Reproduction efficiency of the leech Whitmania pigra and multiple paternity revealed by microsatellite analyses

ABSTRACT Whitmania pigra is used in traditional Chinese medicine for the treatment of cardiovascular diseases and other chronic diseases, but its reproductive behaviour has not been well studied. The purpose of this study was to investigate the reproduction efficiency and mating system of W. pigra. The study was conducted under laboratory conditions. A total of 28 gravid leeches weighing 22.3 ± 6.1 g were used. The leeches deposited 6.00 ± 0.82 cocoons by losing 46.68 ± 9.89% in body weight. The cocoons, with a length of 20.93 ± 4.84 mm and diameter of 17.20 ± 4.41 mm, had 30.97 ± 11.19 hatchlings. An average of 182.70 ± 51.16 hatchlings per leech were obtained from the leeches. There was a significant negative correlation between the cocoon laying period and cocoon size. By genotyping 10 adult leeches and 200 of their offspring (20 offspring per leech) with six microsatellite loci, multiple paternity was observed for all families. We inferred a minimum of 2–5 mates per family, with an average of 3.30 ± 0.95 mates. This was the first direct evidence of multiple paternity in W. pigra. This result will be useful inartificial production and conservation of the leech W. pigra.