Additional Adaptations Against Predation

Abstract

As butterflies, monarchs (Danaus plexippus) (Fig. 7.1) do not fight predators or act passively if an attack by a predator is imminent; instead, the monarch uses warning coloration and chemical defenses against predation. As adults, monarchs are brightly colored in orange, black, and white; they, therefore, stand out in the environment to a predator, much like the pattern of a poisonous coral snake (Micrurus fulvius) (Zug et al. 2001). What does the coloration of a monarch signal to a potential predator? That is unpalatable, so stay away. Monarch becomes unpalatable because of toxins that larvae feed upon in milkweed (Asclepias syriaca). These toxins are cardio glycosides, which elicits vomiting in birds that may feed upon them. Only two bird species, the black-headed oriole (Icterus abeillei) and the black-headed grosbeak (Pheucticus melanocephalus) are known to feed on monarch with no ill effect. In fact, the viceroy butterfly (Limenitis archippus) mimics the coloration of the monarch to offset predation on it, which is a form of mimicry known as Batesian.