Ultraviolet coloration in tiger swallowtail butterflies (Papilio Glaucus Group, Papilionidae) with a method for objectively quantifying adult butterfly wing wear

Abstract

Tiger swallowtail butterflies in the genus Papilio have an ability to visually distinguish between a large array of colors including those in the ultraviolet spectrum (UV). However, very little is known about UV reflectance patterns in these butterflies. Using a combination of UV photography and spectral analysis, we here show that several areas on the wings of tiger swallowtails reflect UV light including areas of blue scaling and the anterobasal region of the hind wings. We also discuss how a low level of UV reflectance from the wing membrane itself may be combined with UV photography to quantify wing wear. This technique could be used to objectively place wild-caught individuals into wear classes, approximating their age. Finally, we examine male mating preferences for pristine or artificially aged females and present preliminary results that suggest a strong preference for those that are pristine.