Stressful Body Temperatures as a Maternal Effect on Lizard Reproduction

AbstractUnderstanding the relationship between the environment parents experience during reproduction and the environment embryos experience in the nest is essential for determining the intergenerational responses of populations to novel environmental conditions. Thermal stress has become commonplace for organisms inhabiting areas affected by rising temperatures. Exposure to body temperatures that approach, but do not exceed, upper thermal limits often induces adverse effects in organisms, but the propensity for these temperatures to have intergenerational consequences has not been explored in depth. Here, we quantified the effects of thermal stress on the reproductive physiology and development of brown anoles (Anolis sagrei) when thermal stress is experienced by mothers and by eggs during incubation. Mothers exposed to thermal stress produced smaller eggs and smaller offspring with reduced growth rates, while egg stress reduced developmental time and offspring mass. Hatchling survival and growth were negatively affected by thermal stress experienced by mothers but not by thermal stress experienced as eggs. We found mixed evidence for an additive effect of thermal stress on offspring; rather, thermal stress had specific (and most often negative) effects on different components of offspring phenotypes and fitness proxies when experienced either by mothers or by eggs. Stressful body temperatures therefore can function in a similar manner to other types of maternal effects in reptiles; however, this maternal effect has predominantly negative consequences on offspring.