Spiders

 It is true that not all species live only on the ground, since spiders can be found in grasses, bushes, trees and houses, but many spiders live on the surface of the ground.

Classification (systematic position) Source : INPN   Animal Kingdom Embranchement (Phylum) : Arthropoda Subphylum: Chelicerata Class: Arachnid Subclass: Micrura Order: Araneae

Morphological characteristics
Arachnids with a body divided into 2 parts (cephalothorax (fusion of the head and thorax which differentiate them from insects) and abdomen), cephalothorax covered with a thin carapace and soft abdomen, 4 pairs of long legs attached to the cephalothorax, 2 pairs of oral appendages (chelicerae and pedipalps); spiders have up to 8 eyes which can be very well developed (especially for stalking spiders); presence of spinnerets at the end of the abdomen which make it possible to form a thread of silk for all the spiders as well as the protective cocoons of the eggs. These spinnerets also allow the manufacture of the web for the spiders hunting using a web.

Life cycle
Depending on the species of spider, these arachnids can live from a few months to several years. For example the pardoses which are part of the Lycosidae (wolf spiders) live about a year and a half while the spiders live 3 to 10 months. Some species are born in summer and grow in winter like pisaurs, while others overwinter as eggs that hatch in spring. The females lay eggs which are wrapped in a cocoon of silk. Some females carry their cocoon below the abdomen until the young hatch, such as the female wolf spider. Once born, the young remain attached to the female's abdomen for more than three weeks. The young spend the winter sheltered in the ground or under mulch.

Diet
Spiders are all carnivores and exclusively eat live prey such as mosquitoes, butterflies, winged aphids, woodlice, small beetles and orthopterans. Some species catch their prey by jumping on them, such as pardoses, lycoses, pisaurs, saltises (jumping spiders) or thomises (crab spiders). Others build a web like the linyphies which weave a horizontal web above the surface of the ground.

Natural predators or regulators
Spiders are preyed upon by birds, rodents, amphibians, lizards and some wasps.

Habitats
Spiders are found in all environments provided that there is prey to feed on, on the surface of the ground, in the forest, in the meadow or even in the houses. Web-hunting spiders need supports to build their webs while stalking spiders need hiding places. silk at night to hunt prey.

Interests in the garden
Spiders have an essential role in regulating populations of many invertebrates such as flies, mosquitoes, wasps, aphids and many more. They are important auxiliaries of the gardener.

Did you know ?
The protein constituting the cobweb is synthesized artificially in an attempt to manufacture bulletproof vests, due to the high resistance of the cobweb.

The remains of beetles (elytra or heads) found empty on the ground are often due to an attack by a spider. Indeed, once the prey has been caught, the spider injects venom through its chelicerae into the body of its prey, venom which liquefies the inside of the body using digestive enzymes before being able to feed on it. The too rigid parts of the prey's body (chitinized skeleton) are therefore abandoned.