Looking around the laboratory of Associate Professor Chen Shyh-hwang of National Taiwan Normal University's biology department, apart from the spiders collected from the wild as taxonomic specimens, "there are also four species that have come uninvited." Chen enumerates them: the dusty, dirty-looking spider webs in the corner were built by "tiny house dweller" spiders (Oecobius sp.), which are aptly named "dust spiders" in Chinese; another spider that likes to live in corners is the cellar spider (Pholcus sp.), which in summer carefully guards its next generation by holding its round white egg sac firmly in its upper mandibles; Adanson's house jumper spider (Hasarius adansoni) uses its first-rate jumping ability to roam about inside buildings; and the spitting spider Scytodes thoracica likes to hide in wall cracks and bookcases, and always pops up when one is least expecting it.

Unwelcome guests

There are few people who, like Professor Chen, regard spiders in the house as "honored guests." On seeing a spider-such as the alarmingly large "laya" (Heteropoda venatoria, a type of brown huntsman spider commonly seen in homes in Taiwan)-most people will either blanch and scream in horror, or immediately try to "exterminate" it.

Spiders are arthropods, which also include various other "critters" such as insects, centipedes and millipedes. Arthropods have always been among the things that many people fear the most, and people in Taiwan generally believe spiders to be poisonous. Nonetheless, in evolutionary terms, like humans the arthropods have been extremely successful, and form one of the earth's great families. There are a huge number of arthropod species distributed all over the world, and many can be found at close quarters with human beings. To date, over 30,000 species of spiders alone have been recorded.

In fact, the venom of 99.8% of the world's known spider species is harmless to humans. "Apart from a small number that can cause pain and itching in allergic people, there are no more than five species that are a genuine danger to human life," says Chen Shyh-hwang. There is a popular misconception among people in Taiwan that contact with the "urine" of the laya can cause skin blisters and ulceration, but in fact the spider has been made a scapegoat for the real culprit, the blister beetle (Paederus fuscipes).

As for the most poisonous of all spiders-the black widow-Taiwan has only one species of the same genus: the redback spider (Lactrodectus hasselti). Because redbacks live in areas rarely visited by humans, to date there have only been occasional reported sightings. Chen Shyh-hwang, who has been researching spiders for over ten years, has only seen one, at Mt. Chiuchiu in Nantou County. Meanwhile Macrothele taiwanensis, a funnel-web spider whose venom also contains a dangerous nerve toxin, lives mainly underground and is rarely seen.

In fact, the spiders that like to "participate" in the noisy life of humankind represent only a tiny proportion of the enormous number of spider species. Most spiders stick to the wild.

Forest track, spider kingdom

As spring gives way to summer, the natural world is at its most vibrant, and this is also the breeding season for many kinds of spider. When Chen Shyh-hwang and his students walk onto a thickly overgrown mountain path close to Huangti Temple in Taipei County's Shihting Rural Township, it is as if they have entered a spider kingdom.

Lifting up a damp stone, Chen reveals five or six different species of spider crouching beneath it. Lycosa coelestis, a type of wolf spider, scuttles off in a flash, carrying its egg sac on its back. The young of a Pardosa takahashii-another wolf spider-who are riding on her body, all fall off in a panic, but fortunately they have inherited a handy turn of speed, and in an instant they climb back on board, whereupon their mother carries them off into the undergrowth.

Amid the foliage, Leucauge magnifica, a type of orb-web spider with a white underbelly and a green back, is quite unperturbed by the presence of humans. With its long legs stretched out like an octopus, it sits resolutely on its web built on palm grass, patiently waiting for a meal to arrive. On a nearby tree branch above head height, a light-green Oxytate striatipes, a type of crab spider, has attached her egg sac to the underside of a leaf. The female spider remains crouching over the eggs, guarding them night and day.

On a moss-covered rock face beside the path, a dangerously poisonous Macrothele taiwanensis occupies a small hole, across the mouth of which she has stretched a web smaller than the palm of a hand. Lying in wait in the mouth of the hole, when a passing insect disturbs the web, she grabs it with lightning speed and pulls it inside.

Along just 300 meters of mountain path, Professor Chen variously squats down to turn over stones, carefully pushes aside foliage, or bores with his eyes into the rock faces or tree trunks, in search of spiders. In the space of two hours, the group has "close encounters" with over 30 species. In the three-dimensional spaces created by rock walls, foliage and broken rocks, the spiders display a dazzling variety of natural histories.

Hairy legs and silk

Both spiders and insects are arthropods, but they have very different body patterns. Insects have six legs and a distinct head, thorax and abdomen, but spiders' bodies are divided into only a "cephalothorax" (combined head and thorax) and abdomen, along with eight hairy legs that may be many times longer than the size of their bodies. They are very unique in form, and have some remarkable physical attributes. Spiders have fully developed digestive, circulatory, respiratory and nervous systems. Their legs have seven segments each, with claw-like end segments used for gripping and climbing. The fourth pair of legs is usually used for handling the spiders' silk. The fine hairs of varying lengths on their legs serve as taste and smell organs, and are also used for hearing and for judging orientation. They are highly sensitive to air flows on the ground, on water or across the spider's web, and are thus indispensable survival tools for hunting and for escaping predators.

Apart from their all-purpose hairy legs, the way spiders spin silk and weave webs is also one of the wonders of nature. Spider silk is a composite mixture of proteins. It is mostly white or translucent. In the movie, Spiderman shoots out silk from his wrists, but in real life, spiders' spinning methods are more elaborate and complex, and they secrete different silks according to different needs. Numerous silk glands in their abdomens link into silk ducts that open into spinners. Some of the threads they spin are sticky to catch prey, while others are used to build nests; and the silks they use to make egg sacs or to wrap and immobilize prey are also different.

Spiders all have remarkable spinning abilities, but they can be divided into two categories: web-building and non-web-building species. Web-building spiders like to build a web in a fixed position to catch food. If not disturbed they can spend the whole year on their web, and their temperament is calm and composed. As for those spiders that are not in the habit of building webs, but which roam freely on the ground, on trees, on plants and on walls, they always reel out a "dragline" behind them, which they secure every so often to the surface they are on. When they jump from a high place or are blown by the wind, this dragline provides the best of safety lines. The jumping spiders that are often seen in human habitations, and the much maligned laya, are both non-web-builders of no fixed abode.

Up into the treetops

Web-building spiders' ability to catch food by building webs is closely bound up with the evolution of their main prey-insects. As insects developed from crawling on the ground, to climbing up into the branches and leaves of trees, and finally flying through the air, spiders' skills in using their silken webs also advanced by leaps and bounds. Spiders were originally ground-living animals, but they later began to stretch their webs high in the air, and to produce all kinds of carefully crafted webs in response to different insects' habits and characteristics.

Biologists broadly divide spider webs into orb webs (the typical wheel-pattern web), sheet webs, funnel webs, line webs, mesh webs, and irregularly shaped festoon webs (tangle webs). If you look closely at spider webs, you will discover that they come in a remarkable number of shapes and sizes and employ a great variety of strategies, showing what highly specialized feeders spiders are. Tales of American black widow spiders eating their husbands after mating only seem to confirm people's impressions of spiders' rapaciousness.

Spiders have an average lifespan of two to three years, and only breed once, generally in spring or summer. At this time, the male spiders leave their webs in search of partners, and because in most species the female spiders are larger than the males, the males do indeed have to be extremely cautious. "They have to first perform a mating ritual, to avoid being mistaken for food themselves," says Chen Shyh-hwang.

But do spider "brides" really make a meal of their grooms after mating? Chen explains that in Taiwan, apart from the sheet-web spiders (family Linyphiidae), most spider couples are able to walk away from their nuptial encounters unscathed. "In fact, spiders interact in a great variety of ways. For instance, Philoponella prominens, a type of feather-legged spider common in central and southern Taiwan, even lives in mixed social groups of both sexes; they build their webs alongside each other, and coexist peacefully," says Chen. Biological interactions are complex mechanisms. When male spiders mate they are generally at the end of their natural lifespan anyway, so even in the cases where the female spiders do eat the males, it is not simply a case of ruthless treachery as people may imagine.

After mating, the female spider usually looks after her eggs alone until they hatch. The mother spider wraps the eggs tightly in a waterproof egg sac made up of many layers of silk, and when the spiderlings hatch out they have to break their way out, like silkworms emerging from a cocoon. Depending on the species, spiders may lay as few as a dozen eggs, or as many as 1000. The eggs take around a month to hatch, and it is then another week before the young spiders can leave their mothers and live independently.

At least 1000 species

As biologists' understanding of spiders has advanced, in recent years both spider silk and spider venom have become hot topics of research, in the hope of developing new industrial products. Researchers in Thailand are working hard to develop bullet-proof vests using spider silk; and based on analysis of the chemical structure of spider venom, scientists in Germany have isolated a protein which may be useful for treating heart disease.

In Taiwan, spider research started late. A decade or so ago when Chen Shyh-hwang was revising the species list of Taiwanese spiders, he discovered that of the more than 300 species already described at the time, the bulk had been recorded by early adventurers, and of the 65 species newly recorded in the previous 20 years, almost all had been found in surveys by Japanese scientists.

Taiwan's spiders fall into over 40 families. Relatively large numbers of species have been recorded in the families Psechridae (psechrid spiders), Oxyopidae (lynx spiders) and Theridiosomatidae (ray spiders), but in other families such as Lycosidae (wolf spiders), Salticidae (jumping spiders), and Heteropodidae (brown huntsman spiders-which include the familiar laya), only three to four species have been formally described in each. Chen Shyh-hwang's own experience of field surveys shows that if one only takes the time to study any of these families in more depth, one can find two to three times as many species as were already known. Furthermore, due to the isolation of habitats that results from Taiwan's being an island with mountainous topography and great geographical diversity, the proportion of endemic (unique) species among Taiwanese spiders is as high as 10%.

"In just one spider survey zone on Mt. Chiuchiu in Nantou County, we discovered 200 species," says Chen Shyh-hwang. He states that the number of spider species thus far discovered in Taiwan stands at between eight and nine hundred, but over half of these have not yet been properly identified, so the next major task to be tackled is to compare the specimens of newly discovered spiders, classify and name them, and include them in illustrated field guides.

"For instance, the sheet-web spiders are a big family, but at present there's no-one in Taiwan who knows how to identify them." Chen freely admits that many spiders are small and very similar in appearance, so that their identification takes ample literature, large collections of specimens, and great powers of discernment. Hence spider research in Taiwan is still in its early stages. In Chen's own laboratory alone there are 100 species of spider awaiting classification.

Nature takes care of itself

Chen Shyh-hwang has already published many papers describing new species and reporting species newly recorded in Taiwan. Apart from his efforts to fill in the gaps in Taiwan's spider map, in coordination with other zoologists he has set up sampling plots to observe changes in spider populations on Mt. Chiuchiu in Nantou, which was denuded of large areas of vegetation by the earthquake of 21 September 1999.

Although the observations are still in progress, Chen has discovered that as the denuded areas are recolonized, first by herbaceous plants and shrubs and then by fast-growing broadleaved trees, the spider populations are also quickly recovering. "The largest number of species, and the largest populations, are of spiders that prefer a grassland habitat. But in the areas where there is still no vegetation cover, and there is no place to hide except under stones, the numbers are lowest, due to the limited habitat." Chen says that spiders' diversity is underlined by their ability to survive in very different natural environments.

The environment in Taiwan is under great pressure from development, but Chen Shyh-hwang is generally optimistic about spiders' future. "The destruction of wetlands may have a long-term impact on damp-loving spiders like Leucauge magnifica that build their webs by rivers or ditches." But overall, spiders are small and reproduce prolifically; as long as they have fixed locations where they can build their webs, Chen is not worried that they will have difficulty surviving.

Perhaps what we humans can do for spiders is to put away our ignorance and fear, open our minds, and-just as we admired the feats of Spiderman on the movie screen-appreciate the variety and vitality of spiders in nature.

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In nature, no two spider webs are exactly alike. The brightly colored Argiope aetheroides-a type of golden orb-web spider-adds a cross-shaped "stabilizer" to its web which in fact reflects ultraviolet light to attract insects into the web, like moths to a flame.

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The study and classification of Taiwan's spiders are still in their early stages. Associate Professor Chen Shyh-hwang of NTNU's biology department is the first trained local scientist to delve into the mysteries of Taiwanese spiders. (photo by Hsueh Chi-kuang)

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Chrysso trimaculata, a golden comb-footed spider, carries her egg sac with her wherever she goes.

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Rhene atrata, a jumping spider commonly seen in Taiwan's lowlands, is a non-web-builder that roams where it pleases.

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The nocturnal Deinopus waits to cast its net and trap a passing insect.

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Is it a UFO? No, it's Gasteracantha sauteri, an orb-web spider that has a body covered with sharp spines.

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This rare redback spider is a Taiwanese cousin of the feared black widow.

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A female Chrysso trimaculata and her spiderlings. Different spider species produce anything from a dozen to a thousand offspring at one time.

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Spiders are seriously hairy. They have stiff bristles, fine whiskers, feeling hairs, listening hairs. . . each with their own function. The brown huntsman spider shown here is distinguished by the dense covering of fine orange hairs on its mouthparts.

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The horseshoe-pattern main web of the black-legged golden orb-web spider (Nephila pilipes) is flanked front and back by a pair of simple auxiliary webs.

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Octonoba spinosa, a feather-legged spider, is a master web builder. It hides itself from view behind a spiral "stabilizer" woven into its web.

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The long-legged laya-the brown huntsman spider Heteropoda venatoria-is a common sight in Taiwanese homes. It is an expert cockroach killer.