Geographic variation within species
Collection location and its interaction with Tissue type were highly significant in the full model (Supplementary Table S1) but to account for unbalanced sampling and understand drivers of these interactions, we also compared the effect of location within each species and tissue type separately. For X. sonorina , samples collected in Davis and Tempe locations differed in species composition for both the crop and gut (Supplementary Table S4; Bray-Curtis crop R2 = 0.16 F = 4.47 p <0.001; gut R2 = 0.093 F = 3.10 p <0.001). For X. tabaniformis , samples from Davis and ABDSP differed in species composition, but only significantly in the gut, but to a lesser extent in the crop (Bray-Curtis dissimilarity gut R2 = 0.17 F = 4.18 p <0.001, crop R2 = 0.15 F = 1.58 p = 0.073).