Edition: U.S. / Global

The Scorpion, Bizarre And Nasty, Recruits New Admirers

Published: November 27, 1990
(Page 2 of 3)

Scientists are deciphering the chemical signals that control the scorpions' behavior at each step of the intricate mating ritual. They have also gathered evidence that the reason for the extended dance is to allow the female to assess the male's genetic worth before accepting his sperm. Lure of Research Foreign Policy To Wanderlust

Neurobiologists are beginning to appreciate the scorpion's brain, which offers them a rare combination of simplicity and complexity. Unlike other arachnids and insects, which have their nerve cells disseminated up and down their body, a scorpion has a cluster of neurons in its head, just as a mammal does. But a scorpion's brain has far fewer nerve cells than a mammal's, making it easier to study.

It is not only scientists who are interested in scorpions. As a result of the current Persian Gulf crisis and the stationing of American soldiers in Saudi Arabia, the Pentagon is, too. The Defense Department recently asked Dr. Polis and other scorpion experts to travel to the Middle East to study several of the potentially deadly species found there.

Dr. Polis is considering accepting the Pentagon's offer, but he and his colleagues doubt that the scorpion threat to American troops is so pressing. They say excellent anti-venom medications are available to prevent death or even serious illness. Pain, however, is another matter.

"For soldiers in the Mideast, it's rather important to make sure every morning that no scorpions have crawled into their shorts or pants," said Dr. Dean D. Watt, a biochemist at the Creighton University School of Medicine in Omaha, Neb. "The scrotal area is highly vascularized, so if you happen to get stung in that area, it may not kill you, but it will hurt a lot worse than it would on the finger." The pelvic network of blood vessels, he explained, permits the excruciating pain from the venom to spread across the legs and torso.

Lest anybody think them odd for spending their days and nights on one of humanity's ancient foes, scorpion mavens emphasize the many pleasures of their chosen specialty. Not only are scorpions intrinsically bewitching, they say, but the best places to study them also happen to be the most exotic locations. "They live in absolutely beautiful environments," Dr. Brownell said. "I have the built-in excuse to travel around the world."

But scorpion specialists will not always own up to their obsession. "I don't like to talk about my work at the average cocktail party in Nashville," Dr. Polis said. "I'll go through six layers of explanations before I mention scorpions. People will probe and probe, and when I finally tell them what I study, they say, 'You do what? What kind of weirdo are you?' "

Dr. Polis and others insist they pursue their studies for the most rational of reasons -- because scorpions are an ideal "model system" to approach the scientific questions that interest them. "If you ask me do I love scorpions, I'd answer a flat no," Dr. Polis said. "I love the information I get from them."

Naturalists from Aristotle on have been mesmerized by scorpions, but only within the last two decades have researchers had the wherewithal to extensively study the animals in the field. The invention that has revolutionized scorpion biology is the portable ultraviolet light. Another of the scorpion's exceptional features is its ability to glow under ultraviolet light like a psychedelic poster.

The exoskeleton of the scorpion is made of a tough layer of tissue that feels like fingernail but is in fact chitin, a type of cuticle protein. The coat reflects back the ultraviolet rays from moonlight and other light sources so brightly that even a black scorpion glows a fluorescent shade of green or pink. Fossilized scorpions from 300 million years ago still gleam brilliantly under ultraviolet light.

Scientists are not sure why scorpions fluoresce, although some suggest that the glow evolved to attract insects, which are drawn to ultraviolet light. Whatever the reason, the unmistakable shine, visible from 20 feet away, makes it easy to spot scorpions in the dark, when they emerge to eat, mate, fight and otherwise carry on.

"With UV light, we can locate them, capture them, mark them, let them go, and recapture them," said Dr. Neil Hadley, a zoologist at Arizona State University in Tempe. "We can study their metabolic rate, their oxygen consumption, anything we please. UV light has really changed the way we study scorpions." Feeding A Brew of Poisons And Eaten Rivals

Through the use of ultraviolet lamps and other technologies, researchers have learned that scorpions have changed little since the Silurian epoch, 400 million years ago, when they were among the first animals to crawl from sea to land.

Scorpions are commonly associated with the desert but in fact the 1,500 known species are found in almost every possible setting: deserts, rain forests, savannahs, grasslands, temperate forests. Blind ones creep around caves half a mile underground; tiny ones burrow in the cracks of pineapples; stout ones cling to the slopes of the Himalayas 14,000 feet above sea level. Scientists believe that 500 to 1,000 other species remain to be discovered. "If you go someplace where few other scientists have been, there's a good chance you'll find a new scorpion," said Dr. W. David Sissom, a biologist at Elon College in North Carolina.