Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

December 18, 2015
Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees

Parasitic mites Varroa destructor together with the pesticide imidacloprid hamper bees in their search for pollen. The pesticide and the bee parasite reduce the honeybees' flight capacity, causing bee colonies to weaken and possibly even collapse. This was concluded by researchers from Wageningen University & Research Centre in their article in Proceedings of the Royal Society B.

Honeybees fly shorter distances when they originate from colonies with many Varroa mites, the researchers note. The distances they travel are even smaller when those colonies were also exposed to the chemical pesticide imidacloprid in a dose that bees may encounter in the field. The effect of the Varroa was found to be larger than that of imidacloprid, but the pesticide increases the negative effect of the parasite.

Colony losses

The study shows that the ability of the colony to collect food may be hampered due to imidacloprid in combination with the parasitic mite Varroa destructor. When this effect lasts long enough, it may lead to weakening and ultimately collapse of the colony.

The role of the Varroa mite in winter mortality of is well known among beekeepers. A heated debate has been going on for several years already about the role of neonicotinoid pesticides, like imidacloprid. In previous studies on the effects of these pesticides on , often individual bees were exposed to relatively high doses of the pesticide. In this study, however, entire bee colonies were exposed to both the Varroa mite and imidacloprid for several months.

Flight mill

The researchers used foraging bees for the experiment. These were caught when returning to their colony with pollen on their hind legs. From this, the researchers deduced that these bees had fetched pollen at least once successfully. Because 'very sick' bees probably not even become a foraging bee, this means that the researchers rather underestimated than overestimated the impact of the Varroa mite and imidacloprid on individual bees in these colonies.

The flight capacity of the bees was tested in a flight mill. Travelled distance and the speed of the bees were measured. To standardize the flight measurements, the were given a fixed amount of fuel in the form of sugar water beforehand.

Interaction between Varroa destructor and imidacloprid reduces flight capacity of honeybees
Bee in flight mill. Credit: C. van Dooremalen, Wageningen UR

Varroa mites (chesnut) on bees' back. Credit: Cornelissen, Wageningen UR

Explore further: Of bees, mites, and viruses

More information: Lisa J. Blanken et al. Interaction between and imidacloprid reduces flight capacity of honeybees , Proceedings of the Royal Society B: Biological Sciences (2015). DOI: 10.1098/rspb.2015.1738

Related Stories

Of bees, mites, and viruses

August 21, 2014

Honeybee colonies are dying at alarming rates worldwide. A variety of factors have been proposed to explain their decline, but the exact cause—and how bees can be saved—remains unclear. An article published on August ...

Some honeybee colonies adapt in wake of deadly mites

August 10, 2015

A new genetics study of wild honeybees offers clues to how a population has adapted to a mite that has devastated bee colonies worldwide. The findings may aid beekeepers and bee breeders to prevent future honeybee declines.

Parasite-free honey bees enable study of bee health

July 1, 2014

An international team of researchers has discovered honey bee colonies in Newfoundland, Canada, that are free of the invasive parasites that affect honey bees elsewhere in the world. The populations offer a unique opportunity ...

Recommended for you

Mice can smell oxygen

December 2, 2016

The genome of mice harbours more than 1000 odorant receptor genes, which enable them to smell myriad odours in their surroundings. Researchers at the Max Planck Research Unit for Neurogenetics in Frankfurt, the University ...

How single-celled organisms navigate to oxygen

December 2, 2016

A team of researchers has discovered that tiny clusters of single-celled organisms that inhabit the world's oceans and lakes, are capable of navigating their way to oxygen. Writing in e-Life scientists at the University ...

Natural nomads, leatherback turtles opt to stay in place

December 2, 2016

Endangered leatherback sea turtles are known for their open-ocean migratory nature and nomadic foraging habits – traveling thousands of miles. But a Cornell naturalist and his colleagues have discovered an area along the ...

Neural stem cells serve as RNA highways too

December 1, 2016

Duke University scientists have caught the first glimpse of molecules shuttling along a sort of highway running the length of neural stem cells, which are crucial to the development of new neurons.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

BrettC
not rated yet Dec 18, 2015
I wonder if anyone has tried the Bait and trap method for the mites.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.