Necrophagous insects, mainly Diptera and Coleoptera, are attracted to specific stages of carcass decomposition, in a process of faunistic succession. They are very important in estimating the postmortem interval, the time interval between the death and the discovery of the body. In studies done with pig carcasses exposed to natural conditions in an urban forest (Santa Genebra Reservation) Key words: forensic entomology -Diptera -Coleoptera -carrion insects -decomposition -death timeThe decomposition of a dead body starts firstly through the action of microorganisms such as fungi and bacteria, followed by the action of a series of arthropods, with the predominance of the sarcosaprophagous insects (Nuorteva 1977). Notable differences were noted in the decomposition process, basically related to time of disintegration, being faster in the presence than in the absence of insects (Payne 1965, Jirón & Cartín 1981.After death, the body undergoes natural changes, going through different stages of decomposition that are attractive to necrophagous insects. According to Bornemissza (1957) the decomposer community of a carcass goes through a process of ecological succession. Therefore, the insects arrive in a determined sequence, producing an addition and/or substitution of species. Knowing this sequence as well as their preference for the different stages of decomposition, and the meteorological data, it is possible to determine the postmortem interval (PMI). Insects can also verify the cause of death and if the body was moved (Catts & Goff 1992, Anderson 1997.The basic reason for using insects in criminal investigations, a science denominated as forensic entomology, resides in the fact that insects are the first ones to detect and to find a cadaver and are present in all stages of decomposition and, furthermore, some species are specific for certain areas and seasons. Another important point to be considered is that oviposition can occur minutes after death (Smith 1986). It is interesting to point out that insects of forensic importance are those that do not just visit the corpse or carcass in the adult form, but also breed in these substrates because, by knowing the developmental time of their larvae, it is possible to estimate the time of death.Our objective was to determine the insects that are of importance in estimating the time of death for the study area. Samples were collected from pig carcasses exposed to a natural urban forest and from human corpses at the Institute of Legal Medicine (ILM) 136 136 136 136 136 Arthropods of Pig Carrion and Human Corpses in Brazil LML Carvalho et al. MATERIALS AND METHODSThe study was done in two different environments: in a natural forest area (Santa Genebra Reservation) and at the ILM, both located in the city of Campinas, State of São Paulo. The data were collected from 1994 to 1998.In the natural area (Morellato & H Leitão-Filho 1995), 16 pig carcasses (Sus scrofa Linnaeus) weighting approximately 10 kg each were used as baits. They were killed mechanically with a blow to th...
Abstract. The decomposition of small carcasses in the open is frequently neglected although it may provide information of forensic importance. This paper describes an experimental study of arthropod species associated with carcasses of mouse, Mus musculus (Linnaeus, 1758) and rat, Rattus norvegicus (Berkenhout, 1769) (Rodentia: Muridae). Four carcasses were left inside iron cages in sunlit and shady areas in a secondary forest in Southeastern Brazil twice a season for four seasons (n = 16 carcasses of each rodent). The carcasses were removed when arthropods ceased to visit them. The visiting and colonizing invertebrates were collected daily and identified. Immatures were also collected and reared in a laboratory for identification. We collected 6,514 arthropods (820 adults and 5,694 juvenile forms) belonging to 53 species from the families Sarcophagidae, Calliphoridae, Muscidae, Fanniidae, Syrphidae, Richardiidae, Sepsidae, Micropezidae, Otitidae, Drosophilidae, Phoridae, Dolichopodidae, Anthomyiidae, Asilidae and Lauxaniidae (Diptera), Formicidae, Ichneumonidae, Encyrtidae and Apidae (Hymenoptera), Staphylinidae (Coleoptera) and Gonyleptidae (Opiliones). Lucilia eximia (Wiedemann, 1819) (Diptera: Calliphoridae) and Peckia (Pattonella) intermutans (Walker, 1861) (Diptera: Sarcophagidae) deserve special attention because both adult and immature forms were collected in all seasons and in both areas. Our results indicate that the frequency of occurrence of these arthropods was positively associated with carcass size (mouse or rat); no marked insect succession on the carcasses occurred; and the diversity of Calliphoridae and Sarcophagidae was high, irrespective of season.
-Forensic entomology uses biological and ecological aspects of necrophagous insects to help in criminal investigations to estimate the post-mortem interval (PMI) or to determine the cause of death. Recent papers demonstrated that the presence of toxins in decomposing tissues may alter the insect developmental rate of insects exploiting such tissues as food. Thus, preliminary tests with artifi cial diets in laboratory are necessary to create a database to investigate and quantify the modifi cations that can occur with the collected insects from a criminal scene, avoiding any errors on the PMI estimates. The present study aimed to evaluate the developmental rate of Chrysomya albiceps (Wiedemann) reared on: a) artifi cial diets containing animal tissues: bovine liver (D1), raw muscle (D2), stomach (D3), and chicken heart (D4); b) artifi cial diet without animal tissue (D5); and c) a control group (C), which had only meat. The effi ciency of each substrate was assessed by immature weight gain (mg), larval developmental time, larval and pupal survival, emergence interval and adult size. D1 to D4 diets did not restrict C. albiceps development; however, larvae reared on D1 and D2 diets presented a lower adult emergence rate. D3 and control group showed similarities regarding the effi ciency parameters (rate and emergence interval). Thus, the use of diet D3, artifi cial diet with stomach, is the most recommended.KEY WORDS: Nutritional source, immature rearing, blowfl y, forensic entomology RESUMO -A entomologia forense utiliza dados biológicos e ecológicos de insetos necrófagos com o objetivo de auxiliar as investigações criminais, na estimativa do intervalo pós-morte (IPM) ou na descoberta da causa da morte. Trabalhos recentes têm demonstrado que a presença de toxinas nos tecidos em decomposição pode alterar a taxa de desenvolvimento de insetos que usam esse recurso. Assim, testes preliminares usando dietas artifi ciais em laboratório são necessários para a criação de um banco de dados como padrão para investigar e quantifi car as possíveis modifi cações em insetos coletados da cena criminal, para não gerar dados imprecisos sobre o IPM. No presente estudo objetivou-se avaliar a taxa de desenvolvimento de imaturos de Chrysomya albiceps (Wiedemann) criados em diferentes substratos: a) dietas artifi ciais contendo tecido de origem animal: fígado (D1), músculo moído (D2) e rúmen (D3) bovinos, além de coração de frango (D4); b) dieta sem tecido animal (D5) e; c) um grupo controle (C), somente em carne bovina. A efi ciência de cada substrato foi observada pelo ganho de massa dos imaturos, tempo de desenvolvimento larval, sobrevivência larval e pupal, intervalo de emergência e tamanho dos adultos. As dietas D1 a D4 não restringiram o desenvolvimento larval de C. albiceps, no entanto, D1 e D2 apresentaram baixa emergência de adultos. D3 e o grupo controle foram muito similares em relação a alguns fatores de efi ciência (taxa e intervalo de emergência). Assim, o uso da dieta D3, dieta artifi cal mais rúmen de bovinos é...
Helminths can be transmitted to human beings in several ways, but little attention has been given to vector or mechanical transmission of infective forms by insects. The present study surveys the helminth species present in three orders of insects that coexist in proximity with the human environment. A total of 700 insects (54 Blattodea, 275 Diptera, and 371 Hymenoptera) were collected and examined externally and individually. In the Blattodea order, only specimens of Periplaneta americana were collected, and 58.3% were carrying the following helminth forms: Oxyuridae eggs (36.4%), Ascaridae eggs (28.04%), Nematoda larvae (4.8%), Cestoda eggs (3.5%), other Nematoda (0.08%), and Toxocaridae eggs (0.08%). No Diptera and Hymenoptera were found to contain parasitic forms. This study evaluates the importance and role of insects as mechanical vectors of helminth parasites, correlated with social and environmental conditions, and suggests the use of these data for preventive purposes.
This study aimed to provide the first checklist of forensically-important dipteran species in a rainforest environment in Northeastern Brazil, a region exposed to high rates of homicides. Using a decomposing pig, Sus scrofa L. (Artiodactyla: Suidae), carcass as a model, adult flies were collected immediately after death and in the early stages of carcass decomposition. To confirm actual colonization of the carcass, insects that completed their larval development on the resource were also collected and reared until adult stage. A diverse assemblage of dipterans composed of at least 28 species from seven families with necrophagous habits was observed within minutes after death. Besides Calliphoridae and Sarcophagidae, species from forensically-important families such as Phoridae, Anthomyiidae, and Fanniidae were also registered. Eleven species were shown to complete their development on the carcass. The majority of individuals emerged from larvae collected at the dry stage of decomposition. Hemilucilia segmentaria Fabricius (Diptera: Calliphoridae), H. semidiaphana (Rondani), and Ophyra chalcogaster (Wiedemann) (Muscidae) were the dominant species among the colonizers, which supports their importance as forensic evidence in Brazil.
Cases of myiasis in man associated with preexisting lesions are quite common. However, in the forensic field, certain behavioral habits related to insects may be useful to ratify mistreatment. This is a register of a case of oral myiasis by Cochliomyia hominivorax (Diptera: Calliphoridae), an obligate parasite of warm-blooded animals, in a 95-year-old man with Alzheimer's and Parkinson's disease. The identification of immatures removed (n = 87) was based on their morphological characteristics. Considering the developmental time and length of the maggots, it was possible to estimate an infestation of at least 143 h. Undoubtedly, the poor state of health was one of the cofactors for the infestation; however, the long time of infestation observed denotes negligence in the conduct of patient care. In terms of prophylaxis, it would be recommended that individuals who need special care must have access to more comprehensive physical examinations and periodicals, as well as hygienic conditions should be meticulously observed. Additionally, the immatures causing myiasis after being removed must be stored and forwarded for analysis, since their identification can be crucial to determine the exact time and circumstances of an infestation, and consequently its pathogenesis. If we consider the aggressiveness of C. hominivorax, a fast and reliable diagnosis becomes even more important for an adequate treatment. Finally, it is expected that this study encourages the health care professionals to improve the treatment of incapable patients.
Since insect species are poikilothermic organisms, they generally exhibit different growth patterns depending on the temperature at which they develop. This factor is important in forensic entomology, especially for estimating postmortem interval (PMI) when it is based on the developmental time of the insects reared in decomposing bodies. This study aimed to estimate the rates of development, viability, and survival of immatures of Sarcophaga (Liopygia) ruficornis (Fabricius 1794) and Microcerella halli (Engel 1931) (Diptera: Sarcophagidae) reared in different temperatures: 10, 15, 20, 25, 30, and 35 ± 1 °C. Bovine raw ground meat was offered as food for all experimental groups, each consisting of four replicates, in the proportion of 2 g/larva. To measure the evolution of growth, ten specimens of each group were randomly chosen and weighed every 12 h, from initial feeding larva to pupae, and then discarded. Considering the records of weight gain, survival rates, and stability of growth rates, the range of optimum temperature for the development of S. (L.) ruficornis is between 20 and 35 °C, and that of M. halli is between 20 and 25 °C. For both species, the longest times of development were in the lowest temperatures. The survival rate at extreme temperatures (10 and 35 °C) was lower in both species. Biological data such as the ones obtained in this study are of great importance to achieve a more accurate estimate of the PMI.
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