Portia (spider)
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''Portia'' is a
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
jumping spider Jumping spiders are a group of spiders that constitute the family (biology), family Salticidae. , this family contained over 600 species description, described genus, genera and over 6,000 described species, making it the largest family of spide ...
that feeds on other spiders (i.e., they are arachnophagic). 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.


Taxonomy and evolution

The genus was established in 1878 by German arachnologist Friedrich Karsch. The fringed jumping spider (''
Portia fimbriata ''Portia fimbriata'', sometimes called the fringed jumping spider, is a jumping spider (family (biology), family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adul ...
'') is the type species.
Molecular phylogeny Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...
, a technique that compares the
DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...
of organisms to construct the
tree of life The tree of life is a fundamental archetype in many of the world's mythology, mythological, religion, religious, and philosophy, philosophical traditions. It is closely related to the concept of the sacred tree.Giovino, Mariana (2007). ''The ...
, indicates that ''Portia'' is a member of a basal
clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
(i.e. quite similar to the ancestors of all jumping spiders) and that the '' Spartaeus'', '' Phaeacius'', and '' Holcolaetis'' genera are its closest relatives. Wanless divided the genus ''Portia'' into two
species group In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...
s: the ''schultzi'' group, in which males' palps have a fixed
tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
l apophysis; and the ''kenti'' group, in which the apophysis of each palp in the males has a joint separated by a membrane. The ''schultzi'' group includes ''P. schultzi'', ''P. africana'', ''P. fimbriata'', and '' P. labiata''. At least some species of Portia are in the state of
reproductive isolation The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, ethology, behaviors and physiology, physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensu ...
: in a laboratory, male ''P. africana'' copulated with female ''P. labiata'', but no eggs were laid; during all cases, the female ''P. labiata'' twisted and lunged in an attempt to bite. Some specimens found trapped in
Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
amber Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia ...
were identified as related to ''Portia''.


Distribution and ecology

The 17 described
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
are found in
Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
,
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
,
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
,
Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
,
Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...
,
Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...
,
Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...
,
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
, the
Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
,
Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...
,
Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
, and
Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
. ''Portia'' are vulnerable to larger predators such as
bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s and
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s, which a ''Portia'' often cannot identify because of the predator's size. Some insects prey on Portia, for example,
mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate a ...
es, the
assassin bug The Reduviidae is a large cosmopolitan family of the suborder Heteroptera of the order Hemiptera (true bugs). Among the Hemiptera and together with the Nabidae almost all species are terrestrial ambush predators; most other predatory Hemiptera ...
s ''Nagusta'' sp. indet. and ''Scipinnia repax'' (that is, Scipinia rapax ).


Appearance

Portia are relatively small spiders. For example, adult females of ''Portia africana'' are in body length and adult males are long.


Intelligence

''Portia'' often hunt in ways that seem intelligent. All members of ''Portia'' have instinctive hunting tactics for their most common prey, but can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach. They exhibit
spatial memory In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Sp ...
and
object permanence Object permanence is the understanding that whether an object can be sensed has no effect on whether it continues to exist. This is a fundamental concept studied in the field of developmental psychology, the subfield of psychology that addres ...
, and are capable of trying out a behavior to obtain feedback regarding success or failure, and they can plan ahead (as it seems from their detouring behavior). ''Portia'' species can make detours to find the best attack angle against dangerous prey, even when the best detour takes a ''Portia'' out of visual contact with the prey, and sometimes the planned route leads to
abseiling Abseiling ( ; ), also known as rappelling ( ; ), is the controlled descent of a steep slope, such as a rock face, by moving down a rope. When abseiling, the person descending controls their own movement down a static or fixed rope, in cont ...
down a silk thread and biting the prey from behind. Such detours may take up to an hour, and a ''Portia'' usually picks the best route even if it needs to walk past an incorrect route. Nonetheless, they seem to be relatively slow thinkers, as is to be expected since they solve tactical problems by using brains vastly smaller than those of mammalian predators. ''Portia'' has a brain significantly smaller than the size of the head of a pin, and it likely has less than 100,000
neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...
s (for comparison, a mouse brain has about 70 million neurons and a human brain has 86 billion). ''Portia'' can distinguish their own draglines from conspecifics', recognizing self from others, and also discriminate between known and unknown spiders.


Hunting techniques

Their favorite prey appears to be web-building spiders between 10% and 200% of their own size. Many species of ''Portia'' have protrusions of clusters of hairs on their cephalothorax, legs, and abdomen that when combined allow the spider to look like leaf
detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...
caught in a web, and this is often enough to fool web-building spiders, which have poor eyesight. One of the most famous examples of these protrusions is the fringed jumping spider, ''
Portia fimbriata ''Portia fimbriata'', sometimes called the fringed jumping spider, is a jumping spider (family (biology), family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adul ...
'', which has many of these protrusions, the most pronounced of which being the two tufts above its eyes When stalking web-building spiders, ''Portia'' try to make different patterns of vibrations in the web that aggressively mimic the struggle of a trapped insect or the courtship signals of a male spider, repeating any pattern that induces the intended prey to move towards the ''Portia''. ''Portia fimbriata'' has been observed to perform vibratory behavior for three days until the victim decided to investigate. They time invasions of webs to coincide with light breezes that blur the vibrations that their approach causes in the target's web, and they back off if the intended victim responds belligerently. Other jumping spiders take detours, but ''Portia'' is unusual in its readiness to use long detours that break visual contact. Laboratory studies show that ''Portia'' learns very quickly how to overcome web-building spiders that neither it nor its ancestors would have met in the wild. ''Portia''s accurate visual recognition of potential prey is an important part of its hunting tactics. For example, in one part of the Philippines, local ''Portia'' spiders attack from the rear against the very dangerous spitting spiders, which themselves hunt jumping spiders. This appears to be an
instinct Instinct is the inherent inclination of a living organism towards a particular complex behaviour, containing innate (inborn) elements. The simplest example of an instinctive behaviour is a fixed action pattern (FAP), in which a very short to me ...
ive behavior, as laboratory-reared ''Portia'' of this species do this the first time they encounter a spitting spider. On the other hand, they will use a head-on approach against spitting spiders that are carrying eggs. However, experiments that pitted ''Portia'' against "convincing" artificial spiders with arbitrary but consistent behavior patterns showed that ''Portia''s instinctive tactics are only starting points for a trial-and-error approach from which these spiders learn very quickly. Against other jumping spiders, which also have excellent vision, ''Portia'' may mimic fragments of leaf litter detritus. When close to biting range, ''Portia'' use different combat tactics against different prey spiders. On the other hand, when attacking unarmed prey, such as flies, they simply stalk and rush, and they also capture prey by means of sticky webs. ''Portia'' can also rely on movement cues to locate prey. In this specific strategy, when potential prey knows it's been seen and stands still to avoid detection, undirected leaps occur in the vicinity of the prey. As a result, the prey will then react to this visual cue, believing itself to have been seen, providing motion that allows ''Portia'' to see and attack it. ''Portia'' may also scavenge corpses of dead arthropods they found, and consume nectar.


Social behavior

Members of the species '' Portia africana'' were observed living together and sharing prey. If a mature ''Portia'' male meets a sub-mature female, he will try to cohabitate with her. ''P. labiata'' females can discriminate between the draglines of familiar and unfamiliar individuals of the same species and between their own draglines and those of conspecifics. The ability to recognize individuals is a necessary prerequisite for social behavior.


Vision

''Portia'' species have complex eyes that support exceptional spatial acuity. They have eight eyes. Three pairs of eyes positioned along the sides of the cephalothorax (called the secondary eyes) have a combined field-of-view of almost 360° and serve primarily as movement detectors. A pair of forward-facing anterior median eyes (called the principal eyes) are adapted for colour vision and high spatial acuity. The main eyes focus accurately on an object at distances from approximately to infinity, and in practice can see up to about . Like all jumping spiders, its main eyes can take in only a small visual field at one time, as the most acute part of a main eye can see all of a circle up to wide at away, or up to wide at away. Jumping spiders' main eyes can see from red to
ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...
. The secondary eyes have low spatial resolving power, but a wide field of view. The inter-receptor angles of ''Portia''s eyes may be as small as 2.4 minutes of arc, which is only six times worse than in humans, and is six times better than in the most acute insect eye. It is also clearer in daylight than a
cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...
's vision. ''P. africana'' relies on visual features of general morphology and colour (or relative brightness) when identifying prey types. ''P. schultzi''s hunting is stimulated only by vision, and prey close by but hidden causes no response. ''P. fimbriata'' use visual cues to distinguish members of the same species from other salticids. Cross and Jackson (2014) suggest that ''P. africana'' is capable of mentally rotating visual objects held in its working memory. However, a ''Portia'' takes a relatively long time to see objects, possibly because getting a good image out of such small eyes is a complex process and requires a lot of scanning. This makes a ''Portia'' vulnerable to much larger predators such as
bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s,
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s and
mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate a ...
es, which a ''Portia'' often cannot identify because of the predator's size.


Movement

When not hunting for prey or a mate, ''Portia'' species adopt a special posture, called the "cryptic rest posture", pulling their legs in close to the body and their palps back beside the
chelicerae The chelicerae () are the arthropod mouthparts, mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated ...
("jaws"), which obscures the outlines of these appendages. When walking, most ''Portia'' species have a slow, "choppy" gait that preserves their concealment: pausing often and at irregular intervals; waving their legs continuously and their palps jerkily up and down; moving each appendage out of time with the others; and continuously varying the speed and timing. When disturbed, some ''Portia'' species are known to leap upwards about often from the cryptic rest pose, and often over a wide trajectory. Usually the spider then either freezes or runs about and then freezes.


Reproduction

''Portia'' exhibits a mating behavior and strategy different from that of other jumping spiders. In most jumping spiders, males mount females to mate. The ''Portia'' male shows off his legs and extends them stiffly and shakes them to attract the female. The female then drums on the web. After the male mounts her, the female drops a dragline and they mate in mid-air. Mating with Portia spiders can occur off or on the web. The spider also practices cannibalism before and after copulation. The female usually twists and lunges at the mounted male. (''P. fimbriata'', however, is an exception; it does not usually exhibit such behavior.) If the male is killed before completing copulation, the male sperm is removed and the male is then eaten. If the male finishes mating before being killed, the sperm is kept for
fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...
and the male is eaten. A majority of males are killed during sexual encounters.


Health

''Portia'' species have a life span of about 1.5 years. ''P. fimbriata'' can regenerate a lost limb about 7 days after moulting. ''Portia''s palps and legs break off very easily, which may be a defense mechanism, and Portias are often seen with missing legs or palps.


Species

it contains 21 species, found in Africa, Asia, and
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
: *'' Portia africana'' ( Simon, 1886) – West,
Central Africa Central Africa (French language, French: ''Afrique centrale''; Spanish language, Spanish: ''África central''; Portuguese language, Portuguese: ''África Central'') is a subregion of the African continent comprising various countries accordin ...
,
Ethiopia Ethiopia, officially the Federal Democratic Republic of Ethiopia, is a landlocked country located in the Horn of Africa region of East Africa. It shares borders with Eritrea to the north, Djibouti to the northeast, Somalia to the east, Ken ...
*'' Portia albimana'' (Simon, 1900) – India to Vietnam *'' Portia assamensis'' Wanless, 1978 – India to Malaysia *'' Portia bawang'' (Xu, Peng & Li, 2021) – China (Hainan) *'' Portia crassipalpis'' (Peckham & Peckham, 1907)
Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...
,
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
(
Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...
) *'' Portia erlangping'' (Xu, Peng & Li, 2021) – China *'' Portia fajing'' (Xu, Peng & Li, 2021) – China *''
Portia fimbriata ''Portia fimbriata'', sometimes called the fringed jumping spider, is a jumping spider (family (biology), family Salticidae) found in Australia and Southeast Asia. Adult females have bodies 6.8 to 10.5 millimetres long, while those of adul ...
'' (Doleschall, 1859) (
type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...
) –
Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...
,
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
,
Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...
, Taiwan to Australia *'' Portia heteroidea'' Xie & Yin, 1991
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
*'' Portia hoggi'' Zabka, 1985
Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
*'' Portia jianfeng'' Song & Zhu, 1998 – China *'' Portia labiata'' ( Thorell, 1887) – Sri Lanka to China, Vietnam,
Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...
, India *'' Portia orientalis'' Murphy & Murphy, 1983 – China (
Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...
) *'' Portia quei'' Zabka, 1985 – China, Vietnam *'' Portia schultzi'' Karsch, 1878 – Central, East, Southern Africa,
Mayotte Mayotte ( ; , ; , ; , ), officially the Department of Mayotte (), is an Overseas France, overseas Overseas departments and regions of France, department and region and single territorial collectivity of France. It is one of the Overseas departm ...
,
Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
*'' Portia songi'' Tang & Yang, 1997 – China *'' Portia strandi'' Caporiacco, 1941 – Ethiopia *'' Portia taiwanica'' Zhang & Li, 2005
Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
*'' Portia wui'' Peng & Li, 2002 – China *'' Portia xishan'' (Xu, Peng & Li, 2021) – China *'' Portia zhaoi'' Peng, Li & Chen, 2003 – China


In popular literature

Portia jumping spiders as the dominant species evolving on a terraformed planet feature prominently in the science fiction novel Children of Time by the writer Adrian Tchaikovsky.


References


Further reading

* D.Harland and R.Jackson. Portia Perceptions: the Umwelt of an Araneophagic Jumping Spider / Complex Worlds from Simpler Nervous Systems. MIT Press, 2004 * * Harland, D.P & Jackson R.R. (2000): 'Eight-legged cats' and how they see - a review of recent research on jumping spiders (Araneae: Salticidae). ''Cimbebasia'' 16: 231-24
PDF
- vision and behavior in ''Portia'' spiders. *


External links




Frontal view of ''P. fimbriata''

Information about ''P. fimbriata''
(with distribution in Australia)

* ttps://www.youtube.com/watch?v=usCNem9ixbU Video of ''Portia'' hunting web spiders {{DEFAULTSORT:Portia (Genus) Salticidae Salticidae genera Spiders of Africa Spiders of Asia