Washington: The highly promiscuous mating behaviour of queen honey bees holds the key to a healthier bee colony, finds a new study, providing clues to how populations of this important pollinators can be prevented from declining.
Researchers at Wellesley College at Massachusetts in the US found that queen bees' promiscuous behaviour gives rise to a genetically diverse population of workers bees which are benefited from diverse symbiotic microbial communities, less loads of bacteria from pathogenic groups and more bacteria related to helpful probiotic species.
This significantly improves the health of their colonies, the researchers said, adding that the findings can be used to improve the declining number of bees which pollinate over 400 crops worldwide and contribute to about a third of our diet.
"We have never known how healthier bees are generated by genetic diversity, but this study provides strong clues," said Heather Mattila, a honey bee ecologist at Wellesley College and that lead researcher of the study.
"Our findings suggest that genetically diverse honey bees have the advantage of broader microbial communities, which may be key to improving colony health and nutrition -- and to understanding factors that can mitigate honey bee decline."
A deadly disease called Colony Collapse Disorder (CCD) is believed to be the reason behind the rapid decline in honey bee populations. However, researchers have long observed that a high level of genetic diversity within a colony improves the overall health and productivity of the colony.
But how colony members produce this effect was largely unknown. To find out, Mattila and his team compared two groups of honey bee colonies -- one consisted of genetically diverse populations and another with genetically uniform bees.
Using 16S rRNA pyrosequencing -- an advanced molecular technique that had never before been used to study active bacteria in honey bees -- the scientists were able to identify and compare bacteria across the colonies.
The results were astonishing, said the researchers, as they found that diverse colonies had a significantly greater variety of active bacterial species with 1,105 species, while only 781 species were found in uniform colonies.
Furthermore, the researchers found that active bacteria from genetically uniform colonies consisted of 127 per cent more potential pathogens, while diverse colonies had 40 per
cent more potentially beneficial bacteria.
The team made another surprising discovery: four bacteria known to aid in food processing in other animals dominated bacterial communities in colonies, many of which had never been reported in honey bee colonies.
The discoveries are important because honey bees, like humans and other animals, depend on the helpful communities of bacteria that live within their guts.
In honey bees, active bacteria serve a critical function -- they aid in the transformation of pollen collected by worker bees into "bee bread", a nutritious food that can be stored for long periods in colonies and provides honey bees with most of their essential nutrients.
Most researchers believe that poor nutrition has hindered the ability of colonies to defend themselves against health problems, such as CCD.
Mattila, who has been investigating the benefits of genetic diversity in honey bees for seven years, was thrilled by these findings, which were made possible by incorporating
Newton's microbial expertise into the study.
"It is our first insight into a means by which colony health could be improved by diversity. It shows one of the many ways that the function of a honey bee colony is enhanced when a queen mates promiscuously, which is an unusual behavior
for social insects," Mattila said.
First Published: Tuesday, March 13, 2012, 16:13