Bacterial diversity
Nestlings from fumigated nests had higher bacterial richness than
nestlings from sham-fumigated nests (Figure 1A, χ2 =
4.04, P = 0.04). Shannon diversity index was not significantly
affected by parasite treatment (Figure 1B, χ2 = 1.10,P = 0.29). Urbanization did not significantly affect observed
richness (Figure 1C, χ2 = 2.30, P = 0.13), but
did influence the Shannon index (Figure 1D, χ2 = 7.50,P = 0.006). Non-urban nestlings had higher Shannon diversity
index values compared to urban nestlings. Observed richness and Shannon
index were not affected by the interaction between parasite treatment
and urbanization (Figure S1, Observed richness: χ2 =
0.28, P = 0.60, Shannon Index: χ2 = 0.21,P = 0.65). The year that samples were collected (2018, 2019) did
not significantly affect the observed richness (Table S1,
χ2 = 2.55, P = 0.11) or Shannon index
(χ2 = 0.38, P = 0.54).