Effects of Metarhizium anisopliae on host choice of the bee-parasitic mite Varroa destructor

Abstract

The ectoparasitic mite Varroa destructor poses one of the biggest threats to the western honeybee Apis mellifera. Possibilities to control the mites are limited; therefore, it is important to assess the performance of novel alternatives like the use of biological control agents. The goal of our work was to evaluate the effects of the entomopathogenic fungus Metarhizium anisopliae var. anisopliae BIPESCO 5, which is a potential biological control agent against the bee parasitic mite V. destructor, on the behavior of the parasite. In detail, we investigated whether the presence of fungal spores on the surface of host nurse bees, A. mellifera, affects the host choice behavior of adult female mites. We conducted two behavioral assays to monitor the behavior of the mites towards adult bees inoculated with a solution of fungal spores. Both choice and no-choice experiment revealed that M. anisopliae has a significant repellent influence on V. destructor‘s host selection behavior. The mites preferred, and stayed longer on, nurse bees free from fungal spores over bees carrying fungal spores. Our study provides the first evidence of sub-lethal behavioral effects of a fungal biocontrol agent against Varroa mites.

Varroa destructor from the Laboratory to the Field: Control, Biocontrol and IPM Perspectives—A Review

“…Italian researchers shed light on sub-lethal behavioural impacts of the fungi (M. anisopliae var. anisopliae BIPESCO 5) on the mite that held a repellent effect from nurses carrying conidia [225]. They led as well a field experiment for 24 days which resulted in lower pressure of the acari, although honeybees losses were detected [226].…”

Mycelial Beehives of HIVEOPOLIS: Designing and Building Therapeutic Inner Nest Environments for Honeybees

“…A targeted approach to therapeutic design problems can be about designing with specific and known medicinal properties of some fungi. Recent research shows that fungus species with antiviral and antibacterial compounds modulating microbial communities that are beneficial to humans can also boost the immune system of honeybees against specific viruses and bacteria when fed to the bees [ 49 , 50 , 51 ]. For embedding such properties in the enclosure material by growing specific fungal strains into hive morphologies the mycelia need to be kept alive during the honeybee colony inhabitation.…”