The microbiome of Ips typographus throughout its life cycle
Bacterial and fungal communities significantly change throughout the life cycle of I. typographus (p=0.001). We found significant differences between the individual beetle’s developmental stages; however only part of them was kept between seasons. In both seasons, the fungal microbiome of parental adults significantly differs from pupal samples (p<0.04 in Bray-Curtis permanova test) and pupal samples differ from teneral adult samples (p<0.02 in Jaccard permanova test). Ancom analysis shows that in both seasons larval and pupal samples differ from parental and teneral adults by higher proportion of ASVs belonging to yeasts Kuraishia molischiana andNakazawaea ambrosiae and almost absence of filamentous fungiOphiostoma brunneolum and Morchella importuna . Pupae and parental adults differ from larvae and teneral adults by lower abundance of ASV belonging to yeast Wickerhamomyces bisporus . In the summer season, yeast Saccharomycopsis lassenensis and ASV belonging to closely undefined family Enterobacteriaceae was found to be specific for parental adult samples. We are limited by a low number of parental adult samples in the spring season; however, our data suggest similar findings. In the summer season, we also analyzed the microbial community of intact and infested phloem. Intact phloem hosted much higher microbial diversity than infested phloem (Supplementary Figure 2 and 3), which was largely dominated by Ophiostoma bicolor , a filamentous fungus that is known to be vectored by I. typographus , and bacteria belonging to the genus Pseudoxanthomonas . All taxa of the gut microbiome, except of E. polonica and O. bicolorwere presented also in uninfested phloem.