Think of it as the changing of the guard, if you will. It’s that time of year when the big spring mosquitoes die off, only to be replaced by those pesky little ankle-biters.
“What we’re seeing now is the end of that spring species group,” Edmonton’s resident bug man Mike Jenkins explained. “It’s a big mosquito, often yellowish in colour and it’s often one of the last spring species that we usually see.
“It is a fairly aggressive biter. It prefers to go after large mammals for its blood meal, so that includes humans and they can be out and active in the day, as well as being largely dawn and dusk feeders. So they make their presence known even more than their numbers would overall indicate.”
What Edmontonians are about to experience are the “really stealthy…small, fast little ankle-biters,” Jenkins said. But the good news is, limited rain over the past few weeks has kept the hatching at bay.
“We’re not seeing large numbers of those appearing yet, which we usually do by this time of year,” he explained on Wednesday.
“The rainfall that we had in the last week or so — our crews have been out there and treating it and reducing the numbers. And even where the habitat was forming, it’s also been very dry and the vegetation out there is really thirsty so a lot of that habitat got sucked up almost immediately.”
But, as with the weather, the situation could change. And how much precipitation the city receives – or lack thereof – could change the type of mosquito species that rears its ugly head.
Any additional rain in the area will likely lead to more of the typical summer species, the Aedes vexans, which are the quick ankle-biters, Jenkins said. But a lot of really hot days could lead to a very different situation.
“If we do see lots of really hot days, that could trigger the development of culex tarsalis, which is the species that’s a potential vector for West Nile. But at this point, we’re not at the level that we’re expecting any large numbers of culex tarsalis either.”
West Nile arrived in Edmonton in 2003, according to the City of Edmonton. Since then, the number of cases reported in Alberta has fluctuated rather drastically from a high of 320 cases in 2007 to zero cases in 2011, 2014 and 2015. Last year, there were seven cases of West Nile virus in Alberta.