Danaus chrysippus (Linnaeus, 1758)

What are insects?

The term insect originates from the word “in-“ in Latin, which means “above something;” while “sect” originates from “sectum” in Latin meaning “section!” The word insect means “many sections.”

    During its adult stage, the body of an insect can be seen as having three parts: a head, thorax, and abdomen. Each portion can be further seen as divided into many sections. In addition, insects have: a pair of antennae, a pair of compound eyes, 0~3 simple eyes, and mouth parts on the head. An insect has three pairs of legs and may have wings as well, usually two pairs. Insects breathe through openings called spiracles connected to air ducts and use a Malpighian tubule system as the major organ of excretion. There is an opening to the genital orifice at the end of the abdomen.

    Spiders, on the other hand, are not insects. They have four pairs of legs and the body is divided into a cephalothorax and abdomen. This is quite different from the structure of insects. However, spiders belong to the phylum Arthropoda as do insects, but fall into a different Class, the Arachnida, so they can be considered fairly close relatives of the insects.