Effects of maternal age on reproductive performance of the southern medicinal leech, Hirudo verbana Carena, 1820

Abstract

Medicinal leeches can be used to address important needs in medicine and veterinary medicine, as well as pharmaceutical and cosmetic industries. These leeches, however, are among the endangered species. The reproductive processes of the medicinal leeches are not well-known. The aim of the present study was to elucidate effects of maternal age on reproductive performance of medicinal leeches (Hirudo sp.). This study was conducted on Hirudo verbana which were 1, 2 and 3 years of age. The results from the study indicate the youngest maternal leeches have greater reproductive performance. Cocoon production was 4.30 ± 0.72, 3.00 ± 0.71 and 2.80 ± 0.65 cocoons/leech at 1-, 2- and 3-years of age, respectively. Offspring production was greater in younger leeches with there being 11.16 ± 0.63, 10.60 ± 0.96 and 7.14 ± 1.20 offspring produced per cocoon when the cocoon was produced by leeches that were 1, 2, and 3 years of age, respectively. With increasing age of leeches producing the cocoon, the number of cocoons from which there are no offspring produced and the rate of abnormalities of cocoons and morphological abnormalities of offspring increased. The mortality rate of offspring was 10% and 40% in offspring from cocoons produced by 1- and 3-year-old leeches, respectively, being greater when from cocoons produced by 3-year old leeches. Consistent with these findings, younger maternal leeches during their first reproductive phase after hatching from a cocoon have the greatest reproductive performance and should be utilized in leech aquaculture enterprises.