Big wasps

By Shauna Dobbie

Yikes! What’s that?

As a gardener, you thought you’d seen everything, but suddenly, you’re looking at a huge flying creature you swear you’ve never seen before.

It could be a wasp, but don’t worry; it probably doesn’t sting. Here is a selection of the biggest wasps in Canada to help you identify that thing that gave you a heart attack.

Asian giant hornet (Vespa mandarinia). The stuff of which nightmares are made. Well, along with media reports of “murder hornets”. The Asian giant hornets are far more likely to murder honeybees than people.

Queens can be 2 inches long and workers tend to be around 1.5 inches. The stinger alone can be a full ¼ inch long, four times as long as a honeybee stinger. They prefer forests or green spaces to live in, and in the past, they were found only in Asia.

For the last three summers, they’ve been found in the Vancouver area. Canadian and American authorities have been doing their best to eradicate them. If the insects get a foothold in North America, they could decimate honeybee populations. One hornet can decapitate 40 honeybees per minute by biting their heads off.

Asian giant hornets can kill a person who is not allergic, but at least 30 stings are usually required. In Canada, the hornet hasn’t been found outside the Lower Mainland of BC.

Cicada killer (Sphecius speciosus). A kind of yellow and black wasp found only in the southern fringes of Eastern Canada, the cicada killer is often mistaken for a murder hornet because of its size of up to 2 inches. It isn’t interested in humans though; its target is cicadas. The female brings a cicada back to her nest and lays an egg on it. When the egg hatches, the larva eats the cicada.

Cicada killers have stingers and can sting you, but they probably won’t.

The “killer hornet” got its name for killing honeybees, not humans.

Mud dauber preparing a ball of mud to grasp for flight.

Giant ichneumon wasps (Megarhyssa). There are a few species of these across Canada, but most have a body about 1.5 inches long with an alarming-looking spike of 2 inches or longer coming out the back of the females. People get upset upon seeing this because they think it’s a stinger. It isn’t, it’s an ovipositor—an egg-layer.

Ichneumon wasps lay eggs onto or into other living insects or caterpillars; when the eggs hatch, they eat their host.

Once you understand that the giant ichneumon wasp can’t hurt you, it’s fascinating to watch one flit from flower to flower, sipping nectar.

Black and yellow mud dauber (Sceliphron caementarium). This wasp is incredible to watch for how it builds homes for its eggs: they gather mud to form the structures. Each egg gets a pretty big room because it is otherwise stuffed with live spiders, paralysed by a sting from mama mud dauber. An egg hatches, eats some spiders, then pupates in the muddy home. Eventually, out comes an adult.

A pelecinid wasp with her giant, jointed abdomen.

A giant ichneumon wasp. They come in various colours.

An eastern cicada killer lugging its prey back to the nest.

You’ll recognize this insect by its very long waist. The entire insect is about an inch long. This one is not aggressive, but the female can sting people who are persistently bugging her. You cannot see her stinger in most pictures because it is so short, but it is there. Follow the QR code for a picture.

In addition to the black and yellow, some are all-black and others, dark metallic blue.

Pelecinid wasp (Pelecinus polyturator). One more parasitic wasp in our giants list. This one is so strange looking, it absolutely must make the list. The female of the species is shiny black with a long, skinny, jointed abdomen that is about five times the length of the rest of her body. The male, well, you hardly ever see them here because the female can reproduce without the male. Really!

The jointed abdomen is for forcing into the ground to lay eggs on the grubs of June beetles. There is no stinger.

Paper wasps, hornets and yellowjackets

These are the social wasps that have stingers. They all have queens, drones and workers, and tend to the larvae in a hive, some above the ground, some below. A few aren’t too concerned about you, but a couple, particularly hornets and yellowjackets, seek you out if you have given offence to them by swatting them away. Studies show that one can remember your face, so act accordingly!

These are the ones that become ubiquitous in the late summer as they search for food in the dying days of their hives, while the flowers are fading. They are omnivorous, looking for sweet nectar from flowers and protein from insects and, as it may happen, the steak you are eating.

Try pointing a fan at the patio table while you are eating to discourage them or put a dish of sugar water at some distance from your party to provide risk-free food. If the stinging menace is still buzzing about your group, go inside.

Nobody wants to be stung, so stay calm when you encounter them and move away. And if you are allergic, know where your epi-pen is.