author: Norm Wagenaar
Dragonflies aren’t just beautiful, they eat mosquitoes and are eaten by fish It’s time to get over our annoyance and look at the vital role of insects
BZZZAAAP!......ANOTHER ONE GONE! The neighbour’s purple-death-ray-bug-killing-zap machine carries on its gruesome work just a few metres from your bedroom window, accomplishing what, exactly?
Insects or, in the vernacular, bugs, have a lousy reputation. They’re annoying, they bite and sting, some even carry disease. So we try to kill them, in vast numbers. Wouldn’t it be nice, we ponder, to live in a world without bugs?
The short answer? No!
Much as insects may torment us – and anyone who has ever done a June canoe trip in Algonquin Park and been devoured by mosquitoes and black flies will know torment is a mild word – they are integral to the functioning of our wildly interconnected ecosystem. No insects would mean a lot less life on Earth, and likely no you and no me. And that’s no exaggeration.
Here in central Ontario there’s an innumerable number of insect species. We have something like 4,000 different species of moth; multiply that by all the other insect orders – the dragonflies and damselflies, the mayflies, the grasshoppers, mantises and crickets, the ‘true bugs’ (whose lower lip is modified into a sucking tube), the beetles, the flies and the ants, wasps and bees, and you get some idea of the magnitude. We even have one kind of stick insect, an order much more common in the tropics where, no surprise, there are thousands of different species.
But for all of the thousands of species of insects that inhabit our part of the world there is only a handful of serious biters – mosquitoes, horse flies, deer flies, black flies, bees, wasps and blacklegged ticks, which can carry life-altering Lyme disease. The Prince Edward Point National Wildlife Area here in Watershed country is one of the tick hot spots identified by the Government of Ontario, so keep yourself well-covered when you go and check yourself and your dog before climbing back into your car.
As for the rest, the benefits clearly outweigh the bother of a few bites. We’ve all become aware, and with good reason, of the urgency of maintaining healthy bee populations to pollinate our fruit, vegetable, oilseed and fibre crops. But bees don’t carry the entire load. “A lot of flies are pollinators, wasps are important pollinators,” says Antonia Guidotti, an entomology technician at the Royal Ontario Museum. “People don’t give these insects enough credit.”
Also on the list are some species of ants, beetles, butterflies and moths, although Antonia says butterflies perhaps get too much good press in this regard, lacking the hairs that make bees prime pollinators. The list of good work done by insects continues. Beetles and flies not only contribute to pollination, they’re part of nature’s cleanup crew, recycling dead tissue and animal dung. Other insects provide a service by hunting and eating insects that we, as humans, choose not to like because of their bites or their foraging in our gardens. Dragonflies dine on mosquitoes, ground beetles eat snails, slugs and cutworms, and the always-welcome lady beetle dines on aphids, mites and mealy bugs.
One of the under-celebrated roles played by insects in the ecosystem is as a primary protein source. Insects are eaten by reptiles, birds, mammals and, in watery environments, fish. When we think of insect-eating birds most of us probably name those that do their hunting in graceful flight, such as swallows, warblers, Cedar waxwings and the aptly named flycatcher. But most birds eat insects as some part of their diet and, points out Antonia Guidotti, many species are reliant on catching caterpillars – a protein-packed food source – to feed their young during the nestling stage.
Unfortunately, as detailed in “Songbirds In A Nosedive” (Spring 2017 Watershed), the numbers of many bird species are plummeting due to a list of reasons that’s topped by habitat loss. Guidotti explains that, along with losing places to live, bird species miss out on their insect food sources when meadows and forests are turned into subdivisions and farm wetlands and fencerows are incorporated into ever-larger fields. Insects and plants native to our region co-evolved; when we plant non-native annuals, perennials, shrubs and trees, the inevitable result is fewer insects, fewer birds, less pollination.
Another way to look at the significance of native species is to go back to those songbirds feeding caterpillars to their fledglings. On his Bringing Nature Home website (under “What to Plant?”), University of Delaware professor Doug Tallamy lists the number of caterpillar species supported by native plants. Oaks are the big contributor, hosting 534 different types of moths and butterflies. Black cherries and willows are also significant habitat, each supporting more than 400 species. Among the native herbaceous plants, goldenrod, asters and sunflowers support around 100 species each.
THE TRUTH ABOUT ZAPPERS
You might want to consider taking that chunk of metal to the recycling centre. Research by Doug Tallamy and Timothy Frick, also of the University of Delaware, showed that less than .25% (yes, that’s point 25) of insects trapped and counted in a suburban setting over the course of a summer were ‘biting flies’ such as female mosquitoes and gnats. The largest number, nearly half, were harmless nonbiting aquatic insects from rivers and streams where they’re important fish food.
Bug zappers may be worse than useless. Along with attracting and killing beneficial and harmless species, their ultraviolet lights don’t actually attract mosquitoes, which find their victims through the carbon dioxide we emit. More disconcerting is that the satisfying zap is the sound of an explosion spreading bug bits to all points of the compass, including the direction of your hamburger. A better solution? Try an oscillating fan on your patio. Research conducted by Michigan State University, and reported in the Journal of Medical Entomology, found that fan-generated wind “strongly reduced” the number of mosquito catches in a wetland buzzing with bugs. The mosquitoes were simply not strong enough fliers to beat the artificial headwinds. So this summer, keep cooler and bug-free with a fan, and consider welcoming pollinators to your property with native plants. Check out the North American Native Plant Society for lists of species and other helpful info: nanps.org/