Pollinator-mediated selection is considered a principal driver in floral diversification and shifts in functional pollinators frequently propel transitions in floral phenotypes. Abronia (sand verbenas), an ancestrally night-blooming and nocturnally-pollinated genus, contains striking trait shifts away from the nocturnal moth pollination syndrome, both within and between taxa. Throughout most its expansive range, Abronia fragrans has white, day-closing flowers, while a narrow portion of its range is populated by a pink-flowered morph that remains open into late morning. Previous work has demonstrated that only nocturnal pollinators contribute to A. fragrans reproduction in a white-flowered population, while a pink-flowered population also receives pollination by diurnal floral visitors (i.e., butterflies and day-active moths). To explore whether this shift in floral characters is driven by local pollinator or herbivore communities, we reciprocally transplanted white and pink floral morphs into a pink-flowered and a white-flowered population. We simultaneously applied day, night, and always-open pollinator-exclusion treatments to inflorescences, and estimated inflorescence and leaf herbivory. Pollination success (proportion seed set per inflorescence) and herbivory rates (percent tissue damaged) did not differ between floral morphs at either site for any treatment; thus, this experiment rejects local adaptation to pollinator or herbivore communities. However, diurnal pollination was significantly higher for both morphs in the pink-flowered population than in the white-flowered population, and the most-destructive herbivore guild changed between sites: leaf herbivory was greater in the pink-population, while florivory was greater in the white-flowered population. Therefore, it remains possible that population-specific biotic or abiotic agents of selection play roles in this floral trait transition.