Wasps: What to Know

Medically Reviewed by Mahammad Juber, MD on January 17, 2023
5 min read

When you think of wasps, you might first think of an insect that wants to sting you. However, of the thousands of species of wasps in North America, most are harmless to humans. Even the bothersome ones are beneficial because they are significant pollinators and feed on nuisance insects that can harm plants. 

Some wasps do have very painful stings that can be fatal to people who are allergic. Understanding which wasps pose a threat can help you decide the best way to manage them.

There are two main types of wasps: solitary wasps and social wasps.

Solitary wasps, such as mud daubers and cicada killer wasps, are rarely a problem for people. They don't build large colonies. Though they do have venom, they use it to paralyze their prey. They aren't aggressive and will only sting if pressed against your skin. These wasps are beneficial and don't need any control. If a mud dauber builds its nest — a tube-like, mud-colored structure — in an inconvenient place, you can simply knock it down and wash away the debris with a garden hose. 

Social wasps, which are the types of wasps that live in colonies, begin with a queen who hibernates over the winter. The queen will start building the nest and laying eggs in the spring when the weather warms. The eggs will hatch into larvae, then pupae, and will finally become adult wasps. The queen cares for the first eggs, larvae, and pupae, but once these are grown, they take over caring for new eggs. The queen is then free to focus solely on laying more eggs. By the end of summer, some colonies can have up to 5,000 adult members. 

Social wasps live in large colonies where they have specific roles, and the workers will aggressively defend the nest. The most common types of social wasps you're likely to encounter include: 

Paper wasps. Paper wasps are usually brown with yellowish markings and long legs that hang beneath them as they fly. European paper wasps are often mistaken for bees because they're black with yellow markings. They capture insects such as caterpillars, flies, and crickets to feed their larvae, but adults feed on nectar and other sources of sugar. They build their nests underneath horizontal surfaces such as eaves, limbs, and overhangs. 

Bald-faced hornets. Though they're named hornets, bald-faced hornets are a species of yellowjackets. They are black with white markings on the face and the tip of the abdomen. Like paper wasps, bald-faced hornets feed their young insects, and the adults eat nectar. They build their nests in shrubs or trees, or under the eaves of buildings. Their nests are gray and pear-shaped, about the size of a basketball. 

Yellowjackets. Other yellowjacket species build nests underground. Many of these species are medium-sized wasps with jagged yellow and black bands. Many species of yellowjackets are aggressive not only in defending their nests but also when foraging for sugar sources.

Although wasps are beneficial, they pose a serious health risk, particularly to people who are allergic to them. Around 225,000 emergency room visits and 100 deaths per year are due to wasp stings. When wasps feel their nest is threatened, they can coordinate a defensive attack. Most stinging wasps can sting repeatedly. 

The most significant risks you face from wasp stings are infections and allergic reactions. However, the majority of stings only cause minor discomfort. Unless you have a severe reaction or are stung multiple times, you can treat a wasp sting at home. Some people develop large, localized reactions that don't usually lead to more serious general reactions unless they occur in the nose, mouth, or throat area. Swelling in these areas can cause difficulty breathing.

If you have a localized reaction to a wasp sting, such as redness, swelling, itching, and pain at the site, wash it well with soap and water. Remove the stinger by scraping over the area with an object such as a credit card or dull knife. If the sting occurs on your arm or leg, elevate it to help with the swelling. Apply a cold pack wrapped in a cloth to the area for 10 minutes, then remove it for 10 minutes, for a total of 30 to 60 minutes. 

Take acetaminophen or an over-the-counter antihistamine — with your doctor's approval — for pain or itching. You can also use an over-the-counter cream for insect stings. 

Call 911 or seek immediate medical help if a more serious reaction occurs, such as: 

  • Chest or throat tightness
  • Trouble breathing
  • Wheezing
  • Nausea or vomiting
  • Sweating
  • Dizziness or fainting
  • Anxiety
  • Hives that cover a large part of your body

Prevention is important in controlling foraging wasps. Place food garbage in containers with tight-fitting lids to avoid attracting wasps. You can also set out traps for them by placing a piece of fish suspended above a container of water with a few drops of dish soap. The rotting fish will attract them, and they'll break off a piece too heavy to carry. When they fall in the water, the soap will prevent them from escaping. 

If your problem is a wasp's nest, you're better off catching them early in the year. Smaller nests are easier to knock down. If the nest is larger, wait until night when most of the wasps have entered the nest and spray it with insecticides formulated for wasps and hornets. Observe the nest so you know where the entrance hole is. Take a red flashlight or cover a regular flashlight with red cellophane. Wasps can't see red light, and they'll instinctively go towards light and attack if you use a regular flashlight. 

Wear protective gear such as goggles, long sleeves, and gloves. You're likely to get stung treating a nest, so if you have a history of allergic reactions, call in a professional. Don't attempt to remove an above-ground nest by covering it with a trash bag because they can easily escape.