Intraspecific differences in hatching phenology of the fairy shrimp Chirocephalus diaphanus Prévost, 1803 (Crustacea, Anostraca) in relation to habitat duration

The influence of environmental characteristics on hatching phenology in the fairy shrimp Chirocephalus diaphanus Prévost, 1803 was investigated by comparing the hatching behaviour of two populations living in mountain pasture pools differing in size and in duration of filling. Significant differences observed at population level confirmed that an influence of the environment in determining hatching pattern does actually exist. C. diaphanus seems to be able to adjust the cyst reactiveness to the stochastic nature of its habitat. The cysts laid by females adapted to a predictable and relatively constant environment are characterized by higher hatching percentages with respect to those produced in a temporary pool having erratic hydrocycles.