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A North American bat regarded as one of the most voracious insect-eaters in the world faces extinction in parts of the continent within the next 16 years, scientists say.

The little brown myotis bat is one of the most abundant in the US and Canada, but the population is threatened by a fungus that causes a lethal disease known as white-nose syndrome.

The fungus, Geomyces destructans, causes a loss of body fat and disrupts the usual hibernation behaviour of the bats, causing them to wake early and leave their roosts during the daytime. In affected areas up to 99% of bats will die out.

The infection was first discovered four years ago in Albany, New York, but the disease has since spread more than 1,200 kilometres, to bats as far afield as Tennessee and Oklahoma.

“This is one of the worst wildlife crises we’ve faced,” said Winifred Frick, a biologist at the University of California, Santa Cruz and lead author of a paper published in Science today.

Loss of the bats poses a threat to the ecosystem and biodiversity. The animals consume their own body weight in insects each night, including mosquitoes that can transmit human diseases such as West Nile virus.

Frick’s team analysed 30 years of data on bat populations from 22 caves and hibernating sites in five states in north-eastern US. From these, they built a computer model to predict how the populations would vary over the next 100 years. Their most advanced model suggested that the little brown myotis bat would become extinct in the regions by 2026.

Other bats may also be at risk from the fungus. Frick warned that two more species have been infected with the fungus in recent years. These include two federally listed endangered species, the Indiana and Gray bats.

Researchers think the disease may have been introduced to North America by travellers from Europe who carried the fungus on their bodies.

It is unlikely that humans would be harmed by the fungus, since it only grows at temperatures under 20C. But people can carry the disease from one place to another. To minimise the risk, the US Forest Service has ordered some caves to be closed to the public.

“We still need to do much research on the basics of the disease, including research on transmission of the fungus, exactly how and why the bats are dying so readily, and how the fungus interacts with the bats’ immune systems,” Frick said.

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This entry was posted on 星期五, 八月 6th, 2010 at 11:25 上午 and is filed under Global. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.