Wild bumblebees worldwide are in trouble,
likely contracting deadly
diseases from their commercialised honeybee cousins, a new study shows.
That's a problem even though bumblebees
aren't trucked from farm to farm like honeybees. They provide a significant
chunk of the world's pollination of flowers and food, especially greenhouse
tomatoes, insect experts said. And the ailments are hurting bumblebees even
more, according to a study published 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.
said his study confirmed that a major source of the decline was "the spillover of parasites
and pathogens and disease" from managed honeybee hives.
Spillover turning into a 'boilover'
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 country-wide scale and include three diseases
and parasites. The study tracked nearly 750 bees in 26 sites throughout 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] boilover," University of Illinois
entomology professor May Berenbaum, who wasn't part of the study, said in an
Study co-author Matthias Furst of the
University of London said the team's 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 don't produce surplus honey, like honeybees.
Bumblebees more vulnerable
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.
"It's like Wal-Mart versus a
mom-and-pop store," Berenbaum said in an interview.
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, which is more of a mysterious problem in North America than
elsewhere. Other diseases and parasites have killed even more honeybees than
the more recent colony collapse disorder.
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