Meeting Abstract
Climate change may affect the visual ecology of butterflies by altering temperature and food availability, which are environmental factors known to influence the development of morphological traits important for mate selection in these animals. These traits include eye size, as well as sexually dimorphic wing patterns and colors. To investigate how temperature variation may impact butterfly visual ecology, we collected Speyeria mormonia from different sites across a temperature gradient and studied the natural variation of two of their sexually dimorphic traits. The dorsal sides of wings from male and female S. mormonia are similar in color, but the ventral sides of their forewings are dimorphic: females have an orange patch that is absent in males. The eyes of S. mormonia are also sexually dimorphic: the eyes of males have larger absolute and relative surface areas than those of females. We collected S. mormonia from five different elevations, spanning approximately 2000 ft., within the Rocky Mountain Biological Laboratory in Colorado. We used image-analysis software and reflectance spectroscopy to measure the wing color of individuals from the different sites. We studied the interaction between elevation and a study population’s wing color or eye surface area. We found that female S. mormonia from higher elevations generally have redder patches of color on their ventral forewings than those from lower elevations. We also found that S. mormonia from an elevation of 11,000 ft. had the smallest average relative eye surface area (0.25 mm2/mm) while those at 9,400 ft. had the largest (0.31 mm2/mm). We suspect that the morphological differences present across elevations may impact mating interactions. This study may ultimately hold implications on how climate change affects the visual ecology of S. mormonia.
