Role of Escape from Predators in Periodical Cicada (Homoptera: Cicadidae) Cycles

Evolution of unusually long life cycles and synchronized emergence of periodical cicadas, Magicicada spp., is one of the mysterious problems in evolutionary biology. Yoshimura presented a hypothesis to explain this by the elongation of the life cycle during glacial periods and the extinction of some yearclasses because of difficulty of mating in years of low adult density. Yoshimura assumes large fluctuations of abundance in ancient cicada populations, but cicada populations are far more stable than those of many other insects. By examining such data, I concluded that escape from predator pressure by synchronized massemergence is the most important factor for the evolution and maintenance of long-year periodicity, which has so far been found only in cicadas.