Things haven’t been great for honeybees lately; colonies around the world have been disappearing due to colony collapse disorder (CCD), an affliction that scientists believe is caused by a combination of factors including harmful neonicotinoid pesticides, malnutrition, and parasitic mites which feed on the bees and can transfer viruses.
If losses of bee populations continue, it could mean serious trouble for the world’s food supply—without bees, the pollination of many plants wouldn’t be possible, and shortages of important crops could ensue.
Thankfully, new research suggests there may finally be some good news for the bees.
Watch: The Death of Bees Explained:
After a Mite Invasion, the Bees Bounced Back:
According to the new study, led by researchers at Okinawa Institute of Science and Technology Graduate University (OIST) in Japan, wild honeybees appear to be capable of rapidly evolving in order to overcome the threat posed by the Varroa destructor mites, which have played such a large role in the decline of both wild and domestic bee populations across the globe.
The researchers studied wild honeybee colonies in near Ithaca, NY in order to see how they had managed to cope with an invasion of varroa mites which occurred there in the 1990’s. Although the mites initially took a significant toll on the population, the bees managed an eventual rebound, and the colonies, today, appear to be healthy and thriving...and more genetically advanced than their ancestors when it comes to dealing with parasitic mites.
“They took a hit, but they recovered,” said Alexander Mikheyev, the lead author of the study, “The population appears to have developed genetic resistance.”
Thanks to museum specimens carefully collected and stored in 1977 by Cornell University professor Tom Seeley, Mikheyev and his team had the rare opportunity to observe specific ways in which natural selection had transformed and strengthened the forest’s honeybees over time. Using a new tool developed by the team specifically to analyze preserved DNA samples, the researchers compared evolutionary changes between the 1977 specimens and new samples taken in 2010 from the same forest.
The differences were striking, signaling that the bee populations had evolved over the course of only a few decades.
Genetic Changes Mean Stronger Defenses:
One of the most notable changes the researchers observed in the genetics of the bees was in a dopamine receptor that is linked to aversion-based learning, suggesting that it’s possible the bees may have learned to brush the mites off of themselves and destroy them before they have a chance to cause any harm.
There were also differences in the development of the bees; the bees of 2010 were much smaller, with a different wing shape than their 1977 predecessors. This indicates a shorter growth cycle, something that could foil the attempts of mites to feed on vulnerable developing larvae.
In addition, the researchers noticed changes in the mitrochondrial DNA of the bees, indicating that there had been a large population reduction, or “genetic bottleneck”, and that only a few queen bees survived the first onslaught of the mites.
Fortunately, the bees managed to come back from the hit and have attained a high level of genetic diversity, due perhaps in part to the integration of escaped domestic queen bees as well as the immigration of African bee species to North America.
Hopefully, keepers of domestic bees will be able to use this new information to breed bees with traits that could help them fend off attacks by invading parasites.
“These findings identify candidate genes that could be used for breeding more resistant bees, such as the dopamine receptor gene,” said Mikheyev. “More importantly, it suggests the importance of maintaining high levels of genetic diversity in domestic bee stocks, which may help overcome future diseases.”
Overall, it seems there is a reason to be optimistic about the survival of the bees, and, in turn, the resilience of nature when left to its own devices.
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