Introduction

Many of us are aware of the fact that role of terrestrial and aquatic insects has given a significant contribution to Ecological prospects. But what about the Forensic aspect do they have any significant purpose in terms of Investigation? The answer to this question is “Yes”. The dynamics of terrestrial and aquatic insect species seek to understand how majorly these two species help in contributing to the Forensic Investigation purpose. This article will explore some of the aspects of terrestrial and aquatic insects that are interesting because they suggest different processes predominate in the two ecosystems as well as in Forensic Investigation. The interesting part of studying the aspects of terrestrial and aquatic insects in Forensic investigation is “to exhibit the exponential growth from early roots in limnology and sport fishery types of inquiry almost five decades ago” (Merritt et al.2008a). In a court of law, terrestrial and aquatic insects i.e. in forensic investigating aspects is the core application is used to identify the violent crime such as murder, suicide, rape, as well as physical abuse. 

According to Wayne Lord (1990), the human corpses whether they have been produced naturally or as the result of foul play they are later on being processed by insect decomposers in the same manner as any other carrion. Despite this increase in interest, over 80% of the terrestrial organism are in the actual effect or existence in a specified place or at a specified time whereas rest of the 20% of the pertaining aquatic organism has given a contribution in terms of forensic investigation or death investigation. With few of the exceptions speaking of the evolutionary phase, there is zero existence of the aquatic insects that have evolved somehow to function to feed on carrion alone. 

Role of Terrestrial Organism in Forensic Investigation

In general terms, terrestrial organisms are those who completely or say predominantly live on a land example like spiders, ants, etc. The forensic aspect in context with terrestrial organism has a significant impact as the application of Zoological principle in terms of Forensic Entomology helps to identify or tells the estimated time of the post mortem interval i.e. the time that has elapsed since the death of a living being is vital in probing the death of humans and animals. Scientifically, the post mortem interval can be defined as the estimated scientific evaluation of an insect that is present on the body of the victim during the scene of the crime. It also requires a thorough examination of the environment of which in which the corpse is found to study the succession patterns of the insects. As the role of a terrestrial organism is very much useful for conducting the investigation in legal as well as in criminal cases also. 

The evolution of Forensic Entomologist an Italian physician named Francesco Redi proposed a theory of Spontaneous Generation in 1668 which states that Maggots developed spontaneously from a rotting piece of meat. However, through a series of experiments Redi was able to prove that when meat was fully or partially exposed to air that it developed fly maggots. In Forensic Entomology, the discovery that Maggots didn’t develop on rotting meat that was not exposed to air brought a major revolution. Further study on insect life cycles and forensic entomology as a whole was spurred on. 

Here are some of the list of Flies & Beetles which are helpful in Forensic Investigation purpose. 

• House Flies – The most common type of flies and is found everywhere, during the initial phase of death this type of flies are supposed to be found on the victim’s body.  
• Flesh Flies – These types of flies are mostly found on those sorts of dead bodies that are supposed to get decay. Most they breed on a decayed corpse, cow dung, garbage, etc. An interesting fact about these fly is they lay their eggs in exposed wounds of mammals. Because of the viviparous fresh flies gives birth on the decaying humans and animals corpse. 
• Cheese Flies – These flies are mostly found in animal products and fungi. Most of their Larvae infest smoked fish, cured meat, cheese, and decayed beasts. For determining the time of death of humans, the existence of cheese fly larvae is very important. 

On the other hand, some of the beetles have their significant role in forensic investigation, as they mostly manifest in a corpse in the later stages of decomposition compared to flies. In dry conditions, beetles are replaced by moth flies. 

Following are the list of the Beetles which are used in Forensic Investigation purpose.

• Scarab Beetles – They are generally found on or under carrion and corpses. They feed on fungi, dung, or decaying flesh and act as a clean-up crew for various other purposes as well. 
• Hide Beetles – They mainly form the cluster around the resources feed on dry animals’ products such as dried fish, dog treats, or bacon and sometimes in humans as well. 
• Dung Beetles – The larvae feed on the decaying fungi and any other vertebrate carcasses during the process of decomposition. Here no matter what stage the process of Decomposition is taking place, the moment they saw the resource the process of decomposition gets initiated. 

Role of Aquatic Insects in Forensic Investigation

Stating with the general facts, Aquatic Insects are those who spend some part of their life cycle closely associated with water, either living beneath the surface or skimming along on the top of the water. The immature stage is truly aquatic while the adult one is the winged terrestrial form (Subhashini et al. 2008). Co-relation of Aquatic insects with Forensic Investigation portrays its importance and highlights how useful this evidence could be in the legal prospects of a particular case. Although post mortem interval or time since death includes various methods to estimate post-mortem intervals like algor mortis, livor mortis, rigor mortis, and chemical and enzymatic changes. Aquatic insects, however also play an important role in estimating the period after death which is a key concern in the forensic investigation area. 

The importance of aquatic insects in terms of Forensic Investigation can be very much useful in Drowning cases like death due to submersion which is substantial which is most probably accidental. Aquatic insects like Anax Parthenope, Lestes Sponsa, Scarlet Skimmer, etc. are a few which are very much useful in a death investigation. The investigation of submerged bodies in context with aquatic insects usually requires a coordinated effort and the expertise of multiple agencies especially dealing with natural water bodies. As per medicolegal death scene researchers, forensic pathologists, and other professionals with varying forensic scientific experience would be required by death scene involving submerged bodies. The extent of their involvement will be dictated by the death circumstances. A complete review of submersion deaths must include the aspects of drowning cases, which varies depending on the source, ranging from the broadest of description to the use of more concise medical terminology, mostly with an asphyxia basis. 

Conclusion 

Therefore, both the criteria of species are very much useful in terms of the forensic investigative approach. Several cases also have been solved with the help of terrestrial and aquatic insects. But countries like India still they did not get that much kind exposure as a forensic scientist in India are completely relying on the physical shreds of evidence which is found at the scene of the crime. But most of us are not aware that the existence of both species on the body of the victim is also the form of pieces of evidence that is to be examined and is not be neglected. As per my own opinion, the existence of terrestrial and aquatic insects is also considered to be one of the important physical evidence in the forensic investigation approach. 

References

1. Díaz, M., & Rossini, C. (2012). Bioactive natural products from Sapindaceae deterrent and toxic metabolites against insects. Insecticides–Pest Engineering” (F. Perveen, ed.), InTech, Rijeka, Croatia, 287-308.
2. https://ifflab.org/forensic-entomology-using-insects-for-forensic-investigations/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474464/
4. https://www.researchgate.net/publication/324184498_Correlation_of_Insects_with_Forensic_Sciences
5. Lord, W. D., & Rodriguez, W. C. (1989). Forensic entomology: the use of insects in the investigation of homicide and untimely death. The Prosecutor. Winter, 41-48.
6. Merritt, R. W., & Wallace, J. R. (2001). The role of aquatic insects in forensic investigations. Forensic entomology: the utility of arthropods in legal investigations, 177-222.