Mimicry-related Predation on Two Viceroy Butterfly (Limenitis archippus) Phenotypes

Abstract

Abstract In the eastern United States, the mimetic viceroy butterfly (Limenitis archippus) exhibits clinal variation in wing color, ranging from a tawny orange phenotype (L. a. archippus) in the N to a dark mahogany phenotype (L. a. floridensis) in Florida. Geographic distributions of these two subspecies are roughly coincident with the ranges of the viceroy's two eastern mimicry models: the monarch (Danaus plexippus) in the N, and the queen (D. gilippus) in the S. This coincidence has historically been attributed to “model-switching”: presumably, southern viceroys have switched from mimicking the monarch to mimicking the locally predominant queen, due to selective pressure exerted by visually foraging predators. As an initial test of this hypothesis, I sought evidence of selective predation on light and dark viceroys by captive red-winged blackbirds previously exposed to either monarchs or queens. Results were consistent with the model-switching hypothesis: queen-conditioned birds preferentially avoided ...