Reproduction in the threatened crayfish Austropotamobius pallipes (Decapoda, Astacidae) in the Licenza brook basin (central Italy)

摘要

Austropotamobius pallipes is a vulnerable crayfish, and therefore it is necessary to analyse reproduction in the extant populations. Details of the female annual reproductive cycle in a Mediterranean population are provided for two consecutive years.Maternal-size-related variables and date of collection have been considered in relation to the number of ovarian and pleopodal eggs. Reproductive data from 2587 females collected by hand and traps are reported. In total, 204 (14.69%) and 231 (15.93%) individuals in 2003 and 2004, respectively, were ovigerous. Demonstrable differences exist between ovarian and pleopodal egg counts. In particular, ovarian egg counts were considerably higher than expected pleopodal egg numbers. Mating begins in November and is followed by egg laying in early December-January. Berried females occur until May-June, when hatching occurs. The numbers of both ovarian and pleopodal eggs are correlated with the size of females, although fecundity slightiy decreases in larger females. The histology of the reproductive organs of both sexes is also analysed.