Meeting Abstract
Many environmental conditions affect egg survival and hatching timing in amphibians. Variation in temperature and humidity can strongly influence terrestrial and arboreal egg clutch properties and therefore embryo fates. Despite increasingly unpredictable rainfall patterns in the tropics, how changes in egg mass properties due to climate change affect embryo behavior and survival remains poorly studied. We investigated whether gliding treefrog embryos (Agalychnis spurrelli) adaptively shift their hatching timing in response to desiccation risk, at the cost of smaller hatchling size. We raised embryos in more and less humid treatments and determined their hatching timing, level of egg and clutch hydration, and mortality rates. Mean relative humidity in all treatments was > 90%, however a decrease from ~98 to 96% humidity induced premature hatching and hatchlings that were small for their age. Clutches and eggs in these less humid conditions decreased in size over time and a mean humidity of 92% led to egg desiccation and death. Our results suggest that A. spurrelli embryos are extremely dependent on consistent precipitation and particularly vulnerable to climate change. Although we did not directly measure differences in hatchling fitness, our results and previous findings suggest that small, dehydrated A. spurrelli hatchlings would suffer higher mortality rates in the wild, thus creating a trade-off in hatching timing in response to dehydration. These findings add to our understanding of how anuran embryos may respond to predicted climate changes and the fitness consequences they face across life stages.
