Crab Spiders and Running Crab Spiders (Running Spiders)




Crab Spider (family Thompisidae)

The Crab Spider is a group of free-roaming spiders that don't build webs. Instead they hides on plants and flowers and waits for an unsuspecting victim to land or stumble into its path before grabbing the prey with their powerful front legs and injecting a lethal dose of fast-acting venom. Their prey includes bees, wasps, flies and butterflies, and many of these can be considerably larger in size than the spider itself.

The Crab Spider pictured above is a Xysticus Sp. This group of Crab Spiders has 17 different species in Europe. This one is believed to be a Common Crab Spider (Xysticus cristatus) although identifying these species is very difficult without a microscope.



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. Xysticus cristatus is very similar in appearance to Xysticus ulmi, however Xysticus ulmi lacks the sharp dark point at the end of the triangle on the carapace. 

LINK 1    LINK 2    LINK 3


Another Crab Spider form the group Xysticus Sp. (Ground Crab Spiders)








A large Ground Crab Spider (Xysticus cristatus) with prey. Photographed on grassland in SE London, May 2020.








A large Ground Crab Spider (Xysticus cf cristatus). Photographed on grassland in SE London, May 28th 2021.








5mm male Crab Spider (Xysticus Sp.) hunting on vegetation in my garden pond in SE London, 26th April 2020






5mm male Crab Spider (Xysticus Sp.) hunting on vegetation in my garden pond in SE London, 26th April 2020








Adult female Misumena vatia

Flower Crab Spider (Misumena vatia)

Flower Crab Spiders, also known as Goldenrod Crab Spiders, are true Crab Spiders and are usually found hiding on white, yellow or pink flowers where they can be excellently camouflaged. Adult females can be found in white, yellow, pale green and pink. Some specimens can display two red longitudinal stripes on their abdomen. They're frequently seen on woodland edges where grassland meets shrubbery, but they can also frequent open areas and gardens too. Females grow to a maximum body-length of around 9-11mm, but the far smaller males only reach 3-4mm. Female Flower Crab Spiders can vary in colour from white, pale green, yellow and pink. Some specimens display two red longitudinal stripes along their abdomen. Males look very different with a predominantly dark brown thorax and legs and a cream / light green coloured abdomen and matching band in the centre of the thorax.

This Crab Spider is an excellent ambush predator with the remarkable ability to slowly change its body colour to match the flower that it is hiding on. This colour-changing process can take 4-25 days to complete. Changing from yellow to white can be done as quickly as 4-6 day as the spider just has to secrete the yellow pigment. However changing from white to yellow takes 10-25 day, far longer as the yellow pigment must be built up inside the spider. Male specimens lack this colour-changing ability completely.

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. Adults are most often seen from May-June but they can be seen from April right up until September. Males are seldom seen after June though.

LINK 1    LINK 2    LINK 3    LINK 4


The male Crab Spider is much smaller than the aggressive and powerful female. Male spiders often risk injury or death during any attempt to mate with the female.








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. The females do not emit pheromones but they do leave draglines of silken thread which the males follow to locate her. After giving birth the adult female will guard her young for a while before dying off. Most adult males die shortly after mating if they survive the mating process without being eaten. The young usually overwinter in leaf litter until the following spring when the spring flowers emerge. Very occasionally an adult female may also overwinter in leaf litter.





Female Flower Crab Spider. Still holding on to her lunch in the centre photo.








Female Flower Crab Spider morphing from white to yellow.








Flower Crab Spider (Misumena vatia) found on a Buttercup in grass field in SE London, 2nd June 2021.

This stunning yellow Flower Crab Spider was the brightest and most colourful spider I have ever photographed. Its colour was so luminescent that it was difficult to photograph without overexposing the image.






Flower Crab Spider (Misumena vatia) in pale green. Found on nettles in my SE London garden, 21st May 2018.









Flower Crab Spider (Misumena vatia) on Buttercup in grass field in SE London, 2nd June 2021.








Flower Crab Spider (Misumena vatia) on Buttercup in grass field in SE London, 2nd June 2021.








Flower Crab Spider (Misumena vatia) on Buttercup in grass field in SE London, 2nd June 2021.








Female Flower Crab Spider (Misumena vatia) feeding on a smaller spider.








Female Flower Crab Spider (Misumena vatia) waiting to ambush its prey by the side of my garden pond.








Female Flower Crab Spider (Misumena vatia) waiting to ambush its prey by the side of my garden pond.

Although this is the typical ambush or defence stance for the Flower Crab Spider there is also another reason why they sit with their legs stretched out in front of them. Crab Spiders have both motion-sensing and chemical sensing hairs on their front legs. Stretching out their legs in this manor allows them to gather far more information about their surroundings than relying on their restricted eyesight, which is believed to be quite limited at any distance further than about 10cm away from the spider.





Female Flower Crab Spider (Misumena vatia) with Solitary Bee








Female Flower Crab Spider (Misumena vatia) waiting to ambush its prey by the side of my garden pond.








Female Flower Crab Spider (Misumena vatia) on rose bush in my garden in SE London, 14th June 2018.








Female Flower Crab Spider (Misumena vatia) on lavender.








Female Flower Crab Spider (Misumena vatia)








Flower Crab Spider (Misumena vatia) waiting to ambush its prey.








Flower Crab Spider (Misumena vatia) on Buttercup in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Buttercup in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Buttercup in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Buttercup in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Brambles in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Brambles in grassland field in Kent, 20th May 2020.







Flower Crab Spider (Misumena vatia) on Brambles in grassland field in Kent, 20th May 2020.








2.5mm juvenile Flower Crab Spider (Misumena vatia) on my garden privet bush in SE London, 19th April 2022.

Even at this size this tiny juvenile / sub-adult Flower Crab Spider is a perfect miniature replica of an adult specimen. At this time of year it won't be long before the spider reaches maturity and rapidly increases its body-mass in preparation for egg production. 






3.5mm Male Flower Crab Spider (Misumena vatia) found in a garden in SE London, 19th April 2021.








3.5mm Male Flower Crab Spider (Misumena vatia) found in a garden in SE London, 19th April 2021.








3.5mm Male Flower Crab Spider (Misumena vatia) found in a garden in SE London, 19th April 2021.









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.

LINK 1    LINK 2


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 and comparison to other closely related species of the genus.




Running Crab Spider  (Philodromus cf albidus)  helping to keep the flies off my Porsche!








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 mature males have a dark upper body and head and white or light coloured legs and underside and are sometimes referred to as the "Tuxedo Spider".

LINK  1    LINK  2    LINK  3



4mm female House Crab Spider  (Philodromus dispar) found on low vegetation in my SE London garden, 21st May 2018.








Male House Crab Spider  (Philodromus dispar) found on my garden fence in SE London, 3rd May 2019.







Male House Crab Spider  (Philodromus dispar) photographed in my garen in SE London 19th April 2020








Female Wandering Crab Spider Female (Philodromus cf Aureolus) found wandering on my Ivy-covered garden fence, 7th June 2020.

Wandering Crab Spider   (Philodromus Aureolus)
One of six species of Running Crab Spider in the Aureolus group that are very difficult to separate (P. aureolus, P. buxi, P. cespitum, P. collinus, P. longipalpis and P. praedatus). The Wandering Crab Spider is common and widespread across Britain, especially in the SE of England. They are frequently beaten from low branches of trees and bushes and tend to be found in woodland, gardens or scrub in early to mid-summer. The body-length is variable and males range from 3.5-6.5mm. Females range from 4-8.5mm. These spiders use their camouflage and sudden bursts of rapid speed to catch their prey. There is the possibility that Wandering Crab Spiders may have the ability to slightly change their colour to match their surroundings. Males are dark with a metallic pink / green sheen to the upper surface.

LINK 1    LINK 2    LINK 3    LINK 4


Male Wandering Crab Spider Female (Philodromus cf Aureolus) found on a metal gate at Rainham Marshes, Essex, 23rd June 2021.








Female Wandering Crab Spider  (Philodromus cf aureolus) photographed in my garden in SE London 19th April 2020








Male Running Crab Spider, Philodromus cf rufus, found in my SE London garden 18th May 2018
Running Crab Spider  -  (Philodromus rufus)
Philodromus rufus is a small species of Running Crab Spider, and another of the six species of Running Crab Spider in the Aureolus group that are very difficult to separate. Male Philodromus rufus grow to a body-length of around 3-4mm, whilst the larger female reaches 4-6mm. Philodromus rufus is confined to the south of England, with most records coming from the SE of England, around the London area. Philodromus rufus is virtually indistinguishable from the very similar Philodromus albidus. However Philodromus rufus tend to have a more reddish colour and usually favour more open scrubland and bushes at the sunny edge of woodland. Adult specimens are usually found from April through to September, with peak numbers of both sexes being recorded in May.
LINK 1    LINK 2    LINK 3



Grass Spider (Tibellus cf oblongus) found in long grass on Swanscombe Marshes, Kent 16th August 2020.

Grass Spider / Slender Running Spider  -  (Tibellus oblongus)

The Grass Spider is a member of the Running Crab Spider family although with its long slender abdomen if differs in appearance considerably from other species of Running Crab Spider and is pretty easy to identify in the field. Adult males grow to around 7-8mm in body-length whilst the females grow to 8-10mm. They are fairly common throughout the UK but are more often encountered in Southern England from May until September. Although Grass Spiders can be found in a variety of habitats they have a preference for tall grass as their name suggests. The Grass Spider is an ambush predator and waits at the top of vegetation for its prey to come within range. At rest the Grass Spider often lays flat with its legs stretched out in front and back, similar to the Wide-Jawed Orb-Weaver, and is excellently camouflaged amongst dry grass in the summer. Egg-sacs are laid at the top of vegetation and are guarded by the female. Other common names include the Grass-Blade Spider and the Slender Crab Spider.

The Tibellus genus has two species in the UK which are indistinguishable without microscopic examination of the genitalia. Both are found in a variety of habitats including damp fields and meadows, but Tibellus maritimus seems to have a preference for coastal sites. Tibellus oblongus is the more common and widespread of the two species.

LINK 1    LINK 2    LINK 3


Grass Spider (Tibellus cf oblongus) found in long grass on Swanscombe Marshes, Kent 16th August 2020.








Grass Spider (Tibellus cf oblongus) at rest in long grass on Swanscombe Marshes, Kent 16th August 2020.








Grass Spider (Tibellus cf oblongus). One of several seen on low vegetation at the edge of a grass field in SE London 27th May 2021








Cricket-Thief Spider (Thanatus vulgaris) found as a stowaway amidst imported crickets, June 2021.

Cricket-Thief Spider  -  (Thanatus vulgaris)

The Cricket-Thief Spider is a non-native species of Running Crab Spider, in the family Philodromidae, that is regularly found as a stowaway amidst imported crickets and locusts supplied to the exotic pet trade. As its name suggests this spider feeds on other invertebrates, with a preference for crickets and grasshoppers, and in its native range is usually found in areas of long grass. In the UK it is very rare to find this species outdoors in the wild as it prefers a warmer and drier habitat. It has occasionally been spotted outdoors here since 1992 but most UK sightings occur in pet shops or by exotic pet owners. The Cricket-Thief Spider is native to much of Europe, Asia and North America. Adult females reach a body-length of around 10mm whilst the smaller males reach around 6mm.

* I'd like to say a huge thank you to Vicky Butterfield-Reffin for kindly sending this specimen to me so it could be cared for and added to my website. *

LINK 1    LINK 2    LINK 3    LINK 4

On 26th January 2018 the Sun Newspaper, known for its sensationalised stories, reported a case of one Cricket-Thief Spider being found in London by a 12 year old boy, claiming it to be the highly venomous Brazilian Wandering Spider.  LINK