Variability and genetic structuring of Sitophilus zeamais according to agroecological zones in Senegal (West of Africa)

Abstract

Maize plays a socio-economic role in Senegal. However, it is considerably damaged by Sitophilus Zeamais, a beetle of the Curculionidae. Areas likely to favor the survival or extinction of Sitophilus zeamais can be identified because genetic diversity influences the adaptability of the individual. Our study aims to highlight a possible variation and structuring of Sitophilus zeamais according to five agroecological zones (AEZ) in Senegal, namely Nord Bassin Arachidier (NBA), Sud Bassin Arachidier (SBA), Sénégal Oriental Haute Casamance (SOHC), Basse Moyenne Casamance (BMC) and Zone Sylvo-Pastorale (ZSP). The purpose of this study is to reduce crop losses by recommending to farmers peas where the insect is reluctant to survive. So far, genetic studies on this insect have traced its phylogeny and its geographical distribution in Africa in general. Senegal has never been specifically studied. To achieve this goal, 89 individuals were captured in the 5 zones. The exploitation of the cytochrome B gene corresponding to these individuals revealed a high genetic diversity in the NBA, SBA, and SOHC and low in BMC and ZSP, but also a genetic structuring of the insect according to agroecological zones. Thus, the agroecological zones of the NBA, the SBA and the SOHC are favorable to its survival, while those of the BMC and the ZSP limit its expansion.