''Xysticus cristatus'', the common crab spider,
is a European spider from the family
Thomisidae
The Thomisidae are a family of spiders, including about 170 genera and over 2,100 species. The common name crab spider is often linked to species in this family, but is also applied loosely to many other families of spiders. Many members of thi ...
.
Description
The adults of ''Xysticus cristatus'' can reach a body length of about in the female, of about in the smaller male.
The colour varies from light cream, dark brown to greyish. It is much darker in males, with contrasting designs.
In both sexes the carapace shows a broad whitish median band containing a brown triangle facing the back and ending with a sharp, black apical macula. The dorsum (upper surface) of the
opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma (cephalothorax). It is a distinctive feature of the subphylum Chelicerata (arachnids, horseshoe crabs and others). Although it is similar in most respects to a ...
has a dark leaf pattern with white edges and light transverse stripes on the right and left.
[Heiko Bellmann: Kosmos-Atlas Spinnentiere Europas. Und Süßwasserkrebse, Asseln, Tausendfüßer. Franckh-Kosmos, 2006, ISBN 3440107469 ] This cryptic colouration is used to blend in with its normal environment of dried leaves.
The
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...
crab spider arises because they sometimes move in a crab-like way, from side to side.
Habitat
''Xysticus cristatus'' is usually found in low vegetation, often on the ground.
It is shade intolerant and avoids woodland and closed canopy habitats but it is otherwise found in almost every habitat type.
Biology
''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.
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.
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.
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.
After mating, female builds a flat white ovisac containing the developing eggs, usually fixed on the plants. Then the female sits on it to protect it, until a myriad of little spiders are released.
[
In Britain ''Xysticus cristatus'' has been observed as a prey item for the spider wasp '' Dipogon bifasciatus''.]
Distribution
The species has a Palearctic
The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa.
The realm consists of several bioregions: the Euro-Sibe ...
distribution,Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
) to South Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...
, Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
, Caucasus
The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range, have historically ...
, Russia, Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
, Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
, Central Asia
Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...
, China, Korea
Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...
, Japan. It has been introduced to Canada and United States.
References
{{Taxonbar, from=Q900724
Spiders of Europe
Thomisidae
Palearctic spiders
Spiders described in 1757
Taxa named by Carl Alexander Clerck