Socio-demographic characteristics of informants
The results of the surveys show that in the study localities covered by the study, there are more men (97.17%) than women (5.83%). The age of informants varies from 18 to over 50 years old, with 46.80% of them are between 31 and 40 years old. The majority of the informants has a high level of education, 46.80% of them are high school graduates and 26.30% have university level.
Extent of local knowledge on necrophagous insects in Burkina Faso
Knowledge of necrophagous insects cited on open corpses
Fourteen species of adult insects and two Calliphoridae larval stages from open corpses, belonging to three orders and eleven families were cited by the six target groups of this survey (Fig. 2;3) (Table 5).
Figure 3 shows the knowledge of nerophagous insects in the open air. Diptera Lucilia sp., Musca domestica adults, Calliphoridae larvae and pupae were the most cited with a frequency of citation of 15.56%, 14.58%, 16.54% and 13.48% respectively.
Distribution of scavenging insects identified on open corpses according to climatic zones
The figure 4 shows more of the diversity of necrophagous insects in the Sudano-Sahelian zone (Koudougou, Ouagadougou) and in the Sudanian zone (Bobo-Dioulasso, Gaoua). Species belonged to Diptera, Coleoptera and Lepidoptera order were cited by informants in the Sudano-Sahelian zone. However, in the Sudanian zone, the only species cited by informants was Attagenus unicolor. In the two climatic zones studied, significant differences were observed in the knowledge of the insects cited (Table 4). The chi-square test shows that there is significant relationship between species knowledge and climate zones.
Distribution of necrophagous insects identified on corpses in the open air according to locality
Table 5 shows the frequency of citations of necrophagous insects in the studied cities.Attagenus unicolor was the only specie cited in Bobo Dioulasso while Anthrenus fuscus was only cited in Koudougou. In the city of Bobo Dioulasso, the most cited species were Musca domestica (18.64%), and Lucilia sp. (16.95%). In Gaoua city, Musca domestica (19.28%) and Chrysomia sp. (18.07%), were well known. In the city of Koudougou, informants cited Lucilia sp. (16.84%) and Sarcophaga carnaria (16.84%). The main species cited in the city of Ouagadougou were Chrysomia sp. (14.98%) and Lucilia sp. (14.66%). Depending on the locality, significant differences were observed in the knowledge of Chrysomia sp., Sarcophaga carnaria, Lucilia sp., Eristalis sp. (Table 6).
Distribution of necrophagous insects identified on open corpses according to informants professsion
Table 7 presents the knowledge of necrophagous insects according to profession. Lucilia sp. (20.00%) and Musca domestica (16.25%) were the most cited by criminal investigators. Health officials have most cited, Chrysomia sp. (20.69%) and Lucilia sp (17.24%). For the magistrates, Chrysomia sp.(25.00%) and Lucilia sp (25.00%) were most cited. As for funeral workers, Lucilia sp. (13.59%) and Sarcophaga carnaria (12.62%) were the most cited. Crime scene investigators cited Musca domestica (17.86%) and Lucilia sp. (16.07%). Fannia lustrator was only cited by Funeral workers (1.94%) and gravediggers (1.46%). The PCA (Figure 5) shows that funeral workers and traditional gravediggers have more cited necrophagous insects than other informants. Among these two target groups funeral workers have cited more necrophagous species than the traditional gravediggers.
Knowledge of necrophagous insects in connection with stages of cadaveric decomposition
Tables 8 and 9 show the presence of necrophagous insects in connection with decomposing corpses according to informants of Bobo-Dioulasso and Ouagadougou cities.
In the city of Bobo-dioulasso (Table 8), according to the informants, Chrysomya sp. and Musca domestica were globally found in fresh corpse stage. The same information was collected in the city of Ouagadougou (Table 9).
Knowledge of necrophagous insects cited by respondents on exhumed corpses.
General knowledge of necrophagous insects cited by respondents on exhumed corpses
Figure 6 shows the knowledge of necrophagous insects cited on exhumed corpses. Seven species of adult insects, two larval stages, belonged to seven families, two orders were cited by the informants. The most cited species from all localities were Astrapaeus sp., Calliphoridae pupae and larvae.
Knowledge of insects in exhumed bodies according to locality and climate zone
The PCA shows the distribution of species by locality (Figure 7) according to two climatic zones (Sudano-Sahelian and Sudanian zones). The necrophagous insects on exhumed corpses were more cited by informants in Bobo Dioulasso city than other localities.
Table 9 and table 10 presents the frequency of citations of necrophagous insects found on exhumed corpses by locality. Astrapaeus sp. was the only species cited in all four localities.
Frequency of citation according to informant occupation
Table 11 reports the frequency of citation of necrophagous insects on exhumed corpses by informants. It shows the species Astrapeus sp. cited by the traditional gravediggers and the hygiene officers. The other species Rhizophagus sp., Alliopsis sp. Chrysomya sp. and Hydrotea sp. are only mentioned by traditional gravediggers.