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.
The researchers genetically analyzed museum samples collected from wild honeybee colonies in 1977 and 2010; the bees came from Cornell University's Arnot Forest. In comparing genomes from the two time periods, the results – published Aug. 6 in Nature Communications – show clear evidence that the wild honeybee colonies experienced a genetic bottleneck - a loss of genetic diversity - when the Varroa destructor mites killed most of the bee colonies. But some colonies survived, allowing the population to rebound.
"The study is a unique and powerful contribution to understanding how honeybees have been impacted by the introduction of Varroa destructor, and how, if left alone, they can evolve resistance to this deadly parasite," said Thomas Seeley, the Horace White Professor in Biology at Cornell and the paper's senior author. Sasha Mikheyev '00 [sic], an assistant professor of ecology and evolution at Okinawa Institute of Science and Technology (OIST) in Japan, is the paper's first author.
More after the break.
"The paper is also a clear demonstration of the importance of museum collections, in this case the Cornell University Insect Collection, and the importance of wild places, such as Cornell's Arnot Forest," Seeley added.
In the 1970s, Seeley surveyed the population of wild colonies of honeybees (Apis mellifera) in Arnot Forest, and found 2.5 colonies per square mile. By the early 1990s, V. destructor mites had spread across the U.S. to New York state and were devastating bee colonies. The mites infest nursery cells in honeybee nests and feed on developing bees while also transferring virulent viruses.
A 2002 survey of Arnot Forest by Seeley revealed the same abundance of bee colonies as in the late 1970s, suggesting that either new colonies from beekeepers' hives had repopulated the area, or that the existing population had undergone strong natural selection and came out with good resistance.
By 2010, advances in DNA technology, used previously to stitch together fragmented DNA from Neanderthal samples, gave Mikheyev, Seeley and colleagues the tools for whole-genome sequencing and comparing museum and modern specimens.
The results revealed a huge loss in diversity of mitochondrial genes, which are passed from one generation to the next only through the female lineage. This shows that the wild population of honeybees experienced a genetic bottleneck. Such bottlenecks arise when few individuals reproduce, reducing the gene pool. "Maybe only four or five queens survived and repopulated the forest," Seeley said.
(Score: 1, Interesting) by Anonymous Coward on Tuesday August 11 2015, @10:32AM
We now know the mites are the culprit for colony collapse?
(Score: 0, Disagree) by Anonymous Coward on Tuesday August 11 2015, @12:49PM
It would seem they are one major contributor but in fact the collapse itself was overreported and overblown. The latest stories have seemed almost unanimous in that the populations are already at completely normal levels again and doing quite well.
(Score: 1, Insightful) by Anonymous Coward on Tuesday August 11 2015, @01:04PM
(Score: 2) by DeathMonkey on Tuesday August 11 2015, @06:42PM
Citation Provided, GP is incorrect. [time.com]
(Score: 5, Informative) by Hartree on Tuesday August 11 2015, @03:41PM
They're a factor in it. They put massive stress on the colonies, and weaken them. It appears that it's a combination of factors, some understood, others not well understood at all.
We do a lot of research on honeybees where I work. Here's a link to an interview in 2013 with Gene Robinson, one of our entomologists: http://illinois.edu/lb/article/72/73513 [illinois.edu]
Another is a bit older, and is more just illustrating the type of work Robinson and our head of entomology, May Berenbaum do: http://news.illinois.edu/news/09/0824colonycollapse.html [illinois.edu]
(Score: 0) by Anonymous Coward on Tuesday August 11 2015, @07:31PM
...illustrating the type of work Robinson and our head of entomology, May Berenbaum ...
Cool, thanks for posting this. May (pardon me, Dr. Berenbaum!) and I were in the same high school, she was class of '71 and I was '72). If you happen to see her, please say "Hello" from Williamsville South. I remember that she was a top science student back then for sure.
(Score: 3, Informative) by Hartree on Tuesday August 11 2015, @08:15PM
She rocks! Every year she coordinates the Insect Fear Film Festival which features all sorts of horror movies that use insects. That's a big draw.
I've not talked to her much, (outside of hello at the snack truck), but everyone who deals with her says she's a very cool person.