Meeting Abstract
To understand what makes an invasive species successful, we must understand the behavioral mechanisms these invaders employ. In this study, we examined traits associated with the “boldness” behavioral syndrome (i.e., aggression, general activity levels, and behavioral flexibility), and the morphology of brain regions associated with those traits. We assessed boldness by conducting a series of four behavioral tests designed to measure aggression towards prey, aggression towards a conspecific, overall activity in an open field test, and flexibility in completing a novel task. We compared these measures in two species pairs: the native green anole (Anolis carolinensis; n = 12) and the invasive Cuban brown anole (Anolis sagrei; n = 15), and the native Texas banded gecko (Coleonyx brevis; n = 4) and the invasive Mediterranean house gecko (Hemidactylus turcicus; n = 8). We found that the brown anole was “bolder” than the green anole in two of the four behavioral tests conducted, but there was no difference between the two gecko species for any of the behavioral tests conducted. In contrast to our predictions, the native green anole had a larger brain-to-body mass ratio (a general indicator of behavioral flexibility) and a larger brain diameter than the invasive brown anole. However, the Mediterranean house gecko had a larger brain-to-body mass ratio than the native Texas banded gecko, consistent with the predicted pattern. Our current work examines cellular morphology in regions of the brain involved in aggression (the amygdala) and exploratory behavior (the hippocampus and hypothalamus) by measuring the neuron size and density in these regions. Together, these results will provide one of the first studies of the relationships between brain and behavior in invasion biology.
