The influence of incubation temperature on offspring traits varies across northern and southern populations of the American alligator (Alligator mississippiensis)

Abstract

Maternal provisioning and the developmental environment are fundamental determinants of offspring traits, particularly in oviparous species. However, the extent to which embryonic responses to these factors differ across populations to drive phenotypic variation is not well understood. Here, we examine the contributions of maternal provisioning and incubation temperature to hatchling morphological and metabolic traits across four populations of the American alligator (Alligator mississippiensis), encompassing a large portion of the species' latitudinal range. Our results show that whereas the influence of egg mass is generally consistent across populations, responses to incubation temperature show population‐level variation in several traits, including mass, head length, head width, and residual yolk mass. Additionally, the influence of incubation temperature on developmental rate is greater at northern populations, while the allocation of maternal resources toward fat body mass is greater at southern populations. Overall, our results suggest that responses to incubation temperature, relative to maternal provisioning, are a larger source of interpopulation phenotypic variation and may contribute to the local adaptation of populations.

Potential Implications of Acid-Sensing Ion Channels ASIC2 and ASIC4 in Gonadal Differentiation of Dicentrarchus labrax Subjected to Water Temperature Increase during Gonadal Development

“…Fish are poikilothermic animals (cold-blooded); they show a wide range of temperature tolerance, and their reproductive processes are known to be sensitive to water temperatures [6,7]. The important role of water temperature in sex determination in fish may be due to temperature fluctuations known to occur during embryonic development in extreme environments.…”

“…The European seabass (Dicentrarchus labrax) is a gonochoristic species that does not display secondary sex morphological characters. Furthermore, it exhibits obvious sex-linked growth: it has been observed that females grow faster and reach a larger size than males [7][8][9][10]. Females of this species are observed to be about 30% heavier than the males from 300-400 days after hatching (dph) until over 1000 dph [9].…”