It’s hard to think of a less popular insect than the yellowjacket, maligned because they can sting. First, I should be clear that “yellowjacket” is an imprecise, generic common name that conceals a good deal of diversity. On the Vineyard, we have a total of six species, plus two species of paper wasps (which are in a different subfamily). Of the ground-nesting yellowjacket species, the eastern yellowjacket (Vespa maculifrons) is by far our most common; the widow yellowjacket (V. vidula), less numerous, also seems less inclined to nest around humans; and the non-native German yellowjacket (V. germanica) and native downy yellowjacket (V. flavopilosa) appear to be rather scarce.
Distinguished by a few minor anatomical details and a tendency to build exposed nests high off the ground, our so-called “aerial yellowjackets” include Dolichovespula arenaria (the common aerial yellowjacket) and D. maculata (the bald-faced hornet, though “hornet” is a misnomer). Both are abundant on Martha’s Vineyard. The one true hornet in our region, Vespa crabro, or the European hornet, is a non-native species that is well established as close to us as Cape Cod, but has never, as far as I know, been detected on the Vineyard.
These insects share a lot of similarities in appearance and biology. All are good-size insects, roughly an inch long, black with distinctive patterns of yellow or white markings. Males (which I rarely see), worker females, and reproductive females, or queens, are also distinctively patterned, so with practice and a good look or a photograph, you can easily determine the species, sex, and caste of a yellowjacket. Their life histories are also quite uniform. All form annual colonies, founded by a single fertile queen from the previous season, which may grow to contain several hundred workers. Adults of all species tend to feed on pollen or nectar on flowers, while feeding their developing young a protein-rich diet of masticated scavenged insects or prey items captured by workers and brought back to the nest. The colonial lifestyle is actually something of an oddity among wasps: The vast majority of the hundreds of wasp species that live in our region are solitary nesters, with each female building and provisioning her own nest. But among social wasps, their colonies are central to the lives of these insects, and a successful colony reflects the lifelong labor of a queen and many workers.
It’s no wonder, then, that these insects defend their nests, stinging vigorously and repeatedly if they perceive a threat to their communal home. But it’s important to note that stinging people is not the primary interest of any of these wasps. A wasp that stings a human generally ends up smashed; a colony that is regularly defended by its occupants typically ends up sprayed with poison. So there is strong selective pressure on social wasps not to be too aggressive. Moreover, when they are foraging away from their nests, individual yellowjackets are relaxed, almost gentle insects, stinging only if their lives are threatened, and generally posing a threat only to potential prey items.
While I found no real scientific evidence to support the observation, my impression is that wasp colonies vary in how defensive they are. And it is well established that social wasps can grow familiar with repeated disturbances, learning, for example, that an opening and closing door near their nest, and the people routinely passing through it, are harmless. In the summer of 2023, I nearly found a nest in our yard the hard way, clipping grass to within a few inches of a nest I hadn’t yet noticed. But the wasps, perhaps a calm bunch to start with, or perhaps familiar with my size, shape, and chemical signature, ignored me. (I did not push my luck!)
Setting aside their ability to sting, social wasps are about as beneficial as insects can be: pollinators, scavengers, and predators that help regulate the population sizes of a host of potentially harmful species. From a purely ecological perspective, anyone with a social wasp nest in the yard is lucky indeed. So I advocate a policy of cautious coexistence. What constitutes caution varies: I’d be less tolerant of yellowjackets if there were a lot of kids around, or if someone allergic to stings was going to be near the nest on a regular basis. Sometimes a nest gets started in a place that just isn’t going to work. More often, though, it’s possible to give the wasps a little space and let them do their thing. In the case of this year’s nest in our yard, I roped off a six- or eight-foot perimeter around the nest, and everyone has been happy. It’s a temporary issue in any case. At our latitude, social wasp colonies die out with the onset of cold weather. Any new queens the nest was able to produce disperse, overwinter in sheltered spots, and found new colonies in new locations in the spring. All of this year’s workers, and the old queen, eventually starve or freeze. As odd as it sounds, I’ll miss them.
