Abstract: Rabbits were injected with morphine hydrochloride. After the rabbits were killed, their different tissues were used to feed the newly-hatched larvae of Chrysomya megacephala. The effect of morphine of different doses on the growth of larvae and its implication for the estimation of postmortem interval (PMI) were studied. The deviation of PMI estimation based on larvae growth was calculated. The results showed that at 28℃, starting at 28 h during the growth-circle the lengths and weights of larvae that fed on the muscles and livers of the rabbits injected with morphine hydrochloride were larger than those from the control in different extents and this trend continued into the late phase of larvae growth-circle. Within the range of morphine doses designed for this experiment (2.67-10.66 mg/kg), morphine could accelerate the growth of larvae. Morphine could result in a maximum PMI deviation of 18 hours when the growth rates of the larvae was used to judge PMI.

Key words: Chrysomya megacephala, morphine hydrochloride, forensic entomology, postmortem interval