Sawflies Ichneumons Chalcids Ants Wasps and Bees Order Hymenoptera

Identification: Wings, when present, 4 in number, membranous; FW a little larger than HW; wings with relatively few veins, venation in some minute forms nearly lacking. Antennae usually fairly long, generally with 10 or more segments. $ with well-developed ovipositor, which is sometimes longer than the body, and is sometimes modified into a sting. Tarsi 5-segmented (except in a few minute forms). Mouth parts chewing, sometimes with the maxillae and labium modified into a tonguelike sucking structure. Metamorphosis complete.

Similar orders: (1) Diptera (p. 260): only 2 wings; antennae often 3-segmented; mouth parts sucking; softer-bodied. (2) Lepidoptera (p. 218): wings covered with scales, at least in part; usually with a coiled proboscis. (3, 4) Ephemeroptera and Odonata (pp. 65, 68): antennae very short; wings with a more extensive venation. Immature stages: Larvae caterpillarlike (Symphyta) or maggotlike with a well-developed head (Apocrita). Larvae of Symphyta resemble those of Lepidoptera, but usually have 6 or more pairs of prolegs that lack crochets, and 1 pair of large ocelli. Many larvae are plant feeders, feeding on or in foliage, stems, fruits, and other parts of the plant; many live as parasites in or on bodies of other insects; others live in nests constructed by the adults and feed on material put in nest by the adults. Pupation occurs in a cocoon, in special cells, or (in many parasitic species) in the host. Habits: Adults are found in many habitats; most occur on flowers or vegetation, but some live on the ground or in debris, and many nest in the ground. Species whose larvae are plant feeders usually lay their eggs in or on the food plant; parasitic species generally lay their eggs on or in the host. Many Hymenoptera construct a nest of some sort and lay their eggs in this nest. Ovipositor of some species is modified into a sting, which is often used to paralyze prey and is an effective means of defense.

Importance: Some Hymenoptera, especially bees, are important plant pollinators. The Honey Bee provides us with useful products (honey and wax). Many parasitic and predaceous species aid in keeping noxious insects under control. Some plant-feeding species are serious pests of cultivated plants.

Classification: Two suborders, Symphyta and Apocrita, which differ in body shape and wing venation. Each suborder is divided into superfamilies.

No. of species: World, 105,000; N. America, 16,300. Characters used in identification: Principal characters used in separating families of Hymenoptera are those of wing venation, legs, antennae, pronotum, certain sutures on the thorax, and the

0 0

Post a comment