Genetic structure of mediterranean fruit fly (Ceratitis capitata) populations from Moroccan endemic forest of Argania spinosa

The Mediterranean fruit fly (medfly), Ceratitis capitata (Diptera: Tephritidae), widely distributed around the World, is regarded as the most important pest of agricultural resources. The genetic structure of this species remains unexplored at microgeographical level, specifically in the African countries. In Morocco, the endemic Argan forest of 800,000 hectare is considered as the world main refuge of medfly and probably a continuous source of medfly infestations and invasions to neighbouring regions. In this study, RAPD was used to analyze the genetic structure of Moroccan medfly populations, collected from distant regions and at different altitudes within the Argan forest, a Kenyan medfly population and a Moroccan medfly laboratory strain. Based on the analysis of 169 RAPD loci, the population genetics parameters were estimated and two dendrograms (UPGMA & neighbor-joining clustering) were constructed. The genetic diversity parameters ( Shannon information index; total number & percentage of polymorphic loci) were very high in Moroccan medfly populations (P = 81%; 0.112 plus minus 0.015 less than I less than 0.175 plus minus 0.020), particularly in populations sampled at higher altitudes (I = 0.175 plus minus 0.020). However, these parameters were slightly lower compared to Kenyan ones (P= 89%, I = 0.227 plus minus 0.020). The AMOVA and F-statistics showed the occurrence of important genetic differentiation between Moroccan medfly populations (Fst = 0.448). Furthermore, our data indicate that the genetic structure of Moroccan medfly populations was determined predominantly by altitude. Inferences about the historical colonization and establishment of medfly populations in this country were discussed.