土壤湿度及稻草基质对宽体金线蛭繁殖性能的影响

[目的]探明土壤湿度及稻草作为基质对宽体金线蛭繁殖性能的影响,为促进宽体金线蛭规模化养殖发展提供参考依据.[方法]将规格整齐的2龄性成熟且具有生殖环带的宽体金线蛭亲本放养到30%、40%、50%、60%和70%等5个土壤湿度及40%湿度稻草基质的养殖箱中,分别观察其亲本存活率、产茧数、卵茧规格、卵茧孵化率及孵化量情况.[结果]经过30 d的繁殖周期,不同土壤湿度下的宽体金线蛭亲本存活率、产卵茧数和产茧率存在显著差异(P<0.05,下同),但所产卵茧规格无显著差异(P>0.05,下同).其中,土壤湿度为60%时,亲本存活率、产卵茧数及产茧率最高,土壤湿度为30%时最低.通过拟合的回归方程计算得出:土壤湿度为58.80%时,卵茧孵化率最高,达95.56%;土壤湿度为57.61%时,卵茧孵化量最高,为27.59尾.40%湿度稻草基质条件下的宽体金线蛭亲本存活率、产卵茧数和产茧率均显著低于相同湿度土壤基质的结果;在两种基质条件下,宽体金线蛭卵茧的孵化率和孵化量也无显著差异,孵化率均高于90.00%,孵化量为20.67~22.00尾.[结论]土壤湿度对宽体金线蛭的繁殖性能和卵茧孵化效果影响显著,但对所产卵茧规格无显著影响,其中以土壤湿度保持在60%时的效果最佳.

Effects of soil water content and straw substrate on reproductive performance of Whitmania pigra

[Objective]This experiment was conducted to determine the effects of soil water content and straw sub-strate on reproductive performance of Whitmania pigra to provide reference for scale artificial reproduction of it.[Method]Sexually mature parental W. pigra(2nd instar)with clitellum were cultivated in culture tanks with soil water content of 30%,40%,50%,60%,70%,and straw substrate moisture of 40%,and then survival rate of larval W. pigra,cocoon number,cocoon size,cocoon hatching rate and hatching number were observed during the experiment.[Result]The 30-day artificial breeding experiment showed significant differences in survival rate of parental W. pigra,cocoon number and cocoon rate among different soil water contents(P<0.05,the same below)but no significant difference in cocoon size(P>0.05,the same below). The maximum survival rates of parental W. pigra cocoon number and cocoon rate occurred when the soil water content was 60%,while the minimum occurred when the soil water content was 30%. According to fitted re-gression equation,cocoon hatching rate reached the maximum(95.56%)under 58.80%soil water content,and the maxi-mum hatching number was 27.59 ind under 57.61%soil water content. Survival rate of larval W. pigra,cocoon number and cocoon rate under straw substrate moisture of 40%were significantly lower than those under the same soil substrate moisture. There were no significant differences in hatching rate and hatching number of W. pigra under the two substrats. The hatching rates were both higher than 90.00%and hatching numbers were 20.67-22.00 ind.[Conclusion]Soil water content has significant influence on the reproductive performance of W. pigra and cocoon hatching effect,but has no sig-nificant influence on cocoon size. The experiment indicates that the optimal soil water content should be maintained at 60%.