Possible influences of habitat characteristics on the evolution of semelparity and cannibalism in the hump earwig Anechura harmandi.

摘要

The possible influences of life history and habitat characteristics on the evolution of semelparity and cannibalism in Anechura harmandi were studied in Japan. This species is univoltine and overwinters as an adult. Females laid single egg-batches during winter in nests under stones at a riverside in a valley. They took care of the eggs which hatched in early spring and the offspring ate their mother before dispersing. The valley was sometimes flooded in summer. Nymphs emerged as adults and dispersed to elsewhere before the rainy season arrived. They returned to the riverside after the rainy season. The flooding and/or summer heat seemed to be the selective force for the evolution of dispersal behaviour and semelparity in this species. The cannibalism of the female parent by her offspring seemed to have readily evolved after the evolution of semelparity. The unfavourable environmental conditions seemed to have a large effect on the evolution of semelparity and cannibalism in this species.