''Thomisus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of crab spiders (family Thomisidae) with around 150 species described. The genus includes species that vary widely in their ecology, with some that are

ambush predator Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey ...

s that feed on insects visiting flowers. Like several other genera in the family Thomisidae, they are sometimes referred to as flower crab spiders, from their crab-like motion and their way of holding their front legs, reminiscent of a crab spreading its claws as a threat.

Description and behavior

As with most ''

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 th ...

'' species, ''Thomisus'' exhibit sexual size dimorphism: females are in length, whereas males are only . Many species are brightly colored, usually matching the color of the flower in which they are waiting in ambush. Not all species are flower-dwelling, but among those that are, at least some species can change their colour over a period of some days to match the flower colour. Studies suggest that bees are inclined to avoid a flower that contains a spider-sized object of a non-matching colour; whether this is specifically a mechanism for avoiding crab spiders, or simply that they are not attracted to flowers whose

nectar guide Nectar guides are markings or patterns seen in flowers of some angiosperm species, that guide pollinators to their rewards. Rewards commonly take the form of nectar, pollen, or both, but various plants produce oil, resins, scents, or waxes. Such ...

s are obscured however, is a more difficult question. The colour changes that such species can achieve are typically in ranges of white, pink, and yellow. For example, in ''

Thomisus spectabilis ''Thomisus spectabilis'', also known as the white crab spider or Australian crab spider, is a small spider found in Australia and far east Asia. The body length of the female is up to 10 mm, the male 6.2 mm. Including legs, the spider ...

'', the method of camouflage is similar to the ''

Misumena vatia ''Misumena vatia'' is a species of crab spider with a holarctic distribution. In North America, it is called the goldenrod crab spider or flower (crab) spider,Acorn, John and Sheldon, Ian. (2003). ''Bugs of Ontario'' Edmonton: Lone Pine Publish ...

'', though ''T. spectabilis'' are visible to their prey, but not their predators. This species of crab spiders is UV reflective while the flower is UV absorbing creating a contrast between the spider and flower through the eyes of the pollinator.Gawryszewski, F. M., A. L. Llandres, and M. E. Herberstein. "Relationship between colouration and body condition in a crab spider that lures pollinators." Journal of Experimental Biology 215, no. 7 (2012): 1128-1136. The contrast created greatly attracts pollinators such as honeybees. This evolutionary method of camouflage increased the likelihood the crab spiders encountered prey, which in turn effects the fitness of the crab spiders. Due to the increased encounter rate of prey the spiders are able to focus energy on reproduction therefore leading to increased fitness in the spiders. The evolutionary method of camouflage greatly increases the survivability and fitness of crab spiders.

Distribution

The distribution of ''Thomisus'' species is almost worldwide, with the notable exception of most of South America. Although ''Thomisus'' species can be found almost anywhere on earth, most species occur in the tropics and the warmer regions of the Old World, with fewer species in the region from New Guinea to Australia and the

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...

. Only '' Thomisus guadahyrensis'' is known from South America (in Peru).

Species

, the

World Spider Catalog The World Spider Catalog (WSC) is an online searchable database concerned with spider taxonomy. It aims to list all accepted families, genera and species, as well as provide access to the related taxonomic literature. The WSC began as a series of ...

accepted the following species: *'' Thomisus albens'' O. Pickard-Cambridge, 1885 – Pakistan, Yarkand *'' Thomisus albertianus'' Strand, 1913 – Gabon, Congo, Uganda, Angola *'' Thomisus albohirtus'' Simon, 1884 – North, East Africa, Yemen *'' Thomisus amadelphus'' Simon, 1909 – Vietnam *'' Thomisus andamanensis'' Tikader, 1980 – India, Andaman Is. *'' Thomisus angulatulus'' Roewer, 1951 – Gabon *'' Thomisus angustifrons'' Lucas, 1858 – Gabon *'' Thomisus arabicus'' Simon, 1882 – Yemen *'' Thomisus armillatus'' (Thorell, 1891) – Nicobar Is. *'' Thomisus ashishi'' Gajbe, 2005 – India *'' Thomisus australis'' Comellini, 1957 – Central, Southern Africa *'' Thomisus baghdeoi'' Gajbe, 2004 – India *'' Thomisus bargi'' Gajbe, 2004 – India *'' Thomisus beautifularis'' Basu, 1965 – India *'' Thomisus benoiti'' Comellini, 1959 – Congo *'' Thomisus bicolor'' Walckenaer, 1837 – USA *'' Thomisus bidentatus'' Kulczyński, 1901 – West Africa to Saudi Arabia, Yemen *'' Thomisus bigibbosus'' Keyserling, 1881 – USA *'' Thomisus blandus'' Karsch, 1880 – Africa, Yemen *'' Thomisus boesenbergi'' Lenz, 1891 – Madagascar *'' Thomisus bonnieri'' Simon, 1902 – Oman *'' Thomisus bueanus'' Strand, 1916 – Cameroon *'' Thomisus bulani'' Tikader, 1960 – India *'' Thomisus callidus'' (Thorell, 1890) – Sri Lanka, Singapore, Sumatra, Nias Is., Java *'' Thomisus cancroides'' Eydoux & Souleyet, 1841 – Unknown *'' Thomisus candidus'' Blackwall, 1866 – Tropical Africa *'' Thomisus castaneiceps'' Simon, 1909 – Vietnam *'' Thomisus cavaleriei'' Schenkel, 1963 – China *'' Thomisus citrinellus'' Simon, 1875 – Mediterranean, Africa, Seychelles, Yemen, Socotra, Iraq *'' Thomisus congoensis'' Comellini, 1957 – Central, Southern Africa *'' Thomisus dalmasi'' Lessert, 1919 – Africa *'' Thomisus danieli'' Gajbe, 2004 – India *'' Thomisus daradioides'' Simon, 1890 – South Africa to India *'' Thomisus dartevellei'' Comellini, 1957 – Congo, Ethiopia, Malawi *'' Thomisus dentiger'' (Thorell, 1887) – Myanmar *'' Thomisus destefanii'' Caporiacco, 1941 – Ethiopia *'' Thomisus dhakuriensis'' Tikader, 1960 – India *'' Thomisus dhananjayi'' Gajbe, 2005 – India *'' Thomisus duriusculus'' (Thorell, 1877) – Sulawesi *'' Thomisus dyali'' Kumari & Mittal, 1997 – India *'' Thomisus elongatus'' Stoliczka, 1869 – India *'' Thomisus eminulus'' Tang & Li, 2010 – China *'' Thomisus galeatus'' Simon, 1909 – Vietnam *'' Thomisus ghesquierei'' Lessert, 1943 – Congo *'' Thomisus godavariae'' Reddy & Patel, 1992 – India *'' Thomisus gouluensis'' Peng, Yin & Kim, 2000 – China *'' Thomisus granulatus'' Karsch, 1880 – Southern Africa *'' Thomisus granulifrons'' Simon, 1906 – India, Sri Lanka *'' Thomisus guadahyrensis'' Keyserling, 1880 – Peru *'' Thomisus guangxicus'' Song & Zhu, 1995 – China *'' Thomisus hararinus'' Caporiacco, 1947 – Ethiopia *'' Thomisus hui'' Song & Zhu, 1995 – China *'' Thomisus hunanensis'' Peng, Yin & Kim, 2000 – China *'' Thomisus ilocanus'' Barrion & Litsinger, 1995 – Philippines *'' Thomisus iswadus'' Barrion & Litsinger, 1995 – Philippines *'' Thomisus italongus'' Barrion & Litsinger, 1995 – Philippines *'' Thomisus janinae'' Comellini, 1957 – Congo, Tanzania *'' Thomisus jocquei'' Dippenaar-Schoeman, 1988 – Malawi *'' Thomisus kalaharinus'' Lawrence, 1936 – Africa, Yemen *'' Thomisus katrajghatus'' Tikader, 1963 – India *'' Thomisus keralae'' Biswas & Roy, 2005 – India *'' Thomisus kitamurai'' Nakatsudi, 1943 – Ryukyu Is. *'' Thomisus kiwuensis'' Strand, 1913 – Central Africa *'' Thomisus kokiwadai'' Gajbe, 2004 – India *'' Thomisus krishnae'' Reddy & Patel, 1992 – India *'' Thomisus labefactus'' Karsch, 1881 – China, Korea, Taiwan, Japan *'' Thomisus laglaizei'' Simon, 1877 – Myanmar, Philippines, Java, Sumatra *'' Thomisus lamperti'' Strand, 1907 – Madagascar *'' Thomisus leucaspis'' Simon, 1906 – India, New Caledonia *'' Thomisus litoris'' Strand, 1913 – Central Africa *'' Thomisus lobosus'' Tikader, 1965 – India *'' Thomisus ludhianaensis'' Kumari & Mittal, 1997 – India *'' Thomisus machadoi'' Comellini, 1959 – Angola, Cape Verde Is., South Africa *'' Thomisus madagascariensis'' Comellini, 1957 – Madagascar *'' Thomisus magaspangus'' Barrion, Barrion-Dupo & Heong, 2013 – China *'' Thomisus manishae'' Gajbe, 2005 – India *'' Thomisus manjuae'' Gajbe, 2005 – India *'' Thomisus marginifrons'' Schenkel, 1963 – China *'' Thomisus meenae'' Gajbe, 2005 – India *'' Thomisus melanostethus'' Simon, 1909 – Vietnam *'' Thomisus mimae'' Sen & Basu, 1963 – India *'' Thomisus modestus'' Blackwall, 1870 – Italy *'' Thomisus natalensis'' Lawrence, 1942 – Southern Africa *'' Thomisus nepenthiphilus'' Fage, 1930 – Sumatra *'' Thomisus nirmali'' Saha & Raychaudhuri, 2007 – India *'' Thomisus nossibeensis'' Strand, 1907 – Madagascar *'' Thomisus obscuratus'' Caporiacco, 1947 – East Africa *'' Thomisus obtusesetulosus'' Roewer, 1961 – Senegal *'' Thomisus ochraceus'' Walckenaer, 1841 – Algeria *'' Thomisus odiosus'' O. Pickard-Cambridge, 1898 – Mexico *'' Thomisus okinawensis'' Strand, 1907 – Thailand to Ryukyu Is., Philippines, Indonesia *''

Thomisus onustus ''Thomisus onustus'' is a crab spider belonging to the genus ''Thomisus''. These spiders are found across Europe, North Africa, and parts of the Middle East and Asia. ''T. onustus'' reside in flowers in lowland vegetation. Females are distinguish ...

'' Walckenaer, 1805 (

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

) – Palearctic *'' Thomisus oscitans'' Walckenaer, 1837 – USA *'' Thomisus pateli'' Gajbe, 2004 – India *'' Thomisus pathaki'' Gajbe, 2004 – India *'' Thomisus penicillatus'' Simon, 1909 – Vietnam *'' Thomisus perspicillatus'' (Thorell, 1890) – Borneo, Sulawesi *'' Thomisus pooneus'' Tikader, 1965 – India *'' Thomisus pritiae'' Gajbe, 2005 – India *'' Thomisus projectus'' Tikader, 1960 – India *'' Thomisus pugilis'' Stoliczka, 1869 – India *'' Thomisus rajani'' Bhandari & Gajbe, 2001 – India *'' Thomisus retirugus'' Simon, 1909 – Vietnam *'' Thomisus rigoratus'' Simon, 1906 – India *'' Thomisus rishus'' Tikader, 1970 – India *'' Thomisus roeweri'' Comellini, 1957 – Tanzania *'' Thomisus schoutedeni'' Comellini, 1957 – Congo *'' Thomisus schultzei'' Simon, 1910 – Southern Africa *'' Thomisus scrupeus'' (Simon, 1886) – Africa *'' Thomisus shillongensis'' Sen, 1963 – India *'' Thomisus shivajiensis'' Tikader, 1965 – India *'' Thomisus sikkimensis'' Tikader, 1962 – India *'' Thomisus simoni'' Gajbe, 2004 – India *'' Thomisus socotrensis'' Dippenaar-Schoeman & van Harten, 2007 – Socotra *'' Thomisus sorajaii'' Basu, 1963 – India *''

'' Doleschall, 1859 – India to Australia *'' Thomisus spiculosus'' Pocock, 1901 – West, Central, Southern Africa *'' Thomisus stenningi'' Pocock, 1900 – Africa, Seychelles, Yemen *'' Thomisus stigmatisatus'' Walckenaer, 1837 – USA *'' Thomisus stoliczkai'' (Thorell, 1887) – Myanmar *'' Thomisus sundari'' Gajbe & Gajbe, 2001 – India *'' Thomisus swatowensis'' Strand, 1907 – China *'' Thomisus telanganaensis'' Pravalikha & Srinivasulu, 2015 – India *'' Thomisus tetricus'' Simon, 1890 – Yemen *'' Thomisus transversus'' Fox, 1937 – China *'' Thomisus tripunctatus'' Lucas, 1858 – West Africa *'' Thomisus tuberculatus'' Dyal, 1935 – Pakistan *'' Thomisus turgidus'' Walckenaer, 1837 – USA *'' Thomisus unidentatus'' Dippenaar-Schoeman & van Harten, 2007 – Yemen, Iraq, Iran *'' Thomisus venulatus'' Walckenaer, 1841 – Algeria *'' Thomisus viveki'' Gajbe, 2004 – India *'' Thomisus vulnerabilis'' Mello-Leitão, 1929 – Myanmar *'' Thomisus wangi'' Tang, Yin & Peng, 2012 – China *'' Thomisus whitakeri'' Gajbe, 2004 – India *'' Thomisus yemensis'' Dippenaar-Schoeman & van Harten, 2007 – Yemen *'' Thomisus zaheeri'' Parveen, Khan, Mushtaq, Ahmad & Rana, 2008 – Pakistan *'' Thomisus zhui'' Tang & Song, 1988 – China *'' Thomisus zuluanus'' Lawrence, 1942 – South Africa *'' Thomisus zyuzini'' Marusik & Logunov, 1990 – Turkey, Saudi Arabia to Central Asia

References

{{Taxonbar, from=Q1070241 Thomisidae Araneomorphae genera Cosmopolitan spiders