Promiscuous queen bees produce healthier colonies

Bees have lost the option of reverting to a solitary lifestyle, so the queens aren't risking losing their workers by mating multiple times. Image: Shutterstock

If you’re a queen bee, mating more than once means better genetic diversity and more bacteria.

Many queen bees and other social insects only mate once, producing colonies with little genetic diversity. A new study has shown that bee colonies with more promiscuous queens not only have higher genetic diversity, they are also healthier.

Scientists from Wellesley College in the US have analysed the microscopic life found inside the bees’ guts. The study revealed that genetically diverse populations of worker bees benefited from a greater variety of microbial communities than those with more uniform populations.

“We know that colonies that are genetically diverse are better at fighting infection with pathogens, but have little idea how this effect is created,” honey bee ecologist Dr Heather Mattila says. “Our study provides us with some insight into the means by which enhanced disease resistance could be produced.”

The colonies with high diversity were found to have with 1105 active bacterial species, while only 781 species were found in the genetically uniform populations. The diverse colonies also have 40 per cent more potentially beneficial bacteria — the uniform colonies had 127 per cent more potential pathogens.

The researcher discovered four well-known probiotic bacterial species dominating the bacterial colonies: Succinivibrionaceae, a group of fermenters in animals such as cows; Oenococcus, used by humans to ferment wine; Paralactobacillus, used to ferment food; and Bifidobacterium, found in yoghurt.

Many of these bacterial species hadn’t been reported in bee colonies and the researchers aren’t sure exactly what they are doing there. “We know something about what these bacterial groups do in other environments. Many of them are good at fermentation, which is a critical step for turning pollen that bees collect from flowers into the ‘bee bread’ that bees store as a long-term food source in their colonies, and we know that they can act as probiotics,” Mattila says.

Mating only once and producing a colony with uniform diversity suggests to Mattila that having such a tightly knit family was fundamental to the evolution of sociality; but in a small subset of social insects where workers have lost the option of reverting to a solitary lifestyle, the queens started mating multiply as they weren’t risking of losing workers due to increased genetic diversity and because of the benefits that this diversity brings.

Source: PLoS ONE

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