Gender- and Size-based Variation in Wing Color in Large Milkweed Bugs (Oncopeltus fasciatus) in Georgia

Abstract

Abstract Milkweed bugs are aposematically colored, with orange and black on their forewings, and the degree of both colors varies among individuals. Despite the attention given to the warning nature of this color, there has been little research directed at this variation. In this study, the subtle variation in wing colors of one species of milkweed bug, Oncopeltus fasciatus (Large Milkweed Bug) was measured to determine if the color variation was related to sex or body size. Fifty-eight bugs were hand-collected at three sites in northeast Georgia, and their wings scanned using a slide scanner and measured digitally using image analysis software. Wings of females were larger than those of males in general, and the color analyses showed statistically significant differences in wing hue between males and females. Females also had darker black wing sections than males, which could be evidence of a sex-related difference in immune function. Regardless of sex, wings of larger bugs had deeper orange color and da...