Effects of abamectin and acetamiprid pesticides on the survival and behavior of Scaptotrigona aff. xanthotricha (Apidae, Meliponini)

Abstract

Pesticides have been described as a major cause of bee mortality, and thus are predictors of population decline and decrease in pollination services. Standardized tests with Apis mellifera are already common, and there is a need to create adequate parameters for the native solitary and eusocial species of stingless bees. In this study, we evaluated lethal dosages (LD₅₀ and LD₉₀), lethal time (LT), and sub-lethal effects (SLE) of two pesticides used in soybean crops, abamectin, and acetamiprid, in Scaptotrigona aff. xanthotricha. All tests were performed through contact poisoning. The LD₅₀ and LD₉₀ for acetamiprid were higher than those obtained for abamectin. Survival analysis of S. aff. xanthotricha exposed to LD₉₀ indicated significant differences between pesticides. The LT₅₀ under abamectin (8.25 hours) was significantly lower than acetamiprid (14.25 hours). Considering the PER tests, our results suggest that positive responses to food offerings were reduced by pesticide effects. It was also observed that only the acetamiprid affected the locomotion of the bees. Our results revealed that both pesticides are highly toxic to S. aff. xanthotricha and that acetamiprid was the most toxic for all parameters evaluated.

Keywords:

• stingless bees
• acetamiprid
• abamectin
• neonicotinoid
• avermectin
• proboscis extension reflex
• locomotor activity

Acknowledgements

We are grateful to Msc. João Paulo Soares de Cortes, Dr. Gustavo da Silva Claudiano, Dra. Alanna do Socorro Lima da Silva, Dra. Graciene Conceição dos Santos and Francesca Nicolle Angiolani Larrea from Universidade Federal do Oeste do Pará for helping and supporting us. In addition, to Coordenação de Pessoal de Nível Superior (CAPES) which provides a postdoc fellowship (PNPD) to RF. Dra. Solange Cristina Augusto received research fellowships from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and M.e. Maria Fernanda de Oliveira Ferreira received a fellowship from Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).