Butterfly Defense

The life cycle of a butterfly includes four stages: the egg, the larva or caterpillar, the pupa or chrysalis, and the adult butterfly.  Butterflies are eaten by many predators including birds, frogs, toads, ants, wasps, snakes, rodents, and mammals.  They are vulnerable during any of the life cycle stages, but mostly as caterpillars or adults.  Butterflies have developed several strategies to avoid predation including flight, camouflage, poison, and mimicry.

Four life cycle stages….egg laying, larva, pupa with adult emerging

Butterflies in flight are hard to follow.  Large, flexible wings brought together in a clapping motion forcefully expels the air caught between the wings.  Butterflies have control over which way the wings are aligned and the direction the air is expelled, pushing the butterfly where it wants to go.  They use this ability to direct their flight in sudden changes of direction to avoid flying predators.

Camouflage is another highly effective defense strategy.  Dark, round spots located farther back on the wings appear to an observer as eyes on a much larger face.  Deimatic behavior involves sudden movement in combination with this type of pattern that causes potential predators to hesitate or stop from attacking.

Butterflies often have many splendid colors on the backs of their wings.  The underside of the wings of many species are quite drab.  In this way, the insect can sit still with wings folded together and draw very little attention to itself.  Patterns and colors may also blend in with their surroundings making them appear as sticks, leaves, tree bark, or bird droppings.

Bright colors, such as the oranges seen on Monarch butterflies, are a warning display to potential predators that this butterfly is bad tasting or toxic.  Several plants, such as milkweed, have developed chemical toxins as a defense against herbivores eating them.  Monarchs and other species can eat these plants, separate out the toxin, and store it for their own use.  After becoming sick from eating one or more of these butterflies, predators learn to avoid them.

Some species have developed bright colorful patterns that are quite similar to toxic species.  The viceroy butterfly can be difficult to distinguish from a monarch, especially given only a quick look.  Advertising their bright colors, viceroy butterflies fool predators into thinking they are also toxic.  This is referred to as mimicry.

Butterflies are out in large numbers throughout the high summer, and you can observe many of these strategies in backyards, public areas, or open fields.