One Death, Many Insects Species Yet One Insects Generation

摘要

The decomposition processes of 48 white pigs ( Sus scrofa Linnaeus) with mean weight of 22.3±1.20 kg (Mean±SD) resulting from four death agents (oxygen deprivation, slaughtering, aluminium phosphide and monocrotophos poisonings) was monitored throughout the Wet and Dry seasons of 2006/2007 and 2007/2008 seasons at Benson Idahosa University Demonstration farm, Benin City on Latitude 06°17'01.6"N and Longitude 05°36'10.6"E, 73 m of elevation from sea level. The insect fauna and periods of invasions were recorded. A consistent pattern of decomposition and insect invasion in both the dry and wet seasons regardless of killing agents was observed. The consistent insects from the earliest to the latest arrival being; Lucilia sericata ; Chrysomya rufifacies , Musca domestica , Sarcophaga carnaria , Hermetia illucens and Ophyra aenescens from the order Diptera; Dermestis maculatus and Necrobia rufipes from the order Coleoptera. The other insect order, Hymenoptera was represented by members of the Formicidae (ants) family which was opportunistic. It also revealed that, the insects species that bred ( Lucilia sericata , Chrysomya rufifacies , Musca domestica , Sarcophaga carnaria , Hermetia illucens , Ophyra aenescens and Dermestis maculatus ) within the decomposition process in either seasons, all had one complete generation (egg, larva, pupa and adult or larva, pupa and adult) without an emerged adult from the process initiating and completing another cycle. This suggests that, the phenomenon of decomposition of animals is predictable from insect evidences since carrion insects seem to be decomposition-stage dependent, with only one generation of such insects species guaranteed, except where unpredictable circumstances present themselves. This understanding would enhance the global acceptability and applicability of testimonies from entomological data.