Temperature models of development for Necrodes littoralis L. (Coleoptera: Silphidae), a carrion beetle of forensic importance in the Palearctic region

Analysis of insects can provide evidence in death cases, for example, by answering the question about the time of death. Apart from flies, beetles are the second most useful insect group in forensic entomology. To elucidate the time of death based on insect evidence, developmental models of a given species are necessary. In this study, we developed such models for Necrodes littoralis, a necrophagous beetle, which is common in the Palearctic region and has great potential in forensic entomology. We monitored the development at 10 constant temperatures (14-30 degrees C). Larvae were reared in aggregations. Thermal summation models, isomorphen and isomegalen diagrams and growth curves were derived using the data. Depending on the temperature, development lasted between about 23 and 89 days. Mortality was high at the extremes of the temperature range. The thermal summation constant for the total development was 434.7 +/- 28.86 accumulated degree-days above a developmental threshold of 9.04 +/- 0.55 degrees C. This is the first comprehensive dataset on the development of N. littoralis. Implications for its use in forensic casework are discussed.

Automated summary

Insect analysis can provide evidence in death cases, such as determining the time of death. Beetles are the second most useful insect group in forensic entomology. In this study, developmental models for the Necrodes littoralis beetle were developed, which is common in the Palearctic region and has potential in forensic entomology. Depending on the temperature, development lasted between 23 and 89 days.