User:Philcha/Sandbox/Portia labiata

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Portia labiata is a jumping spider (family Salticidae) found in Sri Lanka, India, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. Adult females have bodies 7 to 10 millimetres long, while those of adult males are 5 to 7.5 millimetres long. The carapaces of females and males are orange-brown, slightly lighter around the eyes, but have slightly different markings in the two sexes. The abdomens of females are mottled brown and black, while those of males are brown with lighter markings, and the abdomens of the two sexes have different patterns of hairs. 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.

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 * ... that the jumping spider Portia labiata has populations in different regions, but only one knows how catch a spitting spider safely and how to work out the best way to cross a small lagoon
 * ... that females of the jumping spider Portia labiata use silk draglines as territory marks, and use these to avoid females of higher fighting ability and spend more time around less powerful fighters
 * ... that subadult females of the jumping spider Portia labiata mimic adult females to lure males and eat them

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Portia labiata is a jumping spider (family Salticidae) found in Sri Lanka, India, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. Adult females have bodies 7 to 10 millimetres long, while those of adult males are 5 to 7.5 millimetres long. The carapaces of females and males are orange-brown, slightly lighter around the eyes, but have slightly different markings in the two sexes. The abdomens of females are mottled brown and black, while those of males are brown with lighter markings, and the abdomens of the two sexes have different patterns of hairs. Females' chelicerae, which house the fangs, are dark orange-brown, and those of males are orange-brown. The legs of both sexes are dark brown, with light markings in the femora. All species of the genus Portia have elastic abdomens, so that those of both sexes become almost spherical when well fed, and females' can stretch as much when producing but not yet laying eggs.

The vision of a jumping spiders' main eyes is more acute than a cat's during the day and 10 times more acute than a dragonfly's, so that in practice they can see up to about 75 centimetres. Like all jumping spiders, P. labiata can take in only a small visual field at one time, and takes a relatively long time to see objects, probably because a lot of scanning is needed. This makes P. labiata and other jumping spiders vulnerable to much larger predators such as birds, frogs and mantises, which a jumping spider often cannot identify.

The genus Portia have been called "Eight-legged Cats", as their hunting tactics are as versatile and adaptable as a lion's. All members of Portia have instinctive hunting tactics for their most common prey, but often can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach. While most jumping spiders prey mainly on insects and by active hunting, females of Portia also build webs to catch prey directly and sometimes join their own webs on to those of web-based spiders. When hunting in another spider's web, a Portia′s slow, choppy movements and the flaps on its legs make it resemble leaf detritus caught in the web. P. labiata and some other Portias use breezes and other disturbances as "smokescreens" in which these predators can approach web spiders more quickly, and revert to a more cautious approach when the disturbance disappears. P. labiata more often pursues small jumping spiders and web spiders than larger prey. A female P. labiata is effective against insects up to twice P. labiata′s size when the insect is stuck in a non-salticid's web, and against insects up to P. labiata′s size when not in webs. Both females and males prefer web spiders as prey, followed by other jumping spiders, and finally insects. In all cases females are more effective predators than males.

Populations from Los Baños and from  Sagada, both in the Philippines, have slightly different hunting tactics. In laboratory tests, Los Baños P. labiatas rely more on trial and error than Sagada P. labiatas in finding ways to vibrate the prey's web and thus lure or distract the prey. Around Los Baños the web-building Scytodes pallida, which preys on jumping spiders, is very abundant, and spits a sticky gum on prey and potential threats. A P. labiata from Los Baños instinctively detours round the back of S. pallida while with plucking the web in a way that makes S. pallida believe the threat is in front of it. In areas where S. pallida is absent, the local members of P. labiata do not use this combination of deception and detouring for a stab in the back.

In a test to explore P. labiata′s ability to solve a novel problem, a miniature lagoon was set up, and the spiders had to find the best way to cross it. Specimens from Sagada, in the mountains, almost always repeated the first option they tried, even when that was unsuccessful. When specimens from Los Baños, beside a lake, were unsuccessful the first time, about three quarters switched to another option.

Adult P. labiatas sometimes uses "propulsive displays", in which an individual threatens a rival of the same sex, and unreceptive females also threaten males in this way. P. labiata females are extremely aggressive to other females, trying to invade and take over each other's webs, which often results in cannibalism. A test showed that they minimise the risk of confrontations by using silk draglines as  territory marks. Another test showed that females can recognise the draglines of the most powerful fighters and prefer to move near the draglines of less powerful ones. Females try to kill and eat their mates during or after copulation, while males use tactics to survive copulation, but sometimes females outwit them. Before being mature enough to mate, juvenile females mimic adult females to attract males as prey.

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Portia labiata is a jumping spider (family Salticidae) found in Sri Lanka, India, Burma (Myanmar), Malaysia, Singapore, Java, Sumatra and the Philippines. Adult females have bodies 7 to 10 millimetres long, while those of adult males are 5 to 7.5 millimetres long. The carapaces of females and males are orange-brown, slightly lighter around the eyes, but have slightly different markings in the two sexes. The abdomens of females are mottled brown and black, while those of males are brown with lighter markings, and the abdomens of the two sexes have different patterns of hairs. 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.

The genus Portia have been called "Eight-legged Cats", as their hunting tactics are as versatile and adaptable as a lion's. All members of Portia have instinctive hunting tactics for their most common prey, but often can improvise by trial and error against unfamiliar prey or in unfamiliar situations, and then remember the new approach. While most jumping spiders prey mainly on insects and by active hunting, females of Portia also build webs to catch prey directly and sometimes join their own webs on to those of web-based spiders. Both females and males prefer web spiders as prey, followed by other jumping spiders, and finally insects. In all cases females are more effective predators than males.

Populations from Los Baños and from  Sagada, both in the Philippines, have slightly different hunting tactics. In laboratory tests, Los Baños P. labiatas rely more on trial and error than Sagada P. labiatas in finding ways to vibrate the prey's web and thus lure or distract the prey. Around Los Baños the web-building Scytodes pallida, which preys on jumping spiders, is very abundant, and spits a sticky gum on prey and potential threats. A P. labiata from Los Baños instinctively detours round the back of S. pallida while with plucking the web in a way that makes the prey believe the threat is in front of it. In areas where S. pallida is absent, the local members of P. labiata do not use this combination of deception and detouring for a stab in the back. In a test to explore P. labiata′s ability to solve a novel problem, a miniature lagoon was set up, and the spiders had to find the best way to cross it. Specimens from Sagada, in the mountains, almost always repeated the first option they tried, even when that was unsuccessful. When specimens from Los Baños, beside a lake, were unsuccessful the first time, about three quarters switched to another option.

Adult P. labiatas sometimes uses "propulsive displays", in which an individual threatens a rival of the same sex, and unreceptive females also threaten males in this way. P. labiata females are extremely aggressive to other females, trying to invade and take over each other's webs, which often results in cannibalism. A test showed that they minimise the risk of confrontations by using silk draglines as  territory marks. Another test showed that females can recognise the draglines of the most powerful fighters and prefer to move near the draglines of less powerful ones. Females try to kill and eat their mates during or after copulation, while males use tactics to survive copulation, but sometimes females outwit them. Before being mature enough to mate, juvenile females mimic adult females to attract males as prey.