Meeting Abstract
An ectotherm’s ability to acclimate to changes in environmental temperature may provide a buffer from extinction. Acclimation capacity reflects the ability of an individual to alter its critical thermal limits and performance as a function of temperature. Here, we assessed the acclimation capacity for members of the genus Ambystoma, and a cool-adapted relative, Dicamptodon. Because members of these genera may have evolved a capacity to acclimate due to their variation in life history strategies, we hypothesized that obligate paedomorphic species will have little capacity for acclimation, while metamorphic and facultative paedomorphic species will have the highest acclimation capacity. We raised larvae of Ambystoma mexicanum, Dicamptodon ensatus, Ambystoma mavortium, and Ambystoma macrodactylum in our lab under treatments of 15, 18, and 21 °C, which reflect predicted climate change scenarios, and allowed them to acclimate for 4-6 weeks. After a 3-hour cooling period, we measured the thermal preference of each individual in aquatic gradients for two hours. The larvae were then transferred to a second temperature in a block design (15, 18, 21 °C) for 4 weeks of acclimation and we again measured thermal preference. Our results indicate that A. mexicanum, an obligate paedomorph, is unable to adjust its thermal preference with rising temperatures and show little capacity for acclimation (p<.047). Facultative paedomorphs, like A. mavortium and D. ensatus, and metamorphic A. macrodactylum show increasing thermal preference with temperature and show a greater capacity for acclimation. The greater acclimation capacity suggests that these species will not just survive the elevated temperatures expected under climate warming, but maintain normal function, while A. mexicanum will not be able to adjust as successfully.
