Toxicidade de inseticidas neonicotinoides sobre abelhas Apis mellifera L. (africanizadas)

Abstract

Honey bees play an important role in both economic and environmental part. However, in recent years there has been observed a decline in the worldwide bee colonies, causing concern among researchers and beekeepers. Exposure to pesticides can cause serious problems for bees and pollination services. Therefore, it is extremely important to determine the toxicity of insecticides, which are used for pest control. The aim of this study was to determine the toxicity of the products (Actara® 250 WG - Thiamethoxam); (Evidence® 700WG - Imidacloprido1); (Orfeu® 200WG - Acetamiprid); (Focus® 500WG - Clothianidin) and (Nuprid® 700WG Imidacloprido2) on Apis mellifera, for it was evaluated some toxicological endpoints, such as lethal time (LT50) topical and oral lethal dose (LD50) topical and lethal concentration (LC50) by intake, and to determine the hazard ratio (HQ). For that bees were exposed to insecticides in different concentrations and mortality data submitted to analysis of survival and logit regression. Independent of all tested insecticides exposure caused the death of 100% of the bees with the TL50, ranging from 0.68 to 3.85h for topical exposure, and exposure for 4.2h at 0.64 with respect to CL50 and DL50, the Thiamethoxam , Imidacloprido1, Acetamiprid, Clothianidin, and Imidacloprido2, presented their values for LD50, 7.5, 38, 57, 131, 10.5 ng / bees and LC50, 5.56, 24.4, 278, 50.8, 6,8 ng.μl-1 . As for the risk coefficient (HQ) all regardless of culture or pest insecticides had a higher HQ to 50, ranging from 157.7 (Acetamiprid used in cotton for control of Aphis gossypii) to 66666.7 (thiamethoxam used in breakfast control Leucoptera coffeella and Dysmicoccus texensis), showing the highest level of danger of these pesticides to bees