The Toxicity Test of Synthetic Insecticides on Tetragonula laeviceps (Apidae: Meliponini)

Abstract

Intense insecticide application is thought to cause a decline in bee colonies worldwide. Bees are effective pollinators in increasing the production of agricultural commodities. The stingless bee Tetragonula laeviceps (Apidae: Meliponini) is widely cultivated and found around plantations. The insecticides used in the toxicity test were imidacloprid 200 g/L, fipronil 50 g/L, lambda-cyhalothrin 25 g/L, profenofos 500 g/L, and chlorantraniliprole 50 g/L followed by a semi-field test using imidacloprid, fipronil, and profenofos insecticides on the cucumber plant. The LC₅₀ value showed that exposure to imidacloprid, fipronil, and profenofos insecticides caused toxic effects on T. laeviceps by contact and orally. Lambda-cyhalothrin was found harmful on contact exposure, in contrast, chlorantraniliprole was harmful through oral. Classification of insecticide toxicity based on LD₅₀ contact for imidacloprid, fipronil, lambda-cyhalothrin, and profenofos were very toxic and needed a risk assessment. However, chlorantraniliprole was classified as moderately toxic and low risk. In semi-field test results, imidacloprid and fipronil insecticides caused a significant decrease in the leave-return and bee-visiting activity on cucumber flowers. These insecticides also produced a low average yield of fruit weight. Insecticide application can affect the role of T. laeviceps as the pollinator which impacts the production of agricultural commodities.