Crab spider
Onustus Thomisus, females
The crab spiders ( Thomisidae ) are among the most species-rich families of the Real spiders. The 2042 worldwide species in 164 genera comprehensive family includes many color very appealing spiders. The lurking predators are found worldwide from the temperate zone to the tropics in; few species are also found in subarctic or alpine habitats. Equally varied are the inhabited Strati. The crab spiders, like all spiders Two -mouth ( Dionycha ), for example, jumping spiders, good climbers and therefore in higher vegetation at home.
Features
Crab spiders are easily recognized by the very long front two pairs of legs. The first pair of legs, some males may be three to five times as long as the rear pair of legs. The front two pairs of legs are slightly bent at rest held forward so that the animal looks like a crab with large claws. In addition, these limbs enable the crab spiders to run sideways. Because of the strikingly different from most other spider families leg length thick pine spiders ( Philodromidae ) were often counted among the crab spiders ( Tetragnathidae ) and running spiders, but it involves a apomorphes feature and not an analogy. Particularly striking is the colorful abdomen in some species.
Way of life
Crab spiders are pure ambush predator, who did not even weave no fishing nets and their local representatives living fantasies. The ability of silk production is used differently as with other so-called "modern running spiders ": The crab spider Misumena vatia operates stock and constricts its prey together to pack that is mounted below the inhabited bloom. Xysticus she uses when mating and most species as fall protection. In case of danger, they can be secured with the wire fall and fall into a " suspension Rigid ".
Mating and parental care
Silk also plays a role in the combination. The female can be hanging by a thread or behaves rigidly, while it can captivate the much smaller males. The male " fixed " the female on the pad and then crawls under the opisthosoma to insert the bulbs into the vagina. This behavior show Xysticus ( crab spiders ), also similar Tibellus and silk spider ( Nephila, Family Dick jaw spiders); However, the function is uncertain, because the female could free themselves from the weaving. The pairing is a courtship ahead and pheromones, " knocking " (see also: Wolf spiders) as well as the sense of sight likely to play a greater role. Also in this context is the behavior of canopy spiders ( Linyphiidae ) noted the time- share limited after mating a network.
The female lays the equally well-camouflaged eggs on a silk pad and spins a lenticular cocoon of several layers. The perennial Animals mate only once and the female guards without eating the cocoon. It can also not be distracted by noise. Just before hatching, the mother bites the cocoon on, makes Obstetrics and dies thereafter.
Predation and camouflage
Many crab spiders lurk on flowers and leaves on prey and can actively adapt as a master of disguise and deception their body coloration in a few days the ground, so you usually can read their habitat at the color of the female. The colors range from snow white with red stripes to pale green or brownish ( crab spider, Misumena vatia ), bright yellow to emerald green ( species of the genus Heriaeus ), spotted, striped lengthwise ( Runcinia ), yellow to orange ( Synaema ). Green or bright colored animals live on flowers and leaves, while darker species live on tree trunks or near the ground.
Bizarre body shapes with bumps and pits, dots and vertical stripes help camouflage the color of the animals by surface resolution. Thomisus onustus takes for example the color of the flower on the hunt the way.
Often the flowers on hunting, well color matched animals by many people to be perceived only after prolonged viewing of a flower.
As with the related jumping spiders ( Salticidae ) of the visual sense of this two claws spider plays a more and more important. They reflect UV light, giving them a particularly attractive for their prey. For this, the spider is almost invisible and so the prey gets almost in physical contact before the crab spider honey bees and other pollinating insects flowers packed with their powerful front two pairs of legs. The crab spider avoids the sting of larger prey and bites wasps and bees in the neck. The poison of her jaw jaw is very effective. In contrast to the network be built spiders see and recognize crab spiders prey from 10 to 20 cm away, after it was already perceived by low air and substrate noise.
Local genera, species and their distribution
- Coriarachne Bugs Spider ( Coriarachne depressa ), the only European species
- Ebrecht Ella tricuspidata
- Tmarus piger
- Xysticus audax
- Brown crab spider ( Xysticus cristatus)
- Xysticus kochi
- Xysticus lanio
- Xysticus ninnii