Abstract
Wolbachia is a widespread endosymbiotic bacteria infecting different arthropod species. Key factor of its successful lifestyle is the ability to manipulate the reproduction of its host and promote vertical transmission. However, incongruence between Wolbachia and host phylogenies showed the absence of long-term Wolbachia-host coevolution and that the bacteria can be transmitted horizontally among species. Key factor for horizontal transmission between two different species is the close physical contact between donor and recipient. The ecological overlap of two phytophagous species attacking the same host can provide horizontal transmission paths. Therefore, the colonization of new habitats of invasive species and the interaction with co-occurring native species can have effects on their endosymbiont community. The genus Rhagoletis comprises important agricultural pests with abroad geographic distribution and different host plant associations. The eastern cherry fruit fly Rhagoletis cingulate infests the fruits of several cherry species in its native range in North America. R.cingulata was recently introduced to Europe where it co-infests cherries with the native European cherry fruit fly Rhagoletis cerasi. Here we characterize the Wolbachia infection of native and invasive cherry-attacking Rhagoletis fruit flies and show multiple horizontal transmission events of Wolbachia between the two species. We describe the infection dynamics of the newly acquired Wolbachia strain and discuss its potential influence on the evolution and ecology of its host.