Abstract
Wolbachia is the most common and widespread intracellular bacterium found in arthropods that attracted considerable interest in the past decade for its fascinating effects on hosts. To ensure its own survival, this endosymbiont successfully manipulates host reproduction in a number of different ways, including cytoplasmatic incompatibility, a mechanism that prevents infected males from successfully mating with females that lack the same Wolbachia type. The European cherry fruit fly Rhagoletis cerasi (Diptera, Tephritidae), is a serious pest of sweet cherries in Europe. Crossing experiments of flies between southern and central European populations and northern populations showed strong unidirectional incompatibility, caused by the Wolbachia strain wCer2. Geographical distribution of wCer2 in populations of R. cerasi in central Germany show clear transition zones, areas in which wCer2 infected fruit flies introgress into populations not infected by this strain. These transects offer a unique opportunity to study the spread of the endosymbiont in action. Here we present a study of the infection dynamics of wCer2 and its association with mitochondrial haplotypes in R. cerasi in Hesse (Germany). By comparing new data with previous findings of a 15-year-long survey, we aim to get new insights on invasion dynamics and spread of this fascinating organism.