Transgenic corn decreased total and key storage and lipid transport protein levels in honey bee hemolymph while seed treatment with imidacloprid reduced lipophorin levels

Abstract

Pollen substitutes are currently widely used in apiculture because of a lack of natural forage and an increasing need for bees for pollination services. A major concern in the confection of bee diets is whether specific ingredients, such as GMO grain, or contaminants such as pesticides that are applied to crops, negatively impact bee health. We measured hemolymph protein levels and the lifespan of honey bees fed on diets containing non-hybrid (IAC-Airan), hybrid (AG 7088) or transgenic (AG 8088YG) maize, the seeds of which had been treated with fipronil, imidacloprid or left untreated. Corn from these plantings was harvested, dried and finely ground, and then used for the preparation of corn-based diets. Groups of 100 newly emerged bees were placed in cages, where the diets were offered ad libitum. Honey bee lifespan was similar for all the corn diets, though shorter than for bees fed beebread and longer than for bees fed only honey. Total protein in the hemolymph of bees fed with transgenic maize was 15% lower than in bees fed on non-hybrid maize; lipophorin and vitellogenin, were more reduced, by over 30%. Irrespective of corn variety, imidacloprid resulted in over 25% lower levels of lipophorin compared with the control. Lower storage and transport protein levels would compromise the ability of the bees to rear brood and develop an adequate immune response to pathogen challenge. Consequently, transgenic maize, as well as any maize produced from seed treated with imidacloprid should not be included as ingredients in honey bee diets.