Development of Forensically Important Megaselia scalaris and Dohrniphora cornuta (Diptera: Phoridae) in Sandy Loam Under Constant Moisture and Different Temperature Regimes

The Phoridae are relatively common insects on buried corpses, and their developmental information plays an important role in estimating post-burial interval (PBI) for buried corpses. Developmental time, larval body length, and intra-puparial developmental changes in two forensically important phorid flies, <i>Megaselia scalaris</i> (Loew, 1866) and <i>Dohrniphora cornuta</i> (Bigot, 1857) (Diptera: Phoridae), were studied in sandy loam with 20% moisture content at 18, 21, 24, and 27 °C. The juvenile development time of both species decreased with increasing temperature. At 18, 21, 24, and 27 °C, the larval development time of <i>M. scalaris</i> was 165.18 ± 2.96 h, 119.72 ± 2.74 h, 90.28 ± 3.54 h, and 63.04 ± 3.45 h, respectively, with corresponding intra-puparial development times of 606.67 ± 3.38 h, 404.62 ± 3.28 h, 269.22 ± 6.04 h, and 237.57 ± 3.41 h. For <i>D. cornuta</i>, the larval development time was 249.37 ± 4.88 h, 154.59 ± 1.81 h, 108.80 ± 2.65 h, and 86.04 ± 3.91 h, respectively, while the intra-puparial development time was 593.37 ± 4.75 h, 414.23 ± 3.51 h, 261.02 ± 3.16 h, and 236.52 ± 2.66 h. The larval body length of both species showed a cubic curve relationship with development time. Based on the morphological characteristics, the intra-puparial period of both species were divided into 12 substages. As the temperature increased, the time required for both species to reach each substage decreased significantly. The present study enriches the developmental information of the two Phoridae species and provides a reference basis for using these two phorid flies to estimate the post-burial interval (PBI) of corpses in China.