Wild Side: Paper wasps

They will defend their paper homes.

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Northern paper wasp, Polistes fuscatus. — Matt Pelikan

My gardening pride and joy is a patch of ‘Jersey Supreme’ asparagus I laboriously planted back in 2009. When two species of asparagus beetles started showing up in the patch a few years back, I squished the little devils without mercy — eggs, larvae, adults. But as the asparagus plants attain their midsummer glory, the task of picking beetles and larvae off them gets too large. The fronds are too dense for me to spot my victims, and the tops of the plants, where the leaf-eating beetles seem to concentrate, are out of my reach.

My fear, of course, is that these pests will proliferate until they weaken the plants and threaten next spring’s yield. But fortunately, I have the assistance of skilled, professional pest suppression: A platoon of paper wasps has keyed in on the beetle larvae, steadily eating the problem down to a manageable level. I’ve watched with approval as the wasps patrol methodically among the tangle of fronds, landing sometimes to eat, chew on, and eventually carry off a rotund beetle larva.

A subfamily related to hornets, yellowjackets, and potter wasps, the paper wasps are named after their remarkable nests. Chewing wood and mixing it with their saliva, worker wasps assemble, papery, honeycomb-like nest under overhangs, on the underside of branches, or in similar sheltered locations. Each cell in the nest is inhabited by a single larva, the offspring of the colony’s queen, or fertile female.

While it’s a respectably large subfamily worldwide, paper wasps exhibit very little diversity in southern New England, including the Vineyard. As far as I can tell, only two paper wasps, both in the genus Polistes, occur here. One of these, the northern paper wasp, Polistes fuscatus, is a widespread native species. Hugely variable in coloration across its range, P. fuscatus is pretty uniform on the Vineyard, a dark brown wasp with a pair of reddish spots near the base of the abdomen.

Our other paper wasp, the European paper wasp Polistes dominula, is an introduced species. It first appeared in North America in the Boston area around 1980; since that time, it has spread explosively, now occupying most of the continental U.S. and Canada. An attractive insect, black with extensive yellow markings, it’s often mistaken for a yellowjacket, but can be recognized by its largely yellow or orange antennae. European paper wasps appear to be displacing native wasps in some regions, and I have to say they seem to be growing a bit too common a bit too fast for me to truly embrace them.

While they differ in their origin, both our paper wasps have similar life histories. Queens — that is, fertile females — overwinter in sheltered sites (often in attics or sheds). Rousing themselves in spring, they begin building their paper nests and laying eggs in the cells. The resulting offspring, all sterile female workers at first, mature and help the queen add onto the nest; the colony may reach a population of 30 or so by season’s end. While adults eat pollen or nectar from flowers, the young are fed bits of insects that adults have caught (around my yard, asparagus beetle grubs must make up much of their diet!).

As the season progresses, fertile females and males begin to hatch as well, and some of these will mate. These fertilized queens will seek shelter so they can repeat the cycle, while males and unfertilized females die with the onset of cold weather. (In the case of the European paper wasp, a few sterile females may survive and help a colony get started the following spring.) Nests are not reused in subsequent years.

Investing a great deal of effort into building their nests, paper wasps will defend them by ganging up to sting the daylights out of interlopers. But paper wasps are notably harder to annoy than yellowjackets, and are considerate enough to (usually) give a warning before they attack: alarmed wasps stare fixedly straight at whatever they perceive as a threat, giving intruders a few moments to back off safely.

Away from the nest, paper wasps are docile animals. They will still sting if they feel their lives are threatened — for example, if you inadvertently begin squishing one. But they rarely take offense at mild or accidental disturbance, and while I’m photographing insects, I readily poke a paper wasp out of the way with a finger if it is photobombing my intended subject.

Having a colony of stinging insects in your yard sounds scary, and to be sure, even I don’t generally allow nests to be completed in high-traffic areas, such as right outside a door. But in general, paper wasps are good neighbors, keeping to themselves. And their predatory habits make them a gardener’s friend.