Reply to Williamson and Black's Comment

We reported a population of Lobelia cardinalis which differs from most red, tubular, temperate-zone flowers (including some nonspecific populations in other areas) by not secreting floral nectar (Brown and Kodric-Brown 1979). We hypothesized that these plants act as Batesian mimics, i.e., they attract hummingbird pollinators through resemblance to other flowers which secrete nectar; by previous experience with rewarding models, birds are conditioned to visit and pollinate effective mimics. Williamson and Black (1981) claim that three alternative hypotheses are more parsimonious than our mimicry hypothesis. We consider these in order, and suggest that none of them adequately and realistically account for all the facts: