When most people come across a spider, they usually avoid it
or try to kill it. Chen Shyh-hwang, however, spends much of his
time seeking out these insects and closely studying them. His
written work on the different species found in Taiwan reveals a
world much more intriguing than many people would imagine.
If spiders have a less than desirable reputation, they have only themselves to blame. They do not possess the beauty of butterflies. They do not go about their business in an open and defenseless manner, as ants do. And they often find themselves unwelcome houseguests, spinning webs wherever they please, much to the disapproval of their put-upon hosts. Their web-spinning and acrobatic talents are not much appreciated, particularly among people in Taiwan. Many people on the island grew up with the belief that spiders caused herpes labialis, or cold sores. Some parents still contribute to the myth by telling their children that herpes is the masterwork of nocturnal spiders that crawl onto people's faces and urinate on them while they are sleeping.
Although most educated people today know that spiders do not cause cold sores, few tolerate spiders living in their homes. Chen Shyh-hwang, a biology professor at the National Taiwan Normal University, is an exception. "Spiders are the innocent victims of a negative image," he says in their defense. "Most domestic spiders in Taiwan are harmless to humans. The Heteropodidae species that we often come across at home are actually well behaved for the most part."
Chen explains that nocturnal Heteropodidae spiders do not disturb people during the day and do not produce any webs. Unlike other spider species that eat their young, the female Heteropodidae spider protects her eggs and cares for the larvae. They even help keep away other unwelcomed houseguests, as they are skillful at capturing and devouring cockroaches. The best way to get rid of this species of spiders in the home is not to kill them at every opportunity, Chen notes. "Rather, all you need is a cockroach-free environment."
Having observed the behavior of various species of spiders for more than two decades, Chen is working to repair their damaged reputation by allowing students to handle the arachnids he has collected. Chen's interest in spiders and his long-term study of them have made him a leading expert in the field. Encouraged and funded by the Cabinet-level Council of Agriculture (COA), Chen compiled part of his study into the book, A Guide to Common Spiders in Taiwan , published in 2001. The book includes general information on 121 species of spiders that inhabit the island, accompanied by photographs Chen has taken of them. It covers about two-thirds of the species commonly seen on the island, most of which are on the larger end of the scale.
Chen estimates that the total number of spider species discovered so far on the island stands at around 320 based on the fact that the "1996 Checklist of Spiders in Taiwan," which he compiled for publication in the Annual of the Taiwan Museum, listed 293 varieties in December 1996. He further believes that there are a total of between 800 and 900 different kinds of spiders on the island, which means that hundreds of species are still waiting to be discovered. Tso I-min, a Tunghai University biology professor who specializes in the ecological and behavioral study of spiders, concurs, adding that by studying less accessible areas, surprising discoveries can be made.
Since 1998, Tso has discovered more than 20 new species of spiders that have been documented in journals. Seven or eight of these spiders were found on Orchid Island, an offshore island off the Pacific coast of Taiwan. In 1990, Chen himself announced the discovery of a new species belonging to the genus Phoroncidia (Araneae: Theridiidae), which he named Phoroncidia alishanense, the Latin version of Mount Ali, where he found the tiny species. This spider can be distinguished from others of the same genus by its separate pairs of dorsal and posterior humps.
The investigation of spiders is still an emerging field in Taiwan. Although organizations that study spiders are common in many other countries, Tso points out, Taiwan has yet to see the establishment of an organized force in the field. In fact, the only known biologists studying spiders in Taiwan are Chen and Tso. Last year, Chen received a grant from the National Science Council (NSC) to conduct a three-year research study on the chromosome diversities of Taiwan's spiders. Meanwhile, Tso is proceeding with another NSC-funded research program observing the interaction between spiders of the genus Nephila and other insects based on their color. Tso's preliminary findings show that spiders with vivid coloring tend to draw the attention of their prospective prey more successfully than those with less vivid coloring. In addition, the COA is supporting a program that monitors the changes in the varieties and population of spiders in the Chiuchiu mountains in central Taiwan. For years, the COA has been documenting the botany of the island as well as diminutive inhabitants, such as frogs, snakes, birds, and small mammals.
In the foreword of Chen Shyh-hwang's book, the then head of the COA, Chen Hsi-huang, wrote that the book reaffirmed both the amazing and the amusing sides of nature. Readers gain not only a practical knowledge of the physical aspects and behaviors of arachnids, but also insight into the small, dynamic universe of spiders. The many interesting pictures in the book are proof of the author's dedication to the topic, although for many years his search for spiders was only for his own pleasure.
Success on his hunting trips, both in the wild and in suburbia, has depended on experience and luck, Chen says. The odds of his being bitten by spiders, venomous or not, are slim, he adds. "Spiders aren't an aggressive type of predator," he says. "In most cases when they feel threatened, they try to flee or play dead by falling from their webs and then quickly run for cover." The reaction to a bite from a poisonous spider, he concedes, varies from person to person, depending on one's physical constitution. For example, the venom of the Latrodectus mactans, or Black Widows, can be fatal particularly for children.
The population of such spiders on Taiwan, however, is relatively small. In his decades of studying spiders, Chen has only twice come across Latrodectus hasselti, a species of Black Widow first documented in 1870. The professor emphasizes the importance of sparing especially rare species of spiders to allow them to live and multiply freely in the wild. "The fierce competition for survival already puts a limit on the population of spiders," he notes. "In many cases, baby spiders can even fall prey to their mothers when they accidentally intrude upon their mothers' webs."
As a result of such dangers, most spiders tend to be loners and do not travel far because of their limited ability to move to other regions. Smaller spiders, on the other hand, often make good use of their natural endowments--the spinnerets, the silk glands, and the spigots--to reach more remote areas. The spigots allow them to extract silk threads from the silk glands inside the several spinnerets, and the smallness and lightness of their bodies enable them to be taken by the threads and thus "balloon" with the wind. They can go as far as the wind takes them with these threads.
Spiders have many different silk glands, and each has various functions, Chen explains. Spinning spiders generally have three or four--some have up to seven or eight--kinds of silk threads. Some of these threads are used to create webs, a thicker drag line is used to support the spiders when they fall, an adhesive type traps their prey, and several other kinds that vary in softness and thickness are used to wrap their eggs. "They're fascinatingly designed," Chen says of his subject of study. "Even a spider of less than one millimeter in size is likewise intricately built." And to add to the variety, different species of spiders produce webs of different shapes. For instance, the Nephila pilipes spiders spin their webs in the shape of a hoof, the Argiope aetheroides species weave a white X shape in their round webs, and the Octonoba spinosa spiders braid spiral-shaped webs.
Chen likes to call spiders environmentalists because they usually "recycle" their webs by eating the protein-enriched threads when they prepare to move on. Another interesting aspect of spiders is the size discrepancy between males and females. Females are generally much larger so they can carry as many eggs as possible. Males, meanwhile, are rather small since their only function is to mate, and they often die soon after they perform this duty. Certain species of female spiders die soon after laying their eggs. But before doing so, they wrap their eggs neatly and hang the egg sacs on trees. The newly hatched baby spiders are forced to start their lives on their own, and many of them either die from hunger or are quickly killed. On the other hand, those species that raise their young tend to produce fewer descendants. In general, most spiders have a life span of one to two years, during which period they molt six or seven times.
Chen believes that hundreds of species of spiders are hiding in the high mountains of Taiwan, waiting to be discovered, named, and added to the list of identified species. With his keen eyesight and years of arachnid study, the biologist can easily detect a spider the size of a grain of sand from its surroundings. But he often fails to find enough time to go through the volumes of documents to determine whether or not he has encountered a new species. And while some pet stores are beginning to include spiders in their inventory, Chen prefers to visit these insects in their natural setting--rain or shine, summer or winter.