Seasonality of Insect Succession and Pig Carcass Decomposition in a Natural Forest Area in Southeastern Brazil

Abstract

In this study, successional patterns, relative abundance of larvae and adults of sarcosaprophagous insects, carcass decay, diversity and seasonality of species, and their potential as forensic indicators were studied. Four experiments were carried out in each season in a natural area of southeastern Brazil. Two pigs (Sus scrofa L.) were used in each experiment and were exposed to sunlight and shade, respectively. The Calliphoridae outnumbered the Sarcophagidae in specimens collected and reared from the carcasses. More insects were collected from carcasses exposed to the sun, while a larger number of specimens were reared from those in the shade. Temperature and rainfall influenced the stages of carcass decay and insect activity and abundance. Chrysomya albiceps was the most abundant species in all four experiments. The carcasses were used as a protein source and substratum for oviposition. The dark putrefaction and fermentation stages yielded more flies than the other stages. These results show that flies are important in carcass decay and are, therefore, also of forensic importance. Seven species can be considered valuable forensic indicators in South-eastern Brazil. However, only three species were useful as forensic indicators in wooded areas: P. intermutans, H. segmentaria, and H. semidiaphana.

The effect of body size on the rate of decomposition in a temperate region of South Africa

“…The nose and mouth emit odours that attract flies and are therefore often the first areas to be colonised by insects [16]. This is in line with the observations made in a study by Lopes de Carvalho [20], with the Diptera (Calliphoridea) more abundant during the earlier stages of decomposition, whereas the omnivorous species were predominant during the later stages of decomposition. In the current study, similar oviposition was observed on carcasses irrespective of size and weight.…”

Dipterofauna Associated withSus scrofaLinné, 1758, Carcasses in Urban and Coastal Regions of São Paulo State, Brazil

“…The number of specimens collected was considered satisfactory and unaffected by the rains during the period of experimentation, which differs from the results found by Eberhardt and Elliot [9], who noted the lowest visitation rates to open-air exposed carcasses and a subsequent deceleration of decomposition during the rainy season. Similar results were published by Lopes de Carvalho and Linhares [33], whose study also coincided with greater rainfall and higher temperatures; thus the decomposition was rapid and intense. The flies were classified as belonging to 11 families, and 27 species were identified from the families with the greatest forensic interest (Calliphoridae, Muscidae, Fanniidae, and Sarcophagidae) ( Table 2).…”

“…Similar to the methods used by Eberhardt and Elliot [9], the fresh phase was calculated from the moment of swine death until the early bloat phase. As expected, less than a month was required for the carcasses to reach total decomposition, which differs from the results found by Martinez et al [8], who found that the carcass decomposition process required 83 days, and those of Lopes de Carvalho and Linhares [33], who conducted a study during the wet season and found that casting decomposition required 45 days. To verify the decomposition phases and climatological monitoring, a standard 30 days of observation was followed in the present study.…”

La Entomología Forense y el Neotrópico

“…En el año 2000, López y col. [13], en el estado de Sao Paûlo al sur-este de Brasil, realizaron un estudio donde se emplearon dos cadáveres de esta especie de cerdo, de 10 Kgs. de peso aproximadamente, los cuales fueron colocados en un área boscosa densa, con una separación de 40 metros, uno del otro, quedando un cadáver expuesto a la luz solar y el otro en la sombra total.…”

“…Cabe destacar que de acuerdo con la colecta de insectos carroñeros hallados en un cadá-ver de cerdo en un área boscosa natural al sureste de Brasil reportado por López y col. [13], Chrysomia albiceps (orden Díptera, familia Calliphoridae) fue la especie más abundante en todos los experimentos. De un total de 14.113 especimenes de insectos adultos representados en 36 fami-lias, 85% pertenecían al orden Díptera y 12% al orden Coleóptera.…”