Some lights repel amphibians: implications for improving trap lures for invasive species

Abstract

Traps with baits or other lures are often used to reduce densities of vertebrate pests. Invasive amphibians often feed on insects at lights in urban settings, but it is unclear whether they are attracted to the light itself, the insect food source (which is attracted to the light), or both. Here we examine the attractiveness of four types of lights (incandescent, white fluorescent, yellow fluorescent and ultraviolet) to cane toads (Rhinella marina) in controlled Y-maze experiments, in the absence of insects. In the Y-maze, more cane toads selected darkness over incandescent and white fluorescent lights, indicating these light types repelled toads. In comparison, toads did not distinguish between ultraviolet or yellow fluorescent lights and darkness. We then used field trapping trials to determine the effectiveness of white fluorescent and ultraviolet light for attracting amphibians to traps in the presence of insects. In the field, traps equipped with ultraviolet light trapped significantly more toads than those with white fluorescent lights. Our research indicates that trapping success for amphibians can be significantly improved by using ultraviolet lights as insect attractants. Traps equipped with these lights could help reduce the impact of invasive cane toads, and possibly other invasive amphibians.