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Meeting Abstract

77-7    Thermal dependence of species interactions: does temperature effect competitive outcomes between native and invasive Anolis lizards? Rej, J.E*; Gunderson, A.R; Tulane University, New Orleans, LA; Tulane University, New Orleans, LA jrej@tulane.edu

The introduction of invasive species has caused major disturbances to endemic wildlife which often leads to the displacement of native species. Anolis sagrei is a successful invasive species that has led to the displacement of the native A. carolinensis along the US Gulf Coast. However, the factors that contribute to their success remain unclear. Previous studies demonstrated antagonistic behavior between the species, with A. sagrei displaying higher levels of aggression. However, these studies conducted experiments at only one temperature. We examined if relative aggression between the species depends on thermal environment. We predicted A. sagrei would aggressively display more than A. carolinensis at all temperatures; however, the magnitude of difference would be lower in cooler temperatures since A. carolinensis has a higher tolerance for cold temperatures. Two temperature regimes were selected: one representing an average day in the spring and the other representing an average day in the summer. Dyadic interactions were conducted between interspecies pairs in both temperature regimes. As predicted, A. sagrei was more aggressive in both conditions and the difference between the species decreased in the cooler environment. Anolis sagrei contributed to an average of 85% of the total aggression displayed in summer conditions, but that decreased to only 65% in spring conditions. The ability to maintain high levels of aggression in a wide range of thermal conditions potentially contributes to A. sagrei's success as an invasive species.