Hornets and yellowjackets are species of wasps common in North America that belong to one taxonomic family, called Vespidae (and bees are another insect entirely). Vespids are known for their caste systems (meaning they live in communities with a queen and workers), and all have wings that are able to fold in half.
Here are 10 fascinating facts about wasps in the Vespidae family—and a few notable others—that prove they’re more than just stinging insects.
1. There are 4932 known vespids, and not all of them are aggressive.
You may think that all wasps are make beelines towards humans, but this couldn’t be further from the truth. Wasps are divided into two categories: social wasps and solitary wasps. Social wasps are further classified into three groups—hornets, yellowjackets, and paper wasps—and live in colonies in communal nests. They’re carnivorous and more aggressive towards humans, which can result in stings. Solitary wasps, on the other hand, often live in individual nests in the ground and aren’t dangerous to humans unless provoked. In fact, they’re valuable pollinators and feed on smaller insects and spiders, depending on their species.
2. Wasps live on every continent except Antarctica.
While wasps live in all of the world’s temperate regions, there has been at least one case of unusual transcontinental migration in recent years. Nests of the Asian giant hornet, native to East and South Asia, were found in the Pacific Northwest of North America in 2019, 2020, and again in 2021, creating concern that the bee-eating species will become invasive in that region. USDA pest response guidelines suggest that the giant hornet may have arrived in the U.S. in a shipment of goods from Asia [PDF].
3. Yellowjacket venom contains a pheromone that encourages other yellowjackets to attack.
Yellowjackets are one of the most familiar and aggressive wasps in American backyards. They often nest in the ground and defend their turf at all costs. “When a yellowjacket stings, it tags the victim with an alarm pheromone that may last for hours,” writes Alabama Cooperative Extension Service specialist Xing Ping Hu. The chemical tag marks the victim as a threat and makes him or her a potential target for other yellowjackets. Unfortunately, pretty much anything can make yellowjackets mad, such as walking near their nests or mowing the lawn over their colonies.
4. Many wasps raise their young on live insects.
While this habit varies by species, it’s common for social wasps to feed their offspring a diet of live insects [PDF], which can include pests that harm cultivated plants. Yellowjackets are an exception—they scavenge dead insects, worms, and garbage.
5. Paper wasps make their nests out of, well, paper.
Species in the subfamily of wasps known as paper wasps chew up bits of wood and bark, mixing it with their saliva, and spit out a rough papery pulp. They form the substance into nests, which can contain individual cells facing downward or resemble a gray football. Paper wasp nests are often located on trees, in vegetation, or under the eaves of homes.
6. Some wasps use color to send messages.
Many wasps fend off predators with distinctive yellow and black bands on their abdomens, but this isn’t true of all species. Wasps sport a variety of colors, including red, blue, green, and orange. The steel blue cricket hunter, for instance, is a blue solitary wasp, while the cicada killer wasp is orange. Bright colors are meant to serve as a warning to other species, while darker colors help the insects blend in with their surroundings.
7. A species of wasp in Brazil could help battle cancer.
Polybia paulista, a species of wasp found in Brazil, Uruguay, and Argentina, produces a compound called Polybia-MP1 that has been heavily studied for its anti-cancer, antifungal, and antibiotic properties. The chemical can attack cancer cells in humans without damaging healthy cells, raising hopes that it could provide new therapeutic options for treating disease.
8. The family Mymaridae contains the world’s smallest known insects.
Fairy flies, a.k.a. fairy wasps, are a family of about 1400 wasp species native to tropical climates. They grow up to 1 millimeter in length, making them the world’s smallest insects known to science. Though parasitic fairy flies are small, they play an important role in agriculture by laying their eggs in the bodies of crop pests, effectively killing them.
9. Some pollinating wasps are highly specialized.
Like bees, wasps play a big role in our ecosystem as pollinators, though wasps are generally not covered in fuzzy hairs so they’re not as efficient at pollen transfer. A particularly important family of pollinating wasp is Agaonidae, the fig wasps. Each of the 900 species of fig wasp is specialized to pollinate one of 900 species of fig.
10. Wasps inspired an extreme fashion trend.
One popular Victorian women’s fashion trend involved these cinch-waisted insects. A woman achieved a “wasp waist”—an extremely narrow waist compared to the proportions of her bust and hips—by tightly lacing a restrictive corset. Some doctors warned against the practice, because repeated tight lacing had the potential to damage the wearer’s lungs, stomach, and rib cage.