Sublethal exposure to clothianidin during the larval stage causes long-term impairment of hygienic and foraging behaviours of honey bees

Abstract

Most studies on the effects of neonicotinoid insecticides on neural processes of honey bees are based on behaviours performed by adult bees exposed as adults. It is unclear how the developing brains of honey bee larvae are affected by sublethal doses of neonicotinoid insecticides when measuring neural processes through behavioural performance in adult bees. In this study, larvae were exposed to three sublethal doses of clothianidin and evaluated 25–36 days later for hygienic and foraging behaviours as adult bees. The medium and highest sublethal doses of clothianidin significantly reduced hygienic and foraging activity. The greatest effects were on the proportion of adult bees foraging and carrying pollen. These results show that exposure of larvae to clothianidin results in negative effects extending into the adulthood of bees, possibly compromising the colony’s fitness by impairing pathogen control mechanisms and by reducing pollen collection.