Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production

TLDR

Neonicotinoid insecticides, introduced in the early 1990s, are widely used worldwide, act on the insect central nervous system, and persist in the environment and plant tissues. The study aims to investigate the mechanisms underlying the controversial links between neonicotinoids and pollinator deaths. Researchers exposed developing bumble‑bee colonies to low levels of imidacloprid and released them to forage naturally, while also testing low‑dose thiamethoxam effects on wild honey‑bee navigation. Imidacloprid exposure reduced colony growth, reproductive success, and queen production, and thiamethoxam exposure markedly decreased foragers’ homing success. The study cites Whitehorn et al.

Abstract

Bad News for Bees Neonicotinoid insecticides were introduced in the early 1990s and have become one of the most widely used crop pesticides in the world. These compounds act on the insect central nervous system, and they have been shown to be persistent in the environment and in plant tissues. Recently, there have been controversial connections made between neonicotinoids and pollinator deaths, but the mechanisms underlying these potential deaths have remained unknown. Whitehorn et al. (p. 351 , published online 29 March) exposed developing colonies of bumble bees to low levels of the neonicotinoid imidacloprid and then released them to forage under natural conditions. Treated colonies displayed reduced colony growth and less reproductive success, and they produced significantly fewer queens to found subsequent generations. Henry et al. (p. 348 , published online 29 March) documented the effects of low-dose, nonlethal intoxication of another widely used neonicotinoid, thiamethoxam, on wild foraging honey bees. Radio-frequency identification tags were used to determine navigation success of treated foragers, which suggested that their homing success was much reduced relative to untreated foragers.