Caterpillars, yellow jackets numbers spike in hot, dry weather

A dry summer in Edmonton may mean you're more likely be to stung than scratching, according to the city's resident "bug guy."

Biological sciences technician Mike Jenkins says mosquito numbers are way down this year a fact he attributes to lack of precipitation.

"It's been pretty remarkable," he said Monday.

"It's been so dry recently so that hasn't been filling up any of the habitats where the mosquito larvae are developing, so we just haven't had any sort of significant hatchlings since the early spring."

By Jenkins' estimation, there are about 15,000 shallow, temporary pools existing in parkland and farmland just outside of Edmonton that offer the perfect place for mosquito larvae to develop. Once hatched, the adult mosquitoes then migrate into the city, often accumulating in the river and creek valleys which provide easy transit to other areas.

"But without the precipitation, there's nothing that's going to increase that population for us," he said.

According to Jenkins, Edmonton is just heading into what would normally be a spike in the mosquito population, but instead, his mosquito traps indicate numbers are at the lowest rate seen in four years.

At the same time, the hot, dry weather is perfect for caterpillars, yellow jackets and ants, he said.

"We have lots of caterpillars around a greater diversity in caterpillars than I've seen in many years," Jenkins said, listing satin moths, forest tent caterpillars and cankerworm caterpillars as species he's seen out and about.

The exploding caterpillar numbers are also a major food source for the yellowjackets, Jenkins said.

Together, the higher-than-average insect numbers are putting additional stress on trees and vegetation, which are unable to protect themselves and already hurting from lack of water.

However, Jenkins says there's not much the average Edmontonian can do but avoid the dangling caterpillars and picnic-seeking stingers and wait it out.

Because the yellowjackets are helping to control the caterpillar population, he advises nests be removed only when they pose danger to humans.