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Class Insecta - Insects
Classification Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Synonyms and other taxonomic changes phylogenetic arrangement of major extant taxa based on latest molecular data shown in (1)Explanation of Names Latin insectum, pl. insecta "cut into, cut up" (refers to body segmentation), a literal translation of Greek entomos (εντομος) Numbers Worldwide, 25-30 extant orders (+ ca. 10 extinct), depending on authority, up to 1000 families, and well over a million species
In our area (US & Canada): 28 orders, over 600 families, ca. 12,500 genera, and >86,000 spp. (2)(3)Identification
Three body parts: head, thorax, and abdomen
typically two pair of wings; some groups have one pair or none
Usually one pair of compound eyes; simple eyes ( ocelli) present in many groups
Anatomy
See Glossary for terminology.
Range worldwide and throughout North America (NB: aquatic marine forms conspicuously absent) Life Cycle There are two prominent types of life cycles among the insects:
1-Hemimetabolous insects (e.g., dragonflies, mayflies, true bugs, grasshoppers) undergo gradual, or incomplete, metamorphosis. Immature stages (usually called nymphs) go through a series of molts, gradually assuming an adult form. Since the wings develop on the outside of the body, these groups are called exopterygotes. Some orders have immature stages that are aquatic. These possess specialized structures for aquatic life, such as gills, and are called naiads, or larvae.
2-Holometabolous insects have a four-stage life cycle: egg, larva, pupa, and adult (imago). The following orders of insects are holometabolous:
Neuroptera - Antlions, Lacewings and Allies
Hymenoptera - Ants, Bees, Wasps and Sawflies
Trichoptera - Caddisflies
Lepidoptera - Butterflies and Moths
Mecoptera - Scorpionflies, Hangingflies and Allies
Strepsiptera - Twisted-winged Insects
They form a group referred to as Endopterygota or Holometabola.
Remarks All the winged insects (including those who have lost their wings over the course of history) constitute a large taxon called Pterygota (sometimes treated as a subclass).
Pterygota orders listed alphabetically
*may be lumped with Cockroaches & Termites Print References Eggleton, P., and Belshaw, R. 1992. Insect Parasitoids: An Evolutionary Overview. Philosophical Transitions of the Royal Society of London B 337: 1-20. doi: 10.1098/rstb.1992.0079
Stork, N. E. 2018. How Many Species of Insects and Other Terrestrial Arthropods Are There on Earth?. Annual Review of Entomology 63: 31-45. https://doi.org/10.1146/annurev-ento-020117-043348
Gaston, K. J. 1991. The Magnitude of Global Insect Species Richness. Conservation Biology 5(3): 283-296. https://www.jstor.org/stable/2385898Works Cited | 3. | Evolution of the Insects
David Grimaldi and Michael S. Engel. 2005. | |
| 4. | How to Know the Immature Insects
Hung-Fu Chu, Laurence K Cutkomp. 1992. Wm. C. Brown Publishers. |  |
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