/The blackfly Catch-22

The blackfly Catch-22

By Jim Poling Sr.

One positive aspect of climate change is the theory that it warms our northern reaches making them less hospitable to blackflies, the spring curse of anyone who spends time in or near the woods.
That is something to cheer, and there has been plenty of cheering this spring in parts of Ontario where the hated blackfly has been little seen, or in some cases, totally absent.
It’s true that parts of Ontario normally tormented by blackflies have been spared this year. But climate change is not the reason.

The blackfly season is roughly three to four weeks, starting in early to mid-May and its intensity is dictated by the spring runoff. This past winter saw a lighter than usual snowpack combined with an earlier spring runoff. Less snow melting earlier was not good for blackfly populations.
Blackflies must have plenty of clear, cold running water in the spring to develop their eggs. When the spring runoff is light and ends earlier than normal, blackfly populations have reduced chances of developing.

That’s the opposite story for our other most despised insect – the mosquito. Mosquitoes love puddles or any other places that collect stagnant water. They will even hatch their eggs in a bottle cap filled with old rain water.
There are more than 2,000 species of blackfly, 161 existing in Canada with 42 species identified in the Algonquin Park area. Only a few species in our part of the world actually bite to get a blood meal for their eggs. But their bites are nasty – actual puncture wounds that can cause swelling, headaches, nausea, fever and even swollen lymph nodes.

Fewer blackflies might be reason for many of us to celebrate, but fewer blackflies actually are not good news. Scientists say that a healthy blackfly presence is a sign of a healthy environment.
Clouds of the pests tell us that clear and cold running water is nearby; water filtered by a healthy forested watershed.
Blackflies are making a comeback in parts of North America and their populations are increasing. That’s because of the environmental movement’s pressure for cleanup of polluted areas and creating clean, running water.
Raw sewage, effluents from paper mills, and runoff of various other industrial waste and agricultural chemicals have been stopped or at least controlled because of pressure from environmentalists.

One example is the cleanup of the English-Wabigoon River system in Northwestern Ontario. That system was basically a sewer with mercury poisoning affecting wildlife and poisoning Indigenous communities.
Tens of millions of dollars have been spent cleaning up the river system, although some mercury and other contaminants still exist in the water and will take many more years to eliminate.
There are numerous other stories of water systems being cleaned up and studies have shown blackfly populations are recovering there.

However, some people and some governments still don’t get it. Pesticides mixed with diesel fuel and kerosene are still being dumped into streams to kill the larvae of blackflies and other insects.  
Recovering blackfly populations mean more irritation to we humans. But other animals, and birds, also are affected. Blackflies have been known to kill animals such as deer because hundreds of bites can cause severe blood loss.
They also are known to drive loons from their nests. If you see a nesting loon constantly shaking its head, it likely is trying to shake off a cloud of blackflies.

Birds get their revenge by eating millions of blackflies, and mosquitoes, providing some control of populations. Bats and dragonflies also eat them.
Some areas have noticed an absence of dragonflies this year and that’s not a good thing. Those heli-like critters not only knock down blackfly populations, they provide food for birds and fish.
Dragonflies, like blackflies, require clean water and stable oxygen levels, and are considered reliable indicators of healthy natural ecosystems.

So, the blackfly, like so many things in life, is a genuine Catch-22. Cleaning up environmental pollution increases blackfly populations, which increase human irritations. More pollution decreases their numbers.
All things considered, a little irritation a few weeks a year, is easier to accept than a polluted world.