by Bethany M. Dunbar
copyright the Chronicle 4-24-2013
NEWPORT — Home gardeners rely on wild pollinators to help their gardens grow, but one species of bumblebee is in big trouble.
Others have already gone extinct, leaving the remaining species to fill in the gaps.
Larry Clarfeld, an educator for the North Branch Nature Center in Montpelier, studies Vermont’s bumblebees. He told a group at Newport Natural Foods and Montgomery Café on April 10 that while there are still lots of bees, biodiversity of the pollinators has dropped dramatically.
The meeting was part of a master gardener lecture series.
Mr. Clarfeld said there are, in all, 33 species of bumblebees in this country. Of those, there are 19 or 20 in Vermont.
“Why is biodiversity important?” he asked rhetorically. Without it, he added, “We’re making our ecosystem more and more fragile.”
He said each bumblebee species has a different lifestyle and niche. Some have long tongues to reach into deep-throated flowers. Others are active earlier or later in the season. Some are most attracted to one particular flower or do better in warmer or cooler climates. The more types there are, the more chance that various plants will get pollinated.
“Certain types of orchids are only pollinated by bumblebees,” he said.
Bumblebees are not the same as honeybees. He said honeybees can be compared to cows. They are domestic animals, useful to people, but not native to the places where they live now.
Honeybees have suffered recently due to a problem known as colony collapse disorder.
An article in the New York Times on March 28 says colony collapse disorder was first discovered around 2005, and the past year saw 40 to 50 percent losses. The article talked about California almond growers, where honeybees pollinate 800,000 acres, using two-thirds of all the commercial hives.
Mr. Clarfeld said some of the theories about what is causing problems for both wild and domestic bees include pesticide and herbicide use, habitat destruction and climate change, and viruses. Between 1994 and 1996 bees were taken to Europe and brought back, and a disease came with them.
Mr. Clarfeld said researchers really don’t know what is causing all the problems but are starting to try to find out.
“It’s hard to protect and conserve something if you don’t understand it and don’t know where it is,” he said. As it happens, some work had been done in Vermont by author Bernd Heinrich, who wrote a book called Bumblebee Economics in 1979.
New research has started to find and map all the bee species in Vermont, and Mr. Clarfeld decided to help as a volunteer.
So last summer he adopted six areas specified by researchers and systematically looked for bees.
“All my free time was spent chasing around bumblebees,” he said. He would drive around a particular quadrant, stop at a specific location and go catch bees. In most cases he killed the bugs he caught, rinsed them, blow dried them, and pinned and labeled them. The one exception was the species that is so rare, bombus terricola. He did not kill any of that species. Over the course of the summer he caught 700 bees.
“As a result, I saw almost every species of bee,” Mr. Clarfield said. Differences in markings are sometimes so small that it can be difficult to tell what species one is looking at until a precise measurement of jaw length is made, for example.
Bombus terricola, the yellow-banded bumblebee, still exists in Vermont even though it has died out elsewhere.
“It seems to have a stronghold in Vermont,” he said. “Something in Vermont is allowing them to survive.”
“This is a bee that is being proposed to be an endangered species,” he said, along with two or three others.
Bombus terricola can be distinguished from other bumblebees by its black body and wide yellow double band in the middle and two narrow yellow bands at the front and back. Mr. Clarfeld said these are sometimes hard to see on the back.
Gardeners who think they might have a bombus terricola in their garden are asked to take a photo and post it to a website about insects called The Xerces Society for Invetebrate Conservation. www.xerces.org.
Another website with good information is bugguide.net. Mr. Clarfeld said if you can’t figure out what bug you have seen, you can post a photo and a naturalist will identify it for you, sometimes in minutes.
More information about the Vermont bee study can be found at this website:
Gardeners who want to encourage and help bumblebees can plant some of their favorite flowers. Mr. Clarfeld said these include red clover, purple vetch, milkweed and bee balm.
“Pollinators are important, and they’re in trouble,” he said.
contact Bethany M. Dunbar at firstname.lastname@example.org