Honeybees have been a hot topic of research ever since the discovery that they were dying in droves — the U.S. Department of Agriculture says Colony Collapse Disorder has been at least partly responsible for the death of 30% or more of U.S. bee populations every year since 2007. Considering bees contribute about $15 billion worth of pollination work in the U.S., and pollinate at least 400 crop species worldwide, any decline is cause for trouble.
That makes sorting out what makes bees tick a research priority. Heather Mattila (pictured above), a bee ecologist at Wellesley College, and Irene L.G. Newton, a microbiologist at Indiana University, just published research in PLoS One looking at how bee diversity affects overall health. Their team found that more promiscuous queens — ones that mated with multiple males before setting up their colony — produced offspring with a far superior ratio of good to bad bacteria in their stomachs as compared to their single-male counterparts.
The team compared two groups of honeybee colonies. One group was made up of genetically diverse populations, produced by queens that had been inseminated by at least 15 different males. The other group was genetically similar, with each queen only mating with a single male. They found that the diverse colonies contained an average total of 1,105 species of bacteria inside the bees, while the genetically uniform populations were host to an average of 781 bacteria species. Now, that might sound bad for the diverse bees, but it’s not: The diverse populations were host to 40% more beneficial bacteria, while the uniform population had 127% pathogens, despite having fewer bacteria species overall.
Those data have one takeaway: More diverse bee populations were host to more diverse, and more beneficial bacteria populations than their genetically uniform counterparts, which were actually host to more dangerous bacteria. In other words, more diverse bee populations are healthier, especially considering some of the bacteria limited to those populations were the same kind of digestion-aiding species that we humans use as so-called probiotics.
Now, if it seems obvious that more genetic diversity would lead to better health — especially in the single-female colonies of the Hymenoptera — it’s because it is. Researchers have known that fact for quite some time. But the mechanisms have long been opaque. This study sheds some light on the equation, showing that diverse honeybee populations at the very least are more likely to take advantage of probiotic bacteria.
Building a good base of knowledge about bee health is key to developing strategies to protect colonies — and, through that, America’s food supply. While it’s just one piece of the puzzle, this research offers an interesting potential course of therapy for colony collapse: Either potential queens can eat some Activia yogurt, or they can get out there and sleep around.
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