Longer decomposition process and the influence on Coleoptera fauna associated with carcasses.

Cadavers are colonized by different species of animals, mainly insects such as flies and beetles (Kocarek, 2003). The succession of these insects and the time they live on the carcasses is used to determine in which circumstances death occurred and to estimate the postmortem interval (Catts and Goff, 1992). The Coleoptera order is the richest and most diverse of the Insecta class with 350,000 species, corresponding to nearly 40% of all insects (Grimaldi and Engel, 2005). This high diversity is present in carcasses as well, Coleoptera being the richest order of importance in forensic entomology. The present paper attempts to better understand the Coleoptera fauna on carcasses, as well as its changes through time. The experiment took place in a fragment of Araucaria forest in the campus of the Universidade Federal do Paraná, in Curitiba, Paraná, Brazil. The samplings were taken from April 18 to September 5, 2005. The average temperature ranged between 15 and 23 °C and the relative humidity between 72 and 92%. The animal used was a 14 kg Sus scrofa Linnaeus, 1758 (domestic pig) killed by a stab in the heart. The carcass was put inside an iron cage with 2.5 cm openings, to avoid the entry of vertebrates. The insects were collected actively and daily in a metallic tray positioned below the cage. There were also passive samplings using pitfall traps with 4% formalin, checked every 14 days and a modified Shannon trap (Mise et al., 2007), the top of which was pyramid-like, having a pot filled with 70% ethanol connected to its apex, checked daily. The decompositional process was divided according to the classification of Bornemissza (1957), and was, in days, as follows: initial decay (2), putrefaction (11), black putrefaction (18), butyric fermentation (34) and dry decay (75). The following references were used for the Coleoptera identification: Booth et al. (1990), Borror et al. (1992) and White (1983). Twenty families of Coleoptera were collected, of which 12 are usually associated with carcasses (Smith, 1986), the others being considered accidental because of their feeding habits (Table 1). The main Coleoptera families of forensic importance and their abundance were: Staphylinidae (1,178), Silphidae (183), Histeridae