UD researcher launches pollination project
1:28 p.m., March 15, 2011----Next month, Delaware farmers will begin planting cucumbers and watermelon in long, straight rows, just like they've done every spring. But several weeks later, when it's time to pollinate these crops, a number of farmers won't be using honeybees.
Instead, these growers will pollinate a portion of the fields with native bumblebees, under the guidance of University of Delaware researchers. The rest of the fields will continue to be pollinated via the traditional method of honeybees. Strawberries, a perennial crop, also will be pollinated with bumblebees, beginning as early as April.
Yuletide at Winterthur
Why the newfound interest in bumblebees?
A part of the reason is Deborah Delaney, an assistant professor in the Department of Entomology and Wildlife Ecology who joined UD last year. A bee researcher who is known to be just as busy as the insect she studies, Delaney quickly developed four major research projects.
The bumblebee project, a partnership with Gordon Johnson, Cooperative Extension's fruit and vegetable specialist, could have a direct benefit for Delaware farmers, who depend on animal and insect pollinators for about 80 percent of all crops.
“Over the past decade, managed honeybee populations have been in decline due to colony collapse disorder and other factors,” says Delaney. “In response, growers as well as researchers have started to pay a lot of attention to native pollinators, and in particular, to bumblebees.”
Until recently, bumblebees were the best-kept secret of the pollination world. In Delaware, bumblebee research hadn't been conducted since the 1940s. And even though home gardeners have long welcomed bumblebees, they only began to be used in commercial growing in the 1980s.
Kevin Evans, who grows watermelons and pickling cucumbers on 70 acres in Bridgeville, was an “early adopter;” he started using bumblebees for his watermelon crop four years ago.
“I wanted to look into alternative forms of pollination to solve some of our needs,” says Evans. “To my knowledge, only two other growers in the state got into bumblebee pollination when I did.”
In the last few years, it's become easier for growers to obtain bumblebees. They can now order boxes of bumblebees online, just as easily as they arrange to rent honeybees from beekeepers.
However, bumblebee boxes aren't fail proof. (In the wild, bumblebees live in nests in the ground.) Johnson says that some Delaware growers have had problems keeping Bombus impatiens (the species stocked in these boxes) alive and active during a crop's entire bloom period.
Currently, there aren't many management strategies to improve the performance and extend the lifespan of bumblebees. So Delaney, assisted by graduate student Jacquelyn Marchese, will visit participating farmers' fields and test bumble bee units by altering their environments. The duo will measure colony survival and crop productivity. Ultimately, these experiments should help growers develop the best ways to use bumblebee units under varying field conditions and with different crops.
Like any good researcher, Delaney is objective about her research subject. But get her away from her lab and it's clear that Delaney is fond of these black-and-yellow-striped bees (that, alternately, display stripes of orange or red, or are entirely black).
Bumblebees are easy to like. For starters, these fat and fuzzy insects are awesome pollinators.
“The behavior, physiology and morphology of bumblebees make them ideal for the job,” says Delaney. “Their attributes include the speed at which they transfer pollen, their buzz pollination behavior, and their ability to fly in adverse weather for long periods of time.”
Not to mention all that fuzz. In a study involving raspberries, bumblebees picked up more pollen on their thick and furry coats than short-haired honeybees did.
As an added benefit, bumblebees are lousy communicators so they can't distract each other from the job at hand. In contrast, honeybees communicate via a dance that can signal (among other things) where another food source is located. This could be wildflowers next to a farmer's field instead of the watermelon blossoms that need pollinating. But bumblebees don't dance or otherwise communicate with their companions.
Evans is eager to participate in UD bumblebee's research project. “I'm interested in seeing what the Extension office comes up with,” says Evans. “Growers see things happening in the field and we experiment on our own. But Extension has the ability to do the research and help farmers develop the best ways to do things.”
Article by Margo McDonough
Photo courtesy Deborah Delaney