Meeting Abstract
Maternal behavior and physiology play a large role in the early environment offspring experience. These factors hold the potential to contribute to the development of offspring phenotypes that are closely related to fitness. However, maternal behavior is often difficult to observe and measure in wild animals, particularly small mammals. To tackle this problem, with a wild population of North American red squirrels (Tamiasciurus hudsonicus) we measured maternal motivation by recording the time until mothers return to their pups following researchers replacing the pups, or a “simulated predator intrusion”. This measurement is similar to pup retrieval latencies recorded in laboratory studies. We investigated multiple factors contributing to natural variation in maternal motivation, including the impact of naturally and experimentally elevated glucocorticoids, maternal age, parity status, and amount of food resources. To examine the long-term impact of variation in maternal behavior, we investigated the role of maternal behavior on offspring growth rate and survival. To further explore the impact of the maternal environment on offspring, we test hypotheses about the impact of maternal glucocorticoid levels on offspring behavior and physiology. We provisioned exogenous glucocorticoids to experimentally elevate circulating glucocorticoids in pregnant or lactating mothers. With offspring from these mothers, we conducted behavioral trials to measure personality traits and performed stress hormone challenges to measure HPA axis activity. Through these studies, we expand on our understanding of the impact of variation in maternal behavior and physiology as well as potential fitness consequences in a wild small mammal.
