52.4 Saturday, Jan. 5 On the evolution of ant thermal performance: clues from a Neotropical forest KASPARI, M*; CLAY, NA; YANOVIAK, SP; REVZEN, S; CZEKANSKI-MOIR, J; LUCAS, J; KAY, A; University of Oklahoma; University of Oklahoma; University of Michigan; University of St. Thomas; University of Oklahoma; University of St. Thomas email@example.com
Thermal performance curves quantify the ability of an individual to interact with its environment across a range of temperatures. Thermal performance curves reflect critical thermal minima and maxima, thermal range, and the activity energy (or Q10) of behavior. They have implications for both ecosystem services and the future of biodiversity in a warming world. We report thermal performance of worker tempo for 92 species of ant from the Neotropical forest of Barro Colorado Island Panama. Consistent with the Thermal Adaptation Hypothesis canopy ant populations averaged Thermal ranges that were 7 °C higher than populations from the understory (n=69), brought about by higher Critical Thermal Maxima. Consistent with the Size-Inertia hypothesis, CTmax and CTmin increased and decreased respectively ca. 2.5 °C for every 10-fold increase in body mass; a pattern repeated within dimorphic species. Moreover, a second mechanism adapting canopy ants to the warmer canopy was suggested by the 3.5 °C greater mass-corrected CTmax for canopy populations. Average ambient temperatures are predicted to increase by 5 °C in this Panama forest by 2080, suggesting a pre-adaptation for canopy ants to a warming world. However the temperatures of surfaces, and not open air, are those experienced by tiny cursorial organisms. The number of sunny hours may be a more important, and far less understood, driver of thermal ecology for invertebrates that live on terrestrial surfaces. Finally, the Q10 of activity ultimately arises from the concerted action of enzymes, most of which require metal atoms. We test the Q10-Bioaccumulation hypothesis that posits that species with lower concentrations of these metals have commensurately higher Q10s.