Responsive nectar secretion in Scrophularia californica

This study explores nectar production in Scrophularia californica, a native California herbaceous perennial. I conducted a series of field experiments to determine whether S. californica can replenish nectar in response to extractions, whether the rate of nectar production varies as a function of sexual phase, how much independence flowers exhibit in nectar production, whether nectar refills and ceases on attaining an optimum level or set point, and whether nectaries can regulate the principal components of nectar. Sugar content of nectar was determined using the anthrone method of carbohydrate analysis. S. californica demonstrates nectar replenishment 2.5 times greater when hourly removals are made, some degree of independence in nectar production, similar rates of nectar secretion during sexual phases, no apparent set point after refilling and the capacity for regulating sugar and water in nectar. Nectar may not be as costly for S. californica as it is for other species, or its costs may be offset by the certainty of high pollinator visitation which may obviate additional regulatory mechanisms.