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Nature in Short / When the arachnid met the autodidact

By Kevin Short / Special to The Japan News

By Kevin Short / Special to The Japan NewsMany of my acquaintances assume I must be a botanist or biologist. To be truthful, however, I’m just a naturalist. My advanced degrees are in anthropology and folklore, and I have no formal training in the biological sciences. All my knowledge of local plants and animals is self-taught.

There are downsides to a lack of formal education. For example, I have to work overtime to understand some specialized terms and concepts.

On the other hand, as a naturalist, I’m not tied down to any specific area of expertise. I can just jaunt around and observe whatever catches my fancy.

For instance, I have never taken even a basic course in botany, but I love plants. Right now, one of my favorites is a common local woodland tree, the uwamizuzakura bird cherry (Prunus grayana). The fruits form in clusters at the tip of the branches, and ripen at different speeds, producing a colorful collage of lemon yellows, tangerine oranges and raspberry reds.

Botanists employ a long list of names for different fruit structures. The bird cherry fruits consist of an outer skin and a soft fleshy inner part that is actually quite tasty. At the center is a very hard shell, called a pit or stone, that surrounds and protects the seed. This structure is characteristic of a type of fruit called a drupe (kakuka).

I also have a great passion for spiders, and never pass up a chance to observe one in the field. Just the other day, on a summer excursion with some students, we ran into a big beautiful black and yellow orb web spider along the side of a narrow farm road. She was well over two centimeters in body length, and was sitting at the center of her web, which was reinforced by four zig-zag lines of shiny silk laid out in an X-pattern.

Here in Japan, excellent illustrated field guides are available for spiders; from the distinctive body markings, this spider could easily be identified as the kogane gumo (Argiope amoena). Arachnologists call the shiny reinforced silk a stabilamentum (kakureobi in Japanese), but are unsure what its real purpose is. One theory is that the silk reflects ultraviolet light and helps attract insects. Another is that the lines serve to disguise the spider sitting in the center. Still another holds that the shiny silk actually advertises the presence of the web, and helps deter birds and animals from accidentally crashing through.

I have never studied entomology either, but I do love insects, particularly beetles. Classified in the order Coeloptera (kochu moku), beetles are protected by an extra heavy-duty exoskeleton. They also have hard front wings, which entomologists call elytra (sayabane), that are useless for flying, but completely cover and guard the body from above. This trade-off of flying ability for protective armor clearly works, as beetles comprise the most diverse group of organisms on earth. Close to half a million species have been identified worldwide.

One of my favorites is a truly incredible woodboring beetle called tama-mushi (Chrysochroa fulgidissima). The elytra, thorax and head are covered by an iridescent metallic sheen that shimmers among various shades of green and purple depending on the light. The larvae of this beetle feed on wood, with a preference for trees in the Elm family (nire-ka). Since ancient times, the Japanese have used the sayabane to decorate crafts and jewelry.

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Short is a naturalist and cultural anthropoloy professor at Tokyo University of Information Sciences.Speech

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