The Spiders

The spiders (order Araneae) are predatory invertebrate arthropod class Arachnida. They have eight legs and have neither wings nor antennae or masticatory pièces in the mouth. Their eyes may be single or multiple. They secrete silk (a protein solution synthesized by glands usually located at the end of the abdomen) that is used to produce wire that allows them to move, to weave their webs or cocoons for trapping prey or protecting their eggs or progeny, or to make a provisional reservation of semen or a dome allowing them to store air under freshwater.
As predators, spiders play a major role in the regulation of insect populations. As all the arachnids, the spider absorbs only the liquid: it must be lysed by exodigestion of the prey, that is to say by means of the liquefying by digestive enzymes injected by the chelicerae, before feeding.
Spiders have some 42,000 species, of which 1,600 listed in France. Spiders have a crucial ecological role by capturing every year 400 million insects per hectare, far ahead of the birds.