Lambda-Cyhalothrin Effect on the Swimming Behavior of Boana pulchella (Anura: Hylidae) Tadpoles.

Abstract

Boana pulchella is an anuran species widely distributed in Neotropical South America and commonly abundant in the Argentine Pampas. The aim of this study was to evaluate the effects of the commonly used insecticide lambda-cyhalothrin on the swimming performance of B. pulchella tadpoles exposed to environmentally relevant concentration in a laboratory bioassay. Mean velocity was measured in two treatments of 1.5 and 10 µg/L and a control, after 2-h and 96-h exposures. The mean speed displacement was estimated using the video analysis software Tracker^®. No mortality was detected. However, tail flexion was observed in all tadpoles in both treatments throughout the entire exposure period, which was not observed in the controls. Swimming velocity was significantly lower in the exposed treatments compared to the control, and lower at the higher concentration exposure. It is concluded that exposure to field-relevant lambda-cyhalothrin concentrations affects the morphology and swimming behavior of B. pulchella, thus influencing its competitive fitness and potentially affecting non-target amphibian assemblages.