Bryan Cobus looks at an adult mosquito in the laboratory as the West Nile Virus program of the Middlesex-London Health Unit kicked off in Strathroy, May 10, 2007.
Why so many bugs?
June 30, 2008
Living Reporter
Itchy, itchy.
If you were camping or cottaging in Ontario last weekend, you're probably scratching as you read this, and possibly even cursing those nasty bugs who recently brunched on your bum.
Reports from cottage country say the black flies and mosquitoes are more populous this year.
Scratchy, scratchy.
So everybody's talking about the pest plague around the campfire, and there's lots of speculation about why biting bugs seem to be multiplying at unnatural rates.
Is it just the wet weather? Or could it be related to the recent collapse of bat populations in North America? Since bats eat bugs, it would make sense that Whitenose Syndrome, which has killed hundreds of thousands of bats in the last two years, could be the real cause of the bug boom.
We called in the experts:
ENTOMOLOGIST – Doug Currie, curator of entomology, Royal Ontario Museum and associate professor, department of ecology and evolutionary biology, University of Toronto.
BUGS
- "I do hear some people with cottages commenting that black flies and mosquitoes are worse this year. I have to take the word of people who have cottages. That doesn't constitute scientific proof, but there is no one that I know of monitoring populations of insects in Ontario.
WEATHER
- "Mosquitoes, by sheer numbers, survive quite well. If they have ups and downs, it's because of breeding habitats. First and foremost, they like wet conditions because that produces their breeding habitat, which is standing water.
- "In the case of black flies, they like running water for breeding. They're very dependent on snowmelt. We had a lot of snow last winter, so it's not particularly surprising that black flies would be numerous this spring."
BATS
- "I would be skeptical about the argument that a decrease in the number of bats would affect mosquito populations. Local breeding conditions are going to have a much bigger impact. Bats don't just eat mosquitoes, they eat everything, so it would strain credulity to say that increases in mosquitoes would have anything to do with bats."
CLIMATOLOGIST – David Phillips, senior climatologist, Environment Canada.
WEATHER
- "The winter was one of the snowiest on record. Up in Muskoka they had 60 per cent more snow than they normally get. March and April were wetter than normal, too. There was 23 per cent more precipitation in the Muskoka area. May and June was precipitation non-stop, 28 per cent more in the Muskokas. The temperatures were up in June, too, and there has been a lot of cloud, with light winds."
BUGS
- "People have been complaining about the lack of summer-like weather, but the bugs aren't complaining. You couldn't have ordered better weather for them. It's a banner year for black flies and mosquitoes. They like it wet. Running water for black flies and standing water for mosquitoes. This year, because of the snowmelt, you had both. My sense is that you had the ideal conditions in June for insects. These critters like the overcast."
- "If we warm up – and I think it will be warmer than usual – I think people will be dealing with these pesky critters for the rest of the summer.
"The mosquitoes like it warm, and the standing water is there. The black fly season may be almost over, but it's the perfect scenario for mosquitoes."
BAT BIOLOGIST – Rob Mies, director of the Michigan-based Organization for Bat Conservation.
BATS
- "Whitenose Syndrome was first reported in 2007. We know bats have died in New York, Vermont, Massachusetts, Connecticut and possibly Pennsylvania. In New York, estimates are that possibly 90 per cent of bats have perished over the last two years. A bunch of those bats would go to Canada for the summer. But we don't know exactly how many."
- "We don't know much, but what we think is that the Whitenose fungus, which doesn't always occur on the nose, is a symptom and not the cause of death. There is still the possibility that there is a fungus or bacteria that's killing the bats, but many researchers are concerned about more complicated issues. What we're finding is bats that are emaciated. That's the cause of death – starvation. They're not putting on enough body fat to make it through the winter. Researchers are looking into it internationally."
BUGS
- "Less bats means they're eating less insects ... but the most important insects for bats are moths and beetles. They do eat mosquitoes, but they don't specialize. In the past there's been a lot of talk that bats eat mosquitoes, and people started to think that's all they eat. They just eat some. They also eat moths, beetles, gnats, flies and spiders."