Effect Of Diazepam On The Growth And Development Of Lucilia Sericata(Diptera: Calliphoridae) And Its Forensic Importance

Objective: To know Effect of diazepam on the growth and development of Lucilia sericata (Diptera:Calliphoridae) and accumulate the development biological datum on necrophagous fly in Shijiazhuang area. It was the research that was done to provide the data on deducing the PMI(Postmortem interval) by development of necrophagous fly. Method: Adult Lucilia sericata were captured from the outdoors and gotten back to the lab. And then it was bred until the third generation,which was used to carry on development research as maternal generation. Four rabbits that one was the control group and the others were experimental groups were used in this experiment. The rabbits in the experimental group,whose weight was 2.6 ㎏,2.65 ㎏,2.65 ㎏individually, were injected with diazepam that injected dosage was 26mg,39.7mg,53mg in turn by auricula vein. All rabbits were killed after 30 minutes by thrashing foramen occipital magnum. Then all livers and muscles which were marked as L0,L1,L2,L3,M0,M1,M2,M3 in accordance with concentration sequentially and stocked in the 4℃refrigeratory to use were taken out as experiment material. Pork was put in to make Lucilia sericata spawn in 28℃constant temperature. When the eggs were found, which was looked as 0 point, they were taken out and put the livers or muscles on. The specimens that we got 12 larvae from each group in every 12 hours interval as specimens, who were put into the 70% alcohol to stock to use in next steps, were taken until eclosion of all flies. After the maggot fall into the 80℃water in free state to kill by hot water, it had been stocked in 70% alcohol until it was used. When we got all specimens, the samples were taken out from 70% alcohol and liquid of surface was blot up by the filter paper. Firstly, length and weight were measured. Then innards of them were digest by potassium hydroxide. They were dehydrated in 30%,50%,70%,80%,90%,95%,100% alcohol. After that, they were marinated in the alcohol and dimethylbenzene mixer about half an hour and maken transparent by dimethylbenzene. They were enveloped in Canada balata and airing. The length of cephalopharyngeal skeleton was measured. Experiment was repeated three times. All specimen are were recorded with the form of mean±standard deviation. Development curve are protracted in weight, length. Then curve are protracted in weight, length. We compared the development rate of larvae in different group to see whether there was any difference in the development of Lucilia sericata and diazepam could effect development rate of Lucilia sericata in analysis of variance when made statistical analysis. Result: There was no significant difference among eachrepeated experiment result. The time of hatch was defined as 0 time. At hour 12,eggs from each group hatched almost at the same time. Of the muscle groups, significant differences in mean lengths and weights were seen from 36 hour to 96 hour. In length or weight, M3 was the biggest among the muscle groups and L3 was the biggest among the liver groups. The results were M3>M2>M1>M0 and L3>L2 > L1 > L0. The result of meteraging length of cephalopharyngeal skeleton was that the biggest slope of M0, M1 and M2 was in 36h～48h and the biggest slope of M3 was in 24h～36h. There was significant difference among the groups reared on liver. And the groups reared on liver were bigger than the groups reared on muscle in length and weight. The result of meteraging length of cephalopharyngeal skeleton was that the biggest slope of L0 was in 36h～48h and the biggest slope of L3,L2 and L1 was in 24h～36h. The difference between L3 and L0 was 48 hours in pupae period. But diazepam has not any effect on the duration of the puparial stadium. we can get an equation on length developing by Logistic model(y=a/(1+b×exp(-cx))).And In this equation, the dosages had significant affection on a, b and c coefficience, which perhaps showed positive correlation. Diazepam cannot affect emergence. In emergence, there was no significant difference between group reared on liver and group reared on muscle.