Use este identificador para citar ou linkar para este item: https://locus.ufv.br//handle/123456789/22474
Tipo: Artigo
Título: Lethal and sublethal effects of azadirachtin on the bumblebee Bombus terrestris (Hymenoptera: Apidae)
Autor(es): Barbosa, Wagner Faria
Meyer, Laurens De
Guedes, Raul Narciso C.
Smagghe, Guy
Abstract: Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and sublethal effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L^−1). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L^−1. Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L^−1. Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L^−1. At 3.2 mg L^−1, azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L^−1. Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of sublethal effects. Taking into account that sublethal effects are as important as lethal effects for the development and survival of the colonies of B. terrestris, this study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. The latter agrees with the recent European Food Safety Authority guidelines to assess ‘potentially deleterious’ compounds for sublethal effects on behavior.
Palavras-chave: Bumblebee
Chronic oral exposure
Insect growth regulator
Neem
Repellence effect
Reproduction
Editor: Ecotoxicology
Tipo de Acesso: Springer Science+Business Media New York 2014
URI: http://dx.doi.org/10.1007/s10646-014-1365-9
http://www.locus.ufv.br/handle/123456789/22474
Data do documento: 10-Out-2014
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