JULY
2004

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

07-08-04

Download the audio of On Six Legs: MP3, WMV.

Wasps Abound in the Good Old Summertime


By definition, wasps are insects of the order Hymenoptera. Other Hymenoptera are the ants and the bees. Many Hymenoptera, especially the bees and wasps, can sting. That's why most people leave bees and wasps alone.

Wasps generally have a slender body. Bees, on the other hand, tend to have stout bodies. Many wasps have a very thin "waist" where the thorax attaches to the abdomen.

We use the term "wasp waist" to describe a person who has a thin waist. The adjective waspish serves to describe a person who is wasplike, irascible and snappish! During World War II, a noncombat flier of the Woman's Air Force Service Pilots was known as a wasp-an acronym that might not be considered a term of endearment!

While all female wasps have modified ovipositors that function as stingers, not all female wasps sting defensively. That is probably the basis for the old saw that holds that wasps that build nests of mud are friendlier than those that build nests of paper. It is true that paper wasps are quick to defend their nest, while mud daubers never sting in defense of the nest.

The difference in stinging behavior between paper wasps and mud daubers might not be related to their choice of nest material, but whether or not they are social or solitary wasps. Most Hymenoptera that are social defend their nests. Such behavior is exhibited by ants, honey bees and bumble bees. The same is true of the social wasps. The solitary bees and wasps, on the other hand, do not defend their nests.

There are a lot of species of wasps in the world. Most are very small and, to many people, look like gnats. The small wasps are parasites on other insects. In most cases, the female wasp uses her ovipositor to deposit eggs into the host insect.

The eggs hatch into larvae that feed on the host insect. Eventually, the larvae exit the host and spin silk cocoons. That is the case with a wasp parasite of the tomato hornworm caterpillar. These wasp larvae attach their cocoons to the skin of the hornworm, where they are visible to gardeners who discover parasitized hornworms.

Other wasps capture the arthropod prey and use their stinger to paralyze it. The prey is then carried to a suitable nest site. Such nests might be a hole in the ground or a hollow in the stem of a plant.

The food of these wasps is specific to the wasp species but includes many kinds of arthropods. For example, there is a group of small, black wasps that are called aphid wasps, because they provision their nest with aphids, leaf hoppers or psylllids. Other wasps feed their larvae grasshoppers and crickets. Still others use flies as a food source. And others feed on beetles.

The largest wasp in North America feeds its young on cicadas and is appropriately known as a cicada killer. The yellow-and-black cicada killers capture cicadas, sting them and haul them to a burrow in the ground. There, the adult deposits an egg that hatches into a larva, which feeds on the cicada food source.

Some of these solitary wasps, including the mud wasp, construct their nests from scratch. Some build organ pipe structures, others little clay pots and still others make mud nests that look as if someone threw a fist full of mud on the wall. All provision the mud cells with arthropods. The organ pipe mud dauber uses spiders, and each cell has 8 or 10 to satisfy the needs of the developing youngster.

Other wasps are social in nature. Such wasps have a queen that starts a nest, until the first offspring maintain the nest and feed the young. As with their nonsocial relatives, they feed on arthropods. However, these wasps chew the food prior to feeding the young. Such wasps build paper nests and include those that build nests under the eves of buildings, the bald-faced hornets that build the balloon nests in trees and the yellow jackets that build their paper nests underground. All feed on other insects.

And, as the old saw warns, these paper wasps will sting when you bother their nest. Otherwise, they are good neighbors, removing undesirable insects from your fields and gardens!

 

 

Writer: Tom Turpin
Editor: Olivia Maddox