Study points to a stinging decline in state’s bumble bee population

  • Scientists found a drastic decline in four bumble bee species, including Bombus terricola. Courtesy of UNH

Monitor staff
Wednesday, December 20, 2017

Close your eyes and picture a bee, any bee.

Chances are, you saw a round little body with black and yellow stripes, rounded wings and an antenna buzzing its industrious way from flower to flower. Maybe you even heard Russian composer Nikolai Rimsky Korsakov’s famous piece in the back of your head.

We’re talking about the bumble bee, of course. And the New Hampshire population is in trouble.

The New Hampshire Agricultural Experiment Station at the University of New Hampshire recently finished the first long-term study of the state’s bumble bee populations. What they found was startling: three of the state’s most important species have experienced drastic population decline and range constriction – where the bees can be found – over the past 150 years, with a fourth bee also in significant decline, according to researchers.

If you think this is old news, you might be thinking of the plight of the honey bee, which has gotten the lion’s share of worry due to its usefulness to the country’s agricultural system and, of course, its honey. But Sandra Rehan, Ph.D, who led the research, said much of that worry is misplaced.

“It’s kind of a blip,” she said of the honey bee’s population decline, noting that the honey bee’s struggles with parasites, pathogens and colony collapse have been mostly a side effect of domestication and over breeding.

That was a problem around 10 years ago, Rehan said. Now, honey bees are making a comeback. In April, the U.S. Department of Agriculture reported that 2.89 million bee colonies existed across the country, an increase of 3 percent compared to April 2016.

Honey bees are an import of European settlers; and thanks to their domestic use, their ailments have spilled over into the wild bee populations, Rehan said, with bumble bees coming into contact with pathogens previously unseen.

There’s a saying for that, Rehan said: “The bees you know about are hurting the ones you don’t.”

“They’re more sensitive than other bees,” she continued. “They act as a canary in a coal mine, because they respond more rapidly to pathogens and pesticides.”

Wild pollinators are also critically important to the global agricultural system. The value of pollination to agriculture is estimated at more than $200 billion a year worldwide. The abundance of and diversity of pollinators are declining in many agricultural landscapes across the United States.

This compounded other factors causing honey and bumble bees alike to struggle, like a shrinking food source, pesticides and climate change. Over time, Rehan said they’ve seen bees species once common in the coastal and southern areas of the state moving north, looking for wild flowers. Some species can now only be found in the White Mountains.

In particular, three of the state’s most important species, Bombus affinis, Bombus fervidus, and Bombus terricola, as well as Bombus vagans, have suffered.

Bombus affinis, or the rusty patch bumble bee, is believed to be locally extinct in the state, with the last specimen collected in 1993, the study found. It was also the first bee listed as an endangered species in the continental United States earlier this year.

Among other species of greatest conservation need, Bombus fervidushas declined by 96 percent over the past 150 years, and Bombus terricola has declined by 71 percent. Bombus vagans has also experienced a significant decline of 42 percent in New Hampshire. The researchers suggest Bombus vagans receive future conservation consideration.

To get the data, Rehan and her team studied 3,333 bumble bee specimens comprised of 16 Bombus species dating back to 1867.

It may be too late to reverse the damage that’s been done, Rehan said. But there are ways we can help. Like mowing our lawns less, and allowing some weeds and wild flower species to grow.

(Caitlin Andrews can be found at 369-3309, candrews@cmonitor.com and on Twitter at @ActualCAndrews.)