Crab Spider (family Thompisidae)
Female Common Crab Spider - Xysticus cf cristatus
Common Crab Spider (Xysticus cristatus)
The Common Crab Spider is found in low vegetation and in leaf litter in a variety of habitats across the UK. Females reach a body-length of around 8mm whilst males are smaller at 5mm. May and June are the peak months for this species although they can be found from March to October. Some specimens have even been found in February and December.
Adult female Misumena vatia
Flower Crab Spider (Misumena vatia)
These true Crab Spiders are usually found hiding on white, yellow or pink flowers. This Crab Spider is an excellent ambush predator with the ability to slowly change its body colour to match the flower that it is hiding on. This colour-changing process can take 6-25 days to complete. Changing from yellow to white can be done fairly quickly as the spider just has to secrete the yellow pigment. However changing from white to yellow takes far longer as the yellow pigment must be built up inside the spider.
This species has a wide range across Europe and the USA. In the UK it is common across the southern half of Wales & England especially around London and the south-east. Usually active from May-August but can be seen from April-September.
This male waits until the female is pre-occupied with killing a large hoverfly before jumping up and seizing this opportunity to mate. Some Crab Spiders are also known to tie up the female in silk-like web before attempting to mate.
Turf Running Spider (Philodromus cespitum)
Turf Running Spider (Philodromus cespitum)
Technically spiders from the group "Philodromus" are Running Crab Spiders and not true Crab Spiders. They do have similar eye and leg arrangements though.
This image is of a small Crab Spider form the group Philodromus Species. It is extremely difficult to identify exactly what species this is but I have been informed that it is most likely to be Philodromus cespitum, the Turf Running Spider. This Running Spider is common throughout Britain especially in the southern half, and is found in low vegetation. It has an average body-length of around 6mm.
Running Crab Spider (Philodromus cf albidus)
Running Crab Spider (Philodromus cf albidus)
Philodromus albidus is another common and widespread small Running Crab Spider from the group Philodromus. This specimen had a body-length of just 4-5mm.
When species cannot be 100% positively identified, it is common practice to add "cf" in the middle of the Latin name to indicate that whilst the name given is highly likely it cannot be guaranteed without microscopic examination.
House Crab Spider (Philodromus dispar)
Another small and frequently encountered Running Crab Spider in England & Wales with a body length of 4-5mm for both sexes. Found in a variety of habitats especially low vegetation and bushes. They are also found in homes on occasion. The female is variable in colour but usually brown-yellow while the male has a dark upper body and head and white or light coloured legs and underside.
