IN­FO­GRAPHIC

The race to stop white-nose syn­drome spread­ing among the con­ti­nent’s bats

Canadian Geographic - - CONTENTS - By Brian Banks

As white-nose syn­drome dev­as­tates bat pop­u­la­tions across North Amer­ica, bi­ol­o­gists are ght­ing to nd tac­tics to save them

W “We sort of knew it was com­ing, but it doesn’t pre­pare you for the hor­ror show of an af­fected cave,” says Craig Willis, bi­ol­ogy pro­fes­sor and bat re­searcher at the Uni­ver­sity of Win­nipeg. The “it” is white-nose syn­drome, a dis­ease caused by a fun­gus that grows on the nose, wings and other ex­posed skin of hi­ber­nat­ing bats. The dis­ease de­hy­drates the crea­tures, dis­rupts their tor­por and has up to a 99 per cent mor­tal­ity rate. This past spring, re­searchers from Willis’s lab recorded its first ap­pear­ance in a lit­tle brown bat hi­ber­nac­u­lum in Man­i­toba. “It was a typ­i­cal mass mor­tal­ity event,” he says, “with bats fly­ing out in the snow and car­casses all clus­tered near the en­trance.” The syn­drome was first de­tected in North Amer­ica in New York state in 2006 and has since spread across eastern North Amer­ica, with an ex­pan­sion into Western Canada seem­ingly in­evitable. The es­ti­mated death toll is seven mil­lion, po­ten­tially the most rapid de­cline of wild mam­mals ever. “It’s dev­as­tat­ing,” says Hugh Broders, bi­ol­ogy depart­ment chair at the Uni­ver­sity of Water­loo. But there are grounds for op­ti­mism. Re­searchers have had suc­cess in the lab fight­ing the fun­gus with chem­i­cals and bi­o­log­i­cal agents akin to an­ti­fun­gal viruses or pro­bi­otics. And in Jan­uary 2018, my­col­o­gists at the U.S. Depart­ment of Agri­cul­ture’s For­est Ser­vice re­ported that the fun­gus is eas­ily de­stroyed by ex­po­sure to UV light. Sub­se­quent test­ing on bats has shown promis­ing re­sults. Still, some bi­ol­o­gists think re­cov­ery of af­flicted bats might de­pend on a few in­di­vid­u­als that have sur­vived the on­slaught. Some bats may pos­sess her­i­ta­ble traits that help them make it through the win­ter with the dis­ease. “If they can weather the con­se­quences of be­ing such a small pop­u­la­tion, they may be able to es­tab­lish again,” says Broders. “But it’s go­ing to take a long time.” Lit­tle brown bats (pic­tured) are found in ev­ery prov­ince and ter­ri­tory ex­cept Nu­navut, and as far south as south­ern Mex­ico. The three species most af­flicted by white-nose syn­drome — lit­tle brown, north­ern long eared and tri-coloured — are en­dan­gered in Canada.

In lab tests in early 2018, sim­ple ex­po­sure to UV light was shown to kill more than 99 per cent of the white-nose syn­drome fun­gus. Ex­cit­ing re­sults, but bi­ol­o­gists still have to de­ter­mine if the treat­ment works on in­fected bats and how it might be ap­plied in in­fected hi­ber­nac­ula. One hy­po­thet­i­cal ap­proach is set­ting up mo­tion-ac­ti­vated lights at cave en­trances to ex­pose bats to shots of UV as they pass in and out.

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