Some petunia flowers use ultraviolet light to attract certain pollinators. And dimming down or cranking up the flowers’ UV light intensity only takes the flip of a genetic switch.
Mutations on one gene in three species of Petunia from South America determine how much UV light petunia flowers absorb, an international research team reports December 14 in Nature Genetics. Variations of the gene, called MYB-FL, cause fluctuations in flavonol, a compound that controls how much UV light the flower absorbs, and, anthocyanin, a pigment compound that controls flower color, the researchers say.
UV and pigment differences among the three petunia species correspond to differences in the flowers’ pollinators. Nocturnal hawkmoths go for flowers that absorb lots of UV light, like the white flowers of P. axillaris. Bees like the small, purple flowers of P. inflata that absorb some UV light. The bright red flowers of P. exserta absorb less UV light and are visited by daytime pollinators such as hummingbirds.