Development of Megaselia spiracularis (Diptera: Phoridae) at different constant temperatures

Megaselia spiracularis Schmitz, 1938 (Diptera: Phoridae) is a pest that often appears in human living areas where it can spread pathogens. Besides, the species is of forensic value. Currently, studies focusing on the development of this species are limited. Understanding the developmental patterns of M. spiracularis, therefore, is important for controlling populations of this pest and for estimating the minimum postmortem interval (PMImin). Here, we studied the development of M. spiracularis exposed to seven constant temperatures ranging from 16 to 34 degrees C. The developmental durations, accumulated degree hours and larval body length changes were measured. Three kinds of development models that can be used to estimate the PMImin were established, including isomorphen diagram, isomegalen diagram and thermal summation model. The duration of M. spiracularis development at 16, 19, 22, 25, 28, 31 and 34 degrees C from egg to adult stage were 1131.1 +/- 34.5, 807.3 +/- 9.3, 529.6 +/- 1.8, 367.0 +/- 8.8, 302.4 +/- 7.0, 250.0 +/- 2.1 and 232.6 +/- 1.9 h, respectively. The developmental threshold temperature and the thermal summation constant were estimated as 12.0 +/- 0.5 degrees C and 4989.7 +/- 308.9 degrees hours, respectively. A general model represented by a logistic equation describing how larval body length will change with the time after hatching was fit to data. The present study provides basic developmental data of M. spiracularis, which can be used for achieving better control of this noxious insect as well as for estimation of its PMImin at different temperatures.