Great black wasps are your friends
As my border collie Idgie and I head out for a walk every day, numerous large black wasps swoop in and out among the flowers lining the driveway. Their blue iridescent wings shine in the sunlight. Just shy of an inch and a half long (males somewhat smaller) and in constant motion, the wasps appear to be somewhat agitated.
But these big wasps ignore us as we walk by within touching distance. They don’t even seem to mind when Idgie sticks her nose into the plants to investigate or swishes her tail against the flowers. The wasps don’t care about us because they are intent on consuming the nectar the blossoms provide. Mountain mint (Pycnanthemum virginianum) and swamp milkweed (Asclepias incarnata) are their clear favorites in my garden.
These scary-looking but docile insects are known as great black wasps (Sphex pensylvanicus), or katydid hunters. Steel-blue cricket hunter is another common name but can be confusing; that name is also used to refer to a smaller type of wasp.
Great black wasps are common throughout the Midwest and beyond. They’re considered solitary wasps rather than social insects because they nest alone rather than in a big group. With no common nest to defend, these wasps are very unlikely to sting you unless you aggressively threaten them.
Each female makes a tunnel in soft earth. She then catches and stings a big soft-bodied insect such as a grasshopper, cricket or katydid. The sting paralyzes the prey but doesn’t kill it. After several of these insects are collected in a chamber, she lays eggs and closes that chamber before making a new one in the tunnel. After the whole tunnel is filled, she seals that off as well. When the eggs hatch, the larvae find fresh “meat” waiting for them.
Sometimes, I’ve been told, a bird will snatch the paralyzed prey from the wasp for an easy snack. The great black wasp simply goes back to hunting for another big juicy insect.
In exchange for allowing the great black wasps to feed and nest undeterred, a gardener gets help controlling insect pests. These wasps are also important pollinators. So welcome them!
Actually, all kinds of wasps have a beneficial side, helping with pest control and pollination. But Mother Nature can be complicated. If paper wasps make a nest in the overhang by your door, for example, they will be irritated every time you go in and out. And a yellow jacket nest in the ground where you mow or might otherwise disturb it poses too much danger to people to tolerate. These highly aggressive insects will sting in mass if disturbed. Much as I hate to kill wasps or use chemicals, we’ve twice had to call in a licensed pest control professional to deal with a yellow jacket nest.