Can a Wasp Sting More Than Once? How Wasp Stingers Work

How does a wasp stinger work?

A wasp’s stinger is a modified ovipositor, the egg-laying tube that female insects of this group inherited from their ancestors. In stinging wasps it no longer lays eggs; instead it injects venom. When it is not in use, it is drawn back inside the tip of the abdomen, out of sight.

The stinger is made of three slender parts that fit together like a sliding rail. A central stylet guides two needle-like lancets, which slide back and forth alternately, working their way into the skin. Venom made by glands in the abdomen is stored in a small reservoir, the venom sac, and muscles pump it down the channel between the lancets into the wound. The whole sting takes only a moment.

Smooth versus barbed stingers

Whether a stinging insect can sting again depends mainly on the barbs on its lancets.

The honey bee worker is the famous exception. Its barbs anchor in elastic mammal skin, so as the bee pulls away, the stinger and venom sac tear out of its body and the bee dies; do bees die after they sting? explains why. When a honey bee stings another insect, its barbs do not catch in the hard shell, and it can sting again too.

Why don’t wasps die when they sting?

A reusable stinger suits the way wasps live. Many wasps use their stingers not only for defense but also for hunting, paralyzing or killing insects and spiders to feed their young. A weapon that broke off after one use would be useless to a hunter.

Social wasps such as yellowjackets mostly kill prey with their jaws, but they still benefit from being able to sting repeatedly. A guard wasp that survives can defend the nest again, while a honey bee’s one-time sting is thought to be an adaptation against large mammals raiding the bees’ long-lived store of honey. Common wasp nests last only a single season and hold no honey reserves.

Each sting uses up part of a wasp’s limited venom supply, so a wasp stinging several times in quick succession probably injects less venom with each sting, although every sting still hurts.

What is in wasp venom?

Wasp venom is a complex mixture rather than a single poison. It contains:

• Amines such as histamine and serotonin, which cause immediate pain, redness and itching.
• Peptides, small proteins including kinins, which add to the pain, and mastoparans, which make cells release histamine.
• Enzymes such as phospholipase, which damages cell membranes, and hyaluronidase, which helps the venom spread through tissue.
• Antigen 5, a protein that, together with phospholipase, is a major cause of allergic reactions in sensitive people.

The common wasp is so important in allergy research that the standard names of several wasp venom allergens, such as Ves v 1 and Ves v 5, come from its scientific name, Vespula vulgaris. Wasp venom differs from bee venom, which is why some people are allergic to one but not the other.

Alarm pheromones: why one sting can lead to more

Wasp venom carries alarm pheromones, scent chemicals that tell other workers there is danger. When a wasp stings, or is crushed, near its nest, nestmates detect the scent and become far more likely to fly out and attack whatever is nearby. This is why disturbing a nest, for example while mowing or digging, can lead to many stings within seconds.

Away from the nest, a single foraging wasp that stings usually flies off. Swatting or squashing a wasp near others, however, can release alarm signals and make nearby wasps more defensive.

Why male wasps cannot sting

Because the stinger is a modified egg-laying organ, only females have one. Workers and queens can sting; males cannot. Male common wasps hatch from unfertilized eggs in late summer and spend their short lives feeding on flowers and searching for queens to mate with. They can be recognized by their longer antennae and slimmer bodies, and they die in autumn.

Not every female wasp can sting a person, either. Most parasitoid wasps, the largest group of wasps, have ovipositors used only for laying eggs in other insects. True stings belong to the stinging wasps, bees and ants, which form a group called the Aculeata.

How dangerous are wasp stings?

For most people, a wasp sting causes sharp pain, redness and swelling that fade within hours or a few days. A small share of people are allergic, and for them a single sting can cause anaphylaxis, a severe whole-body reaction. Dozens or hundreds of stings at once, usually from a disturbed nest, are dangerous even without an allergy.

In the United States, the Centers for Disease Control and Prevention counted an average of about 62 deaths a year from hornet, wasp and bee stings between 2000 and 2017, most of them linked to allergic reactions. Stings are most frequent in late summer, as described in why are wasps more aggressive in late summer?

The best protection is respect: stay calm, do not swat, and keep away from nests. If someone stung has trouble breathing, swelling of the face or throat, or feels faint, seek emergency medical help immediately: call 911 in the US, 112 in the EU or 999 in the UK.