Maternal provisioning interacts with incubation temperature to affect hatchling mercury exposure in an oviparous reptile

Abstract

The thermal environment experienced by developing embryos can influence the utilization of maternally provisioned resources. Despite being particularly consequential for oviparous ectotherms, these dynamics are largely unexplored within ecotoxicological frameworks. Here, we test if incubation temperature interacts with maternally transferred mercury to affect subsequent body burdens and tissue distributions of mercury in hatchling American alligators ( Alligator mississippiensis ). Nine clutches of alligator eggs were collected from a mercury-contaminated reservoir and incubated at either female- or male-promoting temperatures. Total mercury (THg) concentration was measured in egg yolk collected during incubation and in a suite of tissues collected from hatchlings. THg concentrations in residual yolk and blood were higher in hatchlings incubated at cooler, female-promoting temperatures compared to the warmer, male-promoting temperatures. THg concentrations in most tissues were positively correlated with THg concentrations in blood and dermis, and egg yolk THg concentration was the best predictor of THg concentration in many resultant tissues. Our results highlight a hereto unknown role of the developmental environment in mediating tissue specific uptake of contaminants in an oviparous reptile.

Maternal investment and early thermal conditions affect performance and antipredator responses

“…For example, females in poor body condition and with limited access to resources are expected to reduce energy investment into reproduction whereas greater investment is expected when resources are plentiful ( Griesser et al 2017 ; de Zwaan et al 2019 ). Maternal effects can therefore exacerbate, dampen, or counteract negative phenotypic or fitness effects of early-life environments experienced by offspring, and may play an important role in explaining the diversity of phenotypic responses observed within and across species ( Andrews 2018 ; Noble et al 2018 ; Leivesley and Rollinson 2021 ; Johnson et al 2023 ). This might be especially important in the face of climate change.…”