Demographic and phylogenetic evolution of Sitophilus zeamais subservient to maize in different agroecological zones in Senegal

Abstract

In Senegal, maize is mainly exploited in the agroecological zones of the NBA1, SBA2, SOHC3, BMC4, and ZSP5. Where it is heavily ravaged by a beetle Curculionidae, Sitophilus zeamais. The extent of the damage requires the search for alternatives. This article aims to detect the type of selection of populations in agroecological zones and their degree of kinship. The advantage of demonstrating a population demographic signal is to recognize the agroecological zones exposed to a bottleneck or a positive selection, therefore respectively constraining or naturally favorable to the adaptation of the insect. To achieve this goal, 89 insects were harvested in the different agroecological zones. The study of cytochrome b gene sequences revealed that the NBA, SBA and SOHC populations has undergone a positive selection. On the other hand, those of the BMC and the ZSP are victims of a negative selection. The individuals in each zone are closely related. Between two to two populations, BMC and SOHC insects are more closely related.