Researchers discover how honey bees are more faithful to flower patches than bumble bees
Washington, US: When it comes to returning to collect additional pollen and nectar, honey bees are more devoted to their flower patches than bumble bees, according to researchers.
The findings of the study were published in Ecosphere.
In all, 76 per cent of honey bees in the research returned to the same lucerne flower area, compared to 47 per cent of eastern bumble bees.
Size does, however, crucial, especially for bumble bees. They were more devoted to larger flower patches, but honey bees did not change their chance of returning to a flower patch based on patch size. The large patches in the research were about 15 by 15 yards in size, with 225 plants planted in each, more than twice as many as the tiny patches, which were approximately 10 by 10 yards in size and included 100 lucerne plants apiece.
To remain faithful to a given spot, an insect or animal must have dependable spatial memory that allow them to navigate complicated environments and return to the same area repeatedly. Both honey and bumble bees have demonstrated this ability to return to previously visited foraging locations, so other species-specific factors must be present to explain the differences in patch fidelity observed between the two species, according to ecologist Johanne Brunet of the ARS Vegetable Crops Research Unit in Madison, Wisconsin, who led the study with postdoctoral associate Fabiana Fragoso.
Differences in patch fidelity could be the result of bumble bees' more explorative foraging behaviour--their willingness to invest individually in foraging, often visiting more than one type of flower per foraging bout--compared to honey bees' more highly developed communication system--the honey bees' well-known waggle dance. Honey bee foragers perform the dance when they return to the hive to share the location of valuable food sources with other foragers; bumble bees do not.
"So higher patch fidelity of honey bees, relative to bumble bees, may reflect a greater aversion to risk, be it in terms of wasting energy and resources or encountering predators," Brunet said.
The better our understanding of the characteristics that drive patch fidelity in important pollinators like honey bees and bumble bees, the better beekeepers, producers and conservation biologists will be able to support pollinators' health as well as uphold the essential agricultural need to have crops pollinated to produce a harvest, Brunet added.
But the implications go far beyond that. For example, the pattern of pollination can have potential impacts on gene flow, the way in which gene pools of two separate populations of the same species mix.
"Bumble bees' lower patch fidelity can translate into higher gene flow among the patches they visit, creating a higher probability for bumble bees to move genes longer distances," Brunet said, adding, "Higher gene flow in plant populations in the natural environment will also tend to homogenize their genetic diversity."
