Xysticus cristatus

The adult female reaches a length of 8mm and the smaller male 5mm.[2] The colour varies from light cream, dark brown to greyish[3] with a dark triangle on the carapace which ends in sharp, defined point. The abdomen has a broad middle band fringed by two darker rows of triangular marks[2] which extends back to about two thirds of the carapace length from the posterior row of eyes.[4] This cryptic colouration is used to blend in with its normal environment of dried leaves.[5] The common name crab spider arises because they sometimes move in a crab-like way, from side to side.[3]

Xysticus cristatus is usually found in low vegetation, often on the ground.[2] It is shade intolerant and avoids woodland and closed canopy habitats but it is otherwise found in almost every habitat type.[6]

Xysticus cristatus is an ambush hunter which spends much time sitting still, with its fore-legs spread wide, waiting for insects to blunder into them.[3] In grass it adopts a flexible hunting position either at the tips of vegetation, such as flowerheads, or on the ground surface and as a result, the prey taken is varied and is made up of flying insects, including bees and butterflies. When it hunts on the ground the food tends to consist of ants, spiders and other soft bodied prey. It often takes prey much larger than itself.[3] In Great Britain spiderlings balloon, most often between the months of July to September. Active adults have been recorded from February to December, with a peak of male activity in May and June.[6]

To mate the male grasps one of the female's legs, holding on until she ceases to struggle, he then uses silk to tie her down on the ground and then he crawls underneath her and mates.[2]

In Britain Xysticus cristatus has been observed as a prey item for the spider wasp Dipogon bifasciatus.[7]

The species has a Palearctic distribution,[1][8] being found throughout Europe, including Iceland.[9]