# Wasp — Facts, Threats & Conservation

*Order Hymenoptera, suborder Apocrita (excluding ants and bees) — over 100,000 described species*

> Wasps are hymenopteran insects — over 100,000 species — of which the great majority are tiny solitary parasitoids; social wasps such as yellowjackets are a small minority that act as major predators of pest insects and as pollinators.

**IUCN status:** Group page — the vast majority of species are solitary, tiny and unassessed  ·  **WARN range:** Worldwide except polar regions, Every terrestrial habitat; some species introduced far outside their native range

## Quick facts
| Fact | Value |
| --- | --- |
| Described species | 100,000+ |
| Social species | Well under 1% of the total |
| Colony cycle | Annual — only mated queens overwinter |
| Sting | Females only; modified ovipositor, not barbed |
| Larval diet | Animal protein, unlike bees |
| Key mutualism | Fig wasps pollinate ~900 fig species |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Insecta
- **Order:** Hymenoptera
- **Suborder:** Apocrita (excluding ants and bees)
- **Notable families:** Vespidae (social wasps), Ichneumonidae, Braconidae, Agaonidae (fig wasps)

## Conservation status
- **Status:** Varies by species — group page
- **Population:** Not applicable at group level
- **Trend:** Largely unmonitored; declines suspected alongside wider insect decline
- **Assessed:** Very few species assessed
- **CITES:** Not listed
- Parasitoid wasp diversity is poorly documented, and many species are thought to be undescribed. Broad-spectrum insecticide use is the clearest documented pressure.

## Key facts: Wasp
- Over 99% of wasp species are solitary, and most are parasitoids that never interact with people.
- Social wasp colonies are annual: workers die in autumn and only mated queens overwinter.
- Wasps are significant predators of caterpillars, aphids and flies, and are also pollinators.
- Fig wasps and figs have a mutual dependency — no fig wasps, no figs.
- Only female wasps sting; the sting is a modified ovipositor, which is why males cannot.
- Late-summer 'aggression' is a colony with no brood left to feed, switching to sugar sources.

## The 99% nobody sees
Most wasps are parasitoids: a female locates a specific host — a caterpillar, aphid, beetle larva, spider or egg mass — and lays an egg in or on it. The larva develops by consuming the host. Many are under a few millimetres long, and some of the smallest insects known are parasitoid wasps.

This makes wasps a foundational regulator of insect populations. Agricultural biological control relies heavily on them, with species such as Trichogramma and Encarsia reared commercially by the billion. Remove parasitoid wasps and herbivorous insect populations increase sharply — an outcome measured wherever broad-spectrum insecticides have wiped them out.

## How a social wasp colony runs
In spring a single overwintered queen starts a nest alone, chewing wood into paper pulp, building the first cells and raising the first workers herself. Those workers take over foraging and construction, and the colony grows through summer, reaching hundreds or thousands of individuals.

Throughout that growth phase, workers hunt protein — caterpillars, flies, aphids — to feed the larvae, and in exchange the larvae secrete a sugary fluid the adults consume. In late summer the colony produces new queens and males, brood rearing stops, and the sugar supply from larvae ends. Workers, now with no purpose and no larval sugar, go looking for it in fallen fruit, drinks and bins. That is the entirety of the 'wasps get aggressive in September' phenomenon.

## Figs, pollination and mutualism
Fig wasps (family Agaonidae) and fig trees are locked into one of the tightest mutualisms known. A fig is an inverted flower cluster; a female fig wasp enters through a narrow opening, usually losing her wings and antennae doing so, pollinates the flowers inside, lays eggs and dies. Her offspring mature inside the fig, mate, and the females leave carrying pollen to the next tree.

Most of the roughly 900 fig species depend on a specific wasp species, and those wasps depend entirely on their fig. Figs are a keystone food resource for tropical birds, bats and primates, which makes this obscure partnership between a tiny wasp and a tree one of the load-bearing relationships in tropical forest ecology.

## Living alongside them
Wasps sting defensively — around the nest, or when trapped against skin. Unlike honey bees they can sting repeatedly, since the sting is not barbed. Only females have one, because it is a modified egg-laying organ.

Practical coexistence is straightforward: keep bins closed and sweet drinks covered in late summer, do not swat (crushed wasps release alarm pheromone that recruits nestmates), move away calmly, and leave nests alone unless they are genuinely in a high-traffic location. Nests are not reused the following year, so an out-of-the-way nest can simply be left until the colony dies naturally in autumn.

## What WARN does
WARN publishes free, sourced species education for the animals people are most inclined to kill on sight. Wasps do a substantial share of the predation and pollination that keeps gardens and farmland functioning, and the gap between their reputation and their record is one of the widest in the animal world.

If this guide helps you understand wildlife and the pressures it faces, a gift to WARN supports habitat protection and free public education in our partner countries.

## Frequently asked questions: Wasp
### What is the point of wasps?
Wasps are major predators of pest insects — a single social colony removes thousands of caterpillars, aphids and flies in a season — and they pollinate while foraging. The 100,000-plus solitary parasitoid species regulate insect populations across every terrestrial ecosystem, and fig wasps are the sole pollinators of figs, a keystone tropical food resource.

### Why do wasps get aggressive in late summer?
Social wasp colonies stop rearing brood in late summer. Until then, workers were fed a sugary secretion by the larvae they cared for. When that stops, workers seek sugar elsewhere — fallen fruit, drinks, bins — which brings them into contact with people. The behaviour is hunger and colony collapse, not increased aggression.

### Are all wasps able to sting?
No. Only females can sting, because the sting is a modified ovipositor. Most of the world's wasp species are tiny parasitoids whose ovipositor is used to lay eggs in host insects and cannot penetrate human skin.

### What is the difference between a wasp and a bee?
Bees evolved from wasps and switched to feeding their young on pollen and nectar; wasps feed their young on animal protein. Bees are generally hairier, with branched hairs that carry pollen; wasps are smoother and more sharply waisted. Both belong to the order Hymenoptera.

### Do wasps reuse their nests?
No. In temperate regions a paper wasp or yellowjacket nest is used for a single season. The colony dies in autumn, only mated queens survive the winter, and each builds a new nest in spring. An old nest can be removed safely once the colony has died.

### What do wasps eat?
Wasps eat Animal protein, unlike bees. Wasps are hymenopteran insects — over 100,000 species — of which the great majority are tiny solitary parasitoids; social wasps such as yellowjackets are a small minority that act as major predators of pest insects and as pollinators.

### Where do wasps live?
Wasps live in Worldwide except polar regions, Every terrestrial habitat; some species introduced far outside their native range. Wasps are hymenopteran insects — over 100,000 species — of which the great majority are tiny solitary parasitoids; social wasps such as yellowjackets are a small minority that act as major predators of pest insects and as pollinators.

### How long do wasps live?
A precise wild lifespan for wasps is not firmly established in the sources cited on this guide. Wasps are hymenopteran insects — over 100,000 species — of which the great majority are tiny solitary parasitoids; social wasps such as yellowjackets are a small minority that act as major predators of pest insects and as pollinators. Where longevity figures appear in the literature they vary by region, sex and whether animals are wild or captive.

### How big is a wasp?
Common wasps measure about 12–17 mm. The Asian giant hornet, the largest wasp, reaches around 4.5 cm with a 7.5 cm wingspan, while the smallest parasitic wasps are under 0.2 mm — smaller than some single-celled organisms.

## Sources
- [IUCN Red List](https://www.iucnredlist.org/)
- [GBIF — Hymenoptera](https://www.gbif.org/species/1457)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/wasp