温度和密度对日本医蛭繁殖的影响

Effects of Temperature and Density on Breeding of Leech Hirudo nipponia Whitman

在实验室网箱中,研究温度(24±1)℃和(20±1℃)与密度(200尾/箱和100尾/箱)对平均体质量1g左右的日本医蛭Hirudo nipponia亲蛭交配率、减重率、产茧数量和体质量的影响,比较卵茧质量(<0.05g、0.05~0.1g和>0.1g)对孵出仔蛭数量的影响。结果表明:温度(24±1)℃、密度100尾/箱时亲蛭交配率(86±0.06)%和平均产茧量(0.87±0.14)枚/尾最高;亲蛭产茧后平均体质量下降(32.1±0.059)%;繁殖期间共收集卵茧870枚,孵化率87.47%;平均卵茧质量为(0.11±0.009)g(变化范围0.03g^0.25g);密度和温度对产茧量的影响极显著(P<0.01),对卵茧平均质量和长短径的影响不显著(P>0.05);(24±1)℃组亲蛭的产茧时间比(20±1)℃组缩短10~15d,单日卵茧最高收集量为43枚,(20±1)℃时单日最高收集量24枚;卵茧共孵出仔蛭5 648尾,随着卵茧质量增加产出的仔蛭数量和质量也增加。

The effects of temperature （24± 1 ） ℃ and （20± 1 ） ℃ and density （200 individuals and 100 individuals per cage） on mating rate of broodstock, number of cocoon and body weight were studied in leech （Hirudo nipponia） and effects of cocoon weight （〈0.05 g, 0.05-4）.1 g and 〉0.1 g） on number of newly hatched larvae were also investigated. The results showed that the maximum mating rate （86± 0.06）% and number of cocoon （0.87/leech） were observed at （24± 1 ） ℃ and stocking density of 100 leeches/cage, with weight loss of （32.1 ± 0.059） % in the leeches that released cocoons. A total of 870 cocoons with mean weight of （0.11 ± 0.009） g each, varying from 0.03 g to 0.25 g, were collected during breeding, with hatching rate of 87.47%. There was very significant effect of temperature and density on cocoon number released by leeches （P〈0.01）, without significant effect of temperature and density on long and short diameters of the cocoon and cocoon weight （P〉0.05）. The interval time of cocoon released by leeches was reduced by 10-15 d when the temperature rose from （20± 1 ）℃ to （24± 1 ） ℃, and the maximal daily amount of collected cocoon was 43 at （24± 1 ） ℃ and 24 at （20± 1 ） ℃, with 5 648 individuals of newly hatched larvae during the experiment. The quantity and quality of newly hatched larvae was found to be improved with increase in weight of cocoon.