Measuring the impacts of Roundup Original® on fluctuating asymmetry and mortality in a Neotropical tadpole

Abstract

Amphibian larvae are highly susceptible to contamination, which can lead to lethal and sublethal effects. This impact can be measured by fluctuating asymmetry (FA), which is based on differences between the sides of organisms with bilateral symmetry. We evaluated the effect of acute and chronic exposure to Roundup Original Ò on Physalaemus cuvieri tadpoles. We measured tadpole survival and estimated the LC50 96h . We also evaluated whether a sublethal concentration increases the FA. In acute exposure, survival was reduced and the LC50 was 2.13 mg a.i./l. In chronic exposure, nostril-snout distance and eye width had a significantly higher FA in contaminated tadpoles. The chronic exposure to contaminants could lead to several sublethal effects, which would be used in biomonitoring surveys. Morphological traits affected by contaminants, such as malformations or FA, would be relatively more easily measured from field samples. Because it is cost effective, easy to measure, and can be obtained without tagging or housing field-caught animals, we suggest that FA is a promising marker for monitoring the environmental impacts of contaminants like Roundup. However, additional studies are necessary to understand what additional environmental stressors might impact FA, and how this might alter its utility for use in biomonitoring.

Fluctuating Asymmetry of Human Populations: A Review

“…There is a large literature on the effects of toxins, such as heavy metals, chlorinated hydrocarbons, pesticides, air pollution, and sewage on the developmental stability of plants [139][140][141], invertebrates [142,143], fishes [144,145], amphibians [146], reptiles [147], birds [148], and mammals [149]. These select references represent a small fraction of the literature on environmental toxicology and fluctuating asymmetry.…”

Agropastoral activities increase fluctuating asymmetry in tadpoles of two neotropical anuran species

“…Relationship between habitat loss and increase of FA was reported for Eleutherodactylus antillensis and Eleutherodactylus coqui (Delgado‐Acevedo & Restrepo ), as well as the relationship between increase of anthropogenic disturbance and increase of FA levels in Physalaemus cuvieri (Eisemberg & Bertoluci ). Also using P. cuvieri , Costa and Nomura () observed the increase of FA in tadpoles exposed to Roundup.…”

“…Also, the FA has low operational cost, is easily measured from field samples and can be calculated instantaneously, without housing the specimens (Leung et al . ; Costa & Nomura ).…”

“…; Söderman et al . ; Relyea ; Costa & Nomura ). As this process clearly threatens amphibian species, the high phenotypic plasticity of tadpoles makes them eligible as target organisms to evaluate environmental stress, once we can detect changes in tadpole behaviour, morphology and physiology in response to environmental conditions (Alford ; McDiarmid & Altig ).…”

Ecotoxicological evaluation of Glyphosate use in controlling E. crassipes e Salvinia sp. macrophytes

“…Costa and Nomura (2016), carried out toxicity studies of environments contaminated by a commercial formulation based on glyphosate and verified the decline of native amphibian species populations, which are highly susceptible to glyphosate contamination.…”