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The aim of the study was to describe the morphological structure, including chaetotaxy, of the previously unknown early (L₁) and late (L₂₋₃) larval instars of Gyrophaena boleti and to present certain aspects of their behaviour, mainly associated with their means of collecting food. G. boleti is probably the only member of its genus that breeds inside tubes of the open hymenium of the polycarp Fomitopsis pinicola. It was established that certain morphological characters and aspects of the behaviour of the larvae are an expression of the species' adaptation to its preferred host. Thus such characters as body shape, some shortened structures on the head and thorax, the shape of the setae and the length of the urogomphi are the result of synchronic evolution of the larvae with its specific microhabitat, i.e. the narrow tubes of the hymenium. Morphological differences between early and late larval instars of G. boleti involve 17 characters, including 10 new ones that have not previously been noted in gyrophaenines. The level of activity of the tergal gland system varies depending on the age of the larvae, which is probably linked to differences in the structure of the setae on abdominal tergite VIII. The function of these setae was explained for the first time, and a hypothesis was put forth regarding a recognition-aggregation function of tergal gland secretion with respect to individuals within species. The morphological structure of the mature larvae of G. boleti was compared with that of G. nana, which is the only Gyrophaena larva that has been sufficiently well illustrated, and 16 traits differentiating these species were distinguished.
Entomotoxicology deals with the analysis of toxic substances contained in arthropods that feed on dead bodies. Arthropods are a source of material for investigation when a human or animal body is in an advanced state of decomposition. Various chemical air pollutants, drugs, xenobiotics and pesticides can accumulate in the bodies of insect larvae. Entomotoxicology often involves examining insect larvae that have introduced to their metabolism various kinds of pharmaceuticals taken by people when they were alive. Chemical compounds which can cause death affect the development rate of arthropods living on corpses, delay colonization of insects by several days, or affect their number. Some compounds act as attractants or repellents and thereby influence how quickly insects appear on the body. Others have a mixed effect on insect development. During the initial development stage of the insect they act as an attractant, but in subsequent stages they slow down its development or act as a repellent. The concentration of chemical compounds accumulated in the bodies of larvae is different than in human tissues. Sometimes insects are better indicators of the presence of chemical compounds than material taken from the internal organs of a dead body. Moreover, the quantity of toxins detected in arthropods differs at different developmental stages. The concentration of a xenobiotic in the body of an insect depends on its type, the stage of development of the insect, and the part of the body it was collected from. Studies have determined that the best place to collect entomotoxicological samples is the internal organs (e.g. the liver). If this is not possible, insects are collected from the head area and the muscles. Due to the low popularity of entomotoxicological testing, this type of evidence often is either not collected at all or collected improperly, preventing valuable information from being obtained. Thus there is a need to verify and standardize methods for safeguarding arthropods for the purposes of entomological toxicology.
Precisely determined time of death is one of the most important pieces of information obtained during a post-mortem investigation. There are several traditional methods for determining time of death, the most important of which are evaluation of early post-mortem changes, such as the change in body temperature. The study was aimed at identifying insects collected from the body and establishing the time of death by observing the developmental cycle of the indicator species Calliphora vicina. The material for the main experiment was the carcass of a dog. The length of the developmental cycles of insects depends on ambient conditions, so studies should take as many criteria as possible into account. Succession of arthropods, as well as the species composition and indicator insects of particular stages of decomposition, is very similar in human and animal carcasses. The results obtained were considered with respect to the time that had passed since the death of the animal. Experiments on dog carcasses may in the future contribute to the development of research enabling determination of the time of death of animals, which is a subject of increasing interest in forensic veterinary medicine.
Forensic entomology frequently assists forensic medicine in legal investigations. It makes it possible to estimate the time of death when a cadaver is recovered at a relatively advanced stage of decomposition. In criminalistics practice, unburied bodies are found the most commonly, and therefore the fauna of these cadavers is the best investigated. The aim of this study was to collect a succession of insects and other invertebrates occurring on an unburied corpse. The experiment was conducted on the carcass of a cat euthanized due to an advanced cancer process. The carcass was colonized by three phyla of animals: Annelidae, Mollusca, and Arthropoda. They belonged to 7 classes and 10 orders. The most diverse were Arthropoda. They were classified into 5 classes: Insecta, Diplopoda, Malacostraca, Entognata, and Arachnida, and into 8 orders: Julida, Isopoda, Collembola, Diptera, Coleoptera, Hemiptera, Araneae, and Acari. The fly species Calliphora vicina from the family Calliphoridae is of particular interest among the insects collected because it is one of the fundamental indicator species whose life cycle makes it possible to determine an approximate time of death. During the study it was noted that arthropods occurred in a certain pattern of succession, predictable in forensic entomology. The first group was Calliphora vicina (Calliphoridae, Diptera), which laid eggs. The next (second) group consisted of first-instar C. vicina larvae and insects feeding on these larvae, such as Philonthus tenuicornis (Staphylinidae, Coleoptera). The first stage of succession was the appearance of eggs of C. vicina. The second phase was the appearance of adult flies other than Calliphoridae and of accidental species, as well as beetles (e.g. Philonthus tenuicornis, Staphylinidae, Coleoptera) feeding on larvae of C. vicina. The third phase of succession was the appearance of all larvae stages of C. vicina that continued and finished their life cycle.
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