Glyphosate impairs learning in aedes aegypti mosquito larvae at field-realistic doses

Abstract

Glyphosate is the most widely used herbicide in the world. Over the past few years, the number of studies revealing deleterious effects of glyphosate on non-target species has been increasing. Here, we studied the impact of glyphosate at field-realistic doses on learning in mosquito larvae (Aedes aegypti). Larvae of A. aegypti live in small bodies of water and perform a stereotyped escape response when a moving object projects its shadow on the water surface. Repeated presentations of an innocuous visual stimulus induce a decrease in response due to habituation, a non-associative form of learning. In this study, different groups of larvae were reared in water containing different concentrations of glyphosate that are commonly found in the field (50 μg l1, 100 μg l1, 210 μg l1 and 2 mg l1). Larvae reared in a glyphosate solution of 2 mg l1 (application dose) could complete their development. However, glyphosate at a concentration of 100 μg l1 impaired habituation. A dose-dependent deleterious effect on learning ability was observed. This protocol opens new avenues to further studies aimed at understanding how glyphosate affects non-target organisms, such as insects. Habituation inmosquito larvae could serve as a parameter for testing the impact of pollutants in the water.