Are spiders insects?

neelie_447

"Spiders are not insects. Spiders are members of a large category of animals called Arthropoda." http://www.chat11.com/Are_Spiders_Insects May 20 08, 8:03 PM

author

Here is some information about why spiders are not insects. Quote: Spiders, unlike insects, have only two body segments (tagmata) instead of three: a fused head and thorax (called a cephalothorax or prosoma) and an abdomen (called the opisthosoma). The exception to this rule are the assassin spiders, whose cephalothorax seems to be almost divided into two independent units. Except for a few species of very primitive spiders (family Liphistiidae), the abdomen is not externally segmented. The abdomen and cephalothorax are connected with a thin waist called the pedicle or the pregenital somite, a trait that allows the spider to move the abdomen in all directions. This waist is actually the last segment (somite) of the cephalothorax and is lost in most other members of the Arachnida (in scorpions it is only detectable in the embryos). http://en.wikipedia.org/wiki/Spiders May 20 08, 8:13 PM

bassman68

No, they are not. Insects belong to one of the classes of the Arthropoda order of animals known as Insecta. One of the main requirements for membership in class Insecta is the formation of three distinct body parts: the head, thorax, and the abdomen. Another is the possession of four pairs of legs. Spiders, however, though they also belong to the Arthropoda order, belong to a different class within that order: class Arachnida. Spiders do not meet the requirements of being insects in many ways, but the main ones are that they have two body parts instead of three, and have two pairs of legs instead instead of three. http://www.chat11.com/Are_Spiders_Insects May 20 08, 9:15 PM