Ants Sawflies Bees and Wasps: Hymenoptera

Adult hymenopterans (HAI-men-OP-teh-runs) range in size from 0.006 to 4.72 inches (0.15 to 120 millimeters) in length. The bodies of many wasps are slender, while those of bees are robust. They often have large compound eyes, each with many lenses. Some also have simple eyes, or eyes with one lens, located between the compound eyes. The distinct head has chewing mouthparts directed downward. The jaws are used for emerging from the pupa (PYU-pa), or cocoon, and for defense, killing prey, and nest construction. Bees have the combination of chewing and sucking mouthparts, allowing them to drink nectar from flowers.

All four wings are similar in texture, but the forewings, or those in front, are usually longer than the hind wings. The hind wings have a row of hooks along their leading edges that attach to the hind margins of the forewings while the insect is in flight. The legs are usually long and are used for running. In some species the legs are also used for digging. The midsection, or thorax, of sawflies and their relatives is broadly attached to the abdomen. However, ants, bees, and wasps have threadlike waists. In these groups the threadlike segments are made up of the first few segments of the abdomen. Winged species have four membranelike wings with relatively few veins.

The ovipositors, or egg-laying tubes, of hymenopterans have special sensory structures that help the female to find good places to lay her eggs. In some ants, bees, and wasps the ovipositor is not used for egg laying. Instead it is used as a defensive stinger. The stinger is hollow like a syringe and is capable of delivering a painful and venomous sting. The stingers of ants, wasps, and most bees are smooth so that they can be used repeatedly. However, the stings of honeybees can be used only once. Their barbed stingers remain in the flesh of the victim. As the honeybee pulls away, the stinger and internal organs are ripped from the abdomen and the insect soon dies.

The bodies of bees have several special features that allow them to collect pollen. Their bodies are covered with bristly and branched hairlike structures. The hind legs of many bees have special bristles that form either a brush or a basket allowing them to carry pollen. Leaf-cutter bees use brushes on the undersides of their abdomens for carrying pollen.

The larvae (LAR-vee), or young form, of sawflies and their relatives resemble caterpillars. They have distinct heads, three pairs of legs, and fleshy cone-shaped false legs on their abdominal segments. In all other Hymenoptera the larvae are wormlike and lack both legs and a distinct head. In parasitic species the mature larva is wormlike, but the previous stages may be very different in appearance. Parasites are completely dependent on other living organisms, or hosts, for food. Parasitic hymenopteran larvae spend their entire lives on the host. Their feeding activities usually do not kill the host.

The features of adult hymenoptera are clearly visible in the pupae (PYU-pee), or life stage between larvae and adults. The legs and developing wings are not firmly attached to the body along their entire length. Some species pupate within a silk cocoon.