Crab spiders

See also Family Eusparassidae

And Family Philodromidae

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Family Thomisidae

This is a large family with more than 3000 known species. Sixty-two are found in this region. They are not active hunters and make more use of the camouflage techniques than other spiders. The color of the spider is adapted to the hunting terrain they use and is mostly extravagant. They remain unmoved until the prey arrives and catches it. With a venomous bite (not dangerous to humans) they kill their prey and suck it dry. Crab spiders can be found on flowers or leaves of plants. Often the crab spider remains for days, even weeks at the same spot. The front two legs, that are often larger and stronger than the other six, are held sideways, ready to catch the prey immediately. Because they sit on easily spotted places, they are also easy to catch by the predators. When they spot a possible enemy, they move quickly at the other site of the flower or leave. Their eyesight is excellent developed as can be seen on the pictures. They have normally two big front eyes.

The Misumena vatia is a crab spider that can adapt its color to her surrounding. The color of its body can change between snow white, egg sac yellow and green. The change of color takes 2-3 days. Its main menu is bees. The spider seizes the bee by its front legs and bites it in the bee's neck. The spider keeps its hold on the bee until the bee gives up its resistance. If the spider catches a lot of prey, it hangs its surplus stock below its hiding place.
Misumena vatia
Crab spiders are easy recognizable if you tease them. They widen their legs and move side ways like a crab. The size of these spider varies between 4 - 10 mm.
In some genera, there is a great disparity between the male and the female. The Philodromus dispar as shown below is a nice example. The male is completely different from the female.
The females usually stand guard with their egg sacs. The egg sacs are fastened to the vegetation and are usually flat.


Genus Diaea

Diaea dorsata Diaea dorsata male
Diaea dorsata Female Diaea dorsata Male

The spider is characterized by its green thorax and a brown abdomen. As you can see it is very small (5 mm). The spider can be found at the outside of forests.


Genus Heriaeus

Three species can be found in NW-Europe. The male is 4-5 mm while the female is 7-9 mm. The spiders are strikingly hairy and green. The long hairs and spikes are white or very pale green. It can be found on hairy vegetation.

H. hirtus and H. melotteei are very similar.

Heriaeus hirtus


Genus Misumena

See description of the spider at the top of the page. The female spider can adapt its color in 2-3 days to its surrounding.

Misumena vatia male
Misumena vatia female Misumena vatia male
Misumena vatia female
Misumena vatia camouflaged andready to catch a prey Misumena vatia note the difference in leg colours
Misumena vatia Misumena vatia
Misumena vatia Misumena vatia

Genus Misumenops

Only one species can be found in this region. The male is substantial different from the female. The male is 2.5 - 3 mm while the female size varies between 5 and 6 mm. They can be found on leaves of bushes.

Misumenops tricuspidatus female and male.


Genus Ozyptila

Twelve species are known in Europe. Their size is 3-4 mm.

Ozyptila praticola Ozyptila praticola
Ozyptila trux
Ozyptila trux Ozyptila trux


Genus Synaema

Synaema globosum Synaema globosum Synaema globosum
Synaema globosum    

This spider can be found with different colors beside the black pattern. The female size varies between 6 - 9 mm while the male is much smaller (3 - 4 mm). They can be found between flowers that resembles their color.


Genus Tmarus

This spider is very difficult to find. It vanishes almost completely in its surrounding, twigs and branches of conifers and bushes. The spider can be easily identified by it particular shaped abdomen and its typical position. Its size varies between 3 and 6 mm.

Tmarus piger

Tmarus piger

 


Genus Thomisus


A remarkable spider of which only one species, Thomisus onustus, occurs in the southern parts of our regions. The spider can easily be identified the shape of its abdomen.


Thomisus onustus foto Els Latten

The female spider measures 6 -7 mm while the male is very small (2.5 - 3.5 mm). The colors of the spider vary between yellow, white and pink and the spider can be found amongst blooms of heather. Her common name is "Flower spider".

Thomisus onustus (By Klaus Mechsner) Thomisus onustus


Genus Xysticus

Xysticus is found more on plants than on flowers. The color of the abdomen is therefore light to dark brown and the form is oval to triangular. 17 species can be found in NW Europe. Males (around 5 mm) are smaller than females (around 7 mm). Colors and markings are quite variable within species.

Before mating the female is offered a present and secured by some threads. These threads a so minute that is does not fastens her for real but she pretends it does.

Xysticus cristatus female

Xysticus cristatus male

Xysticus bifasciatus female

Xysticus bifasciatus female

Xysticus bifasciatus male

Xysticus lanio

Xysticus ferrugineus

Xysticus ferrugineus

Xysticuskempelini
Xysticus kempelini Xysticus ZZ454
Xysticus sabulosus Xysticus sabulosus

 

 


Ed Nieuwenhuys, 23 february 2010

July 19 2008
May 25, 2008
December 5, 2005
December 8, 1996