Effect of Terbufos (Organophosphate) on the Cadaveric Colonization Process: Implications for Postmortem Interval Calculation.

The determination of necrophagous fly specie's development time is considered an accurate method for estimating postmortem interval (PMI). However, pesticides and other chemicals can alter the flies' life cycle, inducing errors in PMI estimation. Thus, this work aimed to evaluate the effect of different doses of Terbufos (Organophosphates) on the temporal dispersion pattern and development of immature dipterans associated with decaying rat carcasses. For this, 150 g female Wistar rats received, via gavage, 200 µl of Terbufos (5 or 10 mg/kg) or distilled water (control) and, after 30 min of administration, the animals were euthanized and distributed in suspended traps to decompose under environmental conditions. The dispersing immatures were collected daily, and their development time was monitored until the emergence of adult flies. After data analysis, it was observed that Terbufos altered 1) the temporal pattern of larval dispersion; 2) the composition and structure of the colonizing assemblage (emerged adults); 3) species' development time, accelerating or delaying their cycle, depending on the dose used; and 4) the califorids and sarcophagids emergence rate, increasing the mortality of pupae from intoxicated carcasses. Thus, this work demonstrates experimentally that Terbufos directly influences the development of flies with forensic potential and discusses the implications for PMI estimation, which can assist in future investigative processes with suspected poisoning by this organophosphate.

Insects Associated to Crime Scenes in the Northeast of Brazil: Consolidation of Collaboration Between Entomologists and Criminal Investigation Institutes.

In Brazil, many studies on Forensic Entomology analyze the activity and succession of flies in animal models. Data on human corpses are always collected and evaluated in isolated cases. This study aimed to list the insect species associated with crime scenes investigated by the Technical-Scientific Institute of criminal expertise of the State of Rio Grande do Norte (ITEP-RN), in the Northeast of Brazil, a region exposed to high homicide rates. In total, 10 cases were investigated, of which 50% were in the initial stage of decomposition. The examined bodies were colonized by species of three orders of insects, Diptera, Coleoptera and Hymenoptera. The order Diptera represented 96% of the total insects, being represented by the following species: Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae), Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae), Chrysomya putoria (Wiedemann) (Diptera: Calliphoridae), and Cochliomyia macellaria, (Fabricius) (Diptera: Calliphoridae); Musca domestica (Linnaeus) (Diptera: Muscidae); and unidentified females of the Sarcophagidae family. Among beetles, the occurrence of Dermestes maculatus (DeGeer) (Coleoptera: Dermestidae), Necrobia rufipes (De Geer) (Coleoptera: Cleridae), and Onthophagus sp. (Scarabaeidae), as well as unidentified specimens of the families Tenebrionidae and Histeridae were recorded. In addition, specimens of Ectatomma sp. (Formicidae) were also recorded. Considering that the Rio Grande do Norte state presents a high homicide rate and the last cadaver study was conducted over a decade ago, these records update the list of species associated with cadaveric decomposition and contribute to consolidate forensic entomology in the Northeast region.