Ants, wasps, bees and sawflies play key roles in most ecosystems as predators, parasites and pollinators.
Common characteristics of the order include:
- Two pairs of membranous (thin, often see-through) wings. The forewings and hindwings are held together by small hooks and the hindwings are smaller than the forewings and the wing venation (vein arrangement) is often much reduced. However, in many species the wings are not present or are present only during mating flights (eg ants).
- Chewing mouthparts. However, in some groups, the lower lip has been modified to form a tongue (e.g. bees).
- Compound eyes that are usually large (although many are blind eg ants and fig wasps).
- The females generally have an ovipositor which may be modified for sawing, piercing or stinging.
- Complete metamorphosis
Worldwide there are over 100,000 species included in the Hymenoptera group.
In Australia there are about 1275 ant, 10,000 wasp, 2000 bee and 176 sawfly species.
Hymenoptera is further divided into two suborders:
Suborder Symphyta (sawflies)
Sawflies most closely resemble the hymenopteran ancestor group and show the following characteristics that distinguish them from wasps, bees and ants:
- The body has no waist. Most females have a saw-like egg-laying device for cutting slits in plants into which eggs are laid.
- The larvae are caterpillar-like and feed on the outside and inside of plant tissue
- There are one or two parasitic families
Suborder Apocrita (wasps, bees, ants)
Wasps, bees and ants all share the following characteristics:
- The body has a distinct waist. The first segment of the abdomen is incorporated into the thorax. A narrow region called the petiole joins this to the rest of the abdomen, called the gaster.
- The larvae are maggotlike.
- However, members of this suborder also show an extremely wide range of habits and biology. Some are parasites, while others are predators, herbivores, gall-formers, fungus feeders, leaf miners or nectar and/or pollen gatherers. Most species are solitary, while others are organised into social communities of varying size and complexity. Wasps and bees form several families, but ants all belong to a single family, Formicidae.