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No. 41: Sep-Oct 1985

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The deceitful she-males

"In many diverse taxa, males of the same species often exhibit multiple mating strategies. One well-documented alternative male reproductive pattern is 'female mimicry,' whereby males assume a female-like morphology or mimic female behavior patterns. In some species males mimic both female morphology and behavior. We report here female mimicry in a reptile, the red-sided garter snake (Thamnophis sirtalis parietalis). This form of mimicry is unique in that it is expressed as a physiological feminization. Courting male red-sided garter snakes detect a female-specific pheromone and normally avoid courting other males. However, a small proportion of males release a pheromone that attracts other males, as though they were females. In the field, mating aggregations of 5-17 males were observed formed around these individual attractive males, which we have termed 'she-males.' In competitive mating trials, she-males mated with females significantly more often than did normal males, demonstrating not only reproductive competence but also a possible selective advantage to males with this female-like pheromone."

In the competitive mating trials, the she-males were successful in 29 out of 42 trials. The normal males won out in only 13! The authors ask the question: Why aren't all males she-males given such an advantage?

(Mason, Robert T., and Crews, David; "Female Mimicry in Garter Snakes," Nature, 316:59, 1985.)

Comment. Among the fishes, bluegills and salmon (and probably many others) have female-appearing males competing with normal males.

From Science Frontiers #41, SEP-OCT 1985. 1985-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:

Quotes

  • "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