Human costal cartilage, tooth cavities, and femur nutrient canals—new niches for insects used in forensic entomology

The study aimed to analyze the entomological material collected during 13 autopsies performed on the unidentified cadavers revealed at different stages of decay in the Upper Silesia Region (Poland) over 2016–2022. During the preparation of human tissues for genetic identification, we revealed larvae, puparia, and adult insects in previously undescribed locations: costal cartilage, femur nutrient canals (foramen nutrients), and tooth cavities. The taxonomical assessment was done using morphological examination or DNA barcoding, where necessary. Based on our observations, we conclude that the apical constriction, foramen, and cavities may serve as migration paths inside teeth, and the femur nutrient canals to the bone marrow. The study also revealed that the beetle Necrobia ruficollis (Fabricius, 1775) and the moth family Pyralidae Latreille, 1802 (Phycitinae) moths can form pupal chambers inside the costal cartilage, indicating that these insects can complete their life cycle inside this cache. We believe that the newly reported locations of carrion insects in human remains may be relevant to forensic entomology, as they provide new opportunities to collect insect evidence. Key points