WASHINGTON – Wild bumblebees worldwide are in trouble, likely contracting deadly diseases from their commercialized honeybee cousins, a new study shows.
Thats a problem even though bumblebees arent trucked from farm to farm like honeybees. They provide a significant chunk of the worlds pollination of flowers and food, especially greenhouse tomatoes, insect experts said. And the ailments are hurting bumblebees even more, reports a study published Wednesday in the journal Nature.
Wild populations of bumblebees appear to be in significant decline across Europe, North America, South America and also in Asia, said study author Mark Brown of the University of London. He said the study confirms that a key source of the decline was the spillover of parasites and pathogens and disease from managed honeybee hives.
Smaller studies have shown disease going back and forth between the two kinds of bees. Brown said his is the first to look at the problem in a larger, countrywide scale and to include three diseases and parasites.
The study tracked nearly 750 bees in 26 sites in Great Britain. And it also did lab work on captive bees to show disease spread.
What the study shows is that the spillover for bees is turning into (a) boil-over, University of Illinois entomology professor May Berenbaum said.
Study co-author Matthias Furst of the University of London said the teams research does not definitely prove the diseases go from honeybees to bumblebees. But the evidence points heavily in that direction because virus levels and infection rates are higher in the honeybees, he said.
Bumblebees probably pick up diseases when they go to flowers after infected honeybees, Furst said. And sometimes bumblebees invade honeybee hives and steal nectar, getting diseases that way, he added.
Bumblebees can be nearly twice as big as honeybees, can sting multiple times and dont produce surplus honey, like honeybees.
The latest research shows bumblebees are hurt more by disease, Brown said. In general, the average wild bumblebee lives 21 days, but the infected ones live closer to 15 days, he said. And while honeybee hives have tens of thousands of workers and can afford to lose some, bumblebee hives only have hundreds at the most.
Its like Wal-Mart versus a mom-and-pop store, Berenbaum said.
Studies have shown that bumblebees provide $3 billion worth of fruit and flower pollination in the United States, while honeybees are closer to $20 billion, Berenbaum said.
The new study did not look at colony collapse disorder, a mysterious problem affecting North America more than elsewhere.