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

Abstract

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 °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 °C. This is the first comprehensive dataset on the development of N. littoralis. Implications for its use in forensic casework are discussed.

Initial laboratory validation of temperature development models for Necrodes littoralis L. (Staphylinidae: Silphinae)

“…Data for the validation were collected from May 2021 to January 2022 using the same protocol as the one used for the modelling purposes [ 25 ]. However, we used a smaller number of rearing temperatures and smaller numbers of pupae and adult beetles.…”

“…Both larvae and adult insects are frequently found on human cadavers [ 19 – 24 ]. The first comprehensive development dataset for the Central European population of N. littoralis was recently published [ 25 ]. The dataset contains different types of temperature models that probably differ in the accuracy of insect age estimation.…”

Season, decay stage, habitat, temperature and carrion beetles allow estimating the post‐mortem interval of wild boar carcasses

“…Furthermore, people involved in the search for wild boar carcasses are usually not trained in entomology and may therefore not be able to identify carrion insect species that can help in PMI estimates. However, there are a number of large and conspicuous species among carrion‐visiting silphid beetles (Coleoptera: Silphidae) that can support PMI estimation (Gruszka & Matuszewski, 2022; Von Hoermann et al., 2018).…”