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No. 76: Jul-Aug 1991

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Ants as "excitable subunits"

"Abstract. Activity levels within ant colonies are monitored by using a solid-state automatically digitizing camera. The movement-activity levels of whole colonies and of isolated groups of workers are studied. Whole colonies of Leptothorax allardycei show rhythmic changes in movement-activity level. Fourier and autocorrelation analyses indicate that the activity levels of colonies are periodic, with an average period of 26 min. Single, isolated workers do not show the pattern of periodic changes in activity level. Single workers become active spontaneously, but at no particular interval. Pairs of workers, confined together, also do not show periodicity in activity level. One worker can stimulate another worker to become active, thus coupling their movement-activity patterns. As ants are placed in larger groups, the variation in the interval between activity peaks declines in a manner predicted by coupled oscillator theory. It is argued that the colony can be regarded as a population of 'excitable subunits.,"

Activity records from two ant colonies Activity records from two ant colonies. Time (horizontal axis) is measured in 30-second intervals.
(Cole, Blaine J.; "Short-Term Activity Cycles in Ants: Generation of Periodicity by Worker Interaction," American Naturalist, 137:244, 1991.)

Comment. The author also pointed out the "formal" or mathematical similarity of the ant movement-activity levels and the dynamics of epidemics! This makes us wonder whether wars, economic cy-cles, etc. might be explained by considering humans as "excitable subunits."

From Science Frontiers #76, JUL-AUG 1991. 1991-2000 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