[Photo] A wild bee (the bumble bee Bombus vosnesenskii) and a honey bee forage together on a sunflower. Honey bees that interact with wild, native bees are up to five times more efficient in pollinating sunflowers. Credit: Sarah Greenleaf

What do you get when you mix wild bees and honeybees in a sunflower field? Busier bees.

Honeybees, essential for pollinating some crops, are five times more efficient at their job when their wild cousins buzz around them [image], according to a recent study published in the journal Proceedings of the National Academy of Sciences.

Honeybees are good pollinators because there are so many of them, and they live in efficient, cooperative colonies. Certain crops like pumpkins and watermelons depend entirely on animal pollinators like honeybees, which in their quest for nectar and pollen spread pollen from flower to flower.

Fewer bees

U.S. honeybee numbers are dwindling thanks to an alien mite that feeds on the bees and their larvae.

"We don't have the huge numbers of them that we used to," said Sarah Greenleaf, the study's lead author. "There have been years where there weren't enough honeybees to rent" to pollinate some crops.

But Greenleaf's two-year study of the honeybees' pollinating efficiency in sunflower fields found that they visited more flowers when other species of wild bees were present.

One reason was that while looking for mates, male wild bees would go after sterile female honeybees and scare them off to a neighboring flower, making them visit more flowers than they normally would.

"They kind of tackle the honeybees," Greenleaf said, causing a "disruption in their plan of action."

Dive-bombing

Female wild bees also dive bomb the worker honeybees, which Greenleaf attributes to competition for protein-providing pollen.

"If there's another bee on a flower that you want to be on, it makes sense to try to knock that bee off," she said.

According to Greenleaf, farmers could benefit by establishing their fields next to natural habitats, where there tend to be more wild bees, or by planting hedgerows that could provide other sources of nectar for the bees to keep them hanging around.

"If farmers were to do that, I think it could really increase their yield," Greenleaf said.