The appearance of a corpse in the environment is a biological signal for its destruction for numerous representatives of the animal world. The leading role among them belongs to insects representing the entomofauna corpse. Under conditions that provide them with maximum activity, the larvae of flies can completely skeletonize the corpse of an adult person in one month, and the corpse of a newborn in 1.5-2 weeks.
Already a few hours after death, flies lay eggs in the corners of the eyes, in the nasal cavity and mouth, in the folds of the skin, on the wet wound surface. By the end of the first day, white small larvae (puparia) are formed from the eggs, which immediately begin to destroy the soft tissues of the corpse. They secrete an active enzyme that melts soft tissues, which greatly accelerates the process of their destruction. During the first week, the larvae are thin, not more than 6-7 mm long. The second week begins their intensive growth: they reach 1.5 cm and thicken to 3-4 mm.
By the end of the second week, the larvae creep into dark places (under the corpse, under the clothes), lose mobility and pupate. Their yellowish-gray color gradually turns to dark brown. The surface of the pupa is covered with a dense membrane, within which an adult develops within two weeks. A fully formed insect gnaws one of the ends of the shell and crawls out. Within 1-2 hours the wet fly dries up, acquires the ability to fly and after a day can lay eggs. The biological cycle of fly development, covering on average about four weeks, may decrease with increasing ambient temperature, with a decrease - somewhat increase.
Of the insects, corpses and many beetles are also the biological destroyers of corpses: large and small deadheads, sarcophagi, kozheedy, stafiliny, karapuziki, etc. Dense tissues (cartilages, ligaments) are destroyed by some species of ticks. Ants, beetles and mites have different cycles of biological development (this cyclicity can be used to judge the duration of death).
The activity of most insects is seasonal. In the middle latitudes their greatest activity falls on late spring, summer and early autumn. In each climatic zone, the beginning and end of the life of insects have strictly defined seasonal intervals. Therefore, when assessing the activity of insects, you can establish not only the time of death, but also the time of the year when death occurred.
Relatively small regions, due to specific climatic and geographic conditions, preserve their own biologically balanced animal and plant world (biotope). This also applies to insects that kill corpses. The presence on the corpse of insects that are not characteristic of this biotope, indicates a deliberate or passive movement of a dead body (for example, along a river).
Corpses in natural conditions also damage small rodents (mice, rats) and large animals (wolves, jackals, foxes, pigs, birds of prey) that show the greatest activity in winter when they are limited in the quantity and variety of food.
Prescribing the duration of death
Determining the prescription of the onset of death is one of the main questions to which a forensic medical expert must answer in the examination of the corpse at the site of its detection and during exploration in the morgue.
The age of the onset of death is the interval of time during which death may occur, determined in hours, if two to three days have passed since death, or in days (months) if late cadaveric changes are detected. This is a quantitative indicator, the reliability of which directly depends on the number of studies, the quality of their conduct and interpretation. The age of the onset of death is established by the totality of studies of supralital (physiological) reactions in the tissues of the dead body and early (occasionally late) cadaveric phenomena, as well as additional histological, biochemical and histochemical studies.
It is important to remember that the definition of the statute of limitations of the onset of death in the course of investigating crimes against human life is often crucial for identifying a specific person who committed the crime.
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