Spatial pattern analysis of silvery spots in Agraulis vanillae and Dione spp. butterflies.

BIANCHIMANO, LUCIANA; NUÑEZ-BUSTOS EZEQUIEL; BARREIRA, ANA S.; TUBARO, PABLO L.

Dresden

Workshop; Bio-inspired optics and photonics - From metamaterials to applications; 2019

Max Plack Institute or the physics of complex systems

The Gulf Fritillary Butterfly (Agraulis vanillae) and its closely related species of the genus Dione have a wide geographic distribution, from southern United States to the Pampas region in Argentina, inhabiting a large range of different environments. These species possess highly reflective silvery structures on the ventral side of their wings that are usually exposed when these butterflies flap their wings while perched. The biological function that these structures fulfill, if they meet any, has not been described yet. These structures could play a role in visual signaling (i.e. mate choice, and/or species recognition) or as an anti-predatory aposematic signal. Another possibility is that these silvery spots intervene in the regulation of body temperature of these butterflies. Surfaces with high percentage of broadband reflectance in butterflies allow reducing the radiation absorbed and therefore could contribute to reduce overheating when the individuals pose in direct sunlight. This effect is more likely to have an important role in species or populations inhabiting more open environments with higher exposure to sunlight. We explore the hypothesis that silvery spots in these species cover a higher percentage of the wings in those species (or populations) that inhabit more open habitats, and vice-versa. For this, we will use spatial color analysis on photographs of museum specimens of Agraulis vanillae and Dione spp. and investigate the patterns of variation in these highly reflective structures among them, particularly in relation to the environmental structure of their habitats.