Resource: Butterflies

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Judging by their fragile appearance alone, you might think butterflies are extremely vulnerable to predators, which include birds, reptiles, spiders, and other insects, such as dragonflies and wasps. But butterflies have evolved several protective strategies since they first appeared more than 100 million years ago.

Most butterflies use a form of camouflage to blend into their environment so that it is almost impossible for predators to spot them. Some butterfly species are colored or marked to resemble dead leaves, while others look like tree bark. Still others have evolved ways to startle or confuse potential predators. For example, some species feature one or more large circular spots on their wings that make them look like part of the face of a much larger animal. These eyespots, or false eyes, may scare away some predators.

Butterfly predation actually starts during the larval stage. Soft and slow-moving caterpillars make easy targets. Thus, they have evolved numerous defenses, including many of the same survival strategies they’ll use as adults. This is why caterpillars are often colored brown or green to blend in with the plants and trees they live on. Caterpillar bodies may also feature eyespots or stinging hairs to deter predators.

In the natural world, vibrant colors and bold patterns are typical markings of a poisonous species. A brightly colored butterfly more often than not indicates to predators that it may not make a good meal. Were a bird or other animal to eat the butterfly, the predator would become sick from toxins contained inside its prey. When a predator learns to associate the warning sign with sickness, it knows to avoid this species of butterfly in the future. The orange-and-black Monarch butterfly gets its toxicity from the milkweed plant it eats as a caterpillar.

Even some non-poisonous butterfly species have come to imitate the markings of a poisonous species. This survival strategy is a form of mimicry. Since many predators have become sick from eating the poisonous butterfly, they will tend to avoid any animals resembling it in the future. Thus, the mimicking butterfly is protected despite having no toxins at all. The female form of one butterfly species in Indonesia can actually mimic one of five different species of unpalatable butterflies.

Many species of insects play specialized roles in ecosystems, and butterflies are no exception. The survival of butterfly species is essential to the maintenance of many healthy ecosystems. For example, many plant species rely on butterflies for pollination and reproduction.

To learn more about how and why insects evolve to blend in with their environment, check out Evolution of Camouflage, Masters of Disguise, and Seeing Through Camouflage.

To learn how butterflies and some other animals dramatically transform from one body form to another, check out Metamorphosis: Change of Plans.

To learn more about other migrating species, check out Hummingbird Species in the Transitional Zones, Marathon Migrators, Migration of the Monarch, and Ladybug Pajama Party.

Print Questions for Discussion

• During what times of the year are butterflies commonly found in Nevada? Why?
• Describe two adaptations that butterflies have to protect against predators.
• What is “mud puddling”? How does this behavior contribute to a butterfly’s well-being?
• Describe the relationship between the Monarch butterfly and the milkweed plant.