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Araneae (spiders)
The order Araneae is in the phylum Chelicerata (spiders, harvestmen, scorpions, mites, ticks and horseshoe crabs)

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Chelicerata
  Merostomata (horseshoe crabs)
  Pycnogona (sea spiders)
  Arachnida spiders
  Arachnida scorpions
  Arachnida solifugae (sun spiders, wind scorpions)
  Arachnida palpigradi (microwhip scorpions)
  Arachnida Uropygi (whip scorpions)
  Arachnida pseudoscorpiones
  Arachnida mites, watermites
  Arachnida ticks
  Arachnida opiliones, harvestmen

Lycosidae family. The wolf spiders. World wide there are over 2 200 species, and in Europe there are 81 species in 8 genera. They have a characteristic eye arrangement that is one of the first steps in identification. Below are drawings and photographs showing the typical arrangement of the 8 eyes. The 4 small anterior eyes are often quite difficult to spot with the naked eye. Their big eyes reflect light in the dark, though most of them are active during the day. They rely on their eyes to detect prey. They also need good eyesight for mating. The male locates a female by pheromones, but he does not rush up to her. Instead he stops a short distance from her and signals her raising and lowering his palps and legs in a sort of semaphore courtship display, see below. Only if his display is satisfactory, and she has not already mated, will the female accept him. If not she will chase him off, if he is lucky, or lead him on and capture him for food if he is not. It is not an easy life being a mature male wolf spider!

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All Lycosids are hunting spiders, so they do not trap their prey in a web. They are commonly known as wolf spiders. They tend to hunt by day, and hide under stones etc. during the night. Most will eat from 5 - 15 small insects each day. In California the wolf spider Pardosa ramulosa is an important predator of leafhoppers. Lycosids do use silk to make their egg sac (see a photograph of a female with her egg sac below), and some line their burrows with silk. They can run fast, and some can jump short distances. In the UK some will bite humans if they find a patch of soft skin, but they are not dangerous. Most Lycosids are brown or grey in colour enabling them to blend into the background. Adult males tend to be slightly smaller and darker than females of the same species.

Most Lycosid females carry their egg sac around with them attached to their spinnerets by silk. The egg sac is often beige and about the size of a small dried pea or large lentil (see below). It is the light colour of the egg sac that makes the females easy to spot. The female frequently opens the sac to put in some liquid food. In colder areas the female will sit on a stone that has warmed in the sun and sunbathe with her egg sac. The spiderlings cannot escape from the sac by themselves, but need their mother to let them out. Then they climb up her legs on to her abdomen, and she carries them around for a week or two until they are old enough to manage on their own. Lycosid females continue to hunt with their egg sac attached to their spinnerets, and even when they may have as many as 50 spiderlings clinging to the hairs on their abdomen!

Pardosa genus. There are 39 species in Europe. In northern Europe females are easy to spot from mid May onwards as they carry their light-coloured egg sacs around. The young spiderlings are let out after 2 or 3 weeks. A female can have 2 broods of young over the summer.

Lycosidae pardosa spider whole body
Lycosidae head showing arrangement of eyes Left the face of a typical Pardosa spider showing the arrangement of the eyes, the chelicerae and fangs

Above right is a spider in the Pardosa genus. Spiders in the Trochosa (see below) genus look similar, but have a shorter and wider face.

Mating. Lycosid males wishing to mate signal the female from a distance to let her know their wishes, and that they are not prey. Each species has its own semaphore code for signaling females. Pardosa lugubris, right, stretches out his front pair of legs sideways, raises one palp, then raises another.

Pardosa lugubris male Lycosid spider signalling his wish to mate
Lycosidae pardosa eyes
above the palps, 4 small eyes and 2 large, posterior median eyes of Pardosa sp.
Lycosidae pardosa eyes
above the pair of posterior lateral eyes of Pardosa sp.

On the right is a female Trochosa sp. carrying her egg sac. These spiders tend to be nocturnal. I disturbed this one while weeding my garden. She had one leg missing - I may have damaged her with my hand trowel. Anyway, after taking this photograph I made a nice place for her to live in my greenhouse, and a few weeks later her numerous, tiny, colourless babies were running all over my greenhouse wall.

The females make small silk-lined burrows in moss or litter where they spend the day.

Trochosa sp. female spider with egg sac

Thomsid spider, crab spider

The spider on the left is a male of the Thomisidae family. There are 2 500 species world wide. It is easy to see he is a mature male because of his swollen palps. And also that he belongs to the Thomisidae family because his front two pairs of legs are longer than the rear pairs. Thomisids can live in a wide variety of habitats, and are often masters of camouflage. Some (mainly those which capture their prey while they lurk in flowers) even have the ability to change colour. They tend to sit and wait for their prey then make a quick grab with their first 2 pairs of legs, injecting a relatively powerful and quick-acting venom. Because of this method of prey capture none of them spin webs for ensnaring prey. They also have the ability of walking sideways which gives them their common name of crab spiders.

Curious courtship.
Some Thomsids, in the Xysticus genus such as X. lanio and X. cristatus, have a curious courtship. The male is slightly smaller than the female. He climbs over her body tying her down to the ground with numerous lines of silk. Then he pushes up her abdomen and squeezes underneath her to insert a sperm-loaded palp in her epigyne. However after this the female just gets up and walks away. The silk does not restrain her, so we do not yet know what is the purpose of the male tying her down.

Stalticus sp. a jumping spider

Family Salticidae - jumping spiders.

There are 4000 species world wide and 75 in Europe. The Northern European Salticidae are small and most commonly seen during warm sunny weather. The UK species have black and white, or brown and white stripes. They have the greatest visual acuity of all arthropods. Their eyes give them binocular vision and may be sensitive to colour and polarized light. The arrangement of eyes is shown on the right. The pair of small eyes furthest to the back may just detect light and movement. The spider often rears up to get a better look at things, and they can spot prey 20 cm away. They stalk prey then leap on it. They have a fondness for leafhoppers, and will eat 4 - 8 per day. Good vision os also needed during courtship. The male waves his legs and palps semaphore-style as he moves around the female trying to gauge if she is willing to mate. They have pads on their feet making it possible for them to cling to smooth surface - even glass.

Salticus sp. The most common species in the genus is Salticus senicus, commonly called the zebra spider because of its stripes. It is often found on walls, fences and window sills during warm, sunny weather. It's body length is 6 - 7 mm when fully grown. Greenfly are a favourite prey of this genus. The pair of eyes between the 4 at the front and the two at the rear are hardly visible to the naked eye. The two large front-facing eyes are like headlamps (see below) and do reflect the light just like the eyes of a cat. It mates from May onwards.

Salticul sp. a jumping spider, eye layout
the headlamp eyes of Salticus sp. a jumping spider Salticus sp. a jumping spider
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