Insect diversity in the world ecosystem
To understand diversity, we have to know what is present, the science of Taxonomy or Systematics.
Traits used to classify insects
Insects are classified into about 32 orders and 939 families.
ETYMOLOGY: Means toothed jaw. A name surviving from a classification devised by Fabricius (Danish entomologist and sometimes pupil of Linneaus) that was based on mouthparts rather than wings.
METAMORPHOSIS: Incomplete, hemimetabolous but immature nyaids bear little resemblance to adults.
HABITS: Larvae are called nymphs or naiads and are aquatic predators, adults are usually found near water.
IMPORTANCE: Beneficial predators of mosquitoes, gnats, and other flies and insects.
FOLKLORE: Sometimes called the devil's darning needle, if they caught you they would sew up your mouth, nostrils, eyelids, or ears. Snake doctor, thought to guard snakes.
IDENTIFYING CHARACTERS: Two pairs of elongate, membranous wings. Long bodied.
SUBORDER: Anisoptera = Dragonflies
SUBORDER: Zygoptera = Damselflies. Like the dragonflies, damselflies are aerial predators, with extremely good vision. Usually smaller than dragonflies with more delicate bodies.
Link to Tree of Life - Odonata 
ETYMOLOGY: Straight
winged, from Ortho- as in orthopedics,
orthodox.
METAMORPHOSIS: Incomplete.
HABITS: Terrestrial, phytophagous, many sing by stridulation.
IMPORTANCE: Many economically damaging plant feeders. May migrate in enormous numbers.
FOLKLORE: Katydid - A tale told to children. A
little girl named Katy who had told a fib and willfully and stubbornly compounded her error by refusing to say
she had lied was struck dead by God. Thereafter, her shame lived on as even the bugs in the trees debated whether
Katy did or didn't and if you listen closely you will hear that most of them think she did. 
Katydid - Another story. A young woman named Katy fell in love with a handsome young man who scorned her and instead married her prettier sister. After the honeymoon, the couple were found dead, poisoned in their bed. And then the bugs began debating whether Katy did or not.
An old English definition of a "katy" is a wanton.
IDENTIFYING CHARACTERS: Most large to medium sized, jumping insects. Usually two pairs of wings with many veins. Forewings usually long, narrow, and leathery; hindwings broad and membranous.
Link to Tree of Life - Orthoptera
ETYMOLOGY: Half-winged. Most
insects in this order have forewings that are divided into two parts. The first or basal part is thickened and
leathery looking. The second, or distal part, is delicate and membranous.
METAMORPHOSIS: Incomplete.
HABITS: Varied, terrestrial, freshwater, marine. Phytophagous and predacious.
IMPORTANCE: Many economically damaging species, other species are important predators, some disease vectors.
IDENTIFYING CHARACTERS: The basal half of the forewings are thick and leathery, the distal tip is membranous. Characterized by beaked, piercing-sucking mouthparts.
Link to Tree of Life - Hemiptera
ETYMOLOGY: Whole-winged. Both wings membranous.
METAMORPHOSIS: Incomplete.
HABITS: Terrestrial plant feeders.
IMPORTANCE: Many economically damaging species, some vector plant diseases.
IDENTIFYING CHARACTERS: Mouthparts like the Hemiptera but short and arising from the back of the head, often appearing to arise from between the first pair of legs. Two pair of membranous wings. Some without wings.
Green Peach Aphid (Winged Adult and Nymphs)
Link to Tree of Life - Heteroptera (True Bugs)
ETYMOLOGY: Koleon (Greek) - a sheath
METAMORPHOSIS: Complete
HABITS: Largest order of insects, terrestrial and aquatic, predacious, phytophagous, and scavengers.
IMPORTANCE: Many important predacious and plant feeding species.
FOLKLORE:
The firefly is a funny bug.
He hasn't any mind. He blunders all the way through life.
With his headlight on behind.From the poems of A. Nony Mouse (Jack Prelutsky)
IDENTIFYING CHARACTERS: Forewing hardened into a protective covering, the elytra, that encloses the delicate flying wings which are folded underneath it when not in use.
The largest insect group. Both the largest and smallest insects are beetles.
Link to Tree of Life - Coleoptera
ETYMOLOGY: Lepis (Greek) scales, scaly-winged
METAMORPHOSIS: Complete
HABITS: Terrestrial. Adults feed on nectar and other liquid food, most larvae are phytophagous.
IMPORTANCE: Many economically damaging species of crops, stored food, and fabrics.
IDENTIFYING CHARACTERS:
| Groups | Antennae | Active Period | Pupal Chamber | Body | Wing Position at Rest |
| Moths | Feathery | Night | Cocoon | Stout | Roof-like or against body |
| Skippers | Hooked | Day | Cocoon | Somewhat stout | Two wings at different angles |
| Butterflies | Clubbed | Day | Chrysalis | Slender | Vertically above body |
LINKS:
ETYMOLOGY: Dis (Greek) twice, two-winged.
METAMORPHOSIS: Complete.
HABITS: Aquatic, terrestrial, found almost everywhere.
IMPORTANCE: Many predacious and parasitic species, vectors of diseases such as sleeping sickness, malaria, yellow fever, dengue fever, elephantiasis, encephalitis. Many nuisance species. Some are plant pests or vector plant diseases.
FOLKLORE: Two of the 10 plagues of ancient Egypt were flies. Ancient Semitic deity, Beelzebub, was the "Lord of Flies". People thought that Beelzebub would protect them from flies.
IDENTIFYING CHARACTERS: Single pair of flying wings, the second pair of wings as little knobs called halteres.
Mosquito
Link to Tree of Life - Diptera
ETYMOLOGY: Membrane winged.
METAMORPHOSIS: Complete.
HABITS: Terrestrial from the Arctic to the tropics. Some social groups and species. Ovipositor modified into a sting.
IMPORTANCE: Great significance as pollinators, predators, and as parasitoids. Some economically damaging species.
FOLKLORE: "The Ant and the Grasshopper" by Aesop extols the virtues of hard work and preparation. Bees are industrious.
IDENTIFYING CHARACTERS: Wings, if present, are membranous. Chewing mouthparts. Except for sawflies, base of abdomen constricted, may be distinctly thread-like.
Link to Tree of Life - Hymenoptera
Last updated Dec. 30, 2000
Gary Brewer