Microbiome composition of adult Zeugodacus cucurbitae
Differences between the 6 wild F0 parental groups (3 from M, 3 from BP) were preliminary verified. Nearly all F0 adult microbiomes were dominated by Enterobacteriales, with > 99% of all reads belonging to this Order (S2). Identified ASVs in adult microbiomes belonged to 103 different genera. More than 95% of all reads belonged to just six genera, viz. Enterobacter (32.35%), Klebsiella (31.98%),Citrobacter (21.38%), Providencia (6.38%),Raoultella (4.9%) and Pectobacterium (1.8%). Among these, Enterobacter , Klebsiella and Citrobacterwere identified as core genera sensu .
In general, microbiomes of adult flies were less diverse than larval microbiomes (see below) with a mean ASV richness of 26.12 (SD = 8.12) and mean FPD of 5.97 (SD = 1.01) for adult microbiomes. They were also more uneven (more dominated by few abundant taxa) with an average ISI of 4.95 (SD = 2.25). No differences in any diversity metric were found between F0 adults from different sites or different parental groups (S3).
PERMANOVA of parental F0 adult fly microbiomes (S5) revealed significant differences between parental groups when species presence/absence (Unweighted Unifrac distances) was considered (with one out of six significant post-hoc comparisons). However, when relative abundances were taken into account and more weight was given to more abundant taxa (Generalized Unifrac distances), then the F0 parental groups were not significantly different. No significant differences between sites were found for both distances (S4). The PCoA plots (S5), could not resolve distinct parental clusters for both Unweighted and Generalized Unifrac distances.