While hiking, I noticed a wasp with striking bands of yellow and black. It ignored me as I filmed, enraptured by the blossoms of White Snakeroot (Ageratina altissima), a poisonous plant native to the eastern United States.
The insect was a European Paper Wasp (Polistes dominula), a species introduced into Boston in the 1970s. Unlike native paper wasps, it is docile and rarely swarms, only stinging if it or its nest is threatened or, strangely, if it is drinking. Only females have stingers, and they are less likely to sting than bumblebees.
The European Paper Wasp hunts a wide variety of caterpillars. It also consumes aphids and their honeydew, the nectar of flowers, and occasionally ripe fruit.
Only mated females storing sperm survive to see the spring. They overwinter in dead or hollow trees, the walls of houses, or beneath siding. When spring arrives, the female emerges from her quarters and begins construction of a nest, which will be suspended from wood or a rough surface. The female chews wood fibers and, with her saliva, creates a paper pulp, which she uses to build the first few cells of her home.
This founding queen then lays a fertilized egg in each of the cells, which hatch in 3-5 days. The hatched larvae grow over a period of weeks, with the queen caring for them and maintaining the nest herself. During this time, she hunts for insect larvae, which she masticates and then regurgitates to her young. When the larvae are grown and ready to pupate, she seals them in their cells.
The first adults to emerge are female workers. These initial colony members will maintain a preferential status throughout their lifetime and may have more facial spots, an indicator of dominance. Adults that are born as the colony expands will have a lower social status and may be excluded from the colony altogether.
As more and more workers assume responsibility for maintaining the nest, foraging, and caring for young, the queen relinquishes her roles and spends more time at home.
Sometimes, small groups of overwintering females will cooperate and begin a nest together. When this happens, one becomes the queen and the others become founders, or potential queens. If founders lay eggs, the queen eats them. However, if the queen dies or leaves the nest, the highest-ranking founder becomes the new leader.
Some mated females never build their own nest. Instead, they wait and take over an abandoned one. Larger nests are preferred, since they often contain mature larvae that will soon become workers. Younger larvae and abandoned eggs are eaten by the new queen.
As a nest continues to produce workers, space on its surface becomes tighter (a mature nest may be only 8 inches, 20 cm, across). At this point, founders remain in small, restricted areas where cells have been capped. Where crowding requires nestmates to share space, founders prefer to share with founders; workers with workers. At this point, a third of the colony’s residents may spend most of its time away from home or resting in its vicinity.
Fortunately, European Paper Wasps are not excessively territorial. Adults visit other nests, and groups of wasps may work together to recondition old nests. Nests may be close enough to form mini-neighborhoods. At any one time, up to 35% of a colony’s population may be unrelated.
In late summer, no more workers are produced. Instead, adult wasps vibrate the colony’s cells by drumming with their antennae. This signals developing larvae to become founders and males. Workers already in development may be neglected, since food is provided preferentially to individuals having the potential to reproduce.
In late summer and early fall, the founders and males emerge from their cells.
Males establish territories, marking the leaves and stems of large trees with their legs and abdomen. Queens seek out and choose multiple mates, but reject many others in the process—biting, dodging, or even stinging them. When selecting a mate, females prefer attractive males from local nests. An attractive male has smaller, regularly-shaped abdominal markings and scattered facial spots.
As winter approaches, males and non-reproductive females die off. Females carrying sperm spend winter in a hollow and emerge again in the spring, when the cycle repeats.
European Paper Wasps: Everything You Need to Know. Ed’s Dead Bug, 2020 Apr 20.
Cranshaw W, European Paper Wasp – 5.611. Colorado State University Extension.Polistes dominula (European Paper Wasp), Invasive Species Compendium, CABI.
European Paper Wasp (Polistes dominula), Texas Invasive Species Institute.
European Paper Wasp, Plant and Pest Diagnostics, Michigan State University.
Stoud Eliza, Polistes dominula: European paper wasp. Animal Diversity Web, University of Michigan Museum of Zoology.
European paper wasp, Wikipedia.