Arachnids are a class of arthropods, a subgroup of the invertebrates.
They all have eight legs and among them we found highly diverse animals as spiders, scorpions, mites, ticks.
Most of the species are terrestrial.
The term arachnids is derived from Arachne, a Greek mythological figure meaning “spider”, because the spiders were the first members of this class of invertebrates.
You may read about this Greek mythological figure in Arachne the spider.
SPIDERS
You can find spiders on all continents except Antarctica, and they have adapted to a wide range of terrestrial habitats. Spiders have eight legs, but unlike insects they do not have antennae.
Spiders can inject venom. They weave webs that vary in size and shape, are light but strong and offer great elasticity in some aspects better than sintectical materials.
The Brazilian tarantula found in Amazonia is the biggest spider in the world but it is not dangerous to man.
House spider |
Sand spider |
Bazilian spider |
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Redback spider (Australia) |
European black spider |
Black widow spider |
SCORPIONS
They are generally nocturnal animals that spend the day hidden under rocks and crevices. Scorpions, are either ovoviviparous or viviparous, depending on species.
The baby scorpion climbs onto the back of the mother scorpion almost immediately after birth. The mother scorpion will look after her baby scorpions until they are able to hunt for themselves.
Emperor scorpion |
Black scorpion |
Iberian scorpion |
TICKS AND OTHER ACARI
Acari or acarines are extremely diverse, and their tiny size allowed them to live in almost every habitat on earth. In fact, they include more aquatic (freshwater and sea water)
and terrestrial species than any other arachnid. Ticks are the largest of the class. They are parasites living on the blood of mamals and as such transmit a number of diseases.
Male and female ticks |
Ectoparasites of vegetables |
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