Abstract

Some widely used pesticides, such as neonicotinoids, are known to be extremely toxic for bees and
can, even at sublethal doses, significantly decrease honeybee performance and trigger disorders in
colony dynamics and labour partition. The aim of the present work was to assess the effects of
agricultural pesticides on honeybee survival and physiological stress. A large number of foragers
were tracked during their foraging activity in four different agricultural landscapes. Those landscapes
included three agricultural areas that contained large field crops (corn, cotton, soybean, and
sorghum) and one control treatment with no agriculture. Marked bees were recovered from their
colonies after few weeks and analyzed chemically. Expressions of some detoxification genes were
quantified in the recovered bee brains too. Our results show that recovered foragers contained low
doses of pesticides except those foraging in non-agricultural area. Genetic expression of the studied
genes showed no response to pesticide exposure but rather to the bee ages.