Spiders are not insects! They have eight instead of six legs and two main body parts (the combined head and thorax, called cephalothorax, and an abdomen) instead of three. Spiders are arachnids, a class of arthropods that also includes scorpions, mites, and ticks. There are more than 48’000 known species of spiders, found in habitats all over the world. Approximately 1’000 different species of spiders live in Central Europe.
Spiders usually have eight simple eyes, but few have good eyesight. They rely instead on touch, vibration and taste stimuli to navigate and find their prey. The jaws of spiders are adapted for tearing or piercing prey. They cannot swallow their food as is, though spiders inject their prey with digestive fluids, then suck out the liquefied remains. Spiders have abdominal silk spinning organs; their use of silk is highly developed but not all spiders catch their prey in webs. Some hide and wait for insects to come by.
Spiders lay eggs and store them in an egg sac to keep them safe. Some even guard the offspring (maternal care) and provide them with captured prey. Some species show extended care by performing regurgitation feeding, i.e. females provide a nourishing fluid for the offspring by regurgitation. Several genera also show matriphagy, as females are consumed by their offspring following the provisioning period. Whereas most spiders are solitary and even aggressive toward other members of their own species, some hundreds species live in relatively long-lasting aggregations, often referred to as colonies.