Understanding correlation of reproduction with weight,age and stress in Hirudinaria manillensis is useful for artificial breeding.Hirudinaria manillensis used in this study weighed 5~<10 g,10~<15 g,15~20 g,aged 8 mon,2,3,4 yr,and were subjected to stress at frequencies of 1,2,3.It was found that Hirudinaria manillensis weighed at 10~<15 g or aged 2~3 yr had optimal reproductive ability.The number of cocoon,hatching rates,mean hatching numbers showed significant difference under different weight or age condi...