EFFECTS OF INCUBATION-TEMPERATURE ON HATCHLING PINE SNAKES - IMPLICATIONS FOR SURVIVAL

Incubation temperature in ectothermic vertebrates affects incubation p eriods, and in some reptiles it affects sex ratios and behavior. I pre sent evidence that incubation temperature affects emergence and post-h atching behavior of pine snakes (Pituophis melanoleucus) that could in fluence survival in the weeks before hibernation. Hatchlings incubated at low temperatures remained in the nest longer, had Fewer alternate nest openings, and fewer underground tunnels to hide in than did hatch lings from warmer temperatures. These conditions could render hatchlin gs from low-temperature nests more vulnerable to predation because, if a nest is opened, they are not inside tunnels where they would be pro tected. Hatchlings from nests incubated at low temperatures took longe r to find shade during a thermoregulation test, and were less likely t o move about in search of other cover than were those from higher-incu bation-temperature artificial nests. Similarly hatchlings from nests w ith low incubation temperatures were less responsive to a predatory st imulus and had a longer latency to strike than other hatchlings. Taken together. hatchlings from nests with low incubation temperatures migh t be less able to avoid predators and find shade than those from nests incubated at higher temperatures, and thus could be expected to have lower survival in nature.