Last week I received a phone call from an enthusiastic homeowner who had discovered exceedingly large “wasps” inhabiting a large maple tree in her backyard. After a brief discussion of their nocturnal antics, ferocious appearance, but otherwise gentle demeanor, I informed her that her visitors were likely continental in origin, that is to say European, and, perhaps, this explained a kind of six-legged civility not normally seen in a large stinging insect. A visit to the property revealed a magnificent colony of European hornets living in the trunk of an old silver maple. European hornets were introduced into New York from Europe sometime between 1840 and 1860. They have spread and now occupy territory from the east coast to the Mississippi. The story of the hornet colony is fascinating.
Way back in spring the colony was founded by a single queen that had survived the winter in a protected spot such as beneath the bark of a fallen tree or in a rotten log. In this case she used a cavity in a tree, but sometimes hornets will nest in a void in the wall of a home or barn that is exposed to the exterior. After the queen successfully raised her first batch of sterile female workers, she remained in the nest producing more young while her daughters took up the tasks of enlarging the nest, protecting it, and gathering food to feed the young such as caterpillars, flies, grasshoppers and other stinging insects like yellow jackets.
During late August and early September, the colony operates at a fevered pace. Inside the colony, the queen no longer produces sterile daughters. She has shifted production from workers to female and male young capable of reproducing. The females are destined to become the queens of future generations of hornets. The males have just one purpose that is to mate with the new queens. After fulfilling this biological imperative, males die. As autumn winds down, the colony is abandoned and queens find protected places to spend the chilly months of late autumn and winter. Although these hornets are large and scary looking, humans are unlikely to be stung by European hornets unless the nest site is disturbed or attacked. I photographed hornets at a distance of less than a foot as they feasted on fallen pears. To avoid being stung, simply avoid disturbing the nest site. European hornets are somewhat unique in their feeding behaviors in that they hunt at night. They are also attracted to light and can often be found buzzing around porch lights or heard crashing into windowpanes at night.
Managing populations
They feast on fallen fruit. To reduce chances of a sting by a European hornet, yellow jacket, or wasp, if apples or pears are on the ground, then pick them up and compost them. Wear shoes rather than bare feet when you walk near fruit trees. These hornets also have a curious behavior of stripping the bark from several types and trees and shrubs including lilac, birch, and rhododendron to name a few. Apparently, this annoying behavior allows them to feed on the nutritious sap and plant tissues beneath the bark. Unfortunately, small plants may be severely damaged by this bark stripping. If European hornets have nested in a home or another location that poses a threat to human health or safety, they may be annihilated with insecticides. However, I like the approach of the folks who shared their European hornets for this “Bug of the Week”. They have decided to give the nest a wide berth and simply enjoy the comings and goings of these spectacular insects.
References:
Special thanks to wonderful family who shared their hornets for this bug of the week. For more information on these interesting insects, please visit the following web sites.
http://www.ces.ncsu.edu/depts/ent/notes/Urban/eurohornet.htm
http://www.uky.edu/Ag/Entomology/entfacts/struct/ef600.htm
http://ohioline.osu.edu/hyg-fact/2000/2128.html
http://www.vespa-crabro.de/hornets.htm
http://www.agnr.umd.edu/MCE/Publications/PDFs/EB248.pdf