Technical Abstract: We report for the first time on the courtship behavior of a gynandromorph of a solitary bee. Such observational studies on a living specimen that is bilaterally male and female can indentify centers of control for specific insect behaviors. Our observations show that gender in bees is not linked to morphology and is likely affected by a completely different set of neural centers. Our gynander was clearly female-dominant with high sex appeal, despite being unable to mate successfully. We suspect that our bee gynander in Osmia ribifloris, as in other species, can occur when eggs are genetically damaged by extreme temperature changes. We expect greater environmental variation for pollinator species intended for active management, and therefore the incidences of such rare phenotypes might increase.