Apr 20, 2011 – Almost Adults Anyhow

QUESTION:

If you kill wasps that belong to a nest but not the larvae, will they hatch and survive and continue living?

ANSWER:

The larvae of social wasps, like paper wasps and yellow jackets, are totally dependent on the care of the adult wasps in that colony. The adults bring them food and care for them, and without this care the larva hatching from the egg has no chance of survival. However, there comes a point at which the larva is full grown or nearly so, and if its food supply is suddenly cut off it could simply pupate and emerge later as a healthy adult wasp. So, killing all the adults may not cause the death of ALL of the larvae, and definitely may not affect those already sealed up in chambers in the pupa stage. Since a common wasp control material is the "jet" aerosol sprays that kill the insects on contact, if the larvae or pupae are not contacted as well they may survive and continue to develop.

Early on in the development of that colony all of the emerging adult wasps are going to be females, and it's possible that some of these then can become egg-laying "queens" to continue the life of that colony. I also read an interesting article in a recent magazine that tells us that new research shows just how the wasp colony regulates the production of workers versus queens. The worker wasps will tap on the walls of the nest, called "drumming", and this activity inhibits the storage of fat in the larvae, causing them to emerge as adult workers. Later in the season this drumming must stop, leading to the production of new queen wasps that then mate, overwinter, and start new colonies the next year.

Solitary wasps, such as mud daubers, do not care for their offspring beyond providing food for them initially, so once the nest is built, the eggs deposited in the cells along with a food supply, the adult wasp seals off the chamber and the job is complete. Killing these wasps in the adult stage then has no effect on the developing larvae. For this reason, all wasp nests should be physically removed after killing the adult insects. This ensures that you eliminate the potential for new wasps to emerge later. And, given the highly beneficial nature of solitary wasps, which nearly all feed on other insects and spiders, if the nest is in a location that is not an eyesore it might just be left alone. Having these kinds of wasps around the landscape provides more benefit than hazard.