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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Be careful around baldfaced hornets, Dolichovespula maculata


Baldfaced hornet nests can be the size of beach balls and contain hundreds of hornets.


A first encounter with the baldfaced hornet can be memorable. At the age of eleven I discovered a hornet’s nest about the size of a basketball and wondered what would happen if I pitched a rock into the nest. From a distance of about 20 feet, I hit the target squarely and was immediately greeted by an angry hornet that made a beeline from the nest to a spot on my forehead directly between my eyes, where it delivered a wicked sting. It was the kind of “kill shot” that snipers make in movies. I high tailed it out of range and never again tempted a hornet’s wrath.

The nest of the baldfaced hornet is a marvel of engineering. In spring, a queen that survives the rigors of winter selects a location to build the nest. Usually the limb of a tree or shrub will do, but I have seen nests beneath overhangs of sheds and houses. The queen gathers wood and plant fibers, chews them into a papery pulp, and builds a few brood chambers into which she places eggs. She then constructs thin papery envelopes to enclose the brood cells that are home to her daughters. Larvae that hatch from the eggs are fed macerated caterpillars, flies, moths, and other insects captured by the queen. These larvae soon develop into workers that assist the queen in gathering food, enlarging the nest, and tending to the needs of their sisters and the queen. As the colony grows, the mother queen spends less time out foraging and more time at home laying eggs. Her daughters shoulder the load of finding dinner for their sisters and mom.

A guard protects the entrance to a nest near the ground in a shrub.

The rapidly growing nest is in a constant state of transition. Portions of the exterior papery envelope are removed to accommodate an ever expanding number of brood cells. By late summer the colony is in high gear, with hundreds of workers capturing prey and raising young while the queen feverishly lays eggs. By early autumn the nest can reach the size of a small beach ball. As autumn approaches, workers build over-sized brood cells into which the queen deposits eggs destined to become new queens and males. The mother queen dies and the virgin queens fly away and mate before seeking hibernal shelter under bark, inside fallen logs, or in other protected locations. There is a common misconception that the large paper nest will house hornets for multiple seasons. This is not the case. Before winter, the nest is vacated by workers, queens, and males and it will not be used again in subsequent years.

If you come across a large paper wasp nest, please resist any urges to investigate the nest too closely or to hurl stones at it. The sting of a baldfaced hornet really packs a wallop and some people are allergic to the venom in the sting. If you are stung by these or other wasps or bees and have difficulty breathing, swelling in the face, throat, or mouth, difficulty swallowing, anxiety, rapid pulse, or dizziness, seek medical attention instantly. If the nest is out of the way and does not endanger people, perhaps it can be left alone as these hornets consume large numbers of pests of our plants. If the nest is located in a place frequented by people or pets, then removal may be necessary. Professional exterminators can do the job. People allergic to stings of wasps, hornets, or bees should not undertake this task, as baldfaced hornets are quite aggressive. Potent wasp and hornet sprays are available for home use, but if you choose this option be sure to carefully read and follow directions on the label.


From a safe distance, one can watch workers coming and going from a large baldfaced hornet’s nest.


We thank Howard Bernstein for providing the inspiration for this Bug of the Week after discovering a nest of baldfaced hornets near his home and carefully removing it. The ever fascinating book “The Insect Societies” by E.O. Wilson was used as a reference for this episode. 

To learn more about these remarkable hornets, please visit the following web sites: