Toxicity and motor changes in Africanized honey bees (Apis mellifera L.) exposed to fipronil and imidacloprid.

Rodrigo Zaluski,Ricardo O Orsi,Thaís S Bovi

doi:10.1590/0001-3765201820150191

Rodrigo Zaluski, Ricardo O Orsi + Show 1 more

Open Access

https://doi.org/10.1590/0001-3765201820150191

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Abstract

This study evaluated the in vitro toxicity and motor activity changes in African-derived adult honey bees (Apis mellifera L.) exposed to lethal or sublethal doses of the insecticides fipronil and imidacloprid. Mortality of bees was assessed to determine the ingestion and contact lethal dose for 24 h using probit analysis. Motor activities in bees exposed to lethal (LD50) and sublethal doses (1/500th of the lethal dose) of both insecticides were evaluated in a behavioral observation box at 1 and 4 h. Ingestion and contact lethal doses of fipronil were 0.2316 ? 0.0626 and 0.0080 ? 0.0021 μg/bee, respectively. Ingestion and contact lethal doses of imidacloprid were 0.1079 ? 0.0375 and 0.0308 ? 0.0218 μg/bee, respectively. Motor function of bees exposed to lethal doses of fipronil and imidacloprid was impaired; exposure to sublethal doses of fipronil but not imidacloprid impaired motor function. The insecticides evaluated in this study were highly toxic to African-derived A. mellifera and caused impaired motor function in these pollinators.

Highlights

Honey bees are very important pollinators of crops and native vegetation, as well as producers of honey and other goods
Bees that received the LD50 of fipronil or imidacloprid by either route took longer to walk through the 50-cm track in motor activity tests than did bees in the control groups at all observation times (Table II)
Bees that received the sublethal dose of fipronil by either route took longer to walk through the 50-cm track in motor activity tests than did bees in the control groups at all observation times

Summary

Introduction

Honey bees are very important pollinators of crops and native vegetation, as well as producers of honey and other goods. Managed bee colonies have suffered considerable losses in recent years, and reduced diversity of native bees has been observed worldwide (Oldroyd 2007, Stokstad 2007, Van Engelsdorp and Meixner 2010). An additional cause of bee colony loss is the syndrome Colony Collapse Disorder (CCD). Colony Collapse Disorder is associated with multiple factors and characterized by rapid losses of worker bees, with few or no dead bees in or near the hives, abandoned brood and stored food, and delayed invasion of hive pests, has caused high colony losses (Oldroyd 2007, Van Engelsdorp et al 2009)

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