What do wasps do? What good could a wasp possibly be? When most people think about wasps, they think about being stung. Indeed, wasps do sting, and wasp stings hurt. To make matters worse, some wasps can be downright nuisances—they build nests under our eaves or in our lawns and swarm around our guests at backyard barbecues. If this has been your experience with wasps, you're probably wondering if we need these pests at all. So what do wasps do, and are wasps useful?

1:26 Watch Now: Wasps Do Surprisingly Cool Things

Some Benefits of Wasps

Paper wasps, hornets, and yellowjackets all belong to the same family—the Vespidae—and they all provide extraordinarily important ecological services. Specifically, they help us through pollination, predation, and parasitism. Put simply, without wasps, we would be overrun with insect pests, and we would have no figs—and no Fig Newtons.

Hornets and paper wasps prey on other insects and help keep pest insect populations under control. For instance, paper wasps carry caterpillars and leaf beetle larvae back to their nests to feed their growing young. Hornets provision their nests with all manner of live insects to sate the appetites of their developing larvae. It takes a lot of bugs to feed a hungry brood, and it's through these needs that both hornets and paper wasps provide vital pest control services.

Yellowjackets don't get quite as much credit for being beneficial, although they should. Yellowjackets mostly scavenge dead insects to feed their offspring, meaning they prevent the bodies from piling up—like a cleaning service. Unfortunately, their scavenging habits and love of sugar puts them in close proximity to people, which almost never ends well for the yellowjacket or the person.

Wasps and Yeast

Researchers at the University of Florence recently discovered another important role of both hornets and paper wasps: They carry yeast cells in their guts.﻿﻿ Yeast is an essential ingredient in making bread, beer, and wine, but we know very little about how yeast lives in the wild. The researchers found that wasps and hornets feed on late-season grapes, which are rich in wild yeast. The yeast survives the winter in the stomachs of hibernating queen wasps and is passed on to their offspring when they regurgitate food for their young. The new generation of wasps then carries the yeast back to the next season's grapes. So, raise your glass to the wasps and hornets.

New Zealand Eradication Program

In some cases, however, the costs of wasps—particularly for invasive species—far outweigh the benefits. In 2015, the Department of Conservation and Ministry for Primary Industries in New Zealand looked into the economic costs of the invasive species of German wasps (Vespula germanica) and common wasps (V. vulgaris) across industries, society, and the natural environment. They found that wasps cost the country NZ$75 million each year and projected a total cost of NZ$772 million between 2015 and 2050; 80% of this is associated with wasp predation on honeybees and its impacts on pollination.﻿﻿ Wasps kill bees and their larvae for protein, rob hives of honey, and consume 50% of the available honeydew, a food source for bees.

The same year, the Department of Conservation ran a pilot program on five public conservation land sites, testing a government-backed wasp bait called Vespex. Officials saw a reduction of more than 95% of wasp activity.﻿﻿ In early 2018, the New Zealand government began distributing information on how to set up wasp bait traps.