One of the largest group of insects is the Arthropods, means jointed footed. All arthropods posses certain characteristics.
Segmented body – where the body is split into segments.
Joint Appendages – where the appendages have joints.
Exoskeleton – Skeleton on the exterior of the body.
Molting Growth – Growing in stages and the process of replacing the exoskeleton.
3 Body regions.
3 pairs of legs.
1 pair of antennae.
Wings in the adult stage.
Crustaceans are smaller subsection of the arthropod groups and include pill bugs, crayfish, shrimp, sow bugs. They have:
2 pairs of antennae.
5 to 7 pairs of legs.
2 body regions.
Arachnids are another subsection of the arthropods, spiders, ticks, mites and scorpians.
2 body regions.
4 pairs of legs.
Diplopods is another including millipedes.
50 body segments.
2 pairs of legs for each body segment.
Long rounded bodies.
Chilopods include centipedes.
14 to 20 body segments.
1 pair of legs for each body segment.
Long flat bodies.
Most insects start as an egg produced by sexual reproduction between male and female. Some ants, bees and aphids can produce eggs without sex. Eggs are laid by the female. After the eggs hatch insects have distinct stages called instars. Instars are separated by periods when the insect sheds it’s exoskeleton, called molting.
Some insects may be sexually mature from the time they hatch while other may have to go through many instars. No growth is done in between instars, growth only take place during the molt process.
Incomplete Metamorphosis have 3 life stages – egg, nymph and adult. Nymphs have 3 to 5 instars. Such as the grasshopper, crickets, earwigs, and aphids.
Complete Metamorphosis have 4 life stages. Egg, larvae, pupa, and adult. Maggots, grubs, caterpillars are the Larvae. In the Larvae stage there are 3 to 7 instars when the larvae feed. The pupae stage is the cocoon, puparia or chrysalis and is a non-feeding stage. Adults are usually winged and will differ from the larvae stage considerably. Insects that go through complete metamorphosis include moths, butterflies, flies, and beetles.
Information sourced Nevada Department of Agriculture C2 Manual 2014 – Full