Phaeacius

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Phaeacius
Phaeacius lancearius.jpg
Phaeacius lancearius
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Salticidae
Subfamily: Spartaeinae
Genus: Phaeacius
Thorell, 1891
Type species
Phaeacius fimbriatus
Simon, 1900
Species

See text.

Phaeacius is a spider genus of the family Salticidae (jumping spiders), found in sub-tropical China and between India and the Malay Peninsula, including Sri Lanka, Sumatra and the Philippines. Although other spiders can jump, salticids including Phaeacius have significantly better vision than other spiders, and their main eyes are more acute in daylight than a cat's and 10 times more acute than a dragonfly's. The main eyes focus accurately on an object at distances from approximately 2 centimetres (0.79 in) to infinity, and in practice can see up to about 75 centimetres (30 in). They do not spin webs.

Contents

While most jumping spiders are active hunters, Phaeacius is unusually sedentary, generally resting in its unusual flattened pose for hours or days on logs, tree trunks, pieces of wood or any other solid surface, where it is very well camouflaged. Its preferred prey is moths and other insects, and jumping spiders. Insects can usually move around an inactive Phaeacius, or even over its body, but if the insect moves between the spider's first pair of legs, Phaeacius lunges extremely quickly to bite the prey. Sometimes Phaeacius takes a more active approach, especially if without prey for a week or more. Phaeacius does not enter webs voluntary, and moves away if it touches one accidentally. It can bite through the threads and pull strongly with its legs, but cannot escape from very sticky webs.

The genera Portia and Spartaeus are closely related to Phaeacius.

Description

The whole body of Phaeacius is 7.5 to 11.5 millimetres (0.30 to 0.45 in) long, and notably flattened, including the carapace, [1] while the carapaces of some other groups are raised. [2] : 495  [1] The cephalothorax of Phaeacius′ is relatively long, and the highest point is a little behind the last pair of eyes. [3] : 204, 206-208 Phaeacius is very well camouflaged; [1] for example, P. malayensis has a body with dull grey and brown markings that resemble the surface of tree trunks in the rainforest. [4] [5]

Senses

Eye pattern of jumping spiders on "squared-off" cephalothorax Jumping spider eyes layout 2.png
Eye pattern of jumping spiders on "squared-off" cephalothorax

Jumping spiders have eight eyes, the two large ones in the centre-and-front position (the anterior-median eyes, also called "principal eyes" [6] : 51 ) providing acute vision and housed in tubes in the head. The other six are secondary eyes, positioned along the sides of the carapace and acting mainly as movement detectors. [7] [8] : 16  While the middle pair of secondary eyes in most jumping spiders are small, those of Phaeacius and other members of the sub-family Spartaeinae are almost as large as the other secondary eyes. [9] Although other spiders can jump, salticids including Phaeacius have significantly better vision than other spiders, [10] : 521  and their main eyes are more acute in daylight than a cat's and 10 times more acute than a dragonfly's. [7] The main eyes focus accurately on an object at distances from approximately 2 centimetres (0.79 in) to infinity, [6] : 51  and in practice can see up to about 75 centimetres (30 in). [6] : 53 

Spiders, like other arthropods, have sensors, often modified setae (bristles), protruding through their cuticle ("skin") for smell, taste, touch and vibration. [11] : 532–533  Unlike insects, spiders and other chelicerates do not have antennae. [12] [13]

Movement and being undetected

While most jumping spiders walk quickly, in a stop-go gait and jumping over obstacles, the movements of Phaeacius are very unusual. Phaeacius usually uses a "flattened posture" head-down on a vertical surface, with the body, legs and palps pressed against the surface, the hindmost legs upwards and the other legs downwards, [2] : 496–497  and its markings and flattened body make it easily hidden against the bark of a tree trunk. Its habit of walking with its body and legs flattened against a surface helps Phaeacius to be unobtrusive. [5]

Feeding and defence

While almost all jumping spiders are predators, mostly preying on insects, on other spiders, and on other arthropods, [14] Phaeacius does not use the usual hunting tactics. [2] : 502  Most jumping spiders walk throughout the day, so that they maximise their chances of a catch, [15] and jump on their prey and then bite it. [16] Unlike most jumping spiders, Phaeacius and other spartaeines do not leap on prey, but lunge from about half the predator's body length away. [5]

Phaeacius is unusually sedentary for a jumping spider, generally resting in the flattened pose for hours or days on logs, pieces of wood or any other solid surface, [2] : 502  and captures particular types of prey more often when the predator matches this background. [4] Insects can usually move around an inactive Phaeacius, or even over its body or legs. However, if the insect moves between the spider's first pair of legs, Phaeacius lunges extremely quickly, driving its body upward 2 to 3 millimetres (0.079 to 0.118 in) and forward about half the length of its body. The lunge ends with the spider's fangs in the prey and often with the foremost two pairs of legs forming a basket over the prey. When the prey stops struggling, Phaeacius resumes the flattened pose and then feeds. [2] : 502 

However, Phaeacius can adopt other, more active approaches, with different gaits for each. If an insect remains almost stationary while Phaeacius is in the flattened pose and facing the insect, the spider may step slowly forward to its prey, rocking and keeping its flattened pose. To rock, Phaeacius moves about half a body length forward then, without pausing, smoothly back almost to the previous position. It performs about 10 cycles of those movements, progressing by 1 to 2 millimetres (0.039 to 0.079 in) per cycle, and then rests. [2] : 502–504  This rocking motion may disguise Phaeacius as shadows on the tree trunk. [2] : 514–515  The insect occasionally keeps stationary until Phaeacius reaches within about half a body length and then lunges. [2] : 502–504 

When hunting other jumping spiders and when the background matches its coloration, [17] Phaeacius uses "insinuation", in which it waits, sometimes up to an hour, while a jumping spider moves around nearby, and then Phaeacius suddenly turns up to 180° toward the prey and then resumes the flattened pose. Phaeacius then moves a few millimetres toward the prey and resumes the flattened pose. If the prey moves away, Phaeacius continues the insinuation manoeuvre, but if the prey moves toward it, Phaeacius lunges. [5] Other jumping spiders show no awareness of a flattened Phaeacius on a matching background, and apparently survive by luck. [2] : 502–504  When the background does not matches Phaeacius′ coloration, other jumping spiders recognise Phaeacius as a threat. [5]

Sometimes, especially if without prey for a week or more, Phaeacius may approach insects faster, from 50 to 100 millimetres (2.0 to 3.9 in) away, and if necessary turning round to face the prey. Often Phaeacius then adopts the flattened pose after the turn, but sometimes it walks faster than usual and, without pausing, lunges from about half its body length. [2] : 502–504 

In a test on a background matching its own coloration, Phaeacius was most successful against other salticids and then against moths, and was also successful against flies and hunting spiders. On a non-matching background, Phaeacius was most successful against moths. [5]

Phaeacius does not try to eat other spiders' eggs, does not enter webs voluntarily, and moves away if it touches one accidentally. It can bite through the threads and pull strongly with its legs, but cannot escape from very sticky webs. [2] : 502  This behaviour is quite different from that of its close relative, Portia , which hunts actively and can enter any type of web to catch spiders and their eggs. [7] [2] : 491 

When disturbed, some jumping spiders usually run away quickly and leap if chased. Phaeacius stays in its flattened posture unless harassed, when it runs quickly for about 100 to 300 millimetres (3.9 to 11.8 in) and then adopts the flattened posture, and finally walks away about 10 minutes later. [2] : 499–500 

Reproduction

Before courtship, male spiders spin a small web and ejaculate on to it, and then store the semen in reservoirs on his pedipalps, [18] : 581–583  which are larger than those of females. [18] : 572–573 Phaeacius spins a flimsy silken, horizontal or vertical platform, about twice the spider's length in diameter, to moult and lay eggs, but not at other times. After the moult, Phaeacius leaves the discarded exuvia hanging from the platform. [5] A female's egg sac is placed in a shallow cavity on the surface of a log. [2] : 495 

Taxonomy and distribution

Phaeacius is a spider genus of the family Salticidae (jumping spiders). Phaeacius is in the subfamily Spartaeinae, [1] which is thought to be primitive. [2] : 491  Molecular phylogeny, a technique that compares the DNA of organisms to reconstruct the tree of life, indicates that Phaeacius is a member of the tribe Spartaeini, that Spartaeinae is basal (quite similar to the ancestors of all jumping spiders), and that Phaeacius is closely related to Portia and Spartaeus . [19] : 236 

The genus is found in subtropical China [9] and between India and Malaya, [1] including Sri Lanka, Sumatra and the Philippines. [20]

Species

Related Research Articles

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

Jumping spiders are a group of spiders that constitute the family Salticidae. As of 2019, this family contained over 600 described genera and over 6,000 described species, making it the largest family of spiders at 13% of all species. Jumping spiders have some of the best vision among arthropods and use it in courtship, hunting, and navigation. Although they normally move unobtrusively and fairly slowly, most species are capable of very agile jumps, notably when hunting, but sometimes in response to sudden threats or crossing long gaps. Both their book lungs and tracheal system are well-developed, and they use both systems. Jumping spiders are generally recognized by their eye pattern. All jumping spiders have four pairs of eyes, with the anterior median pair being particularly large.

<i>Portia</i> (spider) Genus of spiders

Portia is a genus of jumping spider that feeds on other spiders. They are remarkable for their intelligent hunting behaviour, which suggests that they are capable of learning and problem solving, traits normally attributed to much larger animals.

<i>Portia labiata</i> Species of spider

Portia labiata is a jumping spider found in Sri Lanka, India, southern China, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. In this medium-sized jumping spider, the front part is orange-brown and the back part is brownish. The conspicuous main eyes provide vision more acute than a cat's during the day and 10 times more acute than a dragonfly's, and this is essential in P. labiata′s navigation, hunting and mating.

<i>Brettus</i> Genus of spiders

Brettus is a genus of jumping spiders. Its six described species are found in southern Asia from India to China and Sulawesi, with a single species endemic to Madagascar.

<i>Cocalus</i> (spider) Genus of spiders

Cocalus is a genus of jumping spiders that was first described by Carl Ludwig Koch in 1846, and is named after Cocalus, a Sicilian king of Greek mythology.

<i>Cyrba</i> Genus of spiders

Cyrba is a genus of spiders in the family Salticidae. The genus was erected by Hippolyte Lucas in 1846.

Paracyrba is a genus of jumping spiders found only in Malaysia. It contains only one species, Paracyrba wanlessi. Its microhabitat are the water-filled hollow internodes of decaying bamboo, where it preys for aquatic animals, especially mosquito larvae. P. wanlessi and Evarcha culicivora, a jumping spider, are the only two spiders that have been experimentally studied and considered a mosquito specialist. E. culicivora indirectly feeds vertebrate blood by preying female mosquitos that carry blood. In general only one specimen is found per occupied bamboo internode.

Wanlessia is a genus of Asian jumping spiders that was first described by D. P. Wijesinghe in 1992. As of September 2019 it contains two species, both endemic to eastern Asia: W. denticulata and W. sedgwicki. It is related to Portia, and is the only member of the subfamily Spartaeinae with well-developed palpal conductors. Both species only have descriptions for males. It is named in honor of arachnologist Fred R. Wanless, who described more than a dozen salticid genera from 1970 to 1990.

<span class="mw-page-title-main">Spartaeinae</span> Subfamily of spiders

The Spartaeinae are a subfamily of the spider family Salticidae. The subfamily was established by Fred R. Wanless in 1984 to include the groups Boetheae, Cocaleae, Lineae, Codeteae and Cyrbeae, which in turn were defined by Eugène Simon.

<i>Maevia inclemens</i> Species of spider

Maevia inclemens or the dimorphic jumping spider is a relatively common and colorful jumping spider of North America. In the males there are two forms, a very rare phenomenon in zoology. These use different courting displays, and differ in appearance: the "tufted" morph has a black body and pedipalps ("palps"), three black tufts across its "head", and pale legs; and the "gray" morph has black and white stripes all over its body and legs, orange palps, and no tufts. However, each form accounts for 50% of the adult males, and they are equally successful in mating. A female of Maevia inclemens is 6.5 to 8.0 millimetres long, while males are 4.75 to 6.50 millimetres long.

<i>Portia fimbriata</i> Species of spider

Portia fimbriata, sometimes called the fringed jumping spider, is a jumping spider found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adult males are 5.2 to 6.5 millimetres long. Both sexes have a generally dark brown carapace, reddish brown chelicerae ("fangs"), a brown underside, dark brown palps with white hairs, and dark brown abdomens with white spots on the upper side. Both sexes have fine, faint markings and soft fringes of hair, and the legs are spindly and fringed. However, specimens from New Guinea and Indonesia have orange-brown carapaces and yellowish abdomens. In all species of the genus Portia, the abdomen distends when the spider is well fed or producing eggs.

<i>Portia schultzi</i> Species of spider

Portia schultzi is a species of jumping spider which ranges from South Africa in the south to Kenya in the north, and also is found in West Africa and Madagascar. In this species, which is slightly smaller than some other species of the genus Portia, the bodies of females are 5 to 7 mm long, while those of males are 4 to 6 mm long. The carapaces of both sexes are orange-brown with dark brown mottling, and covered with dark brown and whitish hairs lying over the surface. Males have white tufts on their thoraces and a broad white band above the bases of the legs, and these features are less conspicuous in females. Both sexes have tufts of orange to dark orange above the eyes, which are fringed with pale orange hairs. Males' abdomens are yellow-orange to orange-brown with blackish mottling, and on the upper sides are black and light orange hairs, and nine white tufts. Those of females are pale yellow and have black markings with scattered white and orange-brown hairs on the upper side. P. schultzi has relatively longer legs than other Portia, and a "lolloping" gait.

Portia africana is a jumping spider found in Angola, Cameroon, the Central African Republic, Gabon, Ghana, the Ivory Coast, Sierra Leone, Zaire and Zambia. Its conspicuous main eyes provide vision more acute than a cat's during the day and 10 times more acute than a dragonfly's, and this is essential in P. africana′s navigation, hunting and mating.

Brettus adonis, is a species of spider of the genus Brettus. It is endemic to Sri Lanka.

Gelotia lanka is a species of jumping spider of the genus Gelotia. It is endemic to Sri Lanka.

Brettus cingulatus is a species of jumping spider of the genus Brettus. It is found in Myanmar and India.

<i>Lyssomanes viridis</i> Species of spider

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<i>Asemonea maculata</i> Species of spider

Asemonea maculata is a species of jumping spider in the genus Asemonea that is endemic to Ivory Coast. The spider was first defined in 1980 by Fred Wanless. It is a small spider, with a carapace that is between 2.08 and 2.10 mm long and an abdomen typically 2.4 mm long. The carapace is amber to whitish-yellow and the abdomen whitish-yellow, both with black markings. It is similar to the related species Asemonea pinangensis and Asemonea tanikawai, but can be distinguished by the tibia on the male pedipalp. The female has not been described.

Fred R. Wanless was a British arachnologist. Active in the field especially in the seventies and eighties of the 20th century, he described several dozen taxa, in particular among the spiders of the Salticidae family. Wanless played a significant role in the British Arachnological Society being its member in 1969–1973, 1974–1976 and 1986–1989, and Meetings Secretary in 1973–1978. From 1973 to 1988 he described 137 new species and 13 new genera.

<i>Asemonea murphyae</i> Species of spider

Asemonea murphyae is a species of jumping spider in the genus Asemonea that lives in Kenya and South Africa. First defined in 1980 by Fred Wanless, the spider is named after the British arachnologist Frances M. Murphy. Asemonea murphyae thrives in a wide range of environments, particularly by the side of rivers, streams and tracks. A small spider, with a carapace that is between 1.48 and 2.00 mm long and an abdomen between 2.4 mm long, it is generally yellow with a green tint that enables it to blend into its environment. The female is smaller than the male. The species can be distinguished from other spiders in the same genus by the design of the female's epigyne and the male pedipalp, particularly the male's forked spike on the palpal tibia.

References

  1. 1 2 3 4 5 Barrion, A.T.; J.A. Litsinger (1995). Riceland spiders of South and Southeast Asia. International Rice Research Institute / CAB International. p. 45. ISBN   978-0-85198-967-9.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Jackson, Robert R.; Susan E.A. Hallas (1986). "Predatory versatility and intraspecies interactions of spartaeine jumping spiders (Araneae, Salticidae): Brettus adonis, B. cingulata, Cyrba algerina, and Phaeacius sp. indet". New Zealand Journal of Zoology . 13: 491–520. doi:10.1080/03014223.1986.10422979. ISSN   0301-4223 . Retrieved 1 April 2011.
  3. ↑ Wanless, F.R. (November 1981). "A revision of the spider genus Phaeacius (Araneae: Salticidae)" (PDF). Bulletin of the British Museum (Natural History) . Zoology. 41 (4): 199–212. Retrieved 7 June 2011.
  4. 1 2 Li, Daiqin (2000). "Prey preferences of Phaeacius malayensis, a spartaeine jumping spider (Araneae: Salticidae) from Singapore". Canadian Journal of Zoology . NRC Canada. 78 (12): 2218–2226. doi:10.1139/z00-176.
  5. 1 2 3 4 5 6 7 Jackson, Robert R. (1990). "Ambush predatory behaviour of Phaeacius malayensis and Phaeacius sp. indef. (Araneae: Salticidae) from tropical Asia". New Zealand Journal of Zoology . 17: 491–498. doi:10.1080/03014223.1990.10422948 . Retrieved 3 May 2011.
  6. 1 2 3 Forster, Lyndsay M. (1977). "A qualitative analysis of hunting behaviour in jumping spiders (Araneae: Salticidae)". New Zealand Journal of Zoology . 4: 51–62. doi: 10.1080/03014223.1977.9517936 .
  7. 1 2 3 Harland, Duane P.; Robert R. Jackson (2000). "'Eight-legged cats' and how they see – a review of recent research on jumping spiders (Araneae: Salticidae)" (PDF). Cimbebasia . Proceedings of the 6th International Colloquium of the African Arachnological Society. The African Arachnological Society. 16: 231–240. Archived from the original (PDF) on 18 March 2009. Retrieved 31 March 2011.
  8. ↑ Hill, David Edwin (October 2010). "Use of location (relative direction and distance) information by jumping spiders (Araneae, Salticidae, Phidippus) during movement toward prey and other sighted objectives" (PDF). Peckhamia . 83 (1): 1–103. ISSN   1944-8120 . Retrieved 12 April 2011.
  9. 1 2 Zhang, J.X.; D.Q. Li (December 2005). "Four new and one newly recorded species of the jumping spiders (Araneae: Salticidae: Lyssomaninae & Spartaeinae) from (sub)tropical China" (PDF). Raffles Bulletin of Zoology . National University of Singapore. 53 (2): 221–229. Retrieved 1 May 2011.
  10. ↑ Jarman, Elizabeth A.R.; Robert R. Jackson (1986). "The biology of Taieria erebus (Araneae, Gnaphosidae), an araneophagic spider from New New Zealand: silk utilisation and predatory versatility". New Zealand Journal of Zoology . 13 (4): 521–540. doi:10.1080/03014223.1986.10422980. ISSN   0301-4223 . Retrieved 1 April 2011.
  11. ↑ Ruppert, E.E., Fox, R.S., and Barnes, R.D. (2004). "Arthropoda: Sense organs". Invertebrate Zoology (7th ed.). Brooks/Cole. pp.  532–537. ISBN   0-03-025982-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
  12. ↑ Ruppert, E.E., Fox, R.S. and Barnes, R.D. (2004). "Chelicerata: Form". Invertebrate Zoology (7th ed.). Brooks/Cole. p.  555. ISBN   0-03-025982-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
  13. ↑ Ruppert, E.E., Fox, R.S., and Barnes, R.D. (2004). "Chelicerata: Arachnida". Invertebrate Zoology (7th ed.). Brooks/Cole. pp.  559–564. ISBN   0-03-025982-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
  14. ↑ Hoefler, Chad D.; Andy Chen; Elizabeth M. Jakob (2006). "The Potential of a Jumping Spider, Phidippus clarus, as a Biocontrol Agent" (PDF). Journal of Economic Entomology . 99 (2): 432–436. doi:10.1603/0022-0493-99.2.432. ISSN   0022-0493. PMID   16686143. S2CID   198126575. Archived from the original (PDF) on 14 June 2010. Retrieved 25 April 2011.
  15. ↑ Forster, Lyn M. (November 1977). "Some factors affecting feeding behaviour in young Trite auricoma spiderlings (Araneae: Salticidae)". New Zealand Journal of Zoology . The Royal Society of New Zealand. 4 (4): 435–442. doi: 10.1080/03014223.1977.9517967 . Retrieved 24 April 2011.
  16. ↑ Richman, David B. (2008). "Jumping Spiders (Class Arachnidae, Order Araneae, Family Salticidae)". In John L. Capinera (ed.). Encyclopedia of Entomology. Springer. pp. 2066–2068. ISBN   978-1-4020-6242-1 . Retrieved 11 April 2011.
  17. ↑ Nelson, Ximena J.; Robert R. Jackson (2011). "Flexibility in the foraging strategies of spiders". In Marie Elisabeth Herberstein (ed.). Spider Behaviour: Flexibility and Versatility. Cambridge University Press. pp. 45–47. ISBN   978-0-521-74927-5 . Retrieved 29 May 2011.
  18. 1 2 Ruppert, E.E., Fox, R.S., and Barnes, R.D. (2004). "Chelicerata: Araneae". Invertebrate Zoology (7th ed.). Brooks/Cole. pp.  571–584. ISBN   0-03-025982-7.{{cite book}}: CS1 maint: multiple names: authors list (link)
  19. ↑ Maddison, Wayne P. (2015). "A phylogenetic classification of jumping spiders (Araneae: Salticidae)". Journal of Arachnology . 43 (3): 231–292. doi:10.1636/arac-43-03-231-292. S2CID   85680279.
  20. ↑ Wijesinghe, D.P. (1991). "New species of Phaeacius from Sri Lanka, Sumatra and the Philippines". Bulletin of the British Arachnological Society . 8 (8): 249–255.
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