Acute Artificial Light Diminishes Central Texas Anuran Calling Behavior

Male anuran (frog and toad) advertisement calls associate with fitness and can respond to environmental cues such as rain and air temperature. Moonlight is thought to generally decrease call behaviors - perhaps as a response to increased perceived risk of predation - and this study sought to determine if artificial lighting produces a similar pattern. Using a handheld spotlight, light was experimentally introduced to natural anuran communities in ponds and streams. Custom call surveys where then used to measure anuran calls in paired unlit and lit conditions at six locations in central Texas. Among seven species heard, the number of frogs calling and call index declined in response to the acute light input. Local weather conditions could not explain differences between numbers of frogs calling between species, sites, survey order, or lighting order suggesting the main effect on number calling was light treatment. It appears acute artificial light alone can change calling behavior within several species in natural, mixed species assemblages.