Development Of Chrysomya Pinguis And Nasonia Vitripennis And Their Significances In Estimating PMI

Objective:Insect development is important for the estimate of PMImin.Chrysomya pinguis(Walker)(Diptera:Calliphoridae)is an endemic Asiatic blow fly species of forensic importance.Chrysomya pinguis is one of the first species to colonize a corpse,especially in high altitude areas during spring and autumn when the ambient temperature is lower.Despite its potential for forensic investigations to estimate the minimum postmortem interval(PMImin),little is known about the development of C.pinguis.Nasonia vitripennis(Walker)(Hymenoptera:Pteromalidae)is a common ectoparasitoid that attacks the puparia of fly species of forensic importance,including blow flies,flesh flies,and house flies.The developmental time of N.vitripennis can be added to the host development time,providing the potential for an extended minimum postmortem interval timeframe in cases where traditional dipteran larval forensic timeline indicators have completed their development.In this study,Chrysomya pinguis and Nasonia vitripennis were reared at seven constant temperatures between 16 to 34? to investigate the effect of temperature on development duration,accumulated degree hours and larval body length in order to provide fundamental development data for the use of Chrysomya pinguis and Nasonia vitripennis to estimate PMImin.Method:C.pinguis was collected from the Yangtze River Delta region of China and reared at seven constant temperatures between 16 to 34? to investigate the effect of temperature on development duration,accumulated degree hours and larval body length of C.pinguis.Isomorphen and isomegalen diagrams for C.pinguis were generated using the results,and equations describing the variation in larval body length during development and the temperature-induced variation in development time were also obtained.We used Boettcherisca peregrina Robineau-Desvoidy(Diptera:Sarcophagidae)as the host for N.vitripennis and studied the development of N.vitripennis at seven constant temperatures between 16-34?.The developmental process was divided into 12 periods,and we measured developmental time,changes in larval body length,and thermal requirements for development,including developmental thresholds and thermal constant.Using these data,we created an isomorphen diagram and thermal summation model of N.vitripennis.Result:Chrysomya pinguis can complete its life cycle at 16-34?.The mean(±SD)developmental durations of C.pinguis from egg to adult at 16,19,22,25,28,31 and 34?were 811.0 ± 3.8,544.8 ± 2.0,379.8±1.8,306.7± 2.4,250.0±2.8,203.2±2.1 and 185.3± 1.6 h,respectively.The mean(±SE)developmental threshold temperature D0 and the thermal summation constant K of the whole developmental process of C.pinguis were estimated as 10.88± 0.21? and 4256.50±104.50 degree hours,respectively.The total developmental duration of parasitoids from egg to adult emergence at 16,19,22,25,28 and 31? were 953.3±20.0,698.0±7.7,508.7 ± 13.6,354.7± 4.6,272.0 ±13.9 and 232.0 ± 11.3h,respectively.Nasonia did not emerge at 340C.The developmental threshold temperature of N.vitripennis was 11.52?,and the thermal summation constant was 4,768.8 degree hours.Conclusion:We studied larval growth,development duration,and thermal summation of Chrysomya pinguis and Nasonia vitripennis under seven constant temperatures between 16-34?.These data can be used to estimate the PMImin.