Thomisus
Encyclopedia
Thomisus is a genus
of crab spider
s (family Thomisidae) with more than 100 species described. The genus includes species that vary widely in their ecology, but the best known crab spiders are those species that people call the flower crab spiders, because they are ambush predator
s that feed on insects visiting flowers. The flower crab spiders are the species for which the popular name was coined, because of their crab-like motion and their way of holding their front legs in an attitude reminiscent of a crab spreading its claws as a threat.
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.
.The world spider catalog 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
. Only T. guadahyrensis is known from South America
, and only in Peru
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of crab spider
Crab spider
Crab spider is a common name applied loosely to many species of spiders, but most nearly consistently to members of the family Thomisidae...
s (family Thomisidae) with more than 100 species described. The genus includes species that vary widely in their ecology, but the best known crab spiders are those species that people call the flower crab spiders, because they are ambush predator
Ambush predator
Ambush predators or sit-and-wait predators are carnivorous animals that capture prey by stealth or cunning, not by speed or necessarily by strength. These organisms usually hide motionless and wait for prey to come within striking distance. They are often camouflaged, and may be solitary...
s that feed on insects visiting flowers. The flower crab spiders are the species for which the popular name was coined, because of their crab-like motion and their way of holding their front legs in an attitude reminiscent of a crab spreading its claws as a threat.
Description and habits
In most species females are four to ten mm long, with males two to seven mm. Many 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 guideNectar guide
Nectar guides are patterns seen in some species of flowers, guiding pollinators to their rewards. Rewards commonly take the form of nectar, pollen, or both, but various plants produce oil, resins, scents, or waxes...
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.
Distribution
The distribution of Thomisus species is almost worldwide, with the notable exception of most of South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.The world spider catalog Although Thomisus species can be found almost anywhere on earth, most species occur in the tropics and the warmer regions of the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
, with fewer species in the region from New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
. Only T. guadahyrensis is known from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and only in Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
.
Species
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Thomisus onustus Thomisus onustus is a crab spider species in the genus Thomisus belonging to the family Thomisidae. -Distribution:It has a Palearctic distribution from Great Britain and Portugal in the West to Japan in the East. It is present in most countries of Europe, but it is absent in Iceland, Ireland,... Walckenaer, 1805 — Palearctic
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