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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.

An inside look at baldfaced hornets, Dolichovespula maculata


Fierce guards protect the entrance to the nest.


The nest of a baldfaced hornet is a marvel of engineering and when my brother texted me an image of said nest built on a windowpane of his home in rural New Jersey, well, the opportunity to get up close and personal with these fearsome fliers was irresistible. Usually the limb of a tree or shrub will do as a nest site and I have seen nests beneath overhangs of sheds and houses, but never one plastered against a window. 


How would you like one of these on the front of your home? Watch as hornets leave the nest and return with food for their young while others tend to enlarging the paper shell enclosing the brood chambers.

To construct a nest, 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 look inside the nest reveals sisters hard at work tending the brood. Larvae squirm about and poke their heads from papery cells as the workers move about the brood combs.

Nests can be the size of beach balls and contain hundreds of hornets.

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 early autumn the nest can reach the size of a small beach ball. By late summer the colony is in high gear, with hundreds of workers capturing prey and raising young while the queen feverishly lays eggs. As autumn approaches, workers build over-sized brood cells into which the queen deposits egg 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 hurl stones at it. I succumbed to this misguided temptation at age eleven and pegged a large nest with a stone from the distance of about twenty feet, a marvelous toss indeed. I was immediately greeted by an angry hornet that made a beeline from the nest to a spot on my forehead where it delivered a wicked sting, 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. 


And where does the fiber come from to build the hornet’s paper nest?  I regularly observe them stripping wood from the siding on my tool shed.

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 a baldfaced hornet or other wasps or bees and have difficulty breathing, swelling in the face, throat, or mouth, difficulty swallowing, anxiety (beyond that of being stung), 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. These hornets consume large numbers of pests in our gardens and landscapes. 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.


We thank Ivan and Patricia for providing the inspiration for this Bug of the Week after discovering a nest of baldfaced hornets attached to their home. The ever fascinating book “The Insect Societies” by E.O. Wilson was used as a reference for this episode.