LIGHTON, JRB; DUNCAN, FDD; TURNER, RJ: Shaken, not stirred: Of ants and earthquakes

According to anecdotal evidence, many animals including arthropods such as ants change their behavior during earthquake and earthquake precursor events. This poses the question: Are such behavioral responses real, and if so, are they robust enough to be utilized as a means of earthquake prediction? This is not a subject amenable to conventional experimental approaches, because real earthquakes may be accompanied by electrical and other phenomena difficult or impossible to replicate in the laboratory. We report here a serendipitous study of ant trail dynamics and metabolic rate immediately prior to, during, and on three control days after the Landers earthquake (June 1992; Richter magnitude 7.4, the most powerful to strike the continental United States in several decades). Using a prototype Sable Systems field metabolic/video/thermometric data acquisition system, we examined trail traffic rates (in both directions: to and from the nest), the mass distribution of foragers entering and leaving the nest (the species on which we worked, Messor pergandei, is polymorphic), running speed, and metabolic rate prior to, during, and after the Landers earthquake. Are earthquake precursors and earthquakes detected by ant colonies? Our results do not validate the anecdotal accounts of earthquake effects on ant behavior that have been reported. The Landers earthquake had no effect at all on any measured aspect of ant behavior or catabolism. Newspaper reporters are always asking scientists for the practical uses of their research. We regretfully conclude that the practical uses for ant colony foraging behavior (and its physiological correlates) do not include earthquake prediction.