GONZALEZ, T.; HAZARD , L.C.; SINERVO, B.; Univ. of California, Santa Cruz; Univ. of California, Santa Cruz; Univ. of California, Santa Cruz: Maternal effects on predator avoidance behaviors of hatchling side-blotched lizards (Uta stansburiana)

Maternal effects can have profound influences on offspring phenotype and survivorship. Female side blotched lizards (Uta stansburiana) have the ability to regulate clutch and egg size, as well as levels of hormones (e.g. corticosterone and progesterone) in their eggs. In adult Uta, corticosterone and progesterone influence social interactions and degree of aggressiveness. Lizards with higher levels of corticosterone and progesterone are usually more aggressive and aware, making them potentially more likely to avoid predation. Thus, maternal manipulation of hormones and hatchling size may have an effect on hatchling predator avoidance behaviors. In this study, we experimentally elevated levels of progesterone and corticosterone in female Uta and their eggs prior to incubation. We also manipulated the size of some hatchlings via yolk removal or follicle ablation. We then video-taped and evaluated the predator avoidance behaviors exhibited by the hatchlings in response to a simulated snake. We measured the approach distance of the snake and the initial speed and direction in which the hatchling ran. We also measured their maximum sprint speed on a 1.5 meter track. Overall, behavior was highly variable. Approximately 1/3 of the hatchlings did not run until they were touched by the snake, which could indicate use of crypsis for predator avoidance by hatchlings.