Wildlife

Domestic honeybee diseases threaten wild bumblebees

Bee populations around the world are in decline, among them many species of wild bumblebees.

New research by the University of Vermont in the US has found that diseases transmitted by domestic honeybees could be to blame for this.

Lead researcher Samantha Alger, an expert beekeeper and researcher in the university’s Department of Plant and Soil Science and Gund Institute for Environment, found that several of the viruses affecting bumblebees had spread from managed bees in apiaries to nearby populations of wild bumblebees.

Her research had shown that this was occurring due to different species of bees sharing flowers during pollination.

Honeybees (Apis mellifera) were at a high risk, due to numerous factors, including land degradation and the use of pesticides, she said.

Native bee populations such as the rusty patched bumblebee (Bombus affinis) were being listed as severely threatened in terms of the Endangered Species Act in the US, as populations had declined by an estimated 90%.

This species had long been a key pollinator of various fruit crops such as cranberries, plums, apples and other agricultural plants.

The research team discovered that two well-known RNA viruses found in honeybees, the deformed wing virus and the black queen cell virus were more prevalent in bumblebees collected less than 300m from commercial beehives.

The study also found that active infections of the deformed wing virus were higher near commercial apiaries, but no deformed wing virus infections were found in the bumblebees collected where foraging honeybees and apiaries were absent.