Introduction

Entomology springs from the Greek word Entomon (insect) and Logos (word, reason) meaning the study of insects. Forensic Entomology, is perhaps one of the oldest branches of Forensic Science, is the utilization of the insects and the relative species to arthropod that possess decomposing remains to assist legal investigations. Over the years Forensic Entomology has developed from being utilized just for discovering post-mortem interval for the season of death, the geological area of death, movement, or storage of remains after death. The involvement of Enomo-toxicology has additionally expanded and upgraded the function of entomology in forensic science. The term Entomotoxicology was first coined by Beyer and colleagues in the year 1980 and since then many entomologists have routinely started to detect drugs in insects found on the cadaver after a prolonged period (Pounder, 1991).

Entomotoxicology deals with the “examination of toxins” (poisons) in arthropods (mainly beetles and flies) that prey on carrion. Utilizing arthropods in a dead body or at a scene of the crime, forensic investigators can determine that at the time of death whether the poisons were present in a body or not. Therefore, the study of the helpfulness of insects as an alternative toxicological sample is known as Entomotoxicology (Dayananda and Kiran, 2013).

Entomotoxicology is a collaboration of fields of science, Zoology, and Chemistry that has been implemented as an alternative to toxicological samples. This method for drug detection in corpses is very well-reported and suggested when other biological matrices such as urine, blood, or integral organs have decomposed. One of the main applications of Forensic Science is to identify fatalities recovered after many weeks to months. Such cases arise if an individual has died in an isolated place because of substance abuse or has committed suicide. Insects prey on dead bodies that might have died because of a drug overdose and hence xenobiotics like drugs or any other toxic substances present within the tissue get introduced into the body of the larvae. The drugs then get distributed in their body and also pass onto other arthropods that predate on them (Chophi et al., 28-36).

The maggots may be used to determine the presence or absence of drugs when human body tissues are too badly decomposed to do toxicology on the tissue remains. Death because of abuse of drugs, insecticides, pesticides, and different poisons are normal everywhere in the world. It is reported that about 450,000 individuals died around the world because of drug abuse in 2015. About 275 million individuals aged (15–65 years) were accounted to possess abused drugs in any event once in the year 2016. It is estimated that on the brink of 800,000 individuals die per annum due to suicide, of which 20% (1,60,000) constitute death as a result of pesticide ingestion (Bachmann, 2018; www.who.int). These figures and numbers indicate that massive deaths occur because of drug abuse, and in several cases, dead bodies are recovered after many weeks to months (Carvalho et al., 2001; Goff et al., 1989).

Entomotoxicology would be an excellent tool, in solving the cases of poisoning when the dead bodies are recovered after a delayed period. The fact that the drug got introduced in the body of the insect only because of the human organism upon which the larvae was feeding is a crucial characteristic of this technique. Entomotoxicology also serves as a useful tool to identify the impacts brought about by toxic substances on arthropod development for PMI estimation. The flies lay their eggs on the corpses within a couple of days depending upon the conditions in there. The most found species and the first to show up are the Calliphora as wide geographic distribution is governed by them and are mostly found in urban areas. They are attracted by gases and body fluids and their developmental stages- egg, prepupal or pupal, larval stages, adulthood aid in the determination of time since death. Then as the body further decays, Sarcophagus, Anglossa, Piophilacasie, and other carrion feeders get attracted to the body. The materials of interest can be analyzed from the pupae, larvae, puparial cases, adult insects, cast beetle skins (exuviae), fly predators, beetle fecal material (frass), and scavengers. A study demonstrated that greater sensitivity is obtained by utilizing fly larvae rather than of putrefied material. Moreover, the drug concentration is more stable in the insects compared to that in tissues. Also, the main advantage is that insects are present in greater quantities and their remains are present for an extended time than the toxicological samples. Compounds such as pesticides, drugs, and metals are recognized in insects for forensic purposes. However, quantification of the drug and understanding its relationship to the cause of death observed from insects remains an issue unsolved due to a wide array of influencing factors (Kintz et al., 2001).