Vol. 3, Issue 2 (2018)
Dynamics of the main necrophagous Diptera populations of forensic interest, in the Guinean zone of Côte d'Ivoire
Author(s): Alexandre F Koffi, Louis RN Aboua, Blaise A Kone, Diakaridia Fofana, Hassane Dao, Mathurin Djodjo
Abstract: Recent studies in the Guinean zone of Côte d'Ivoire, by Koffi et al. (2017a), showed that a pig corpse exposed to the open air, was rapidly colonized by necrophagous insects. These authors observed that the very first insects to arrive on the corpse were Diptera belonging to the families Calliphoridae, Sarcophagidae and Muscidae. So they are the ones, experts in forensic entomology, can use to establish a short or minimum post mortem interval (PMImin). But so far, no research work has demonstrated, the ability of these necrophagous Diptera of medicolegal interest, to colonize an exposed corpse, whatever the time of year. This is the reason why the objective of this research work was to study the population dynamics of the main necrophagous Diptera of forensic interest, listed in the southern forest zone of Côte d'Ivoire (Koffi et al., 2018). To do this, a trapping device, inspired by that of Upton (1991), and using as bait, a portion of 500 g of pig’s liver or viscera, was installed on the experimental site of the National Center of Agronomic Research ( CNRA / Adiopodoumé, Km 17), located west of the city of Abidjan. The weekly catches that were carried out from August 26, 2015 to August 23, 2016, allowed harvesting, after 52 weeks, a total of 207275 individuals, divided into 11 taxa grouped into three families, namely, those of Calliphoridae, Sarcophagidae and Muscidae. Individuals (150,845) of the family Calliphoridae (8 taxa), accounted for 72.78% of the total numbers of necrophagous Diptera harvested, with an abundance of Chrysomya albiceps (48.55% of Calliphoridae). The Muscidae family (48,628 individuals) came in second position with 23.46% of the total numbers, with Musca domestica as the main representative. In Sarcophagidae, the most abundant species harvested was Sarcophaga carnaria (3.77% of the total numbers). The study of the sex ratio of the different species, showed a higher proportion of females, oscillating between 59.56 and 74.14%. Although the weekly numbers of the species caught varied strongly throughout the year, no correlation was observed between these variations in population levels and recorded climatic parameters, temperature, rainfall and humidity relative and insolation. However, we can note that these species were present throughout the year, in our different catches. This means that, at any time of the year, a corpse exposed in the open air, in the Guinean zone of Côte d'Ivoire, is likely to be colonized by these necrophagous Diptera of medicolegal interest.