Temperature dependent development of black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae) from Yangtze River Delta region of China

The black soldier fly, Hermetia illucens (L.) (Diptera: Stratiomyidae), isomnivorous andwidely distributed in the world. Black soldier flies usually colonize corpse at a relatively late stage and have a longer developmental time compared to other flies. It can serve as a good supplementary indicator for estimating a longer minimum postmortem interval (PMImin) in forensic investigations. In this paper, the development of H. illucens was investigated at six constant temperatures between 19 and 34 degrees C. Under temperatures of 19, 22, 25, 28, 31, and 34 degrees C, the mean developmental time from eggs to adults was 90.96, 58.29, 54.61, 42.33, 32.33 and 34.52 days, respectively. Developmental time and accumulated degree days results were used to construct thermal sum-mation model and isomorphen diagram. The calculated values of lower developmental thresholds and thermal summation constant estimated by a linear model were 11.88 degrees C and 650.89 degree days, respectively. Through a nonlinear model, the upper lethal developmental threshold temperature, intrinsic optimum temperature and lower developmental thresholds were estimated to be 35.18, 20.50 and 13.17 degrees C, respectively. A growth curve, an equation and isomegalen diagram based on them show the relationship between developmental time and larval body length. The larval body length increased with increased developmental time and eventually plateaued, revealing an S-shape growth curve. These results provide important basic developmental data for H. illucens, which can be used to estimate the PMImin.