11 key questions about wasps, answered

A wasp perched on a flower By John A. Anderson/Shutterstock

Don’t move, there’s a wasp! Stay calm and read this: answers to the essential questions about the most notorious nuisance in cottage country.

1. Are there certain environments that are more attractive to wasps for nest-building?

A colony’s dream home is practical: a dry, secluded spot with rain cover, easy access, convenient food sources, and handy escape routes. Like us, these insects are adaptable and opportunistic. Some species build high, with nests hanging in tree branches or below eaves. Others find hollow spots in trees, walls, or attics, or underneath decks. “They love the overhang of an outhouse, where it’s nice and sheltered,” says Rob Currie, the head of the department of entomology at the University of Manitoba. And they aren’t afraid to get creative. “They might start a nest in a birdhouse,” says Matthias Buck, the assistant curator of invertebrate zoology at the Royal Alberta Museum. “If you have an unused barbecue, they might even start a nest in there.”

2. Do wasps nest in the ground?

In spades. Soft ground that makes for easy excavation is ideal; a pre-existing hole, such as an abandoned mouse burrow, is even better. Underground nests are unnerving, and possibly dangerous: it’s easy to stumble on one unawares. Your only clue may be traffic. If you notice wasps coming and going regularly from a certain spot, steer clear. “Vibrations set them off,” says Currie. “Berry picking, brush cutting, clearing deadfall near an underground nest, even hiking, or children and dogs running and playing nearby, can cause nests to get defensive.”

Ouch! What just bit me?

3. Is it true that wasps are attracted to sweet things?

Show us a bowl of berries, a birthday cake, or a root beer on a cottage deck, and we’ll show you one curious wasp—followed by several pals. Mature wasps gather protein meals such as caterpillars, aphids, and flies for larvae, but chiefly seek out sugar-laden diets for themselves. (Tip: if you’ve got fallen or rotting fruit on your property, bury it deep in the compost pile.) Wasps’ weakness for sweets may work in your favour. Lure them to a dish of water and apple juice laced with dish soap: they’ll drown.

4. What’s with those fake nests? Do they really deter wasps?

No. Don’t believe claims that a fake nest—or a puffed up paper bag—hung in a tree in spring will trick a young queen into thinking that territory is taken. “No one in the industry uses those,” says Alan Vaudry, the owner and president of Professional Ecological Services in Victoria. In fact, wasps have no problem getting cozy with the neighbours. Vaudry has removed three or four nests hanging side by side. And Currie has seen nests built so close together that they grow to “envelop each other and become one.”

Cottage Q&A: Help! Ants are nesting on my septic bed!

5. Are there more wasps around because of climate change?

“Most years, when you hit fall, media are calling and asking whether this is the worst wasp year,” says Currie. “But that’s just the time of year when wasp populations are most obvious.” In fact, like that of many insects, wasp populations fluctuate dramatically from year to year. This depends on how many queens successfully overwinter, and whether we have a warm spring (good for colony establishment). That said, some varieties of paper wasps that traditionally prefer southern climes appear to be extending their range farther north. And a warmer, drier climate—which parts of Canada seem headed for—is conducive to larger colonies. “If it’s sunny, clear, and dry, they can be out foraging all the time,” says Bob Anderson, a research scientist in entomology at the Canadian Museum of Nature. “They produce offspring at a really high rate. That would be a potential effect of climate change.”

Scientist Katharine Hayhoe on the effects of climate change at the cottage

6. What’s the difference between a wasp and a hornet?

You say tomato, I say tomahto. I say hornet, you say wasp. It’s not a perfect parallel. But, generally speaking, hornets are simply larger varieties of wasps with a suitably intimidating nickname. There are thousands of wasp species in North America, most of them small solitary or parasitic wasps that we don’t even notice. Only a small percentage of species are social wasps that build large communal nests, such as the common yellow jacket, which loves cottage country as much as we do. Yellow jackets have yellow bodies about 1.5 cm long, with black stripes. What we colloquially call the bald-faced hornet—a plump black creature with a white face that constructs big, round, gorgeous (and terrifying) nests high up in trees—actually, despite its colouring, belongs to the same family as the yellow jacket (Vespidae). We also see paper wasps, which fly with dangling legs and are smaller and more slender. They build smaller nests too and bother less with people. These three types of “social” wasps all chew up wood to make paper for constructing their nests, which they build up layer upon layer as a colony grows. (Some paper wasps leave their nests uncovered, so all the cells are visible.) There are a few introduced true hornets in North America, chiefly the European hornet: still in the wasp family, but belonging to a different genus than its yellow jacket cousins.

7. I found a hanging wasp nest. How do I safely remove it?

Step one: wait till after dark, when the colony is at home and less active. A daytime assault may incite swarming. It could also leave you with a slew of angry, homeless wasps when workers return from foraging. Wear a hat, long sleeves, and long pants. Come armed with an even-tempered assistant, a sturdy garbage bag (or two), and a long-handled pruner. A headlamp with a red light is handy: you’ll see the wasps, but they can’t see the red wavelengths. While one of you cuts the anchoring stalk, the other should hold the bag open around the nest, enclose it, and seal the bag—pronto. Pop the whole thing in the freezer, and be quick about it: wasps can chew their way out. Leave it for at least a week; that way you can be sure the colony is dead. Then the amateur scientist in you is free to cut the nest apart and check out the multi-level condo inside, or just compost it. For underground nests or those hidden away in cavities, you’re best to call in professionals. And if your nest is high in a tree or off the beaten track, consider letting it be. Destroying it won’t guarantee wasp-free happy hour on the dock anyway.

Can you remove a wasps’ nest without killing the wasps?

8. If you’re stung and have a minor reaction, will your next reactions be worse? How do you know that a reaction is severe and from an allergy?

Most people react to insect stings. But pain, swelling, redness, or itching around the stung area is not necessarily a sign of allergy, and not an indication that a future sting will up the ante. Allergies seldom reveal themselves on first exposure, so a mild reaction with a first sting doesn’t rule out anaphylaxis the next time around—nor does it portend it. But if symptoms worsen after several hours, or a person develops hives, a rash, a red flush, breathing difficulties, or tightness in the throat—anything beyond the place where the sting occurred—this qualifies as an allergy, and, next time, the reaction may be worse. “May” is the operative word. James McGorman, an emergency physician at the Peterborough Regional Health Centre, says allergies are species-specific, and reactions may depend on the strength of venom accompanying a sting. “If you’re stung by a yellow jacket once, and the next time by a honeybee, your chances of a reaction are quite different.” Bottom line: when it comes to stings, don’t take anything for granted. Light-headedness, dizziness, swelling in the face or mouth, and wheezing are all signs of a severe reaction that requires prompt medical attention.

9. Why are wasps more aggressive at the end of the summer?

For every picnic-marring sting, there’s a different theory on why, come August, wasps seem like mobs of teenagers, their love of burgers and ice cream epic, their manners appalling. One notion: the queen, busy prepping her “daughters” (next year’s queens), is losing her dominance, leaving workers confused and unruly. Another popular theory, according to Rob Currie, is that by the end of summer, colonies are large, while, at the same time, natural food flower sources may be drying up. “They start foraging more aggressively,” he explains. Bob Anderson, meanwhile, suggests that our experience is simply a product of there being more wasps around. And Antonia Guidotti, an entomology technician at the Royal Ontario Museum, proposes that our characterization of the wasps’ behaviour as aggression is actually a mistake. On the contrary, they’re having a great time. In late summer, she says, workers no longer have to forage for insects to feed larvae because no more workers are being produced. What the workers have now is freedom, a sweet tooth, and critical mass. “The colony has hit peak numbers,” says Guidotti. “And they don’t have to do their job anymore. They’re on vacation.”

10. If you’re being attacked, should you jump in the lake?

“If the lake is your only escape route, by all means,” says Matthias Buck, “jump in the lake. But you don’t have to.” Your aim is to move away—calmly. That means no flailing, which will only aggravate them. Put 50 metres or so between yourself and the nest you’ve disturbed, and, more often than not, they’ll let you be. If you do leap off the dock, you’d do well to take a big breath and kick good and hard before you surface. “I’d certainly want to come up in a different place from where I went down,” cautions Anderson. Above all, avoid panic in the company of a wasp. Especially when it is just the one. It’s likely probing: are you a flower? Some kind of food? Wait it out; it’ll soon fly off to better prospects.

How do I make my garden more pollinator-friendly?

11. What are wasps good for, anyway? I assume it’s something.

When does a pest that destroys other pests cease to be a pest itself? The wasp may well put us to the test in this regard, for these incorrigible, stinging marauders are actually predators that keep insect populations in check and ecosystems balanced. They love soft-bodied caterpillars, aphids, houseflies, and some cottage-country tree pests—all protein sources for larvae. “A full nest might consume 240 flies an hour,” says Currie. “I’ve seen wasps fly around the cabin and pick mosquitoes off the screens like grapes.” Plus, says Scott MacIvor, a post-doctoral researcher with the University of Toronto, Scarborough campus, “wasps are out there collecting all day long. For one larva, a wasp may collect 20 to 30 aphids.” Even in a solitary wasp nest, there may be 20 cells, one larva per cell—arguably 500 aphid meals. Translate that to a communal nest of several hundred wasps. “There’s a really interesting economic argument for why wasps are important,” says MacIvor. Wasps are also pollinators, but in that respect they can’t hold a candle to bees. Bees have fuzzy bodies that pollen loves to cling to; wasps are sleek

This article was originally published in the Fall 2016 issue of Cottage Life.

Featured Video