Meeting Abstract
Invasive species are a leading cause of global amphibian declines. In many cases, how invasive species negatively impact native amphibians is well established, but in other cases these processes remain enigmatic. For example, the introduction of Cuban treefrogs, Osteopilus septentrionalis, in the southeastern United States is linked to the decline of native green treefrogs, Hyla cinerea, but there is little evidence that predation, competitive exclusion, or transmission of pathogens are contributing factors. Here we examine how reproductive interference and endocrine stress potentially contribute to the negative impacts of invasive Cuban treefrogs on native green treefrogs. We hypothesize that reproductive interference plays a central role in the decline of native green treefrogs following Cuban treefrog invasions because the acoustic communication systems of these species overlap in a way that is predicted to stimulate chronic elevations in circulating glucocorticoids in green treefrogs. For example, male Cuban treefrogs produce advertisement calls possessing similar spectral and temporal features as the aggressive calls of male green treefrogs. Male green treefrogs produce aggressive calls during intraspecific vocal contests and hearing these calls stimulates the production of corticosterone (CORT) in vocal contest losers, which suppresses reproductive behavior. We will present preliminary data from vocal playback experiments examining how the acoustic courtship signals of Cuban treefrogs affect the endocrine physiology of native green treefrogs.
