Comparison of the Sensitivity of Tetragonisca angustula (Apidae‐Meliponini) and Apis mellifera (Apidae‐Apini) to Three Insecticides (Malathion, Imidacloprid, and Fipronil) Used in Costa Rica.

This article focuses on comparing the acute oral toxicity and physiological biomarker responses of three insecticides—malathion, imidacloprid, and fipronil—on the neotropical stingless bee *Tetragonisca angustula* and the honeybee *Apis mellifera*. Malathion, an organophosphate, exhibited the highest toxicity to both species, with *T. angustula* showing greater sensitivity than *A. mellifera*, while fipronil demonstrated similar high toxicity to both species. Imidacloprid, a neonicotinoid, showed the lowest acute toxicity and was better tolerated, especially by *T. angustula*. Biomarker analyses revealed some sublethal effects, such as cholinesterase inhibition by malathion and increased lipid peroxidation by fipronil, but no significant physiological responses overall. The findings highlight species-specific differences in insecticide sensitivity and underscore the need for targeted risk assessments to protect neotropical stingless bees in agricultural landscapes.