Raft spider

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Raft spider
AttackPosition.jpg
Raft spider attack position
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Pisauridae
Genus: Dolomedes
Species:
D. fimbriatus
Binomial name
Dolomedes fimbriatus
Distribution.dolomedes.fimbriatus.1.png
Synonyms [1]

Araneus fimbriatus Clerck, 1757

The raft spider, scientific name Dolomedes fimbriatus, is a large semi-aquatic spider of the family Pisauridae found throughout north-western and central Europe. [2] It is one of only two species of the genus Dolomedes found in Europe, the other being the slightly larger Dolomedesplantarius which is endangered in the UK. [3]

Contents

Habitat and description

Juvenile raft spider JuvenileFimbriatus.jpg
Juvenile raft spider
Dolomedes fimbriatus (video)

Raft spiders are semi-aquatic and adults inhabit freshwater wetlands, specifically wet heaths and acid swamps; [4] although juveniles are predominantly found in terrestrial vegetation surrounding wetland areas. [4] Adults are dark brown with a conspicuous white, cream or yellow stripe along both sides of their abdomen and thorax. Juveniles are similar in appearance but often have green translucent legs. As is common in other spiders, female raft spiders (body length: 9–22mm) are usually larger than males (body length (9-15mm). [5] Dolomedes fimbriatus was described in chapter 5 of the book Svenska Spindlar by the Swedish arachnologist and entomologist Carl Alexander Clerck. It is the type species of its genus.

Behaviour

Like many other species of the genus Dolomedes (Greek translation= crafty or wily), [6] the raft spider typically hunts on the surface of the water with its front appendages outstretched and relies on aquatic vibrations to detect prey. [7] Juveniles are thought mainly to hunt in terrestrial vegetation. [8] Their diet consists largely of freshwater invertebrates such as water beetles, pond striders and dragonfly larvae, but they occasionally feed on small vertebrates such as sticklebacks and small frogs. [4] To avoid predation by birds, the raft spider can fully submerge itself in water and has been known to hide underwater for several minutes. [8]

Female raft spider carrying egg sack Raft spider (Dolomedes fimbriatus) female.jpg
Female raft spider carrying egg sack
Juvenile Dolomedes fimbriatus Juvenile Dolomedes fimbriatus.jpg
Juvenile Dolomedes fimbriatus

As is the case with some other Dolomedes species, Dolomedes fimbriatus is sexually cannibalistic, meaning that the female will sometimes eat the male before, during or immediately after mating. [9] [10] Males will try to court the female and prevent her from attacking by signalling their presence using vibrations on the female dragline. [11] However, Dolomedes fimbriatus is one of the few species known to attempt to attack nearly all approaching males. [11] This behaviour is regarded as unusual among biologists as it can prevent both the male and the female from copulating successfully. [12]

If successful copulation takes place, the female will carry her fertilised egg sac around with her, before placing the egg sac inside a silken nursery tent that she has made. The female will then guard the nursery until the spiderlings are ready to disperse into the surrounding habitat. [13]

Related Research Articles

Nursery web spider Family of spiders

Nursery web spiders (Pisauridae) is a family of araneomorph spiders first described by Eugène Simon in 1890. They resemble wolf spiders (Lycosidae) except for several key differences. Wolf spiders have two very prominent eyes in addition to the other six, while a nursery web spider's eyes are all about the same size. Additionally, female nursery web spiders carry their egg sacs with their jaws and pedipalps instead of attaching them to their spinnerets as wolf spiders do. When the eggs are about to hatch, a female spider builds a nursery "tent", places her egg sac inside, and stands guard outside, hence the family's common name. Like the wolf spiders, however, the nursery web spiders are roaming hunters that don't use webs for catching prey.

Diving bell spider Genus of spiders

The diving bell spider or water spider is the only species of spider known to live almost entirely under water. It is the only member of the genus Argyroneta. When out of the water, the spider ranges in colour from mid to dark brown, although the hairs on the abdomen give it a dark grey, velvet-like appearance. It is native to freshwater habitats in Europe and Asia.

<i>Dolomedes</i> Genus of spiders

Dolomedes is a genus of large spiders of the family Pisauridae. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders. Almost all Dolomedes species are semiaquatic, with the exception of the tree-dwelling D. albineus of the southeastern United States. Many species have a striking pale stripe down each side of the body.

<i>Latrodectus hesperus</i> Species of spider

Latrodectus hesperus, the western black widow spider or western widow, is a venomous spider species found in western regions of North America. The female's body is 14–16 mm in length and is black, often with an hourglass-shaped red mark on the lower abdomen. This "hourglass" mark can be yellow, and on rare occasions, white. The male of the species is around half this length and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus. The species, as with others of the genus, build irregular or "messy" webs: unlike the spiral webs or the tunnel-shaped webs of other spiders, the strands of a Latrodectus web have no apparent organization.

<i>Misumena vatia</i> Species of spider

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, as it is commonly found hunting in goldenrod sprays and milkweed plants. They are called crab spiders because of their unique ability to walk sideways as well as forwards and backwards. Both males and females of this species progress through several molts before reaching their adult sizes, though females must molt more to reach their larger size. Females can grow up to 10 mm (0.39 in) while males are quite small, reaching 5 mm (0.20 in) at most. Misumena vatia are yellow or white, and have the ability to change between these two colors based on their surroundings. They have a complex visual system, with eight eyes, that they rely on for prey capture and for their color-changing abilities. Sometimes, if Misumena vatia consume colored prey, the spider itself will take on that color.

<i>Pisaura mirabilis</i> Species of spider

The nursery web spider Pisaura mirabilis is a spider species of the family Pisauridae.

Spider behavior refers to the range of behaviors and activities performed by spiders. Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms which is reflected in their large diversity of behavior.

Spider cannibalism

Spider cannibalism is the act of a spider consuming all or part of another individual of the same species as food. In the majority of cases a female spider kills and eats a male before, during, or after copulation. Cases in which males eat females are rare.

<i>Larinioides sclopetarius</i> Species of spider

Larinioides sclopetarius, commonly called bridge spider or gray cross spider, is a relatively large orb-weaver spider with Holarctic distribution. These spiders are located in Europe and have been observed as south as the Mediterranean Coast and as north as Finland. They are often found on bridges, especially near light and over water. The species tends to live on steel objects and is seldom seen on vegetation. Females reach a body length of 10–14mm, and males 8–9mm. Their orb webs can have diameters of up to 70 cm.

Sexual cannibalism

Sexual cannibalism is when an animal cannibalizes its mate prior to, or after copulation. It is a trait observed in many arachnid orders and several insect orders. Several hypotheses to explain this seemingly paradoxical behavior have been proposed. The adaptive foraging hypothesis, aggressive spillover hypothesis and mistaken identity hypothesis are among the proposed hypotheses to explain how sexual cannibalism evolved. This behavior is believed to have evolved as a manifestation of sexual conflict, occurring when the reproductive interests of males and females differ. In many species that exhibit sexual cannibalism, the female consumes the male upon detection. Females of cannibalistic species are generally hostile and unwilling to mate; thus many males of these species have developed adaptive behaviors to counteract female aggression.

<i>Dolomedes minor</i> Species of spider

Dolomedes minor is a spider in the family Pisauridae that is indigenous to New Zealand, where it is known as the nursery web spider.

Great raft spider Species of spider

The great raft spider or fen raft spider is a European species of spider in the family Pisauridae. Like other Dolomedes spiders, it is semiaquatic, hunting its prey on the surface of water. It occurs mainly in neutral to alkaline, unpolluted water of fens and grazing marsh.

Six-spotted fishing spider Species of spider

The six-spotted fishing spider is an arachnid from the nursery web spider family Pisauridae. This species is from the genus Dolomedes, or the fishing spiders. Found in wetland habitats throughout North America, these spiders are usually seen scampering along the surface of ponds and other bodies of water. They are also referred to as dock spiders because they can sometimes be witnessed quickly vanishing through the cracks of boat docks. D. triton gets its scientific name from the Greek mythological god Triton, who is the messenger of the big sea and the son of Poseidon.

<i>Svenska Spindlar</i>

The book Svenska Spindlar or Aranei Svecici was one of the major works of the Swedish arachnologist and entomologist Carl Alexander Clerck and appeared in Stockholm in the year 1757. It was the first comprehensive book on the spiders of Sweden and one of the first regional monographs of a group of animals worldwide. The full title of the work was Svenska Spindlar uti sina hufvud-slägter indelte samt under några och sextio särskildte arter beskrefne och med illuminerade figurer uplysteAranei Svecici, descriptionibus et figuris æneis illustrati, ad genera subalterna redacti, speciebus ultra LX determinati, and included 162 pages of text and 6 colour plates. It was published in Swedish, with a Latin translation printed in a slightly smaller font below the Swedish text.

<i>Pisaurina mira</i> Species of spider

Pisaurina mira, also known as the American nursery web spiders, is a species of spider in the family Pisauridae. They are often mistaken for wolf spiders (Lycosidae) due to their physical resemblance. P. mira is distinguished by its unique eye arrangement of two rows. 

<i>Schizocosa ocreata</i> Species of spider

Schizocosa ocreata is a species of wolf spider in the family Lycosidae that is found in North America. The Schizocosa ocreata is a spider that is most commonly known as the “brush-legged wolf spider” because of their distinct dark-colored fur-like coverings around their legs. The S. ocreata are commonly found in North American states, usually in the middle and eastern United States.

<i>Leucauge mariana</i> Species of spider

Leucauge mariana is a long-jawed orb weaver spider, native to Central America and South America. Its web building and sexual behavior have been studied extensively. Males perform several kinds courtship behavior to induce females to copulate and to use their sperm.

<i>Pardosa agrestis</i> species of spider

Pardosa agrestis is a non-web-building spider in the family Lycosidae, commonly known as wolf spiders.

<i>Pardosa pseudoannulata</i> Species of arachnid

Pardosa pseudoannulata, a member of a group of species referred to as wolf-spiders, is a non-web-building spider belonging to the family Lycosidae. P. pseudoannulata are wandering spiders that track and ambush prey and display sexual cannibalism. They are commonly encountered in farmlands across China and other East Asian countries. Their venom has properties that helps it function as an effective insecticide, and it is, therefore, a crucial pesticide control agent.  

<i>Dolomedes dondalei</i> Species of spider endemic to New Zealand

Dolomedes dondalei is a species of large fishing spider endemic to the main islands of New Zealand. It is a nocturnal hunter, feeling the water surface for vibrations, and catches insects and even small fishes – the only New Zealand Dolomedes species able to do so.

References

  1. 1 2 "Taxon details Dolomedes fimbriatus (Clerck, 1757)", World Spider Catalog, Natural History Museum Bern, retrieved 2017-09-13
  2. "Summary for Dolomedes fimbriatus (Araneae)". srs.britishspiders.org.uk. Retrieved 2019-03-01.
  3. "Welcome to the web site dedicated to the fen raft spider | Dolomedes.org.uk". www.dolomedes.org.uk. Retrieved 2019-03-02.
  4. 1 2 3 "Biology | Dolomedes.org.uk". www.dolomedes.org.uk. Retrieved 2019-03-02.
  5. "araneae - Dolomedes fimbriatus". araneae.nmbe.ch. Retrieved 2019-03-01.
  6. Clerck, Carl Alexander (1757). Svenska Spindlar. Sweden.
  7. "Sensory ecology of a semi-aquatic spider (Dolomedes triton)". Behavioral Ecology and Sociobiology. 1984. doi:10.1007/bf00299501.
  8. 1 2 "Raft Spiders - Dolomedes fimbriatus - UK Safari". www.uksafari.com. Retrieved 2019-03-01.
  9. "Courtship Behavior and Sexual Cannibalism in the Semi-Aquatic Fishing Spider, Dolomedes fimbriatus (Clerck) (Araneae: Pisauridae)". The Journal of Arachnology. 1992.
  10. "Precopulatory sexual cannibalism in fishing spiders (Dolomedes triton): a role for behavioral syndromes". Behavioral Ecology and Sociobiology. 2005. doi:10.1007/s00265-005-0943-5.
  11. 1 2 "Mate choice and sexual size dimorphism, not personality, explain female aggression and sexual cannibalism in raft spiders". Animal Behaviour. 2016. doi:10.1016/j.anbehav.2015.10.013.
  12. "Sexual cannibalism and population viability". Ecology and Evolution. 2018.
  13. "Life history | Dolomedes.org.uk". www.dolomedes.org.uk. Retrieved 2019-03-02.

Further reading