Colours of nocturnal hawkmoth-pollinated flowers

MORÉ M., COCUCCI A.A., SÉRSIC A.N HEMPEL DE IBARRA N., FLÜGGE A., VOROBYEV M., WARRANT E. AND KELBER A.

San Luis

Jornada; XXIX Jornadas Argentinas de Botánica y XV Reunión Anual de la Sociedad de Botánica de Chile.; 2003

Flowers pollinated by nocturnal moths appear white or pale in colour to the human eye and, assuming they are seen similarly by hawkmoths, they are usually believed to give strong intensity contrast in low light condition. Kelber and collaborators (2002) demonstrated that nocturnal moths are able to discriminate between different colours -including UV- under night light conditions. We raised the question whether nocturnal flowers present colours, which can be discriminated by hawkmoths at night. We collected hawkmoth-pollinated flowers in the north-western part of Argentina and recorded the reflectance spectra of 17 species belonging to 12 families. Half of them presented spectra corresponding to human whitish colours with low UV-reflection. Three species were white without UV-reflection. Seven species had diverse colours: vivid orange, yellow, pink, and violet. Thus, indicating that these flowers are not truly white under hawkmoth vision and that colour might play an important role for flower detection and discrimination by nocturnal moths. We present model calculations showing how well these flower colours are discriminated by the visual system of the nocturnal moth Deilephila elpenor.