Evaluation of the effects of pesticide combinations and Nosema ceranae in the solitary bee Osmia bicornis

Abstract

Despite the greater representation of solitary bees among the diversity of bees, little is known about the effect of biotic and abiotic factors on their populations. Pesticides and pathogens can interact in the environment and contribute to the decline of the bee populations. For solitary bees, exposure to pesticides may be higher than for honeybees, and currently, studies indicate that Nosema ceranae, a honeybee pathogen, may be able to infect the solitary bee Osmia bicornis. This proposal aims to evaluate the effect of the insecticide neonicotinoid acetamiprid and fungicide strobilurin azoxystrobin on the solitary bee O. bicornis and to evaluate the effect of the pesticide's interaction with N. ceranae. For six months, ecotoxicological tests will be performed at the University of Bologna. O. bicornis will be exposed to pesticides and pathogen through food during the adult stage. Survival, histological alterations, and infection levels will be assessed during and at the end of the experiments. The results obtained will be used to compare with the effects observed in the Brazilian solitary bees and contribute to bee conservation and pesticide regulation in Europe and Brazil. Therefore, the present proposal will provide important data to improve the methodology for solitary bees that are being developed in Brazil and fill the knowledge gap on the effects of pesticides and pathogens on O. bicornis.