Archive for September 19th, 2009


When driving along a country road near here, I noticed a large shape in a road-side tree and stopped to take a closer look. It proved to be the nest of Bald-faced Hornets (Dolichovespula maculata). I was very impressed by its size. At our previous home in the GTA, it was quite common to come across a yellowjacket nest. They are often referred to as football-shaped, and are mostly not all that much bigger than a football. This nest was much larger than any I’ve seen before. I was also impressed by the intricacy of the pattern over the nest, a very decorative design of scallops.


Bald-faced hornets are widespread and common. They aren’t true hornets, but rather, members of the Vespinae subfamily and more closely related to the yellowjackets whose nest their own resembles. Like their nest, the insects themselves are larger than yellowjackets. Their annual life cycle begins in the spring with a queen, who emerges from her winter resting place and seeks out a suitable site for a nest. She begins construction of the nest and lays eggs. The queen feeds the larvae, and after they pupate, they emerge as workers who take over the construction of the nest. The “paper” for the nest is made by chewing wood and mixing it with a special starch in their saliva. The queen continues to lay eggs and the larvae are fed by the workers.


The workers catch insects and feed the masticated insects to the larvae. The workers themselves feed on nectar, sap and fruit pulp. Towards the end of the summer, the queen begins to lay eggs that will become drones and new queens. After pupating, these fertile males and females will mate, preparing for next year’s cycle. Before winter, all the hornets die except the new queens, who seek out spots to overwinter. When they emerge in the spring, the cycle begins again. The large nests are usually empty by late in the fall. The walls offer some insulation from the weather and the old nests may be used by other insects and spiders. Birds sometimes rip into the nests in search of these hidden insects. The hornets themselves don’t use the same nest again.


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