The biological function of “Candidatus Nardonella” endosymbionts in their host weevils is unknown so far, except for the cryptorhynchine West

Indian sweet potato weevil, find more Euscepes postfasciatus. Within this species “Candidatus Nardonella” endosymbionts are involved in growth and development of the host weevil [31]. Implications and future directions of endosymbiosis in Otiorhynchus spp For several Otiorhynchus species, an association with bacteria of the genus Wolbachia has been proven in previous studies [32–34]. Wolbachia cause several reproductive alterations in insects, including cytoplasmic incompatibility, feminization of genetic males or parthenogenesis [35]. In Otiorhynchus species Wolbachia are assumed to rather play a role in normal development of e.g. O. sulcatus eggs [34] rather than in the evolution of parthenogenesis or polyploidy [32, 33, 36]. Unexpectedly, in the present 454 pyrosequencing approach, none of the bacterial sequence reads obtained from four different Otiorhynchus spp. weevil larvae corresponded to Wolbachia. Torin 1 in vivo Instead, bacterial sequences similar to “Candidatus Neoehrlichia”, a close relative to Wolbachia, were

found in however low frequencies in O. sulcatus (~1% of the total reads) and O. rugosostriatus (~5% of the total reads) (Table 1, Figure 4). Species of that genus are known as tick-borne bacterial pathogens [37] and have been isolated from raccoons and rats [38, 39] but their biological function in insects is unclear so far. As the presence of different Wolbachia strains may differ within a given species between geographical regions [40] further studies are required using Wolbachia specific PCR primers to shed light on the prevalence and distribution Mannose-binding protein-associated serine protease of Wolbachia within Otiorhynchus species and between populations, respectively. Figure 4 Phylogenetic analysis of endosymbionts under “ Candidatus Neoehrlichia” subregion in Otiorhynchus spp. The tree represents the “Candidatus Neoehrlichia” subregion of the complete tree (see additional file 1: 16S rDNA

gene-based phylogeny of endosymbionts in four different Otiorhynchus spp. larvae) and was constructed by using parsimony algorithm. Sequences obtained in the present study are coloured. The amount of sequences included in the groups of Wolbachia, Ehrlichia, „Candidatus Neoehrlichia” and Anaplasma are indicated by numbers. Recent microbiological characterization of bacterial endosymbionts in the Curculionoidea of the family Molytinae and Dryophthoridae has demonstrated that endosymbiosis with “Candidatus Nardonella” bacteria is ~125 Myr old in curculionids and is most of the times evolutionary stable, except for a few clades where respective endosymbionts have been lost and were replaced by different microbes during evolution (endosymbiont replacement; [29]).