Common Orders of Insects

Bees, ants, wasps, and sawflies (Order Hymenoptera) have two pairs of membranous wings and chewing mouthparts; some have tongue-like mouthparts for drinking nectar. All except sawflies have a distinct “waist” between their second and third tagmata. Females have a well-developed ovipositor, which is sometimes developed into a venom-bearing stinger. All ants and some bees and wasps are social insects, living in long-lived colonies with a reproductive queen (or queens) and a large number of non-reproductive workers. Other bees and wasps are solitary. Many wasps are parasitoids, meaning they lay their eggs on or inside another insect, and their larvae feed inside and devour the host. Bees feed on nectar and pollen as adults.

Butterflies and moths (Lepidoptera) have four wings covered with colored scales that rub off easily, and mouthparts that form a tube (proboscis) for drinking nectar or sap. Butterflies hold their wings vertically at rest, while moths either hold their wings roof-like, curled around the body, or flat. Also, butterflies have threadlike antennae with a knob at the end, while moths have various other shapes of antennae (whiplike, featherlike, or comblike). While the adults sip nectar to provide energy for flying and mating, the real work of feeding and growth is done by the larvae (called caterpillars), which are powerful eating machines. Each species of moth or butterfly is usually specialized to feed in the larval stage on one or more plant species. The pupa is called a chrysalis in butterflies, and it is attached by a silken belt to a plant. Moth pupae are often hidden in a silken cocoon.

Flies, midges, mosquitoes, and gnats (Diptera) have one pair of membranous wings, while the second pair is reduced into knobs called halteres. The mouthparts are designed for lapping, sucking, or piercing. The larvae (called maggots) are soft, wingless, and legless, and most live in soil or decaying material. Some flies, like some wasps, are parasitoids whose larvae feed and develop inside the bodies of other living insects.

Beetles (Coleoptera) are identified by their modified forewings (elytra) which form a protective and often colorful shell. Most beetles have chewing mouthparts with well-developed mandibles. Beetles may be aquatic or terrestrial, and may be predators, scavengers, or rarely parasites. Beetle larvae, called grubs, may be predators or herbivores. Some feed on wood inside live or dead trees.

Bugs, hoppers, cicadas, aphids, and scales (Hemiptera) have a pair of forewings that fold over the back, covering their short membranous hindwings. The forewings cross each other or are held roof-like over the back, distinguishing bugs from beetles, whose forewings meet in a straight line down the back. Hemipterans have beaklike mouthparts. Many species suck plant juices, while others feed on small insects and even small vertebrates. Most are terrestrial but a few are aquatic with oar-like legs. Many have glands that extrude strong odors to repel predators and enemies. The nymphs are wingless and usually resemble miniature adults.

Grasshoppers, crickets, and katydids (Orthoptera) are heavy-bodied insects with hind legs that often are enlarged for jumping. Their leathery forewings protect membranous hind wings. They may be herbivores or predators. They use characteristic sounds, made by rubbing wings or legs against the body, to attract mates and establish territories.

Mantids (Mantodea) are long thin hard-bodied insects with a flexible neck and a triangular head with strong jaws. They sit perched with their forelegs raised while waiting to catch prey, hence the name “praying mantis.”

Dragonflies and damselflies (Odonata) are large slender insects with long membranous wings, large compound eyes, long legs, and sharp biting mouthparts. Both the adults and the aquatic nymphs (naiads) hunt and capture insect prey. They typically are found near water, but adults can range many miles. Dragonflies perch with wings held horizontal and perpendicular to the body, while damselflies hold their wings more parallel to the body.

Mayflies (Ephemeroptera) have large triangular wings and long slender tails. Adults live only a few days, emerging in swarms to perform aerial mating dances above lakes, rivers, or streams. They live for one to several years as aquatic nymphs (naiads), with gills and two tail-like filaments, feeding on small aquatic plants and animals.

Walking sticks (Phasmatodea) are long slender plant-feeding insects. They have chewing mouthparts and feed on a variety of plants, including toyons and oaks in California. A primitive walking stick, Timema, occurs in the inner coastal range of California. Timema adults and nymphs are wingless and green to brown. Adults only reach about one inch in length.

Other terrestrial insect orders known or likely to occur at Quail Ridge include cockroaches (Blattaria), earwigs (Dermaptera), termites (Isoptera), thrips (Thysanoptera), snakeflies (Rhaphidioptera), silverfish and bristletails (Thysanura), fleas (Siphonaptera), booklice and barklice (Psocoptera), net-veined insects (Neuroptera), scorpionflies (Mecoptera), and webspinners (Embioptera). Aquatic insects that may occur in the Berryessa Reservoir, and perhaps in the Reserve’s stock ponds, are alderflies and dobsonflies (Megaloptera), stoneflies (Plecoptera), and caddis flies (Trichoptera).

Photo Credits: Title, Giant Water Bug and Butterfly (Mike Benard), Stink Beetle (Joyce Gross), Damselfly (Nick Kurzenko), Walking Stick (Robert Potts). For more pictures see: http://elib.cs.berkeley.edu/photos/browse_imgs/insect.html