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Temporal range: Palaeogene–present
Spider and bee June 2008-1.jpg
Thomisus onustus capturing a bee
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Thomisidae
Genus: Thomisus
Walckenaer, 1805
Type species
Thomisus onustus
Walckenaer, 1805

See text

142 species

Thomisus is a genus of crab spiders (family Thomisidae) with around 142 species described. The genus includes species that vary widely in their ecology, with some that are ambush predators 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

The eye arrangement of spiders in the genus Thomisus Thomisus eye group.svg
The eye arrangement of spiders in the genus Thomisus

As with most Thomisidae species, Thomisus exhibit sexual size dimorphism: females are 4 to 10 mm (0.16 to 0.39 in) in length, whereas males are only 2 to 7 mm (0.079 to 0.276 in). Many species are brightly colored, usually matching the color of the flower in which they are waiting in ambush. [1] 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. [2] 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 guides are obscured however, is a more difficult question. [3] The colour changes that such species can achieve are typically in ranges of white, pink, and yellow.

For example, in Thomisus spectabilis , the method of camouflage is similar to the Misumena vatia , 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. [4] 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.


Thomisus Onustus in Behbahan, Iran Thomisus Onustus in Behbahan, Iran.jpg
Thomisus Onustus in Behbahan, Iran

The distribution of Thomisus species is almost worldwide, with the notable exception of most of South America. [5] 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 Thomisus guadahyrensis is known from South America (in Peru).


Male Thomisus kitamurai from Japan Thomisus kitamurai.male.-.tanikawa.jpg
Male Thomisus kitamurai from Japan
Female Thomisus kitamurai in Japan Thomisus kitamurai.female.1.-.tanikawa.jpg
Female Thomisus kitamurai in Japan
Female Thomisus okinawensis in Japan Thomisus.okinawensis.female.1.-.tanikawa.jpg
Female Thomisus okinawensis in Japan
South African species of Thomisus disturbed on Lavandula inflorescence Crab Spider (Thomisus) on Lavandula 5637.jpg
South African species of Thomisus disturbed on Lavandula inflorescence
Female Thomisus labefactus Thomisus labefactus.jpg
Female Thomisus labefactus

As of December 2022, the World Spider Catalog accepted 142 species: [5]

Related Research Articles

<span class="mw-page-title-main">Thomisidae</span> Family of spiders

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 this family are also known as flower spiders or flower crab spiders.

<i>Misumena</i> Genus of spiders

Misumena is a genus of crab spiders sometimes referred to as flower crab spiders. They are similar in appearance to several other genera in the family Thomisidae, such as Misumenoides and Mecaphesa.

<i>Xysticus</i> Genus of ground crab spiders

Xysticus is a genus of ground crab spiders described by C. L. Koch in 1835, belonging to the order Araneae, family Thomisidae. The genus name is derived from the Ancient Greek root xyst, meaning "scraped, scraper".

<i>Thanatus</i> Genus of spiders

Thanatus is a genus of false crab spiders described by Carl Ludwig Koch in 1837, belonging to the order Araneae, family Philodromidae.

<i>Cheiracanthium</i> Genus of spiders

Cheiracanthium, commonly called yellow sac spiders, is a genus of araneomorph spiders in the family Cheiracanthiidae, and was first described by Carl Ludwig Koch in 1839. They are usually pale in colour, and have an abdomen that can range from yellow to beige. Both sexes range in size from 5 to 10 millimetres. They are unique among common house spiders because their tarsi do not point either outward, like members of Tegenaria, or inward, like members of Araneus), making them easier to identify.

<i>Diaea</i> Genus of spiders

Diaea is a genus of crab spiders first described by Tamerlan Thorell in 1869. Most species are found in specific locations except for D. livens, which occurs in the United States and D. dorsata, which has a palearctic distribution. Adults are 5 millimetres (0.20 in) to 7 millimetres (0.28 in) and tend to hide in and around vegetation, especially flowers, where their color allows them to blend in to their surroundings.

<i>Peucetia</i> Genus of spiders

Peucetia is a genus of lynx spiders that is found worldwide.

<i>Neoscona</i> Genus of spiders

Neoscona, known as spotted orb-weavers and barn spiders, is a genus of orb-weaver spiders (Araneidae) first described by Eugène Simon in 1895 to separate these from other araneids in the now obsolete genus Epeira. The name Neoscona was derived from the Greek νέω, meaning "spin", and σχοῖνος, meaning "reed" They have a mostly pantropical distribution and one species, Neoscona adianta, has a palearctic distribution. As of April 2019 there are eight species that can be found in the United States and Canada:

<i>Runcinia</i> Genus of spiders

Runcinia is a genus of crab spiders that was first described by Eugène Louis Simon in 1875. The former R. elongata is a synonym of Thomisus elongatus.

<i>Tetragnatha</i> Genus of spiders

Tetragnatha is a genus of long-jawed orb-weavers found all over the world. It was first described by Pierre André Latreille in 1804, and it contains hundreds of species. Most occur in the tropics and subtropics, and many can run over water. They are commonly called stretch spiders in reference to their elongated body form and their ability to hide on blades of grass or similar elongated substrates by stretching their front legs forward and the others behind them. The name Tetragnatha is derived from Greek, tetra- a numerical prefix referring to four and gnatha meaning "jaw". Evolution to cursorial behavior occurred long ago in a few different species, the most studied being those found on the Hawaiian islands. One of the biggest and most common species is T. extensa, which has a holarctic distribution. It can be found near lakes, river banks or swamps. Large numbers of individuals can often be found in reeds, tall grass, and around minor trees and shrubs.

<i>Pardosa</i> Genus of spiders

Pardosa is a large genus of wolf spiders, commonly known as the thin-legged wolf spiders. It was first described by C. L. Koch, in 1847, with more than 500 described species that are found in all regions of the world.

<i>Tibellus</i> Genus of spiders

Tibellus is a genus of slender crab spiders described by Simon in 1875, belonging to the order Araneae, family Philodromidae. Species of this genus are present in Eurasia, Africa, Americas and Australia.

<i>Oxytate</i> Genus of spiders

The genus Oxytate, commonly known as grass crab spiders, comprises a homogenous group of nocturnal crab spiders. The complete mitochondrial genome of the type species O. striatipes was determined in 2014.

<i>Oxyopes</i> Genus of spiders

Oxyopes is a genus of lynx spiders found worldwide. It includes arounds 300 species and is classified under the lynx spider family Oxyopidae. Like other lynx spiders, they are easily recognizable by the six larger eyes arranged hexagonally on top of the head (prosoma), with the remaining smaller two eyes in front. They are also characterized by long spine-like bristles (setae) on their legs. They are ambush predators, actively hunting prey by sight. Though they produce and use silk, they do not build webs to capture prey.

Monaeses is a genus of crab spiders in the family Thomisidae, containing twenty seven species.

<i>Camaricus</i> Genus of spiders

Camaricus is a genus of crab spiders that was first described by Tamerlan Thorell in 1887.


  1. Murphy, Frances & Murphy, John (2000). An Introduction to the Spiders of South-East Asia. City: Malaysian Nature Society. ISBN   983-9681-17-6.
  2. Filmer, Martin (1997). Southern African Spiders. City: BHB International / Struik. ISBN   1-86825-188-8.
  3. Reuven Dukas and Douglass H. Morse ; Crab spiders affect flower visitation by bees ; OIKOS 101: 157–163, 2003
  4. 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.
  5. 1 2 "Gen. Thomisus Walckenaer, 1805", World Spider Catalog, Natural History Museum Bern, retrieved 2017-02-25