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No. 63: May-Jun 1989

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Caterpillars That Look Like What They Eat

While E. Greene was studying insecteating birds, he was startled when an oak tree catkin started to crawl away from him. The crawling catkin turned out to be a cleverly camouflaged caterpillar (Nemoria arizonaria). When these caterpillars start eating oak catkins in the spring, they soon take on the golden color and fuzzy appearance of the catkins. However, the second brood, which matures after the catkins have disappeared, develop instead a twig-like appearance after consuming oak leaves. Thus, both broods acquire the proper protective camouflage for each season. Experiments show that plant chemicals control the appearance of the caterpillars.

(Green, Erick; "A Diet-Induced Developmental Polymorphism in a Caterpillar," Science, 243:643, 1989. Also: Wickelgren, I.; "Caterpillar Disguise; You Are What You Eat," Science News, 135: 70, 1989.)

Comment. Is it naive to wonder why the oaks contribute to their own destruction by providing the caterpillars with chemicals that help conceal them from predators? Plants are usually very clever about producing insect-discouraging chemicals in their leaves. One would expect that "evolutionary forces" would have produced chemicals that would have made the caterpillars more obvious to their predators instead of visa versa.

From Science Frontiers #63, MAY-JUN 1989. 1989-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987