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No. 86: Mar-Apr 1993

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How A Fly Hears What A Cricket Hears

As we all know, male crickets chirp long and loud for mates from spring until fall. That many males are successful in attracting females is obvious from this insect's population levels. Some of the singing males, however, attract parasitic flies that home in on their songs and deposit their maggots on or near them. Within 10 days, these singers are silent -- they have been consumed by the maggots.

The really interesting part of this tale involves the hearing organs of the crickets and flies. Normally, they are radically different in design and frequency of operation. Crickets usually sing at frequencies above 3 kilohertz, and their ears are attuned to these high frequencies. The usual fly, on the other hand, hums and buzzes at only 100-500 hertz (cycles per second). Their ears are duly optimized at these frequencies. The cricket-hunting flies (genus Ormia), however, would starve to death if they couldn't hear the highpitched cricket songs. Their response was to "evolve" a cricket-type ear so they could home in on their prey. This is a remarkable example of evolutionary convergence.

(Robert, Daniel, et al; "The Evolutionary Convergence of Hearing in a Parasitoid Fly and Its Cricket Host," Science, 258:1135, 1992.)

Comment. How did the parasitic flies survive until they evolved, through small random mutations, just the right sort of ear to tune in on the crickets?

From Science Frontiers #86, MAR-APR 1993. 1993-2000 William R. Corliss

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  • "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