![]() ![]() ![]() They are able to tell what is causing the vibrations that the water is carrying – to distinguish the drawn-out, erratic vibrations of a struggling insect from the one-off vibrations caused by falling leaves or the background noise of the wind or the flow of the water around rocks and other obstacles. Their front legs feel the vibrations carried on the water, just as other spiders feel the vibrations in a web. They stretch out their front legs and wait, as if listening. Dolomedes species tend to be robust with thickset legs that allow them to tackle prey larger than themselves. The method they use to fish for insects is to hold on to the shore with their back legs while the rest of their body lies on the water, with legs stretched out. They extend their legs onto the surface, feeling for vibrations given off by prey.įishing spider with its prey, a Cameroon clawed frog tadpoleĭolomedes are nocturnal hunters, feeding when birds, their main predators, are sleeping. For fishing spiders, the water surface serves the same function as a web does for other spiders. Rather than hunting on land or by waiting in a web, these spiders hunt on the surface of the water itself, preying on mayflies, other aquatic insects, and even small fish. Fishing spider with a dime for size reference Hunting behavior Like other spiders Dolomedes have eight eyes, but their sense of touch is more important when it comes to detecting prey by their vibrations on the surface of the water. If this is insufficient, one can further differentiate them thanks to their aquatic adaptations. Though one could easily identify them, as this genus has two rows of eyes, with two larger eyes at the top, which is unique to this genus inside the Pisauridae family. If any of this species are seen without context, one may confuse them with the family Lycosidae, otherwise known as Wolf Spiders. The trapped air makes them very buoyant and even if they do not hold onto a rock or a plant stem they float to the surface where they pop onto the surface film, completely dry. Like other spiders, Dolomedes breathe with book lungs beneath their abdomens, and these open into the air film, allowing the spiders to breathe while submerged. They can also climb beneath the water, and then air becomes trapped in the body hairs and forms a thin film over the whole surface of the body and legs, giving them the appearance of fine polished silver. This allows them to use surface tension to stand or run on the water, like water striders. Aquatic adaptations ĭolomedes spiders are covered all over in short, velvety hairs which are hydrophobic. Many species are large, some with females up to 26 mm (1.0 in) long with a leg span of 80 mm (3.1 in). plantarius), which lives in fens, also in Europe. fimbriatus), which lives in bogs in Europe, and the great raft spider ( D. There are over a hundred species of Dolomedes throughout the world examples include Dolomedes aquaticus, a forest-stream species of New Zealand, the raft spider ( D. " Dolomedes" is derived from the Greek word "δολομήδης" which means wily, deceitful. ![]() They can also climb beneath the water, when they become encased in a silvery film of air. They mainly eat insects, but some larger species are able to catch small fish. They hunt by waiting at the edge of a pool or stream, then when they detect the ripples from prey, they run across the surface to subdue it using their foremost legs, which are tipped with small claws like other spiders they then inject venom with their hollow jaws to kill and digest the prey. Many species have a striking pale stripe down each side of the body. albineus of the southeastern United States. Almost all Dolomedes species are semiaquatic, with the exception of the tree-dwelling D. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders. fimbriatus) female with juvenile spidersĭolomedes / d ɒ l ə ˈ m iː d iː z/ is a genus of large spiders of the family Pisauridae. JSTOR ( September 2017) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification. ![]()
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