Core Xylocopa gut bacteria
We detected 25 genus-species bins present in the gut of bothXylocopa species (Figure 2). Of those 25 taxa,Bombiscardovia coagulans , Bombilactobacillus bombi , andLactobacillus bxid5692 (BEExact ID number) were highly abundant and prevalent (present in at least ~98% of gut samples) and we refer to these groups as ‘core taxa’ hereafter. DespiteEntomomonas having the highest average abundance of all shared bacterial taxa (Figure 2), it was not detected in a subset of X. sonorina individuals. Gilliamella was detected in 69.1% of samples and had an average of 4.36% relative abundance across all gut samples; Apibacter (87.3% of samples, 10.5% relative abundance) and Apilactobacillus , which was more frequently detected in the gut of X. sonorina (54.5% of samples) compared to X. tabaniformis (13.6% samples).