(A) Sample Collection
Between 2019 and 2020, 33 X. sonorina and 22 X. tabaniformis adults were collected. Bees were captured in one of three ways: netted while foraging, caught using traps over the nest entrance (Supplementary Figure S1) or through excavation of logs to sample entire nests. The type of capture was recorded, with bees caught on the wing denoted as ‘foraging’ and those captured within or exiting a log denoted as ‘nest-caught’. Samples were obtained from Davis, CA (21 X. sonorina ; 14 X. tabaniformis ), Anza-Borrego Desert State Park in Southern California (1 X. sonorina , 8 X. tabaniformis ), and Tempe, Arizona (11 X. sonorina ). Samples from Davis and Anza-Borrego were captured during late summer and early fall while samples from Tempe were collected in early summer (see data file for collection date). Bee species can be distinguished morphologically, and identifications were verified using voucher specimens at the Bohart Museum of Entomology. Captured carpenter bees were photographed, then killed by placing them in a -20 oC freezer where they were stored until dissection.