Effects of foraging behavior on bacterial composition
Within X. sonorina (the only species in which we sampled bees from nests and while foraging), bees caught foraging had significantly greater richness compared to nest-caught bees (F1,49=4.6, p=0.04) and a trend towards higher diversity (Supplementary Figure S3; F1,26=3.1, p=0.08). Bacterial composition differed between foraging bees and nest-caught bees (PERMANOVA p=0.007) and between male and female bees (p=0.04) as well as with location and tissue (p<0.001). No male bees were captured while foraging and no significant interaction between tissue and foraging type was observed (p=0.07). Foraging bees exhibited a lower distance to centroid compared to nest-caught bees (betadisper behavior p=0.016) and male bees had lower distance to centroid compared to females (betadisper sex p=0.001). Notably, the crop of nest-inhabiting bees was nearly entirely comprised by Apilactobacillus , while the crop of foragers varied among individuals, with some foraging bees containing high abundance of known nectar inhabitants includingAcinetobacter nectaris and Neokomagataea thailandica .