Frazier is coordinating research on bees and pesticides. So
far, she says, one analysis of pollen that bees had stored in
affected and unaffected hives has been completed, but the work
didn’t point to a culprit. The colonies
with the greatest variety of pesticides at
the highest concentrations “are doing
quite well,” she says.
That doesn’t settle the matter. Frazier
says that she and her colleagues are
designing direct tests of pesticide effects,
for example by exposing caged colonies
to chemicals in monitored quantities.
Some of Evans’ work, too, has touched
on pesticides. He specializes in honeybee genetics, and he’s approaching the
problem by looking at activity in genes
known to kick in when bees encounter
certain stressors. He and his colleagues
are checking bees from affected and
healthy colonies for any heightened
responses by genes known to indicate
exposure to pesticides or pathogens.
As of the end of June, no clear pattern had emerged in either the pesti-cide- or pathogen-related genes. “I keep
looking,” Evans says.
His project and others’, he says, are
hampered by the limitations of the samples. The disorder doesn’t leave heaps of dead bees in the hives. The workers leave and
presumably die far from home. Would the bees still buzzing
around a depleted colony—the majority of bee researchers have
been able to collect for study—still show signs of whatever
afflicted their hive mates? Or would the survivors escape with
no trace of the malady? “I think we would have solved this
months ago if there had been more dead bodies,” says Evans.
Lipkin uses genetics, too, but in a different way. He sequences
genetic material from samples of bees from afflicted colonies
and compares the results with sequences
from healthy ones. The samples contain
genetic material from the bees themselves plus whatever mites, viruses,
fungi, or other creatures were living on
and in the bees’ bodies.
The critical step is in the analysis of
this hodgepodge. Discounting bee DNA
plus any traces of genes from the people
who handled a colony, Lipkin and his
collaborators look for genetic sequences
that show up in sick colonies but not in
healthy ones. Identifying the source of
those sequences could reveal a pathogen.
Starting in March, Lipkin and his epidemiology team have thrown themselves into the search, working with bee
labs. “This has been a huge project,
absolutely huge,” Lipkin says.
After all this work, Lipkin’s tight-lipped about what his analyses have
revealed. He will say, however, that his
lab, with help from others, is closing in
on a suspicious infectious agent.
It probably won’t tell the whole story by itself, he says. Pesticides or some other insult might need to weaken the bees to
make them susceptible to attack by a microbe. He hopes that
the agent his work has tagged might at least become “an excellent marker” for colony collapse. In the end, it may be that what
bee detectives need to catch their villain is a consult from
human epidemiology. ■
USDA—ARS NATHAN RICE
GONE MISSING — A comb from a troubled
bee hive in Georgia shows plenty of the covered
cells where larvae develop but far too few
workers left to tend them.
