Know your stingers

By: Dr. Susan Jones

Subtle identification differences can help you predict behavior

If you have been stung by a bee, hornet or wasp, you can be certain that it was a female! In this group of insects, the aculeate Hymenoptera, only females possess a stinger – whose primary function is to inject venom. The stinger is a modified egg-laying apparatus, called an ovipositor, which is attached to poison glands. In aculeate Hymenoptera, eggs emerge from the base of the ovipositor rather than passing through it. Many other hymenopterans have a piercing ovipositor, but do not sting humans. Sawflies and most parasitic wasps have ovipositors that are used only to lay eggs.

Stinging incidents occur because hymenopterans are actively defending their nests or themselves. The majority of stings are more likely attributable to wasps and hornets than to honey bees. Each female wasp and hornet can sting numerous times. On the other hand, a female honey bee is capable of stinging only once because her barbed stinger imbeds in the victim. Other types of bees (bumble bees, sweat bees, carpenter bees, etc.), however, have a relatively smooth stinger, and each female can sting numerous times.

Social status and outsiders

Solitary bees and wasps are not inclined to sting and will usually do so only when physically contacted. In the solitary Hymenoptera, individuals live independently of each other and do not share a common nest; males of some species play a role in nest defense. 

Males of social bees and wasps are produced when temperatures are mild, often during autumn. They remain in the nest until new queens emerge, then mating occurs outside the nest. Males of solitary bees and wasps, especially those of the carpenter bee and cicada killer wasp, defend territories where females have located their individual burrows. If you enter one of these territories, the males may buzz back and forth in front of your face. These males may also strike you in the head or back! Although the males cannot sting, who takes the time to determine the sex of a buzzing bee, wasp or hornet?When multiple stinging insects are encountered in a stinging incident, however, you probably are dealing with a social bee or wasp. Social species are those in which numerous individuals live together in colonies. These colonies are comprised primarily of females; males are seasonally produced and are short-lived, primarily serving as sperm donors.

Bees, wasps and hornets are considered beneficial insects that are important pollinators or predators of other pest arthropods. Control measures should be implemented only when stinging insects pose a threat to human health. 

A small percentage of the human population is hypersensitive to insect stings and may experience anaphylactic shock, even death. For the most part, humans suffer less severe reactions, primarily pain, reddening and localized swelling at the site of the sting. Approximately 6 to 10 honey bee stings per pound of body weight can be tolerated by a healthy human or pet, and higher levels of envenomization may be life-threatening. However, the venom of some species is more toxic than others. For example, velvet ants, a type of solitary wasp, are commonly called “cow killers” because of their potent and painful sting.

The basic physical and behavioral characteristics of the common types of stinging insects are outlined in the chart (see page 29 and below). By understanding their nesting habits, you can pinpoint control measures and take needed safety precautions.