Order Hymenoptera - Sawflies, Wasps, Ants & Bees

• Horntail or Wood Wasp
• Pine Sawfly
• Common Wasp
• Yellow Garden Ant or Mound Ant
• Honey Bee or Hive Bee
• RELATED PAGES

Minute to moderate-sized insects, usually with two pairs of membranous wings, the front pair much larger than the hind pair. The wings are coupled together by a row of small hooks on the front edge of the hindwing. At first sight many flies (Diptera) may be confused with hymenopterans, but the flies have only one pair of wings and are easily distinguished on close examination. Eyes usually large. Antennae somewhat variable, but generally thread-like and often thickened towards the apex. Mouthparts of the biting type, many species with powerful jaws, sometimes combined with a tongue-like structure for lapping up sweet liquids. The latter is particularly well developed in the nectar-feeding bees. A well developed ovipositor at the tip of the abdomen is usually present in the female. The ovipositor is used for drilling into plant or animal tissues during egg-laying or it is modified as a sting and no longer used for laying eggs. There is a complex metamorphosis, with several larval stages and a pupal stage. Hymenopterous larvae are of two distinct types: (a) caterpillar-like, with well developed head and legs, and living on plant foliage; (b) grub-like, usually with a reduced head and always legless, and living as parasites, wood-borers, or protected in some kind of nest (see below). The pupal stage is usually enclosed in some sort of cocoon, although this may be so flimsy as to appear absent. The Hymenoptera is perhaps second only to the Coleoptera (Beetles) in terms of numbers of species. It contains over 120,000 described species and no doubt many more are yet to be discovered. Over 6,500 species occur in the British Isles.

The Order is split into two well-defined suborders. These are the SYMPHYTA, in which the thorax and abdomen of the adult insect are joined across their full width without a distinct constriction between the two, and the APOCRITA, in which the abdomen of the adult is attached to the thorax by a narrow 'waist' formed by the first one or two abdominal segments. The Symphyta contains the Sawflies and Wood Wasps (or Horntails), which are the most primitive members of the order; the Apocrita contains the remaining Wasps, Ants and Bees, many of which are highly advanced and specialised insects. Only in this latter group and among the termites (Isoptera), do we find true social behaviour.

From an economic standpoint, the Hymenoptera confer many benefits to our lives. Bees are important pollinators of fruit trees and other flowering plants, while the Honeybee is extensively cultured for its yield of honey and wax. A great many species are parasites of other insects and play a vital role in maintaining the balance of nature; their activities are a recognised feature in the biological control of many insect crop-pests. Among the less desirable members of the Order are the defoliating larvae of Sawflies and the wood-boring larvae of certain Solitary Wasps and Bees. Of lesser importance are the small plant-feeding larvae of some Gall Wasps, which induce unusual plant growth resulting in gall formations, such as the familiar marble galls on oak trees (known as 'oak-apples') and the bright red bedeguar galls on wild roses (often called 'robin's pincushion').

Description. Female 40-60 mm long, body colour black and yellow. Male slightly smaller and lacking the ovipositor or 'tail' of the female, and also the black band on the abdomen.

Biology. Mainly in and around coniferous woodland. The female uses her stout ovipositor to drill into pines and other conifers (usually selecting unhealthy trees) in order to lay her eggs. The legless larvae or grubs spend their time tunnelling and feeding in the timber. Larval development may take several years and larvae can survive even after trees have been felled and cut to make floorboards and rafters. Adults emerging from cut timber sometimes cause great alarm when they appear in or around new houses and other buildings. The 'tail' of the female is often mistaken for a sting, but the insects cannot sting and are quite harmless.

Distribution. British Isles and most of Europe.

Photo: S. Nicholson ©

<<< TOP

Adult female
(with sting-like ovipositor)

Description. Female 10-12 mm long, male slightly smaller. Both sexes mainly black or dark brown, with yellow legs. Some yellow banding on the female abdomen. Antennae serrated in the female, more plumose and feather-like in the male. Larva caterpillar-like, up to 25 mm long, light yellowish-green, with black spots scattered over the body and pale brown head.

Biology. A common and often serious pest in pine forests. The caterpillars live gregariously, defoliating the young shoots of conifers. One generation a year, often with a partial second brood.

Distribution. British Isles and most of Europe.

Illustration: adapted from Gillanders 1912 (Forest Entomology)

<<< TOP

Adult female

Description. Typical social wasp with male, female and worker castes, all with conspicuous black and yellow banding. Male 20-25 mm long, with longer antennae than the other castes and lacking a sting. Female (queen) about 25-30 mm long; workers smaller, around 15-20 mm long. One of several very similar black and yellow species.

Biology. Nests under the ground or in roof cavities, building a spherical, slightly cone-shaped nest from wood pulp chewed into a greyish or yellowish paper-like material. The nest is usually suspend by a short stalk from the ceiling of the nest cavity and has an entrance hole at the bottom (see illustration - more nest images). Nests may reach football-size during the course of a season and contain up to 5,000 or more worker wasps together with the founding queen. Wasp colonies are annual affairs and die-out each year, leaving only the young mated queens, produced at the end of summer, to hibernate overwinter and start new colonies again in the following spring.

Adult wasps feed mainly on nectar and other sweet liquids, but they rear their grubs on insects which the adults capture and paralyze with their sting. The immobilized prey is carried back to the nest and fed to the young stages. This predatory activity is largely beneficial, since many of the insects killed by wasps are harmful crop and garden pests, such as caterpillars and plant-feeding beetle larvae.

Distribution. A common species in the British Isles and throughout most of Europe.

Photo (nest): P. McDowell ©

<<< TOP

Young queen feeding on nectar

Nest suspended from
a roof beam

Description. Social insects with male, female (queen) and worker castes. Male and female winged and brownish-black, but the female sheds its wings soon after mating. Worker is wingless and yellowish-brown. Male and worker up to 7 mm long, female larger. Also called the Yellow Mound Ant.

Biology. Found in all kinds of open habitats, especially grassland, and including gardens. They nest underground, often forming a large mound or hill of excavated soil. All nest building, foraging for food, care of eggs and grubs, etc., is done by the workers. The grubs are reared on a variety animal matter, mainly small insects and mites.

Distribution. One of our commonest ants, found throughout the British Isles and in many parts of Europe.

<<< TOP

Workers, together with winged males
and a larger winged female (top right)

Nest mound

Description. Social bee, with male (drone), female (queen) and worker castes. Queen and drone about 15 mm long, worker 8-10 mm long. Mainly black or dark brown, sometimes with paler yellowish banding on the abdomen.

Biology. Live in large perennial colonies, consisting of a queen and up to 50,000 or more worker bees. All the nest building and food gathering is done by the workers; the queen remains in the nest (or hive) throughout her life, continuously laying eggs, and is tended and fed by the workers. New queens and drones are produced from time to time, usually when the colony is about to swarm or when the resident queen is failing and about to die. In the latter case, after mating with a drone, one of the new queens will take over the colony. Swarming occurs when the old queen or one of her new rivals take off with a swarm of workers to start another colony. Queen bees live for several years, but the drones and workers are short-lived. Summer workers rarely live for more than a few weeks, although later-maturing individuals will survive through the winter. Drones usually die after mating, but in any event they are thrown out in autumn when the colony settles down to hibernate, and soon perish.

Although most Honey Bees originate from man-made hives, swarms do occasionally escape into the wild. Wild colonies sometimes nest in the open on tree branches or other suitable support, but more often they nest inside hollow trees and similar sheltered places, hanging their expose combs in vertical sheets from the roof of the nesting cavity. The comb is made from wax secreted by the worker bees. Each cell of the comb is a perfect hexagon and the cells are used for rearing the young and storing pollen and nectar. The adults and grubs feed exclusively on honey - a mixture of pollen and nectar.

Distribution. Probably originates from south-east Asia, but introduced and cultured nearly everywhere for commercial honey and wax production.

Worker bee

Male or drone bees
on the honeycomb

Further Reading. Honey Bees are probably the most extensively studied insects in the world. Numerous lengthy books have been written on their social behaviour and on the fascinating ways in which the workers communicate with each other and pass on information about good sources of nectar and pollen.

• C.G. Butler (1949). The Honeybee. Clarendon, London.
• C.R. Ribbands (1953). The Behaviour and Social Life of Honeybees. Bee Research Association, London.
• C.G. Butler (1954). The World of the Honeybee. The New Naturalist, Collins, London.
• J.B. Free (1970). Insect Pollination of Crops. Academic Press, London.