Fig. 1.

Boxplots showing the alpha diversity comparisons of the external and internal house fly samples. The upper and lower whiskers correspond to the first and third quartiles, with the bar in the middle marking the median value; the dots indicate the value of each data point. Alpha diversity was measured by Shannon index (top panels) and observed amplicon sequence variants (ASVs) (bottom panels) for a bacteria and b fungi. Each sampling site is colored according to habitat and country as indicated in the key. Significant differences between corresponding external (“E”) and internal (“I”) communities are depicted; *p.adj < 0.05, **p.adj < 0.01, *** p.adj < 0.001