Meeting Abstract

P1-147   -   Light-level dataloggers illuminate seasonal variation in basking behavior in an aquatic turtle species Clifton, IT*; Otten, JG; Refsnider, JM; University of Toledo; University of Toledo; University of Toledo ian.clifton@rockets.utoledo.edu http://www.itclifton.com

Basking is critical for energetic assimilation in ectotherms; however, variation in energetic needs and costs associated with basking should lead to seasonal adjustments in the amount of time individuals spend basking. Northern map turtles (Graptemys geographica), a riverine turtle species widely distributed across the eastern United States, spend most of their lives in the water, emerging only to bask, and in the case of females, nest. We attached light-level dataloggers to the carapace of 10 female and 10 male northern map turtles in late April - early May to measure the amount of time they spent basking throughout their active season. We found that turtles altered the amount of time they spent basking throughout the season in concert with environmental temperatures. Specifically, we found that turtles basked for longer periods of time early in the active season. Turtles continued to bask for long periods of time throughout the day leading up to nesting in early June, after which point the time spent basking dropped precipitously. We hypothesize that turtles spend more time basking early in the active season because underwater activities, such as foraging, are constrained by colder water temperatures, requiring turtles to bask to increase their body temperature. Additionally, females likely spend a large amount of time basking early in the active season to speed up egg development before nesting. As water and air temperatures increase throughout the active season, thermal constraints on underwater activity may decrease while the risk of overheating during basking increases, contributing to the observed seasonal shift in basking behavior. Light-level dataloggers are a reliable, cost-effective means of continuously monitoring basking behavior, and can provide valuable insight into the daily and seasonal activity of secretive aquatic species.