Dear Devidas Bhagat

You can find books and articles on your subject. I answer you so that it would be clear about the importance of this knowledge

tasks that are set:

• determination of the prescription of death or the time of finding a corpse at the place of its discovery;

• Clarification of the season when a corpse enters the place of its discovery;

• determination of the fact of movement of the corpse;

• establishing the place of the original location of the corpse or the place of hiding the corpse;

• determination of one or another degree of decomposition of a corpse in a specific place for a certain period of time;

• identification of toxins and drugs in insect larvae that caused human death (upon detection of skeletonized corpses);

• determination of the place of origin of narcotic raw materials.

A successful solution to the problem of determining the prescription of death is possible only when considering the corpse as a microecosystem that has elements of self-regulation of its development and the processes occurring in it.

The decomposition of tissues of unburied corpses is a complex process, consisting of the destruction of a corpse by birds and animals and the process of biological decomposition (microbes, molds, insects). Microorganisms and insects are involved in the decomposition of all corpses. The presence of molds and algae is noted after the end of feeding of fly larvae in 30% of cases. Moreover, on corpses that began to decompose in the spring, they are found in 55% of cases, in the summer - 35%, in the fall - are not found. This is due to the fact that the larvae of flies, which continue to develop until frost and the covering of corpses with an ice crust, secrete a substance that prevents the development of mold fungi. Damage to corpses by birds and animals occurs in 26% of cases in the 1st year of decomposition and another 20% of their remains in the 2nd year. In spring, 67% of corpses are damaged, in summer - 17%, in autumn - 26%.

Based on the prevailing and manifest activity of one or another group of necrobionts in a given period, the process of decomposition of corpses is divided into 5 stages: each stage corresponds to a certain degree of decomposition of corpse tissues.

Stage I - early microbial decomposition - follows autolytic processes and continues until the appearance of egg-laying flies and the birth of larvae from them. The average duration in May to September is 3 days (1-5 days).

Stage II - active decomposition of the corpse by insects - from the birth of the fly larvae, proceeds simultaneously with the ongoing microbial decomposition and ends with the end of the development of the larvae, which destroy the bulk of the soft tissues of the corpse. The average duration from May to September is 22 days (8-65 days).

Stage III - late decomposition of the corpse by insects - begins with pupation of fly larvae and is carried out mainly by beetle larvae, which destroy almost all remaining soft tissues. Microbial decomposition continues and the activity of molds is added to it. The average duration is 504 days.

Stage IV - microbiological decomposition of the corpse - begins from the moment the beetle larvae leave the remains of the corpse and ends with the disintegration of the skeleton into separate bones. The duration of the stage ranges from 27 to 976 days.

Stage V - decay of bone tissue - was not completed within 4 years of observation.

The duration of individual stages of biological decomposition is significantly influenced by meteorological factors. The inverse dependence of the duration of 4 stages on the total radiation, air and soil surface temperature was established: the 1st, 3rd and 4th stages - on the duration of sunshine, and the 1st stage - also on the amount of precipitation. The direct dependence of the duration of the 1st, 3rd and 4th stages and the 3rd and 4th stages, respectively, on the number of days with precipitation and on the relative humidity is determined. The absence of a pronounced effect on the duration of the 2nd stage of the relative air humidity, the number of days with precipitation and the amount of precipitation was noted. This is due to the ability of fly larvae to maintain the humidity of the habitat at a certain level due to extraintestinal digestion.

The average duration of skeletonization of a corpse ranges from 205 to 823 days (54-1074 days), depending on the month of the beginning of the decomposition process.

So, for example, at death in May-June, complete skeletonization occurs within 1 year only in 65% of cases. The duration of decomposition of corpse tissues in different seasons of the year and in different biotopes is determined by the nature of the radiation regime. In spring and autumn, decomposition occurs faster on slopes oriented perpendicular to the sun's rays, and slower on horizontal terrain. Corpses on higher elevations decompose more slowly than corpses on the soil surface, which is due to their increased heat transfer and mummification of the surface layers of tissues.

The presence of clothing on the corpse does not delay the appearance of insects, but somewhat lengthens the time of its decomposition. Contamination of clothing with fuels and varnishes and paints and varnishes approximately doubles the time until insects appear on the corpse and in 42% of cases causes a significant delay in decomposition.

The main link in the biological decomposition of a corpse is necrobional insects.

On the basis of toxonomic and entomological characteristics, the entomofauna of a corpse is divided into two groups:

1. Actually entomofauna of the corpse. It consists of necrobiont insects, for which the corpse is a habitat and development; they are subdivided by trophic specialization into necrophages and entomophages;

2. The random entomofauna of the corpse. It consists of species for which the corpse is not a place of constant habitation and development; this group is subdivided into polyphages, entomophages and necroentomophages.

The leading place in the corpse entomofauna itself is occupied by representatives of the order Diptera - Diptera, then the order Coleoptera.

The process of the formation of the fauna of a corpse in a human dwelling has its own specifics: 1) a stable microclimate with year-round insect activity; 2) the possibility or not the possibility of access of insects - necrophages to the room with a corpse, as well as the presence of a formed complex of obligate synanthropic insect species capable of year-round development; 3) the species composition of the complex changes depending on the introduction of new species of insects with food products, or the implementation of disinsection measures.

The process of researching the fauna and flora of a corpse in forensic science is divided into 5 stages:

Stage I - preparatory - they prepare the laying before leaving to the place where the corpse was found. Creation of reference collections of the fauna of the corpse of the area.

Stage II - the work of an investigator, a forensic expert and an expert entomologist. Inspection and research of the place of discovery of the corpse, collection of material and samples for research. Already during the first few hours in the summer, a significant number of flies and their larvae are observed around natural openings (mouth, nose, eyes). Particular attention should be paid to the collection of individuals in different phases of development of flies, as the earliest, most numerous and well-studied component of the entomofauna. Be sure to collect young flies in the amount of 30-50 individuals; they differ from adults in solid and undeveloped wings, whitish coloration and temporary absence of flight; they are placed in test tubes indicating the place and time (hour) of capture; they must be in a dead state.

Ovipositions of flies are transported in 200 ml jars on a piece of meat weighing up to 50 g, placed on moist (slightly) soil (sawdust).

Fly larvae are taken from different parts of the corpse and its bed; from each site of the fence at least 30-50 individuals. Each sample is placed in a separate jar, larvae and ovipositions - live.

False cocoons (puparia, in which a real pupa of a fly) is taken from different parts of the corpse, its bed and the soil under it in the amount of 75-100 pieces. in each sample (reddish-brown, dark-brown or black), transported in cans on sawdust.

If there are no pupariums on the corpse, then they should be looked for in the soil at a depth of 30 cm, and indoors - in items of clothing, furniture, floor crevices. It is important to note the ratio of different phases of development of flies on a corpse, because this can determine the rate at which the corpse is populated by flies. One species of flies, as a rule, populate corpses once.

Stage IV is carried out by the investigator. Investigators-biologists are charged with determining the species composition of the corpse's fauna and preparing information about the biology of each species. In the closest to the scene of the incident, the meteorological station receives a detailed weather report, which must contain information about the values ​​of the average daily, maximum and minimum temperature, data on precipitation, sunny days, air movement.

Stage V - the calculation of the possible duration of the development of insects on the corpse may not coincide with the time of death, and the place where the corpse is found does not always turn out to be the place of its occurrence.

The 1st method of calculation - knowing the duration of the development of a species at a constant temperature and the average temperature for the studied period of time, it is possible to determine the possibility or impossibility of the beginning of the development of insects on a corpse at a given time. When calculating the average temperature, the temperature during the development of insects in the laboratory before the emergence of adults is taken into account.

2nd method of calculation.

The lower threshold of development is the extreme lower value of the temperature of the external environment, above which progressive development is possible in the form of insects specific to each species.

Effective temperature - the value of temperature that directly causes forward development is equal to the difference between the temperature of the external environment and the value of the lower threshold for the development of a given species.

The constant heat of the species - the sum of the effective temperatures required for the development of the species from the egg to the emergence of the imago, is species-specific.

The sum of effective temperatures required for development from egg to puparium is constant for each species.

The developmental index is the part of development completed by a species per unit of time (hour, day) at a given temperature. In this case, the duration of development from egg to imago is taken as a unit.

The essence of the technique is that the preimaginal stages of insect development found on the corpse are brought up in the laboratory before the adults emerge. Having determined experimentally the part of the development passed by the species in the laboratory, the part of the development passed on the corpse before removal is established.

On the basis of the temperatures observed in nature in the days preceding the moment of the discovery of the corpse, even the settlement of the corpse by this species is determined by simple calculations.

The species found on the corpse (especially the stages of their development) on the basis of phenological data will make it possible to determine the season and time of their settling in the corpse. The presence of tissue damage by rodents characteristic of a certain season is of similar importance.

The discrepancy between the fauna of the corpse and the fauna of the place of its discovery (especially the presence of obligate synanthropes in the open nature) indicates the previous movement of the corpse. This may be indicated by the complete absence of fauna or its insignificant development when a corpse is found in a place where normal settlement of the corpse by representatives of the fauna could occur.

The stability of the chitinous cover of insects to the effects of the external environment, the withdrawal of the larvae of most species of the corpse fauna into the soil to complete development, the accumulation of detriophages in the soil in the place of its impregnation with decomposition products, the state of the vegetation of the corpse bed - all this can confirm the accuracy of determining the place of the original location of the corpse.

Regards, Sergey Viktorovich Pushkin

my small article on the topic Article The Use of Model Groups of Necrobiont Beetles (Coleoptera) f...

Regards, Sergey Viktorovich Pushkin

That is agood question

Palynology can be used

Forensic sciences study is a very important study for criminal investigation. There are reports on toxic plants having forensic significance. Plant residue such as pollen grains is one of the important resources in forensic investigations as pollen can get attached to the body or cloth of the criminal. By doing forensic analysis with the help of DNA based tools, dogs have been trained so as to use their strong sense of smell for sniffing drugs, missing persons or criminals.