A stinging proposition: bald-faced hornets

A few days ago, a friend called to tell me that there was a nest-like object in a nearby tree behind the house. I went to visit, and there was indeed a basketball-sized object in a hemlock tree. The gray oval shape betrayed the fact that it was a wasp nest. The east-facing entrance hole was busy with arriving and departing wasps, and a look through my friend’s binoculars confirmed that this nest was that of the bald-faced hornet.

Bald-faced hornets (Dolichovespula maculata) are black with pale yellow markings on their head, thorax and abdomen. Like most wasps, they are social insects. A queen establishes a nest in the spring and lays eggs. Most of these eggs will become female workers; they will take over tasks such as nest expansion, foraging and caring for offspring. The only task left for the queen is to lay more eggs. The occasional unfertilized egg will become a male drone. Males are stingless and their sole purpose is to mate with the queen. The entire colony, except for the queen, dies after the first hard frost of fall. The queen finds shelter over the winter to start the cycle again next spring.

The nests are a common sight in the region. Constructed of paper consisting of wood fibers mixed with wasp saliva, these nests are usually found in trees or large bushes. Inside the large oval covering is three or four tiers of upside down hanging combs, where brooding of wasp eggs, larvae and pupae take place. An average colony may consist of 200 to 400 individuals, and they will sting if the nest is disturbed or approached too closely.

Bald-faced hornets are predators, feeding on caterpillars, aphids and other pests and are considered beneficial insects. If a nest is found and it is out of the way of human activity, it is best left alone. However, if a nest is too close to a door or walkway, it may have to be removed. Cold mornings are the best time to do this task; insects are torpid in the cold. Professionals should be consulted if there is any doubt.