RESUMEN
The postburial interval (PBI) can be inferred by using necrophagous insects colonizing the buried corpse. In different seasons, the species composition and succession of necrophagous insects on swine carrion (0.5-0.75 kg) buried at the depths of 30 cm and 60 cm in a Populus alba var. pyramidalis (Bunge, 1854) (Salicales: Salicaceae) grove of Shenyang, China from 2017 to 2019 were investigated. A total of 21 species of necrophagous insects belonging to 5 orders, 17 families were collected. Among them, the species of Phoridae and Platystomatidae were dominant at burial depth of 30 cm and 60 cm in summer and autumn. The species composition and time of colonization of necrophagous insects on the buried baits varied with seasons. Platystoma mandschuricum (Enderlein, 1937) (Diptera: Platystomatidae) and Aleochara puberula (Klug, 1833) (Coleoptera: Staphylinidae), the first arriving insects in spring, occurred on the baits for the longest time, from early June to early December. This work could provide reference data for the PBI estimation in Shenyang and similar geographical areas.
Asunto(s)
Escarabajos , Dípteros , Enfermedades de los Porcinos , Animales , Cadáver , China , Conducta Alimentaria , Insectos , Cambios Post Mortem , Estaciones del Año , PorcinosRESUMEN
Piophilidae are a relatively small family of Diptera that is frequently associated with cadavers at advanced stages of decomposition and are, therefore, considered potentially useful forensic indicators. However, their use in forensic investigations is typically hampered by a deficiency in reliable identification tools. This is particularly evident in countries such as South Korea, where forensic entomology is still in its infancy and the diversity of forensically relevant insect taxa remains largely undocumented. In the present study, we used cytochrome c oxidase subunit I (COI) barcodes to identify samples of piophilid larvae collected during medicolegal investigations performed in South Korea. A total of 174 COI sequences were obtained and have been made publicly available, thus augmenting the reference barcode library for forensically important Piophilidae species. Of the 174 sequenced samples, 172 were identified as Stearibia nigriceps (Meigen), whereas the two remaining samples may represent a previously unsequenced piophilid species. Stearibia nigriceps is recorded from South Korea for the first time, and our results suggest that it might be a particularly relevant forensic indicator in certain case types and scenarios in that country. The findings of this study highlight the utility of COI barcodes for achieving accurate identification of entomological samples, even by non-specialist forensic practitioners. They also contribute to the further development and consolidation of forensic entomology in South Korea and eastern Asia.
Asunto(s)
Código de Barras del ADN Taxonómico , Dípteros/genética , Complejo IV de Transporte de Electrones , Entomología Forense , Animales , Conducta Alimentaria , Humanos , Larva , Filogenia , Cambios Post Mortem , República de Corea , Análisis de Secuencia de ADNRESUMEN
The attraction of necrophagous insects, particularly blow flies, to corpses and carrion is of ecological, economic, and agricultural importance, although the mechanisms by which it occurs are not well understood. Much of the published research on blow fly attractants has focused on volatiles emitted from carrion surrogates, but little attention has been given to the possibility that blow fly eggs themselves may emit chemical cues that are responsible for conspecific and heterospecific insect attraction. In this study, the headspace volatiles emitted from eggs representing two aggregated oviposition events that were collected 1 mo apart from two species of the Calliphoridae family (Order: Diptera), Lucilia sericata (Meigen), and Phormia regina (Meigen) were analyzed via solid-phase microextraction-facilitated GC-MS. The volatiles' profiles were found to be consistent between samples representing the same species, but unique between the two species. Over 100 molecules covering a wide range of compound classes that included alcohols, aldehydes, esters, amines, ketones, and organosulfur compounds were identified. The profile of volatiles emitted from the L. sericata eggs contained several alkanes and aldehydes, whereas salient features of the P. regina headspace included numerous esters and ketones. Between the two species, 42 compounds were shared, several of which were carboxylic acids. Little overlap between the range of compounds detected and those reported to be emitted from decomposing remains was observed.
Asunto(s)
Calliphoridae/química , Óvulo/química , Compuestos Orgánicos Volátiles/análisis , Animales , Femenino , Cromatografía de Gases y Espectrometría de Masas , Masculino , Compuestos Orgánicos Volátiles/químicaRESUMEN
Each biome has its own fauna and intrinsic local conditions that determine the succession patterns of insects on carcasses. For this reason, regional studies are very important to forensics. This study deals with the flies that visit carcasses of Rattus rattus (L., 1758) in the Atlantic Forest remnant of Floresta da Tijuca, Rio de Janeiro, Brazil. We compare the diversity and relative abundance of fly families and species throughout the four seasons of the year and test for correlations between certain environmental variables and fly richness. In each of the four seasons, we exposed the carcasses of three rats. The carcasses were put in traps that were installed on the ground, separated by 100 m. The flies were collected from the carcasses on a daily basis, and were taken to the laboratory and kept in a climate chamber (28 °C day and 26 °C night). A total of 5,537 flies were captured, identified into 12 families: Calliphoridae (4,884 specimens), followed by Sarcophagidae, Micropezidae, Fannidae, Muscidae, Phoridae, and Neridae. Canonical correspondence and redundancy analyses of the environmental variables indicated no relationship between the seasons and fly abundance. Carcass decomposition lasted longer in the winter (12 d) than in the summer (8 d). The Margalef richness index indicated higher richness in the spring and winter, and lower richness in the summer. The Shannon-Wiener index and Simpson dominance indicated greater diversity in the spring. Diptera colonized all stages of decomposition. The families Calliphoridae and Sarcophagidae were more prevalent during the Fermentation stage. Our data have important implications for forensic entomology.
Asunto(s)
Dípteros , Ciencias Forenses , Animales , Biodiversidad , Cadáver , Ratas , Estaciones del AñoRESUMEN
The estimation of postmortem interval (PMI) is affected by several factors including the cause of death, the place where the body lay after death, and the weather conditions during decomposition. Given the climatic differences among biogeographic locations, the understanding of necrophagous insect species biology and ecology is required when estimating PMI. The current experimental model was developed in Romania during the warm season in an outdoor location. The aim of the study was to identify the necrophagous insect species diversity and dynamics, and to detect the bacterial species present during decomposition in order to determine if their presence or incidence timing could be useful to estimate PMI. The decomposition process of domestic swine carcasses was monitored throughout a 14-wk period (10 July-10 October 2013), along with a daily record of meteorological parameters. The chronological succession of necrophagous entomofauna comprised nine Diptera species, with the dominant presence of Chrysomya albiceps (Wiedemann 1819) (Calliphoridae), while only two Coleoptera species were identified, Dermestes undulatus (L. 1758) and Creophilus maxillosus Brahm 1970. The bacterial diversity and dynamics from the mouth and rectum tissues, and third-instar dipteran larvae were identified using denaturing gradient gel electrophoresis analysis and sequencing of bacterial 16S rRNA gene fragments. Throughout the decomposition process, two main bacterial chronological groups were differentiated, represented by Firmicutes and Gammaproteobacteria. Twenty-six taxa from the rectal cavity and 22 from the mouth cavity were identified, with the dominant phylum in both these cavities corresponding to Firmicutes. The present data strengthen the postmortem entomological and microbial information for the warm season in this temperate-continental area, as well as the role of microbes in carcass decomposition.