National Geographic : 1938 Dec
MARVELS OF METAMORPHOSIS A Scientific "G-man" Pursues Rare Trapdoor Spider Parasites for Three Years With a Spade and a Candid Camera BY GEORGE ELWOOD JENKS With Illustrations from Photographs by the Author " THO ever heard of worms chang / ing into butterflies? Why, that Sounds like witchcraft!" Thus reasoned the horrified city fathers of a town in Chile, only a century ago, when they discovered that a German scien tist in their community was raising caterpil lars which magically changed shape and sprouted wings. According to Charles Darwin, who relates the incident in his diary of the voyage of H. M. S. Beagle, the miracle-working biologist was actually arrested and charged with heresy! Is it any wonder that provincial officials of that day saw something supernatural in the transformations conjured up by Na ture's witchcraft? Since then, the four stages of insect life-egg, larva, pupa, and adult-have become familiar to laymen, and watching "caterpillars turn into butter flies" is a favorite schoolboy diversion. Yet, even today, scientists themselves are still baffled by some of the deeper mysteries of insect metamorphosis. THE JOY A MYSTERY HOLDS A mystery of any kind holds a strong fascination for me. When the individual portions of universal human curiosity were handed out, I must have received an extra large slice, for I have found real joy only in experimenting, investigating, and explor ing. That explains why I eventually found myself back where I started in boyhood, "watching caterpillars turn into butterflies." Only in a figurative sense, however, for I had found that far too much of the butter fly's inner development was hidden behind caterpillar skins and chrysalids. The very fact that it was hidden ap pealed to my "Peeping Tom" complex. So I passed up the disappointing butterflies, and hoped some day to find an insect that would not be so shy and secretive about its private life and magic transformations. One insect trail led me on to another, out into the adobe hills of southern Califor- nia, down through the tunnels of trapdoor spiders, and into a dim and little-known insect underworld. There I found strange creatures and explored new trails as alluring to me as any unmapped waterway ever traversed by my canoe in a Canadian wilderness. And there I struck the trail of a mysterious parasite that promised to fulfill my dreams of finding an insect nudist that would reveal its larval and pupal forms, uncon cealed by opaque skins and pupal mummy cases. THE BLACK WIDOW TRAIL Three black widow spiders were instru mental in starting me on the trail that led to the insect underworld. We had moved into a little cottage out near the South west Museum on the outskirts of Los Angeles, and it gave me a jolt when I dis covered these venomous spiders and their families making themselves very much at home in the new garage. Somehow I did not quite like the idea of the black widows' children growing up as playmates for our two-year-old Danny.* I grabbed an old broom and started a war of extermination, but could not resist pausing to take a last look at the third intended victim. Black as a coal, save for the red hourglass mark, she was beautiful in a slinky, sinister way. Here was mystery again. Scientists dis agreed about her, and no one seemed to know the cause of her alarming increase and spread during recent years. And there was her dainty silken egg sac. What was happening inside? Could that hidden life be photographed? The old fever was upon me again-the lure of the unknown-and, as usual, it hit me hard. When I came back to earth, I found that I had a growing colony of black * See "Afield with the Spiders," by Henry E. Ewing, in the NATIONAL GEOGRAPHIC MAGAZINE, August, 1933, and "Potent Personalities-Wasps and Hornets," by Austin H. Clark, July, 1937.