Abstract

TRIANA VELASQUEZ, Teófila María; HENAO MUNOZ, Liliana Marcela  and  BERNAL BAUTISTA, Manuel Hernando. Acute Toxicity of the Insecticide Cypermethrin (CYPERMON ^® 20 EC) on Four Species of Colombian Anurans. Acta biol.Colomb. [online]. 2017, vol.22, n.3, pp.340-347. ISSN 0120-548X.  https://doi.org/10.15446/abc.v22n3.62631.

The cypermethrin (CY) insecticide is used in agriculture for the control of pests; however, due to its neurological action can affect non-target organisms such as anurans. The aim of this study was to evaluate the toxicity (median lethal concentration: LC50, and some sublethal effects: developmental delays, swimming performance and total length of larvae) of the insecticide CY (Cypermon® 20EC) exposed during 96 hours to embryos and tadpoles of four anuran species under laboratory and microcosm tests. The embryos of Rhinella humboldti were the most sensitive in laboratory conditions (LC50= 6.27 mg/L) and Boana xerophylla in microcosms (LC50= 88.32 mg/ha), whereas Engystomops pustulosus (laboratory: LC50= 1 1.80 mg/L, microcosms: LC50= 1 12.37 mg/ha) was the most resistant species. Rhinella marina showed an intermediate sensitivity. It was not possible to calculate the tadpole LC50 values due to the high mortality recorded in the experimental concentrations, both in laboratory and microcosms, which were 40 and 122 times lower than the value suggested for the application of the insecticide in field (500 mg/L and 1.52 mg/ha, respectively). On the other hand, it was found a significant decreasing in the total length and swimming performance of the larvae obtained from the embryos exposed to CY, but not in the embryonic developmental time. In conclusion, the exposure to the cypermethrin produced a high tadpole lethality and sublethal effects on developing embryos; therefore, under the recommended concentrations of field exposition, this insecticide is toxic for the study species.

Keywords : amphibians; LC₅₀; pyrethroid; sublethal effects.

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