As I was riding down the street this afternoon on my bike, I spotted a huge nest attached to a limb of a tree and stopped to take some photos.
This Bald-faced Hornet nest was definitely larger than a football, about 15 inches long and 10 inches wide.
Bald-faced Hornets, sometimes called Blackjackets (probably because they are closely related to Yellow Jackets) or White-faced Wasp, or Black and White Wasp, are large-bodied for wasps and notable for their huge “paper-mache” nest constructions.
Workers were coming and going from the entrance hole at the bottom on the shaded side of the nest. The striations made by continual additions of chewed fiber look like ripples of sand on a beach.
A few workers were adding to the super-structure outside, laying down more papery layers.
Workers chew up wood, mix it with saliva and then add the pasty mixture to the structure using their mandibles and legs. This wasp was spreading new material from left to right, and you can see the slightly moist layer she has added to the left of her head.
A Bald-faced Hornet queen collecting wood fiber to begin construction of her paper nest. From BugGuide.
Fertilized queens overwinter from the previous fall, emerge in the spring ready to begin nest construction and lay a set of eggs that they will tend, feeding the larvae nectar and bits of insects. These workers will then take over the nest construction and larval rearing duties, as the queen lays more and more eggs to fill the nest with tiers of egg chambers.
A cut-away of a bald-faced hornet nest shows the layers of paper fiber covering the central core of tiers of egg/larval chambers. From Wikimedia Commons.
At summer’s end, the nest has reached maximum size, and the queen lays eggs that will mature into new queens and drones, which fly away from the nest to mate, and the cycle begins anew. Those fertilized queens will overwinter in a torpid metabolic state, while the existing colony of worker hornets will die when the temperatures drop below freezing.
I kept thinking of the saying “don’t stir up a hornet’s nest” as I watched these wasps come and go from their nest. They get aggressive and angry when agitated or disturbed, and are capable of delivering multiple stings to the target offender.