Temperature-dependent development of Omosita colon at constant temperature and its implication for PMI_min estimation

Omosita colon (Linnaeus, 1758) (Coleoptera: Nitidulidae) is a species widely distributed in the Holarctic that usually appears during more advanced stages of decay. It is one of the species found on highly decomposed remains. Although O. colon may be a promising indicator of post-mortem interval (PMI) in cases with longer PMI, there is currently no existing research on its growth and development. Therefore, we studied the development of O. colon at seven constant temperatures between 16 and 34 °C and found that O. colon can complete its entire life cycle between 16 and 31 °C, but failed to complete development at 34 °C. At 16, 19, 22, 25, 28, and 31 °C, the developmental duration of O. colon from egg to adult is 95.3 ± 11.4, 62.4 ± 8.5, 45.9 ± 2.8, 34.9 ± 3.4, 30.0 ± 2.6, and 25.2 ± 2.6 d, respectively. Based on the results of development time and accumulated degree days, an isomorphen diagram was plotted and a thermal summation model was established. The mean (±SE) developmental threshold temperature D₀ and the thermal summation constant K calculated using the thermal summation model were 10.65 ± 0.16 °C and 514.1 ± 8.7° days, respectively. The results of this study provide fundamental developmental data for the use of O. colon in minimum post-mortem interval (PMI_min) estimations.