40.4 Thursday, Jan. 5 Evading invaders: Adaptive significance of a behavioral response LANGKILDE, T*; FREIDENFELDS, N.A.; ROBBINS, T.R.; Penn State University; Penn State University; Penn State University firstname.lastname@example.org
Understanding the mechanisms driving adaptations to survive agonistic interactions, and their function, provides insight into how native species respond to aggressive threats. The introduction of non-native species, which can prey upon and compete with native taxa, provides an opportunity to address this issue. The red imported fire ant, Solenopsis invicta, is an invasive species of global importance. Native fence lizards, Sceloporus undulatus, from populations invaded by fire ants have altered antipredator behavior. We staged encounters between these species both on and off the ant mound (nest) to determine the effectiveness of lizard antipredator behavior for surviving ants through ontogeny. We used field caught and lab-reared lizards from fire ant invaded and uninvaded sites to assess the impact of lifetime and evolutionary exposure to this invasive threat. Scouting fire ants quickly detected lizards placed 0.5-4 m from a fire ant mound within natural lizard habitat (within 13 sec - 12 min). In addition to functioning to removing attacking ants, lizards’ body-twitch and flee behavior prevented fire ant attack. Lizards that behaviorally responded after an initial encounter with a fire ant scout reduced their risk of having additional fire ants recruit to the attack – those that did not respond to ants were quickly attacked which, in nature, would have fatal consequences. Fewer adult lizards responded to fire ants than juveniles, and were recruited to significantly more as a result. Within lifetime selection and/or lifetime exposure to fire ants appears to be driving these behavioral differences.