Coleoptera of forensic interest: a study of seasonal community composition and succession in Lisbon, Portugal.

Some Coleoptera are recognised as being forensically important as post-mortem interval (PMI) indicators, especially in the later stages of cadaver decomposition. Because insect species and their timings of appearance in cadavers vary according to geographic location, it is important to know their succession patterns, as well as seasonality at a regional level. In this study, we aimed to contribute to broaden this knowledge by surveying beetle communities from the Lisbon area during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognised during the decomposition process and they could be separated taking into account the occurrence and abundance of the specific groups of Coleoptera collected. Decay stages in general recorded higher abundance and richness of beetle species. A total of 82 species were identified, belonging to 28 families, in a total of 1968 adult Coleoptera collected. Autumn yielded the highest values of species abundance and richness, while the lowest values were recorded during winter. Staphylinidae was the most abundant family in all seasons, although in spring and summer Dermestidae was also quite dominant. In general, most species were related to the decay stages, particularly Margarinotus brunneus (Histeridae) and Creophilus maxillosus (Staphylinidae), and also Saprinus detersus (Histeridae) and Thanatophilus sinuatus (Silphidae), while only few were related to the dry stage, namely Oligota pusillima (Staphylinidae) and Dermestidae spp. larvae. On the other hand, Anotylus complanatus and Atheta pertyi (Staphylinidae) were apparently more associated with the fresh and bloated stages, respectively. The presence of some species was markedly seasonal, allowing a season characterisation based on the occurrence of certain taxa, which can be useful for forensic purposes.