The stinging behavior of social wasps, such as yellow jackets and hornets, is primarily defensive. Unlike honey bees, which die after stinging once, most wasps have a smooth stinger allowing them to sting repeatedly. They deploy their venomous stinger only when they perceive a threat to their colony, their physical safety, or when they feel trapped.
Stinging When Defending the Nest
The most dangerous scenario for a sting is when a wasp colony is disturbed, triggering a fierce, coordinated defensive response. Wasps, particularly yellow jackets, are highly territorial and will defend their nest, which may be located in ground cavities, wall voids, under eaves, or in tree hollows.
Any movement, vibration, or noise within the colony’s “guard radius” can trigger a mass defensive attack. Vibrations from foot traffic, lawnmowers, or tapping on a surface containing the nest can signal an alarm. When a wasp stings, it releases an alarm pheromone that alerts its nest mates, prompting them to swarm and join the attack.
Stinging Due to Accidental Physical Contact
Wasps sting as an act of self-preservation when they feel physically threatened or restrained, even if the contact was unintentional. This localized sting involves only the individual wasp, reacting out of panic rather than territorial aggression. Common examples include stepping on a foraging wasp or accidentally sitting on one that has landed on furniture.
A wasp may also sting if it becomes trapped inside clothing, a shoe, or a glove. Swatting at a nearby wasp can also provoke a sting, as the insect interprets the fast movement as an aggressive act.
Stinging Caused by Foraging Attraction
In late summer and autumn, social wasps shift their diet from protein-rich insects to sugary foods for their own energy needs. This explains why wasps become a nuisance around outdoor dining, attracted to human foods like soda, fruit juices, ripe fruit, and sweet desserts. They are also drawn to open garbage containers and fallen fruit.
Stings occur when a foraging wasp is inadvertently trapped or consumed while feeding. A common scenario is drinking from an open can or bottle where a wasp has crawled inside, leading to a sting in the mouth or throat. To avoid stings, keep all food and drinks covered outdoors and clean up spills immediately. Avoiding bright colors and strong floral or sweet scents can also reduce attraction.