Iowa Insect Information Notes

Parasitic Wasps

Parasitic Wasps

Parasitic wasps, that is, wasps that live part of their lives as parasites inside other insects comprise one of the largest insect groups. There are several hundred species of these wasps found outdoors in the "real world." This very large group is extremely variable in size and color, but most are small to medium-size and brown or black in color.

The parasitic wasps are not the stinging, social wasps more commonly encountered in and around houses (paper wasps, yellowjackets and hornets). Parasitic wasps generally do not sting and are not pests except for their occasional, annoying presence as accidental invaders in the house. They are harmless and beneficial because they provide some biological or natural control of other insects. Parasitic wasps use their stinger to lay eggs inside other insects and can sting if threatened or handled.

Parasitic wasps found indoors are accidental invaders that have crawled or flown into the house by accident or were carried in with firewood. The wasps may have been living inside the wood boring insects that were inside the firewood and emerged when the wood was warmed by the heat in the house.

There is little that can or needs to be done to control parasitic wasps indoors. Carefully picking or vacuuming them up for removal is usually sufficient as is swatting the occasional invader. Parasitic wasps are seldom a persistent problem and special controls are usually not necessary.

Updated 07/14/2005 - 12:48pm