Secondary compounds can change the appearance (Mione and Anderson 1996, Olesen et al. 1998, Weller et al. 1998), taste (Baker 1978, Hagler and Buchmann 1993, Adler 2000, Gardener and Gillman 2002), and digestibility (Tadmor-Melamed et al. 2004) of nectar. In one of the most striking cases, the nectar of a cliffdwelling Mauritian plant Nescodon mauritianus (Campanulaceae) is rendered bright red by the presence of aurones, a product of flavonoid biosynthesis (Olesen et al. 1998)