Survival rates in a natural population of the damselfly Ceriagrion tenellum: effects of sex and female phenotype

1. Ceriagrion tenellum females show genetic colour polymorphism. Androchrom e (erythrogastrum) females are brightly (male-like) coloured while gynochro me females (typica and melanogastrum) show cryptic colouration. 2. Several hypotheses have been proposed to explain the existence of more t han one female morph in damselfly populations. The reproductive isolation a nd intraspecific mimicry hypotheses predict greater survival of gynochrome females, while the density dependent hypothesis predicts no differential su rvival between morphs. 3. Mature males had greater recapture probability than females while the su rvival probability was similar for both sexes. Survival and recapture rates were similar for androchrome and gynochrome females. 4. Gynochrome females showed greater mortality or migration rate than andro chrome females during the pre-reproductive period. This result is not predi cted by the above hypotheses or by the null hypothesis that colour polymorp hism is only maintained by random factors: founder effects, genetic drift, and migration.