Many of us use the words hornet and wasp interchangeably, but that's a vast overgeneralization that does a disservice to these winged creatures. Understanding the differences between hornets and wasps might help you to make better pest control decisions, prevent you from killing beneficial species, and of course, maybe keep you from getting a painful sting.
Here's the biggest thing to know: All hornets are wasps, but not all wasps are hornets.
"Hornets are just a kind of wasp," says Jason Gibbs, assistant professor of entomology at the University of Manitoba in an email interview. "Wasp is a very broad term that covers many different species with different lifestyles."
There are more than 100,000 wasp species on Earth, each a testament to the startling diversity in these winged bugs. They're found in every part of the world except polar areas. It's usually easy to identify them, as they most often have black and yellow stripes, a well-defined and narrow waist, and a tapered abdomen.
Hornets are generally a little chubbier and larger than their svelte wasp brethren, and some species forego common yellow and-black striping for white and black markings. Their increased size means they also carry a substantial load of venom, so in some cases these insects are more dangerous than other kinds of wasps. Fortunately, if you leave hornets and wasps alone, they generally want nothing to do with you, either.
Wasps and hornets chew up wood fragments and use the resulting pulp to build their signature papery nests. You'll find these nests, which have a honeycomb-style segmentation, on many horizontal surfaces, including roof eaves, garage ceilings and other places, dangling from a single thin thread. Some hornets, like the giant European hornet, may also burrow into the ground to build nests. Their nests may be as large as a foot in diameter.
"Hornets are predators [and] scavengers, as are most wasps," says Gibbs. "From an evolutionary perspective, bees are also wasps." Wasps, like bees, are incredibly important pollinators, helping plant to keep plant life and agricultural crops healthy. They tend to chow down on caterpillars and harmful flies, too, making them beneficial to humans. That's one reason some places, like Germany, ban people from disturbing these creatures.
Wasps also exhibit a voracious affinity for sugary foods and drinks, and as such they often make themselves unwelcome guests at outdoor gatherings like picnics or sporting events.
Furthermore, they also love the sweet deliciousness of rotting, fermented fruit that falls to the ground in autumn. They'll gorge themselves to the point that they'll become drunkenly aggressive, sometimes chasing pets or people if they feel annoyed or threatened.
As their natural food sources continue to dwindle in the fall, these insects may become even bolder, one reason you should limit easy access to human foods. That keeps you – and the wasps – safe from harm.
While hornets may eat fruit or picnic food, they're much more likely to feed on insects, like crickets and grasshoppers.
Social and Solitary Wasps
Wasps are broadly divided into two categories: social and solitary species. Social species feature species such as paper wasps, yellowjackets, and yes, hornets.
Most wasp species are regarded as solitary. Females live alone and reproduce using some notable techniques, including laying eggs on other insects (like spiders) which they paralyze and hold hostage in their own nests, eventually killing the hosts which serve as food for wasp larvae.
Social species, on the other hand, live in large colonies — in populations often exceeding 100 members — with an egg-laying queen, as well as workers that do not reproduce.
"Wasps and bees have evolved social behavior more often than any other group of animal, and interestingly have lost it many times too," says Gibbs. "Eusocial behavior (basically overlapping generations with reproductive division labor, i.e. queens and workers) has evolved multiple times in the animal kingdom."
This behavior has also been recognized in sweat bees, Gibbs' area of expertise. "Sweat bees are particularly interesting for studies of social evolution because they are so many back-and-forths in the evolutionary tree. In fact, you can have eusocial and solitary nests within the same species," he says. "It's incredibly complex and interesting and, wonderfully, all of this is going on under our noses."
Yellowjackets are yet another type of social wasp. They're smaller and build ground nests that may feature hundreds of individuals. Some people mistake these pint-sized wasps (which have bodies around half an inch long) for bees. As their ground nests expand, the soil becomes looser and creates a sinkhole. If you're unlucky enough to step into one of these sinkholes, you may find yourself at the mercy of hundreds of angry yellowjackets.
Avoiding Wasp and Hornet Stings
Solitary wasps, like mud daubers, rarely sting. That's true even if you disturb their nests. They don't attempt to defend them.
Social wasps and hornets, on the other hand, can be extremely aggressive if you threaten their lives or their nests. Often, they'll swarm intruders and deliver multiple stings. Swatting at wasps is, shall we say, a bad idea. Doing so triggers the insect to release pheromones alerting other wasps to a threat (you) and that it's time to attack.
Even one wasp sting can be very painful. Multiple stings might cause serious harm, particularly to anyone who's allergic to the venom. And in worst-case scenarios, wasps might sting dozens or hundreds of times, an act that can kill even strong, healthy people who aren't allergic to the venom.
The best strategy is to keep food covered if outside, particularly sugary drinks, so you don't attract wasps. If one wasp flies near you, remain calm; it will probably just fly off. If a swarm comes near you, run away in a straight line without waving your arms.
Editor's Note: The splitscreen image has been updated to include a photo of a hornet. The previous image incorrectly showed a picture of a moth. Also, Gibbs' comments on eusocial and solitary nests within the same species have been expanded to show that he was referring to sweat bees rather than wasps and hornets.