[3] It is especially abundant, along with X. sonorina, in the Central Valley and in Southern California, including the Mojave Desert.

They are agriculturally beneficial insects and pollinators of diverse California chaparral and woodlands and desert native plant species.

The males typically have at least a few light hairs on the pronotum (dorsal prothorax) and the abdominal segments.

[2] Xylocopa californica has been observed to rob nectar from ocotillo, Fouquieria splendens, and are determined to be their primary pollinator in the Big Bend National Park, Texas, USA.

[12] Xylocopa californica inhabit the deserts of southwestern North America and endure high temperatures while they forage.

[11] Foraging in these high temperatures may cause thermoregulatory problems for the bee, which is increased by the heat released from the muscular activity needed for their flight.

[14] If they are not patrolling the nests, then they may exhibit scramble competition at flowering sites, where they hope to catch a female.

[10] Xylocopa californica does not have many predators, but in the southwest of Northern America, the ladder-backed woodpecker, Dendrocopos scalaria, has been observed to attack their nests.

[17] It has also been found in X. californica, except the infected larva does not look the same as the honey bee's; they develop spore cysts beneath the larval integument.