The Solitary Wasps
We have a tendency to focus on the bad things bugs can do to us, probably because it is this information that is so frequently presented to us by the popular media. After all, it may not be newsworthy if it isn't terrifying, and it would appear that too many of us just plain like to be scared. Hollywood is fond of depicting insects ravaging human populations with deadly swarms, with no particular scientific basis for the plot. The internet all too frequently becomes a tool for twisted people to send out scary stories about the horrible, but mythical, things that bugs are doing. Unfortunately, this obsession with the bad can overshadow all the good, and that is the hope of many of the articles you will find on BugInfo - to help you understand when an insect found in your home or garden is worthy of being called a "pest", and when it is just another of Nature's animals doing it's job and leaving us alone.
One wonderful and fascinating group of insects is the wasps, and in this article we are not going to dwell on those we so badly hate - the stinging yellowjackets - but instead we'll take a look at the many kinds of solitary wasps that are highly unlikely ever to harm us with a sting. By "solitary" we are referring to the kinds of wasps that do not create the organized social groups like the yellowjackets or honeybees do, but instead live pretty much on their own, finding food resources for their offspring but not tending them as the "social" bees and wasps do. If we approach a honeybee or yellowjacket nest, which is filled with hundreds or thousands of adult and larval insects, we do run the risk of being attacked and stung. The worker bees and wasps will aggressively defend that colony, its Queen, and all the offspring developing within.
However, solitary wasps simply do not have this instinctive attack behavior, and about the only time you would be stung by one of them would be if you directly threatened the life of the wasp, such as by sitting on it, grabbing it with your hand, or perhaps trapping it within your clothing. What is the implication here, then? Well, if we keep in mind that nearly all wasps feed other insects or spiders to their babies, it becomes pretty evident that having them in our yards serves us a great deal of benefit. And, keeping that benefit and their nearly harmless nature in mind our best course of action when we find them is to encourage their presence, not to kill them.
The Tarantula Hawk:
All that being said, it's easy to understand why we get nervous around some of these solitary wasps, and we'll start with the biggest and most terrifying - the spider wasps. This is a really attractive family of wasps whose larvae feed primarily on spiders, provided for them by their mother who has sought out a spider, stung it to paralyze it, and placed it into a cavity of some sort for the larva to feed on. The biggest species in this group are the enormous Tarantula Hawks, several kinds that can be found in the western United States, particularly in the more arid regions where tarantulas live. With their brilliant metallic blue or bright orange wings spread out sideways, these species can measure nearly 4 inches from wingtip to wingtip, and as they cruise over the soils looking for an available meal they look for all the world like a tiny helicopter. The adult wasps will feed on nectar from flowers, so you may also find them coming to your garden for this reason. They have no reason and no desire to sting you, so it's hoped that you can take the opportunity to enjoy the beauty they bring.
The Mud Daubers:
Another common solitary wasp group is called the mud dauber wasps, and various species are found throughout the United States. One kind is called the Organ Pipe Mud Dauber, because the mud chambers it creates for its larvae to live within are elongated, and lined up side by side much like the pipes of a large pipe organ or calliope. Another common kind is called the Black and Yellow Mud Dauber, and unfortunately the females of this species are not nearly the architects that the Organ Pipe wasp is, making their mud chambers look more like someone just took a blob of mud and threw it against the wall. In the western U.S. this common species will frequently place the mud nests onto the sides and eaves of homes, or just about anyplace else that's convenient and relatively undisturbed. I once found one constructed right onto the top of a plastic laundry basket in my mother's garage.
Our only real beef with the mud daubers is this messy blob of mud that they insist on sticking onto our clean homes. When you find them though, and feel your blood rising, understand that all the larvae living within the chambers in that mud blob have been feasting on spiders that the adult wasp found around your home, and you may then appreciate the benefit they provide. If you still want to remove them you should do so with a stick or putty knife, simply knocking the mud off the surface and disposing of it. You may even consider relocating it to some place in the yard, to allow these beneficial wasps to possibly complete their development and continue to control your spider population. What you should NOT do is to spray the mud nest with any kind of insecticide. Not only will this do no better than just physically removing it, but a liquid spray is likely to cause the mud to disintegrate and cause an even bigger mess on the wall.
Within the mud daubers there is a renegade, which must be inevitable in any large group of animals. This is the Blue Mud Dauber, an inch-long species which is a brilliant dark metallic blue color. It also raises its offspring within the chambers of a mud nest, but it does so with an evil twist. Like the cow bird of the bird world, the blue mud dauber finds a mud nest already constructed by some other species of mud dauber, bores into the cells to kick out the current (and legitimate) occupants, and then deposits her own eggs onto the food supply left there by the true builder of that nest.
The Potter Wasps:
There is another family of wasps that have an interesting twist on this use of mud, and that is the smaller Potter Wasps. These brilliant little architects create tiny little pots of mud that look for all the world like a ceramic pot made by native peoples. The pots have round bottoms and flared tops, with an opening right in the top, and each pot will hold a single wasp larva and its food, which in many cases will be caterpillars that the adult wasps find feeding on your garden plants. You are likely to stumble upon the pots in the strangest of places, such as along a window track, a fence board, by potted plants, or anywhere else that the female wasp is able to wedge that pot in so it will not easily fall off. Again, a solitary wasp, very unlikely ever to sting anyone, and feeding on bugs we'd rather not have on our plants. I once watched one of these wasps attempting to jam a paralyzed caterpillar down through the opening of its mud pot, turning the wasp this way and that to try to get it inside, but without success. It seems that the caterpillar was just too fat to fit through the opening of this particular pot, so after about 5 minutes of struggle and sweat the wasp finally flew off with the caterpillar in its jaws - perhaps it had a larger pot somewhere else?
The Soil Dwellers:
We also have several families of wasps that create chambers in the soil for their larvae, and again supply the larva with a paralyzed insect of some sort that sustains the larvae through this early stage of its life. The variety of insects used runs the entire range of the insect world, but caterpillars, crickets, grasshoppers, and some other easily captured bugs are tops on the list. In the southern parts of the U.S. we have one more enormous wasp called the Cicada Killer, and this one, like the tarantula hawks, causes a great deal of concern among homeowners whose yards are chosen for nesting. A sting is possible, but as with the other solitary wasps it is unlikely. The biggest complaint, really, is the large holes and piles of soil made by the female wasp as she digs her burrows, sometimes in a nicely manicured lawn. As the name suggests, a primary food of these 2 inch long wasps will be cicadas, those large, loud, buzzing insects that sit up in the trees, and are referred to as "locusts" in the northeastern states when they emerge from the soil by the billions.
Controlling Cicada Killers really is best viewed as "discouraging" them, and you can accomplish this by raking over their holes as they try to create them. You may be able to dry out a soil area so that it does not allow the wasp to dig a tunnel, collapsing due to the dryness. Insecticide applications into the holes may be effective, but the use of toxic materials is generally best done by a licensed and trained professional, especially when dealing with wasps. We have similar activity in the soil from a number of other wasp families, and they are given various names such as Digger Wasps, Mason Wasps, Burrowing Wasps, etc. to describe their habits.
Some of them look remarkably like our old enemy, the yellow jacket, and it's very difficult to tell them apart by simple physical appearance. In fact, it is this common black and yellow color scheme of so many wasps that provides them with an overall benefit. Predators, such as birds, may "learn" that to try to eat a wasp can result in a very painful sting, and they will avoid eating all black and insects that behave in a "wasp-like" manner. Rather than having to sample one of each species the predator figures it out after just that first wasp, and wasps in general are less likely to be fed upon.
The Velvet Ants:
One final kind of solitary wasp is worthy of mention, and this is a family called the Velvet Ants. This is probably a bit confusing, calling a wasp an ant, but the confusion comes from the fact that in these wasps the females do not have wings. They are confined to the ground, where they crawl around rapidly, looking for the larvae of any other kind of insect to provide as food for their own larvae. These female wasps, which in some species may be an inch long, look for all the world like an enormous hairy ant. The males do have wings and can fly, but in both males and females the bodies are nearly completely covered with brilliantly colored hair. The hairs may be bright red, orange, white, black, or combinations of these colors on the same individual. I once found one in Mexico that had dark patterns on its back that made this wasp look like a large spider running across the soil.
This is one wasp that does cause some stings on a regular basis, even though it is a solitary kind of wasp. The problems are two-fold. First, because the female is confined to a terrestrial lifestyle she is likely to find her way into things left on the ground, and if this happens to be shoes or a jacket the chance of the wasp encountering the person is greater. Second, being so brightly colored and attractive it's not unusual for someone who does not understand the sting potential to pick one up in his fingers to look at it. The wasp, of course, feels directly threatened by this and defends herself. Notice that I said "her" self, for only female wasps or bees are capable of stinging. On this note, too, only the Honeybee can sting one time only. All other bees, wasps, and stinging ants are perfectly capable of stinging repeatedly. The difference is the stinger itself, which on the honeybee has forward-facing barbs that prevent the bee from pulling the stinger back out of our skin, and as it pulls away the stinger and some rather vital parts of the bees anatomy are pulled from its body, causing it to die.
So, in our effort to encourage you to appreciate many kinds of insects that you might find in your garden we hope this article has been of some enlightenment. There also are a great many insects that need to be controlled in some manner when they are found in or around our homes, and other articles will discuss those. Toxic chemicals - pesticides - often are called for in the management of pest insects, but the professional industry of pest management also encourages the use of non-toxic control methods, such as simple physical removal, whenever possible. If you find a mud dauber wasp or a velvet ant that somehow has managed to make it into your home, hopefully you can find a jar to put it in and deposit it back outside, where it can continue to help you in your bug control efforts in the garden.