Meeting Abstract
Invasive species have altered biotic communities exposing native species to new selective pressures. The consequences of invasive species establishment on native species are variable and include direct evolutionary changes (adaptation, hybridization) and indirect responses (behavioral and trait shifts, competitive exclusion, and extinction). An important invasive insect is the red imported fire ant, Solenopsis invicta; a species that was accidentally introduced into the southern United States in the 1930s from South America that has now expanded its range to cover much of the southeastern USA. Historically it has been difficult to study the impact of fire ants on vertebrate populations generally due to the lack of baseline data. However, some recent work has taken advantage of the well-documented invasion history of this insect and, using a comparative approach, determined that some species appear to be undergoing rapid local adaptation to fire ants in a suite of morphological, physiological, and behavioral traits. Despite demonstration of these comparative patterns, there have been few “controlled” experiments to date that explore the influence of fire ants on vertebrates in natural populations. In this study we take advantage of natural variation in fire ant density on experimental islands to examine the influence of fire ants on hatchling/juvenile lizard mortality, geographic space use, and patterns of natural selection. Increased fire ant density drastically reduces juvenile lizard survival across independent populations and spatially within populations. Due to mortality, fire ant distributions have a significant impact on the spatial distribution of lizards. Finally, fire ants appear to influence the form and magnitude of selection on some phenotypic traits, but not others.
