Social density, but not sex ratio, drives ecdysteroid hormone provisioning to eggs by female house crickets (Acheta domesticus). Issue 20 (2nd October 2018)

• Record Type: Journal Article
• Authors: Crocker, Katherine C.; Hunter, Mark D.
• Is Part Of: Ecology and evolution. Volume 8:Issue 20(2018)
• Page Start: 10257
• Page End: 10265
• Publication Date: 2018-10-02
• Subjects: density dependence -- hormone provisioning -- maternal effects -- non‐Mendelian parental effects; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.4502
• Languages: English
• ISSNs: 2045-7758

Abstract

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. Abstract : Here we show that female crickets respond to social density in provisioning their eggs with hormones that govern hatchling growth and development. This is the first evidence that we are aware of for hormone provisioning as a mechanism for achieving delayed density dependence in a population.