General behaviour

Most species are solitary and build their nests on the ground or in fallen trees. Honey bees, stingless bees and, to a lesser extent, also bumble bees build complex social (eusocial) colonies. Bumble bee colonies are generally small, usually consisting of only several dozen individuals.

Honey bee colonies consist of several thousand individuals.

Wasps of the Vespidae family form obvious social colonies. Hornets and yellowjackets build papery nests. Like most social wasps they build them from plant fibres that they chew and then mix with saliva. Depending on the species, the nests are constructed either underground or aboveground. The lifespan of each colony is generally one year, and only the queen hibernates, to establish a new colony each spring. Vespula vulgaris form the largest colonies, with 5,000 workers or more; the colonies of most other Vespinae are considerably smaller.

Social wasps are often found in large numbers in close proximity to humans, attracted in particular by sweet drinks and food or meat products.

Most species form highly developed societies with usually a single queen, workers (females) and males. In addition, many species have workers of various morphological forms, which carry out different functions. Thus there are often soldiers, which are responsible for the defence of the colony.

Fire ants of the Americas are not only common in rural regions but also in urban areas, but they generally do not enter houses.

Habitats

Often in agricultural zones, but also in forested areas and mountainous regions.

Widely distributed in various habitats.

Widely distributed in various habitats.

Appearance

Hairy bodies. Often packed with pollen.

Less hairy than bees. Hornets with a body length of 4–5 cm, yellowjackets up to 2 cm.

The males and often also young queens possess wings, while these are absent in workers and soldiers.    

Defensive behaviour

If a victim is stung close to a bee colony, rapidly other individuals are attracted and induce defensive behaviour,

since the stings of bees release alarm pheromones.

The Africanized honey bee may pursue intruders for a distance of 200–1,000 m, and the average time it takes for an angry colony to settle again is approx. 30 min! In comparison, Italian honey bees will pursue an invader over a radius of only about 20 m and take only around 3 min to settle again after going on the alert.

A cornered wasp will not hesitate to sting, and close to the nest, wasps and hornets demonstrate aggressive collective defensive behaviour towards enemies of the colony.

As with many other species fire ants are characterised by aggressive defensive behaviour, in that they sting fiercely several times in succession. In their areas of distribution in the USA they are the main cause of hymenoptera sting allergies.

Jack jumper ants from Australia and Tasmania (Myrmecia pilosula, Myrmeciinae) represent a serious cause of hymenoptera sting allergies there. They are considered highly aggressive, as they can jump at their victim from a distance of up to 10 cm in order to sting.

Factors relevant to envenoming

Sting remains in the elastic skin of humans. Sting should be carefully removed from the skin – if possible using tweezers – to avoid squeezing more venom from the attached venom sac into the wound.

Hornets stings are not significantly more serious than those of other wasps or bees. Unlike in bees the sting is retracted again after the attack.

Ant stings or bites are unpleasant, but are generally limited to local effects, even in the case of multiple stings. However, as with other hymenopteran stings, they can be dangerous if allergic reactions occur in pre-sensitised patients.