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...

Many generalist populations may actually be composed of relatively specialist individuals. This ‘individual specialization’ may have important ecological and evolutionary implications. Although this phenomenon has been documented in more than one hundred taxa, it is still unclear how individuals within a population actually partition resources. Here we applied several methods based on network theory to investigate the intrapopulation patterns of resource use in the gracile mouse opossum Gracilinanus microtarsus. We found evidence of significant individual specialization in this species and that the diets of specialists are nested within the diets of generalists. This novel pattern is consistent with a recently proposed model of optimal foraging and implies strong asymmetry in the interactions among individuals of a population.

To determine the species of Diptera and Coleoptera that visit and breed in carrion, four experiments, one for each season, were conducted from November 1992 to October 1993 in the vicinity of Campinas city, Southeastern Brazil. For each experiment two pigs weighting c. 10 kg were killed with a blow to the head with a blunt metallic object and immediately exposed, one in the shade and the other under sunlight. Adult insects and larvae leaving the carcass to pupate were collected daily. In addition, female blowflies were dissected in order to determine the stage of ovarian development. Five species of Calliphoridae: Chrysomya albiceps, C. megacephala, C.putoria, Phaenicia eximia and Hemilucilia segmentaria; three of Sarcophagidae; Pattonella intermutans, Liopygia ruficornis and Adiscochaeta ingens, and three of beetles: Dermestes maculatus, D. peruvianus (Dermestidae) and Necrobia rufipes (Cleridae), were considered of potential forensic importance, for they were able to breed in carrion exposed to natural environmental conditions. In addition, several fly species showed a definite seasonal pattern, with the Calliphoridae breeding more frequently during the warmer months of the year, and the Sarcophagidae preferring the cooler periods.

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