If you’re one of those people who believes there are more mosquitoes and other insects this summer than in the past, their proliferation might be explained by another creature’s demise: In Maine and elsewhere in the United States and Canada, there are far fewer bats.
John DePue, small mammal biologist with the Department of Inland Fisheries and Wildlife, said many people have been calling to complain “that the insects (have been) just horrendous,” both this year and last, while others report seeing fewer and sometimes no bats at all in barns and attics where they had once colonized in great numbers.
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White-nose syndrome, the common name for a mysterious fungus disease that is afflicting hibernating bats, has been spreading throughout parts of North America for several years and reached Maine only two years ago, but its effects are virtually eradicating little brown bats, among other species.
Ann Froschauer, who leads communication efforts about the disease at the U.S. Fish and Wildlife Service, said the syndrome is caused by a “cold-loving, new-to-science fungus” — geomyces destructans — that thrives in caves and mines, where bats retreat for the winter.
Monitoring and surveillance of bats in three hibernation sites in western and northern Maine have uncovered troubling results. In one affected site, the population of little brown and Northern long-eared bats had fallen 94 percent, DePue said. Pretty much across the board, the number of bats is rapidly declining.
Wildlife biologists find these developments frightening, because bats play a crucial role in balancing the ecosystems of farms, forests, ponds and lakes — and, to a lesser extent, your backyard or attic — by consuming anywhere from 500 to 1,200 insects an hour. The little brown bat, in particular, targets mosquitoes for food, researchers say.
Even though the actual impact of bats on mosquito populations is largely anecdotal and mosquitoes have demonstrated the ability to bounce back from assaults — whether from bats or pesticides — it is impossible to say how much worse the insect pest problem would be without the culling accomplished by bats. Or how the ecological dominoes would fall if whole species were wiped out.
The overwhelming spread of the fungus “is a big deal,” DePue said. “And it’s going to be an even bigger deal” as the ripple effects of taking a predator out of the natural food chain become more obvious.
“For a lot of people, bats are the predator of night-flying insects,” Froschauer said. They are credited with saving the agricultural sector $22 billion a year “in not having to treat (crops) with pesticides.”
PR-wise, however, bats typically suffer from a tarnished image; lots of people loathe them. For those who are reasonably — or irrationally — terrified by bats, a tiny percentage of which can be carriers of rabies, spending money to quell a near-epidemic of the fungus can seem a hard sell. Some people might be indifferent to or even cheer the elimination of millions of bats.
But federal and state biologists care.
This month, the Fish and Wildlife Service announced an allocation of $1.4 million in research grants to deal with the problem. Maine received nearly $25,000, much of which will be spent on education efforts to heighten awareness of the disease and the value of bats.
Some of the research is detective work. Scientists are trying to discern why European bats are able to stave off the disease, why only some species of North American bats are heavily affected and how some survive. Froschauer said studies of European species may offer clues to better understanding the disease and its progression — and if not a cure, then at least an effective treatment.
“It’s scary,” she said. “It’s a race against time certainly.”
Staff Writer North Cairn can be contacted at 791-6345 or at:
ncairn@pressherald.com
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