social environments that offspring will face. Despite clear challenges in predicting future environmental conditions, adaptive maternal effects provide a mechanism of passing environmental information from parent to offspring and are now considered pervasive in natural systems. Maternal effects have been widely studied in vertebrates, especially in the context of social environment, and are often mediated by steroid hormone (SH) deposition to eggs. In insects, although many species dramatically alter phenotype and life‐history traits in response to social density, the mechanisms of these alterations, and the role of hormone deposition by insect mothers into their eggs, remains unknown. In the experiments described here, we assess the effects of social environment on maternal hormone deposition to eggs in house crickets (Acheta domesticus). Specifically, we tested the hypotheses that variable deposition of ecdysteroid hormones (ESH) to eggs is affected by both maternal (a) social density and (b) social composition. We found that while maternal hormone deposition to eggs does not respond to social composition (sex ratio), it does reflect social density; females provision their eggs with higher ESH doses under low‐density conditions. This finding is consistent with the interpretation that variable ESH provisioning is an adaptive maternal response to social environment and congruent with similar patterns of variable maternal provisioning across the tree of life. Moreover, our results confirm that maternal hormone provisioning may mediate delayed density dependence by introducing a time lag in the response of offspring phenotype to population size.
Highlights
Social environment profoundly influences the fitness of animals, affecting their probability of survival to adulthood, longevity, and reproductive output (McCullough, 1999; Nieberding & Holveck, 2017; Siracusa et al, 2017)
We hypothesized that variable deposition of ecdysteroid hormones (ESH) to eggs is an adaptive maternal response to environmental stressors, because in a previous study, we found that female A domesticus appeared to negotiate an ESH provisioning/egg number trade-off differently, based on the quality of diet available to their maternal grandmothers (Crocker & Hunter, 2018)
We found that while the ESH provisioned by mothers to their eggs does not reflect social composition, it does reflect social density
Summary
Social environment profoundly influences the fitness of animals, affecting their probability of survival to adulthood, longevity, and reproductive output (McCullough, 1999; Nieberding & Holveck, 2017; Siracusa et al, 2017). Addressing our first hypothesis, we predicted that in high social density, female crickets would deposit more ESH to their eggs (resulting in larger, faster-growing hatchlings) We made this prediction because there is evidence that in many taxa, parents produce more competitive offspring at higher densities (Benton et al, 2005; Meylan, Miles, & Clobert, 2012), and because development rate in a cannibalistic species may been linked to the level of competition faced during development (Garay, Varga, Gamez, & Cabello, 2016). We predicted that female house crickets reared in a female-skewed environment would deposit more ESH to their eggs (producing larger, faster-growing hatchlings) than would females reared in male-skewed social environments We made this prediction based on the observation that the number of reproductive females in a population is a better predictor of the population size of the subsequent generation than is the number of adult animals in that population. Maternal hormone provisioning of ESH to eggs links maternal social environment to the phenotype of her offspring
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
