Friday, January 27, 2006
Biodiversity Corner Bald-faced hornet's nest
I wrote about the bald-faced hornet, Dolichovespula maculata, in the September 26, 2003 issue of the Mosquito but did not devote much space to the nest. The bald-faced hornet nest is a many-splendored thing. I brought one home from the Towle field in the late fall — after the hornets had gone. Nests are often built high in deciduous trees but can also be on shrubs or even on buildings. The one at Towle was only two or three feet from the ground, weighing down the slender branch it was attached to.
Splendid effort: Fertilized females, or queens, are the only members of a bald-faced hornet colony to survive the winter. In spring, each queen, entirely on her own, starts a new nest. Not only does she build the starter nest and the cells, she also lays the eggs, fetches food, and feeds the larvae. After this huge effort which takes several weeks, the first generation of workers emerges and the queen puts her energy into egg-laying for the rest of the season.
Splendid design: The nest has layers of hexagonal cells stacked in tiers like a wedding cake, completely enclosed in "paper" except for an opening at the bottom. The nest from Towle had four tiers of cells and eight separate layers of paper on the outer shell. The nests can be as large as 14 inches across and 23 inches long, but this one, as befits a paper product, was 8x11. Overall, the walls were about an inch thick. The air trapped between the layers of paper provides protection from extreme temperatures.
Last week, when it was warm and there was no snow left, I found part of a hornet nest on the ground in the Conant Land and underneath it was a little patch of snow - demonstrating the insulating property. As the colony increases, the workers continually enlarge the nest, doing brand-new construction as well as breaking down existing walls and re-using the material to expand the frame and create new cells. Each cell is the nursery for another hornet. Cells can be used more than once in a season. The not-so-splendid aspect of the design is that waste material from the prior occupant remains in the cell which then must be extended to make room for the new occupant to develop and deposit its contribution.
Splendid building material: The hornets make the paper for their nests by scraping fibers from old weathered and rotten wood, dead plants, and man-made materials like newspaper or cardboard. They chew on the fibers making them soft and pliable, then spread the pulp into place with their legs and mouth parts. The nests look gray from a distance, but up close you can see the individual pieces of paper as they were laid down, mouthful by mouthful. The different sources of material are evident in the different colors of the paper. Most of the colors are shades of brown, white, green or gray but I have one piece that has a bright pink stripe in it.
Insect recycling: Insects and spiders use old hornet nests to provide some winter shelter. Birds will take apart abandoned nests looking for an insect snack.
References: Clemson University Department of Entomology www.entweb.clemson.edu; Donald W Stokes, A Guide to Observing Insect Lives.
Any kind of information for the Biodiversity Corner is encouraged. Please feel free to write the column, or tell me what you are finding, or send me a photo. The only requirements are that the subject exists in the wild and was seen in Carlisle. Send a note to Kay Fairweather at email@example.com
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