HH was involved in the design and supervision of the molecular studies. FG and PW sequenced the

libraries. PM was involved in designing the experiments. FV conceived and coordinated the study, was involved in its design, and helped to draft the manuscript. All the authors have read and approved the final manuscript. Competing interests The authors declare that they have no competing interests.”
“Background In recent years, an increasing number of endosymbiotic bacteria have been detected in arthropods, often having intimate associations with their host. In some cases, these bacteria are obligatory for the survival and development of their host, providing them with essential nutrients [1, 2], while other endosymbionts are facultative and benefit their hosts’ fitness by protecting them from parasites and diseases [3]. However, some arthropod endosymbionts are considered as ‘reproductive parasites’ [4]. Cell Cycle inhibitor These parasites manipulate

the reproduction of their host to promote their own propagation, but these alterations may affect the fitness of their host [5]. The best studied and most widely spread arthropod endosymbiont is Wolbachia, an obligate intracellular Alpha-proteobacterium this website that infects approximately 66% of all insects [6]. Wolbachia alters its host in various ways, of which cytoplasmic incompatibility (CI) is probably most studied [7]. Cytoplasmic incompatibility occurs when an uninfected female mates with an infected male (unidirectional CI) or when an infected female mates with an infected male bearing another Wolbachia-strain (bidirectional CI). This cross results in embryonic death, while all other crosses produce normal progeny. Other manipulations of Wolbachia are male killing, in which infected male embryos die [8], parthenogenesis, in which nonfertilized infected mothers only produce infected female offspring [9] and feminization, in which genetic males are converted into fertile females [10]. In Forskolin clinical trial rare cases,

Wolbachia is obligate for its insect host: in the parasitoid wasp Asobara tabida, the bacterium is necessary for oogenesis completion [11]. Besides Wolbachia, a wide range of other inherited bacteria are currently being investigated. One of these symbionts, Cardinium, [12] does not infect as many arthropods as Wolbachia, but can affect its host almost as strikingly by causing CI, parthenogenesis and feminization [13–15]. Other important endosymbionts manipulating the reproduction of their host include Spiroplasma, Arsenophonus, Flavobacterium and Rickettsia. Insights into the importance of Rickettsia as a reproductive parasite are increasing rapidly [16]. Rickettsia bacteria are Alpha-proteobacteria closely related to Wolbachia and are best known as arthropod-borne vertebrate pathogens. One Rickettsia is a known plant pathogen, causing papaya bunchy top disease vectored by a leafhopper [17].