Why These Insects Sting 

- Venom is injected along with the stinger -

Summary: Wasps, bees and ants sting in defense of their colonies and in some cases to capture prey. Stings to humans can sometimes result in a very serious allergic condition called anaphylaxis.

Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)

Why do wasps, bees & ants sting?

Wasps, bees and some ants use a modified egg-laying apparatus called an ovipositor (stinger) to subdue prey and to defend their nests. While these insects sting rather than bite to inflict injury they may also use their mandibles to bite in order to anchor themselves before delivering the sting.

Venom is often injected into the wound made by the sharp stinger. The venom contains chemicals that cause pain and may contain toxic proteins. In humans these proteins may induce serious allergic reactions in some individuals. Most of the danger from hymenopteran* stings is from the injection of toxic proteins. About 1-3% of the population is highly allergic to these proteins resulting in a life-threatening reaction called anaphylaxis.

*Hymenoptera is the insect order that contains wasps, bees and ants.

yellowjacket wasp stinger

Yellowjacket wasp with stinger exposed. Original drawing from USDA Ag. Handbook Number 552.

Some dangerous Hymenoptera

A few Hymenoptera are particularly notorious for the potency of their venom and stings. Jackjumper and bulldog ants are native to Australia, New Zealand and Tasmania. Fire ants (Solenopsis spp.) are native to the topics but have invaded parts of North America and Australia. Harvester ants (Pogonomyrmex spp.) are large reddish-brown ants found mainly in drier parts of western North America.

Some reports indicate that harvester ant venom is the most toxic of all insect venom to mammals. It's a good thing that only a very small amount is delivered with each sting!

Yellowjacket wasps (Vespula spp.), hornets (Vespa spp.) and paper wasps (Polistes spp.) occur world-wide. Paper wasps are generally not as threatening  or aggressive as the other species. Finally, the Africanized honey bee is a highly aggressive strain, or subspecies, of honey bee (Apis mellifera) that has invaded South America and southwestern North America.

How dangerous are ant, wasp and bee stings?

Stings from wasps, bees and ants are dangerous because of the small amount of foreign protein, or venom, that is injected. This venom causes localized swelling and pain in most people but can trigger a severe anaphylactic reaction in a small percentage of susceptible individuals. Even a single sting can start the reaction but multiple stings are increasingly dangerous.

Serious anaphylaxis usually occurs quickly following a sting. Anaphylaxis can even occur in individuals who have experienced no prevous reaction. Carefully watch for the symptoms of anaphylaxis following all stings for at least 30 minutes. Seek medical attention immediately if symptoms develop. For less serious reactions most people simply apply ice to the swelling. Since nearly all of the reaction to hymenopteran stings is related to the allergic reaction some people have found antihistimine (otc allergy) medications to be useful. Anti-venoms, in the usual sense, are not used in the treatment of hymenopteran envenomization. However, some venoms are collected for use in desensitization therapy ("allergy shots").

Related Articles

What are Fire Ants?

The European Paper Wasp

The "Killer" Bees

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