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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. 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. The genus ''Portia'' has 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. labiata''s rely more on trial and error than Sagada ''P. labiata''s 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. labiata''s 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. When hunting, ''P. labiata'' mature females emit olfactory signals that reduce the risk that any other females, males or juveniles of the same species may contend for the same prey. == Body structure and appearance == As in most species of the genus, the bodies of female ''Portia labiata''s are 7 to 10 millimetres long and their carapaces are 2.8 to 3.8 millimetres long. Males' bodies are 5 to 7.5 millimetres long, with carapaces 2.4 to 3.3 millimetres long. The carapaces of females are orange-brown, slightly lighter around the eyes, where there are sooty streaks and sometimes a violet to green sheen in certain lights. There is a broad white moustache along the bottom of the carapace, and running back from each main eye is ridge that looks like a horn.〔 Females' chelicerae are dark orange-brown and decorated with sparse white hairs, which form bands near the carapaces. The abdomens of females are mottled brown and black, and bear hairs of gold, white and black, and there are tufts consisting of brown hairs tipped with white. The carapaces of males are orange-brown, slightly lighter around the eyes, and have brown-black hairs lying on the surface but with a white wedge-shape stripe from the highest point down to the back, and white bands just above the legs. Males' chelicerae are also orange-brown with brown-black markings. The abdomens of males are brown with lighter markings and with brown-black hairs lying on the surface, and a short band of white hairs. The legs of both sexes are dark brown, with light markings in the femora (the sections of the legs nearest the body). All species of the genus ''Portia'' have elastic abdomens, so that those of both sexes can become almost spherical when well fed, and females' can stretch as much when producing eggs. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Portia labiata」の詳細全文を読む スポンサード リンク
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