Meeting Abstract
The environmental conditions that embryos experience during development can have profound and long-lasting effects on offspring phenotypes. The hydric conditions of the incubation substrate are particularly important for reptiles with parchment-shelled eggs. Although several studies demonstrate that moisture availability positively affects water uptake by eggs and hatchling body size, few studies have mimicked conditions in the field. In this study, we incubated eggs of the brown anole (Anolis sagrei) under four conditions that mimic natural variation in substrate type and moisture. At our study site (islands in a saltwater estuary), eggs have been found in two substrate types (sand/broken shell mixture and dark organic soil) and likely experience a broad range of hydric conditions. To quantify the effects of this environmental variation, we incubated eggs in a 2×2 factorial design using both substrate types at two water potentials (-30 and –600 kPa). By incubating A. sagrei eggs under these different combinations of substrate types and water potentials, our results reveal relatively rapid water uptake and long incubation periods for eggs experiencing moist conditions, particularly for eggs in sand/broken shell substrate. Furthermore, incubation in moist conditions results in larger hatchlings with decreased desiccation tolerance. A subsequent release-recapture study on four islands that vary in their structural and thermal environments revealed that hatchlings incubated under dry conditions perform best, but only on harsh arid islands. Overall, this work demonstrates how natural environmental variation during early life stages can have critical impacts on variation in fitness-related phenotypes and survival of offspring.
