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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

October 1996

The buzz season

Anita Carpenter

As October blows into November, brisk northerly winds will snatch the few remaining leaves from winter-ready hardwoods. The leafless trees reveal the remains of last summer's hidden activities.

Fox squirrels, which have been busy snipping small leaf-covered branches, have packed and tucked them into globular nests in the tree crotches.

Bobbing in the breeze, a gray, foot-high, papery-looking structure hangs from the tip of a sugar maple branch. Now abandoned, the nest was the focus of a lifetime of activity last summer for a colony of baldfaced hornets.

Not all baldfaced hornet nests are found in trees. Some are attached under the eaves of buildings or at eye level around the trunks of small hawthorn trees. In late May, while searching for birds' nests through tangled stems under a canopy of eight-foot high shrubs, I discovered what I thought was the remains of last year's hornet's nest. While carefully examining the structure, I was darned surprised to discover I was handling the beginning of this year's nest!

It was about two inches across and secured to a branch about two feet off the ground. The top was a few layers of gray, papery substance. Exposed underneath was a single layer of hexagonal cells. Eight of the cells contained wiggling larvae; another six cells were sealed and contained larvae undergoing pupation. This was all the work of one industrious queen who had built the structure, laid the eggs, cared for them and fed the larvae. In about 12 days the pupae would emerge as sterile worker females, who would take over the chores of nest building, care and feeding of the larvae, and colony defense. The queen would continue laying eggs throughout the summer.

To accommodate a growing colony, the nest is continually enlarged and enclosed for protection. An entrance hole is visible at the base. Nest builders seek out old lumber, trees and fence posts, stripping bits of wood, mixing it with saliva and depositing the mixture on either the inside or outside of the nest. Internal construction involves building additional tiers of hexagonal cells. As the nest size increases, the papery envelope is eaten from the inside and redeposited on outside layers.

Cutting open an old abandoned nest reveals the intricate layers of construction. The external sculpturing is really quite beautiful and durable, tough enough to withstand the ravages of rain and wind.

In late summer, the queen lays eggs that develop into males and fertile females. At the time these mate, the social structure of the colony begins to break down and the sterile female workers begin to wander. You will often see them being pesky, buzzing around rotting fruit, flowers, cans of pop and picnic leftovers. They eventually succumb to the cold. Fertilized females overwinter in protected crevices to become next year's queens.

The baldfaced hornet, Vespula maculata, is about 3/4" long. The abdomen is black marked with white at the tip and on the face. Some confuse this species with a similar hornet, the yellowjacket (Vespula maculifrons), which has a yellow abdomen and face with black markings. Yellowjackets generally nest in the ground.

It is unwise to get near active colonies of either hornet. Both have well-deserved reputations for being unneighborly and aggressive. In my ignorance, I was fortunate not to have aroused the ire of that queen last May. Better to save your hornet nest search for late fall.

Anita Carpenter stirs up an interest in nature near her Oshkosh, Wis. home.