Summary: Survival rates in a natural population of the damsel»y
Ceriagrion tenellum: effects of sex and female
J O S E A . A N D R E┬ S and A D O L F O C O R D E R O R I V E R A
Departamento Ecolox§┬a e Biolox§┬a Animal, Universidade de Vigo, EUET Forestal, Pontevedra, Spain
Abstract. 1. Ceriagrion tenellum females show genetic colour polymorphism.
Androchrome (erythrogastrum) females are brightly (male-like) coloured while
gynochrome females (typica and melanogastrum) show cryptic colouration.
2. Several hypotheses have been proposed to explain the existence of more than
one female morph in damsel»y populations. The reproductive isolation and
intraspeci«c mimicry hypotheses predict greater survival of gynochrome females,
while the density dependent hypothesis predicts no differential survival between
3. Mature males had greater recapture probability than females while the survival
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
androchrome females during the pre-reproductive period. This result is not
predicted by the above hypotheses or by the null hypothesis that colour
polymorphism is only maintained by random factors: founder effects, genetic drift,