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• Bald Faced Hornet

Dolichovespula maculata

The bald-faced hornet (also referred to as the white-faced hornet) is actually not a true hornet, but is a classification of a wasp (similar to the yellow jacket or paper wasp). However the term 'hornet' is often used to refer to any wasp with an exposed aerial nest. They are found throughout North America.

Bald-faced hornets are identified by the black and white pattern on most of the face with 2 angled stripes on the thorax towards the head, and on the last 3 abdominal segments. Adult workers are typically 5/8 inch to 3/4 inch or more, queens are usually 3/4 inch or larger. They are considered a minor pollinator.

Nests are aerial, and locations can vary, from shrubs or vines at ground level to trees or structural overhangs. Nests are generally established in exposed locations. At maturity they can reach up to 14 inches in diameter and up to 24 inches in length. Nests are not reused and last only 1 year.

Over-wintering queens harbor in sheltered areas such as underground or in hollow trees until spring, when the queen emerges and selects a site for nesting. Nests are large and football shaped, made of chewed wood mixed with the starch from saliva. The queen will lay 1 egg per cell within the nest. After about 30 days, the first 5-7 workers emerge and shortly thereafter take over the work of continuing to expand the nest by building additional combs one below another, while the queen continues to lay eggs. Nests generally are 3-4 combs with less than 2000 cells and can contain up to 100-400 workers at its peak. As the season progresses, reproductive cells are constructed to raise the new queens. Males can also be reared in these reproductive cells, but are more often reared within the old worker cells. As the season progresses and approaches winter, the workers, unfertilized females, and original queen all die, leaving only the new seasons fertilized queens to again winter-over and establish a new nest in the spring.

Bald-faced hornet adults seek out foods high in sugars and carbohydrates (fruits, flower nectar, etc) while the larvae feed primarily on proteins (insects, meats, fish, etc). Larvae are fed by the adults chewing and conditioning the high in protein foods and feeding it to them. In turn, the larvae produce sugars from those proteins which provide a food source for the adults. This act is called 'trophallxis' In late summer workers are well known for being picnic spoilers due to forging for foods ranging from meat, fruits, soda pop, and human garbage to fill the sugar requirements that the nest no longer produces.

Bald-faced hornets are extremely protective of their nests and will sting repeatedly when disturbed. They are able to sting repeatedly because their stinger does not become stuck in the skin of the victim and remains intact.

Important preventative measures include:

1. Remove available food sources such as sugars, proteins and pet foods. Any food or beverage spills should be cleaned up as soon as possible. Keep garbage cans well sealed. Items such as hummingbird feeders should be removed or kept well sealed.
2. Seal cracks and openings at awnings, roofs and siding. Openings can allow a safe harbor for colony nests or over-wintering queens.

While these preventative measures may help prevent an infestation, if a colony has an established nest, a call to Long Pest Control can develop an Integrated Pest Control program to eliminate the sightings and provide an environment free of unwanted pests year round.