''Portia'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomencla ...
of
jumping spider
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 spi ...
that feeds on other spiders (i.e., they are araneophagic or 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
Ferdinand Anton Franz Karsch or Karsch-Haack (2 September 1853, in Münster – 20 December 1936, in Berlin) was a German arachnologist, entomologist and anthropologist.
The son of a doctor, Karsch was educated at the Friedrich Wilhelm Univers ...
. The fringed jumping spider (''
Portia fimbriata'') 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 of organisms to construct the tree of life
The tree of life is a fundamental archetype in many of the world's mythological, religious, and philosophical traditions. It is closely related to the concept of the sacred tree.Giovino, Mariana (2007). ''The Assyrian Sacred Tree: A History ...
, indicates that ''Portia'' is a member of a basal clade (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 (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...
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, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring ...
: 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 of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
amber
Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...
were identified as related to ''Portia''.
Distribution and ecology
The 17 described species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
are found in Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, Australia, China, Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, Malaysia
Malaysia ( ; ) is a country in Southeast Asia. The federal constitutional monarchy consists of thirteen states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia and Borneo's East Malays ...
, Myanmar
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
, Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, the Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
, Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
, Taiwan
Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast ...
, and Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making it ...
.[
''Portia'' are vulnerable to larger predators such as birds and ]frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
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 and tropical habitats. They ha ...
es, the assassin bug
The Reduviidae are a large cosmopolitan family 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 are aquatic. The main examp ...
s ''Nagusta'' sp. indet. and ''Scipinnia repax''.
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 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 the rope, in contrast to low ...
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. If a ''Portia'' makes a mistake while hunting another spider, it may itself be killed.
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
A pin is a device used for fastening objects or material together.
Pin or PIN may also refer to:
Computers and technology
* Personal identification number (PIN), to access a secured system
** PIN pad, a PIN entry device
* PIN, a former Dutch ...
, and it has only about 600,000 neuron
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. ...
s.
''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. ''Portia'' looks like leaf detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
caught in a web, and this is often enough to fool web-building spiders, which have poor eyesight.
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 both innate (inborn) and learned elements. The simplest example of an instinctive behaviour is a fixed action pattern (FAP), in which a ...
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
Trial and error is a fundamental method of problem-solving characterized by repeated, varied attempts which are continued until success, or until the practicer stops trying.
According to W.H. Thorpe, the term was devised by C. Lloyd Morgan ( ...
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 8 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, ''Portia''s 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 (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...
.
The inter-receptor angles of ''Portias 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'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
'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 birds, frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' is ...
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 and tropical habitats. They ha ...
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 ("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 spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
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:
*'' Portia africana'' (Simon
Simon may refer to:
People
* Simon (given name), including a list of people and fictional characters with the given name Simon
* Simon (surname), including a list of people with the surname Simon
* Eugène Simon, French naturalist and the genus ...
, 1886) – West, Central Africa
Central Africa is a subregion of the African continent comprising various countries according to different definitions. Angola, Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, the Republic of the Congo, ...
, Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the no ...
*'' 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 a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borderin ...
, Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guinea. In ...
(Borneo
Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and ea ...
)
*'' Portia erlangping'' (Xu, Peng & Li, 2021) – China
*'' Portia fajing'' (Xu, Peng & Li, 2021) – China
*'' Portia fimbriata'' (Doleschall, 1859) ( type) – Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
, Taiwan to Australia
*'' Portia heteroidea'' Xie & Yin, 1991 – China
*'' Portia hoggi'' Zabka, 1985 – Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making it ...
*'' Portia jianfeng'' Song & Zhu, 1998 – China
*''Portia labiata
''Portia labiata'' is a jumping spider (family Salticidae) 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 a ...
'' ( Thorell, 1887) – Sri Lanka to China, Vietnam, Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
, India
*'' Portia orientalis'' Murphy & Murphy, 1983 – China (Hong Kong
Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China ( abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta ...
)
*'' Portia quei'' Zabka, 1985 – China, Vietnam
*'' Portia schultzi'' Karsch, 1878 – Central, East, Southern Africa, Mayotte
Mayotte (; french: Mayotte, ; Shimaore: ''Maore'', ; Kibushi: ''Maori'', ), officially the Department of Mayotte (french: Département de Mayotte), is an overseas department and region and single territorial collectivity of France. It is ...
, Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
*'' 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, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast ...
*'' Portia wui'' Peng & Li, 2002 – China
*'' Portia xishan'' (Xu, Peng & Li, 2021) – China
*'' Portia zhaoi'' Peng, Li & Chen, 2003 – China
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