Examine the specimens representing the orders listed below, and note the characteristics (e.g., mouthpart structure, number and structure of wings, type of metamorphosis) that define the orders as well as the diversity shown within each order.

Odonata. Dragonflies and damselflies. These insects are characterized by a lack of wing flexibility such that their wings are held spread out from their bodies at all times (except in damselflies). They are active predators primarily of aquatic habitats.

Orthoptera. Grasshoppers and crickets. Medium to large sized insects, members of this order feature enlarged hind legs for jumping, mandibulate mouthparts for chewing, and pleated wings that can fold like a fan when not in use. Some members of this order have their bodies modified to resemble pieces of vegetation, the most familiar being the walking sticks.

Hemiptera. True Bugs. Mouthparts are modified into a piercing structure that can probe plant or animal tissue and suck nutrients out. The wings are generally folded flat over the abdomen, and the basal portion of the wings are thickened or leathery.

Homoptera. Leafhoppers, aphids, spittlebugs, whiteflies, scale insects, mealybugs, cicadas. These animals are herbivores that feed on the photosynthate in plant phloem. Their mouthparts are modified into a needle-like tube that pierces stems and probes to the phloem layer. Their membranous wings are often held roof-like over their abdomen. This order contains a large number of common plant pests familiar to gardeners.

Coleoptera. Beetles. Members of this order are characterized by sclerotized forewings (elytra) that serve as a protective layer over the body of the adult animal. This is the largest order of insects with over 250,000 described species. Accordingly you can expect great diversity in structure and lifestyle. Most are terrestrial herbivores, but there are also predatory species.

Lepidoptera. Butterflies and moths. These insects generally have enlarged wings that are covered with scales. Most lepidopterans have mouthparts organized as a long coilable “proboscis” through which food is ingested.

Diptera. Flies and mosquitoes. This order is characterized by only one pair of flying wings in adults. The hind wings are transformed into halteres, gyroscopic balancing organs that enhance rapid and efficient flight. Lifestyles of dipterans vary; most are saprophytic, living off of decaying material, while others are efficient pollinators.

Hymenoptera. Bees, wasps, and ants. Members of this order have stiff, membranous wings. All members also possess well-developed mandibles that have been adapted to a wide array of tasks. This group contains many of the more agriculturally beneficial insects, including pollinators, predators and plant-eating insects. To humans many members of Hymenoptera are familiar from their stings and bites.