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Effect of Terbufos (Organophosphate) on the Cadaveric Colonization Process: Implications for Postmortem Interval
J T Jales1, T M Barbosa1, V P Soares2
1Laboratory of Insect and Vectors, Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Av. Sen. Salgado Filho, Lagoa Nova, Natal, RN, Brazil.
Abstract:
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.
Insights
Pesticide exposure, specifically Terbufos, significantly impacts the development of flies crucial for estimating the postmortem interval (PMI). This study reveals Terbufos alters fly life cycles, potentially leading to inaccurate PMI estimations in forensic investigations.
Area of Science:
- Forensic Entomology
- Toxicology
- Ecology
Background:
- Estimating the postmortem interval (PMI) often relies on the developmental stages of necrophagous flies.
- Pesticides and chemicals can interfere with insect development, compromising PMI accuracy.
- Organophosphate pesticides are widely used and can potentially enter the environment through various means.
Purpose of the Study:
- To investigate the impact of Terbufos, an organophosphate pesticide, on the development and dispersion patterns of immature dipterans on decaying carcasses.
- To assess how different doses of Terbufos affect the life cycle of forensically relevant fly species.
- To understand the implications of Terbufos exposure for postmortem interval (PMI) estimation in forensic science.
Main Methods:
- Wistar rats were administered varying doses of Terbufos (5 mg/kg or 10 mg/kg) or a control (distilled water).
- Carcasses were exposed to environmental conditions, and dispersing immatures were collected daily.
- Development time of collected immatures was monitored until adult fly emergence.
Main Results:
- Terbufos significantly altered the temporal dispersion patterns of fly larvae.
- The composition and structure of the adult fly assemblage (emerged flies) were affected by Terbufos exposure.
- Terbufos influenced species' development times, either accelerating or delaying their life cycles depending on the dose.
- Increased pupal mortality was observed in carcasses exposed to Terbufos, impacting the emergence rate of calliphorids and sarcophagids.
Conclusions:
- Terbufos directly affects the development of forensically important fly species.
- The findings highlight the potential for Terbufos contamination to introduce errors in postmortem interval (PMI) estimations.
- This research provides experimental evidence crucial for forensic investigations involving suspected Terbufos poisoning.
