Decoupled honey bee microbiome stages and the role of social transmission. Apis mellifera

Microbiomes provide a range of benefits to their hosts. Ideally, the microbiome should be co-adapted with the host as well as their joint ecological niche. However, holometabolous insects, occupy different niches throughout development, with larva and adults being physiologically and morphologically distinct. Furthermore, the transition between the two stages usually involves the loss of the microbiome since the gut is intensively remodeled during pupation. Eusocial organisms appear to have evolved a workaround to this problem by sharing a communal microbiome, which inoculates newly eclosed adults. However, whether social microbiome transmission can fully overcome perturbations of the larval microbiome composition remains untested. We here used the honey bee (Apis mellifera) system to experimentally modify larval microbiomes to test if variations are mirrored in the later adult stage. We used ampliconsequencing of the V3-V4 region of the bacterial 16S rRNA gene to test for changes in the bacterial community as well as mRNA sequencing to test for gene expression differences in larva as well as adult samples.