Processo de decomposição e padrão sucessional de artrópodes em carcaças de suínos expostas em locais abrigados e desabrigados / The process decomposition and the successional pattern of arthropods in pig carcasses exposed to unsheltered environments

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

18/08/2011

RESUMO

Forensic Entomology uses data, mainly from carrion insects, to estimate the Post Mortem Interval (PMI). The oviposition pattern of these insects can be influenced by several factors, such as the presence of materials in the vicinity of the body, whether the corpses are buried, burned or disposed in open or closed environments, etc. These factors can affect the PMI estimate. The purpose of this work was to study the differences in decomposition, attractiveness and oviposition patterns between carcasses exposed in sheltered and open environments. The influence of the mode of exposure in relation to the abundance of the species that colonized were also been studied. The experiments were conducted in two seasons: warm and wet (summer), and dry and cool (winter). Three carcasses of female pigs (Sus scrofa L.), weighing aproximatelly 10 kg were used per season. The carcasses were placed in iron cages in order to avoid predation by large animals, and exposed in an arboretum located on the State University of Campinas campus, (22 ° 48 57 "S 47 ° 03 33" W), at 640 m above sea level. One pig was placed in and unsheltered area (control) and the other two were exposed inside camping tents measuring 2,05 m x 1,45 m x 1,00 m. One tent was set in a shaded area and the other one was places under direct sunlight. Adult insects visiting the carcasses were collected with an insect net. The immatures leaving the carcasses to pupate were collected in trays placed beneath each carcass, taken to the laboratory, reared at 26 °C in growth chambers until adult emergence, and identified. Soil samples were also collected at the site of the experiment around each carcass. A total of 37.787 specimens of Arthropoda was obtanined, distributed in 11 different orders. Of this total, 8.842 were collected and 28.945 were reared from the collected larvae. Diptera totaled 92.2% of the adults collected (Calliphoridae-28.7% and Muscidae-34.6%). The other collected orders were: Coleoptera (4.5%), Hymenoptera (1.9%), Lepidoptera (0.5%) and Hemiptera (0.3%). Les than 1% of occasional arthropods belonging to the orders Blattodea, Mantodea and Neuroptera, and Acari, Opiliones and Araneae were also collected. More than 99% of the reared insects belonged to the order Diptera, Calliphoridae (93.2%) and Muscidae (5.4%) were the most abundant families. The order Coleoptera accounted for the remaining 0.2%. Considering the different types of exposure, there was a difference in the decomposition time, mode and duration of each decomposition stage of the carcasses. The decomposition process in the control carcasses was much faster and had greater abundance of arthropods in the sheltered carcasses, but species composition was similar. Abiotic factors exerted influence by delaying or accelerating the activity of insects in the carcasses. Chrysomya albiceps was the most abundant species and, together with Hemilucilia segmentaria and Peckia (Euboetcheria) collusor can be considered important indicators in the estimation of PMI, while Hemilucilia semidiaphana and Hemilucilia segmentaria can be also used as indicators for wooded areas, mode of exposure and season. These results evidence the importance of using forensic entomology as a tool in legal investigations

ASSUNTO(S)

entomologia forense decomposição intervalo pós-morte forensic entomology necrophagous fly decomposition post-mortem interval moscas necrófagas

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