Studies On Community Succession Of Necrophagous Insects In Soils Of Chaoyang

Necrophagous insects play an important role in the detection of criminal homicide cases,especially the inference of the most-mortem interval.Buried is the most common way for criminal suspects to deal with corpses.Due to burial,it is difficult to infer the postmortem interval of the corpse,but still has insect colonization,it is possible to use the necrophagous insects to infer the post-burial interval(PBI).In this study,fresh pork was used as bait buried in the soil of 30 cm and 60 cm depth in Chaoyang.It was taken out at 7d,15 d,30d,60 d,90d and 180 d after burial,and needs to record the local environment temperature and the soil temperature of different depths,collecting necrophagous insects on the decayed meat and nearby soil.Identifying the species of the necrophagous insects by means of morphological and molecular biological methods provides the reference material for inferring the postmortem interval by using the necrophagous insects.The main results:1.The temperature change of the environment,30 cm and 60 cm underground is the same in general,the temperature rises from April to August,and decreases from September to October;the fluctuation of the environment temperature is large,under the ground is small;In April,May and September,the sequence of the environment from high to low is: the environment temperature,60 cm underground temperature,30 cm underground temperature;In June,July and August,the sequence of the environment from high to low is: environment temperature,30 cm underground temperature,60 cm underground temperature;in October,the sequence of the environment from high to low is: 60 cm underground temperature,environment temperature,30 cm underground soil temperature.2.In this study,the buried pork experienced four stages: fresh period,decay period,dry period and residual period;the decay speed of the meat in 30 cm underground soil is faster than 60cm;the decay speed in summer is the fastest among the same depth of buried meat;In four stages,the decay period is the longest,and the fresh period was the shortest;the consumption and consumption rate of 30 cm underground in the same buried day were greater than 60 cm underground;After 60 d of burial,the consumption of pork in 30 cm and 60 cm underground is very small..3.Usually,after the pork is buried,the Formicinae Lasius flavus and the Phoridae Metopina saggittata first reach the meat,followed by the Staphylinidae and the Scarabaeoidea insects;the M.saggittata appears more from June to September,Peak number reached from late July to early August.It is the main dominant species,according to its law of occurrence combined with meat corruption,PBI can be inferred.The species in the 30 cm underground soil is more abundant than the 60 cm,the species are the most abundant in summer,autumn is the second,and spring is the least.4.The main necrophagous insects are identified and described by means of morphological character and the COI sequence,which facilitates the rapid identification of necrophagous insect species.