Mother Nature doesn’t suffer creatures lacking in constructive purpose. Even the wasp benefits the planet. But the benefits can be hard to remember when a wasp sting swells human flesh to painful proportions, challenging the best home treatment options.
A wasp is any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. The most commonly known wasps such as yellow jackets and hornets are in the family Vespidae and are eusocial, living together in a nest with an egg-laying queen and non-reproducing workers.
The larvae of wasps resemble maggots, and are adapted for life in a protected environment; this may be the body of a host organism or a cell in a nest, where the larva either eats the provisions left for it or, in social species, is fed by the adults.
The beneficial-to-baneful ratio varies according to the specific type of wasp.
Parasitic wasps are so tiny, some only one-fiftieth of an inch, that their stingers pose no threat to humans, livestock or pets. The stingers are designed to penetrate the eggs of other insects, which serve as unwilling hosts for wasp eggs. Once in the larval state, the new wasps devour their host.
This is good news for man, because those hosts include such garden pests as tomato hornworms, aphids, cabbage loopers and corn borers. For livestock owners, the Muscidafurax and other parasitic wasps similarly help in the battle against bloodsucking flies.
To maximize the impact of parasitic wasps, many of which are native to North America, the consumer can purchase them from retailers like Arbico Organics. Arbico’s fly control program involves monthly mailings of fly pupae already infected with parasitic wasp eggs. I can attest to its gradual effectiveness. After two years there was a significant drop in the number of flies tormenting my llamas.
Mud-dauber wasps are large enough (3/4 inch) to sting humans. Unfortunately, mud-daubers gravitate toward human construction. Roof overhangs, porch siding and the interior walls of barns, sheds and attics are ideal, relatively protected locations for the distinctive, narrow, clay tubes that are mud-dauber nests.
Known as “solitary wasps,” mud-daubers cannot draw upon legions of allies to protect their nests. A single male may serve as a temporary guard while his mate builds the mud home for their offspring. But the primary reason for having a stinger is to paralyze the prey that will feed those offspring. Female mud-daubers are particularly fond of black widow spiders. After stinging the spider, the female wasp will haul the paralyzed body back to her newly made tube-nest, where she will then lay her eggs and seal over the tube. When the eggs hatch, the larvae feed on the trapped spiders.
Nests too close to human habitats can be easily knocked down with a broom. Rarely will the adult wasps, if still present, make any protest. I have done this many times and never been stung. Some observers claim the only way to get a mud-dauber sting is if the wasp is pressed up against the skin. They also claim a mud-dauber’s sting is far less painful than that of a paper wasp or hornet.
The paper wasp is the source of most of the wasp stings I have received. Nevertheless, I don’t rate it as high on the aggression scale. These wasps will certainly defend their open, papery nests, all too often hanging near a house door. As “social wasps,” they have the numbers to go to war against trespassers. But those numbers, ranging from about a dozen to several hundred, are modest compared with other social wasps.
I have often gardened near paper wasp nests with no injury. Blundering into a semi-dormant wasp on a chilly day has been the most common reason for the stings I’ve received. I’ve stepped on sleepy wasps, encountered them hidden inside garden gloves and plucked several flowers where a wasp was hunkered down.
Coexisting with the paper wasp is worthwhile. The critter isn’t too nasty and it dines on all sorts of insect pests.
Yellow Jackets and Bald-Faced Hornets
A subcategory of wasp, the bald-faced hornet also preys on many insect pests. The yellow jacket, which also classifies as a wasp, scavenges on dead insects and carrion and thus serves a useful purpose as a garbage disposer.
The benefits from both of those wasps, however, can be hard to remember in the face of both critters’ ferocity, especially when they are defending their nests. A yellow-jacket colony — most often subterranean, but occasionally built in crawlspaces — may have 15,000 individuals. The bald-faced hornet nest, often the size of a basketball, with a single entrance at the bottom, similarly has thousands of defenders.
The last time I sprayed a bald-faced hornet nest, in the cool of a summer night, I escaped injury only because the getaway truck was close at hand. From the inside, I watched, like the heroine in a Grade-B horror film, as the hornets angrily flailed against the windshield.