Survival Rate of the Neotropical Stingless Bees Nannotrigona perilampoides and Frieseomelitta nigra after Exposure to Five Selected Insecticides, under Controlled Conditions

SIMPLE SUMMARY: In the neotropics, stingless bees co-exist with plant pests in agroecosystems. The use of chemical insecticides used to control sap-sucking insects may pose a risk to the communities of stingless bees. To gain insight into the potential risk of insecticides commonly used for farmers in horticultural crops, we evaluated under laboratory conditions the effects of oral exposure to five insecticides on the survival of two species of stingless bees, Nannotrigona perilampoides and Frieseomelitta nigra. The results showed that some insecticides have a significant negative impact on the survival of stingless bees under laboratory conditions. These results suggest that stingless bees may be negatively affected when foraging flowers of crops that have been treated with insecticides. ABSTRACT: Insecticides used in agricultural pest management pose survival risks to the stingless bees that forage on crops in tropical and subtropical regions. In the present study, we evaluated, under laboratory conditions, the acute oral toxicity of five selected insecticides (dinotefuran, imidacloprid, flupyradifurone, spirotetramat, and cyantraniliprole) to two species of neotropical stingless bees: Nannotrigona perilampoides and Frieseomelitta nigra. At field recommended doses, dinotefuran, imidacloprid, and flupyradifurone caused the highest mortality in both bee species. These insecticides also caused the largest decrease in the survival rate when exposed to a 10-fold dilution of the field recommended doses. Notably, dinotefuran exerted a high effect even at 100-fold dilution (100% mortality). In contrast, cyantraniliprole had a low effect and spirotetramat was virtually nontoxic. These results suggest that some insecticides used to control sap-sucking insects may have a significant negative impact on the communities of stingless bees.