Carpenter bees are considered important pollinators on islands (e.g., McMullen 1989, 1993). Because of their resourceful foraging and nesting behavior (Jackson & Woodbury 1976, Roubik 1989, Scott et al. 1993), they may be extremely resilient to disturbances and unpredictable food sources. With a lack of a patterned flowering period and low availability of flowers per day, the cactus benefits from an asymmetrical relationship with Xylocopa whose populations would not be sensitive to reduced flower densities of a particular species.