Wolf spiders - Lycosidae

Lycosidae family

World wide there are 2320 species of wolf spider, about 200 species in mainland U. S. and Canada, in Europe there are 81 species in 8 genera, and in Britain there are 38 species. All Lycosids are hunting spiders, so they do not trap their prey in a web. They are commonly known as wolf spiders. Usually they have a dense covering of short hairs and can run very fast. 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. Lycosid females carry the eggs sac around with them attached to their spinnerets (see the photograph below). Usually the 4th pair, or rearmost legs are the longest.

Wolf spider egg sac, Lycosidea egg sac

Lycosidae mating and reproduction

Wolf spiders need good eyesight for mating. The male locates a female by detecting 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 the drawing 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!

Most Lycosid females carry their egg sac around with them attached to their spinnerets by silk as shown in the photographs above and below. The egg sac is often beige and about the size of a small dried pea or large lentil. 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 she 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. When the spiderlings are ready to emerge the female tears a hole in the sac, and the spiderlings clamber up her legs on to her abdomen, and even her carapace if the brood is large.

She will carry them around on her body for a week or so before they disperse, and during this time the spiderlings will not feed. Ballooning is a common method of dispersal.

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!

Lycosidae Colouration

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.

Lycosidae Eyes

Lycosidae head showing arrangement of eyes

Lycosids have a characteristic eye arrangement that is one of the first steps in identification. Above and 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.

Pardosa genus

Pardosa wolf spider

There are 39 species in Europe, and 15 in Britain. The British species are difficult to tell apart. In northern Europe females are easy to spot from mid May onwards as they carry their greenish-blue light-coloured egg sacs around. Some species have a whitish seam around the edge of the sac. The young spiderlings are let out after 2 or 3 weeks. A female can have 2 broods of young over the summer. Above is the cephalothorax of a typical Pardosa spider showing the arrangement of the eyes, the chelicerae and fangs.

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

wolf spider Pardosa

Pardosa Mating

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, below, stretches out his front pair of legs sideways, raises one palp, then raises another.

wolf spider Pardosa lugubris  male singalling to female that he wants to mate

Fully grown females are around 6 mm long, and males around 5 mm long.

They are found in woodland edges, and sunny clearings in woods.

Trochosa sp.

Trochosa sp. female wolf spider with egg sac

There are four British species in this genus. They all have the chunky legs of the female above, and all are dark brown with a paler band running down the middle. Above is a female Trochosa sp. (probably Trochosa terricola) 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, and also where they will live with their egg sac until the young hatch.

During the daylight hours it is usually just the males that are seen as they wander around in search of a 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.

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