COS 309-4 - Comparison of shell temperature and habitat characteristics of myiasis infected and uninfected Eastern Box Turtles (Terrapene carolina carolina) at Camp Edwards

Abstract: Myiasis occurs when flesh flies deposit larvae into the living tissue of a vertebrate host. Many ectothermic hosts respond to disease or parasite infection by moving to warmer locations to raise their internal body temperature, a phenomenon called ‘behavioral fever’. Behavioral fever may clear the myiasis infection faster because higher body temperatures can increase larval development rates to reduce time spent in the host, exceed the larvae’s critical thermal maximum to induce parasite mortality, or prevent secondary infections. Eastern Box Turtles (Terrapene carolina carolina; abbreviated as EBT) at Camp Edwards (Barnstable, Massachusetts) are infected by myiasis caused by Cistudinomyia cistudinis. It is unclear if myiasis impacts EBT behavior. We investigated if infected turtles utilized habitat differently from uninfected turtles, potentially to perform behavioral fever. Therefore, we compared shell temperatures and habitat characteristics of myiasis infected and uninfected EBT’s at Camp Edwards. We radio-tracked 48 turtles weekly from May to August 2022. We recaptured 40% of the turtles at least seven times, with a median of two captures per individual. Upon capture, we recorded their infection status, shell surface temperature, and capture location habitat characteristics: understory vegetation, basal area, and canopy closure. We used a Generalized Linear Mixed Effects Model to analyze shell temperature differences between infection statuses, sexes, and age cohorts. We used a MANOVA and 2-way ANOVA to analyze habitat characteristics. We found that shell temperature was not significantly different between infection statuses. Certain understory vegetation variables (leaf litter, woody debris, herbaceous vegetation, and shrubs) at capture locations were significantly different between infection statuses. The average percentage of each vegetation variable was lower for infected turtles than uninfected turtles. The total basal area at capture locations were significantly different, where the average value was 40.24 ± 4.75 sq ft/acre for infected animals and 57.07 ± 3.82 sq ft/acre for uninfected animals. The canopy closure percentage at capture locations was significantly different between infection statuses, where the percent canopy closure at a turtle’s capture location was 55.57 ± 5.03 % for infected animals and 66.5 ± 2.84 % for uninfected animals. Our results suggest that turtles with and without myiasis infection are captured in locations with different habitat characteristics. Despite habitat variation, their shell temperatures are similar. These results could provide natural resource managers with information related to EBT habitat use and response to myiasis infection, which could aid species conservation efforts.