Insect succession and carrion decomposition in selected forests of Central Europe. Part 2: Composition and residency patterns of carrion fauna

Abstract 

The insect fauna of pig carcasses was monitored in different seasons and forests of Western Poland (Central Europe). The composition of carrion fauna and selected features of residency in carrion in adults and larvae of particular taxa were analysed. A total of 131 adult and 36 larval necrophilous taxa were collected. Only 51 adult species and 24 larval taxa were minimally abundant (≥10 specimens) at least on one carcass. As for the composition of carrion fauna, there were large differences between seasons, but no important differences between forest types.

In most species of Diptera, length of the presence period of adults was between 35 and 65% of the sampling interval, while in most species of Coleoptera, it was above 60%. Only in a few species (e.g., Saprinus semistriatus, Necrodes littoralis or Creophilus maxillosus) was the presence period shorter than 35% of the sampling interval. Interestingly, in some adult Coleoptera (e.g., Necrobia violacea) very long presence periods were recorded. In most taxa, the length of the presence period of larvae was between 40 and 65% of the sampling interval. Only Calliphora vomitoria, Phormia regina, Hydrotaea dentipes, N. littoralis and C. maxillosus had shorter presence periods of larvae.

As a rule, residency of adults was broken, whereas residency of larvae was unbroken. Moreover, in adults, two distinct residency patterns were observed; with breaks clumped in the final part of the presence period and with breaks evenly distributed inside the presence period.

Almost in all taxa, the time of appearance showed the closest relationship to the onset of bloating. The relationship was significant, positive and strong in adults of P. regina, Fannia manicata, Hydrotaea ignava, Stearibia nigriceps, S. semistriatus, N. littoralis and C. maxillosus as well as larvae of P. regina, H. dentipes, H. ignava, S. nigriceps, N. littoralis, Oiceoptoma thoracicum, Thanatophilus sp., C. maxillosus and Philonthus sp. Interestingly, in some forensically significant taxa (e.g., adults of N. violacea or Thanatophilus rugosus), we found no significant relationship between the time of their appearance and the onset of any decompositional process.

Implications for the succession-based post-mortem interval (PMI) estimation, determination of the carcass movement and the season of death are discussed.

Keywords: Forensic entomology, Carrion insects, Forest habitats, Post-mortem interval, Movement of remains, Season of death