Butterfly Predators: What Eats Butterflies and Moths?

Guests sometimes ask us what role butterflies play in the ecosystem. Do they serve a purpose? Can you have too many of them? What eats butterflies?

Butterflies are pollinators, which of course offers great benefits to the ecosystem. However, like any other creature on Earth, their numbers have to be kept in check, because caterpillars dine on plants, and too many caterpillars will wipe out a plant population in no time. So even though a female butterfly may lay between 300 and 800 eggs in her short life, only a few of these will make it to the adult butterfly stage, and even fewer of these will survive long enough to mate. Here's a look at some of the butterfly predators that help keep the system in balance.

Lizards, frogs, and other reptiles. Butterflies are quick, but so is the tongue of an anole. The one shown below nabbed this Julia Longwing and immediately chomped off its head. The wings of butterflies don't provide any nutrition, so most reptiles will just eat the bodies, leaving discarded wings behind like peanut shells at a baseball game. (Learn more about anoles here.)

Yup, those are antennae sticking out of this anole's mouth. 

Ants. While a living butterfly is a little hard for ants to take down, butterfly eggs are just the right size to be carried off for a meal. Ants are known to dine on sick caterpillars, those in the process of molting or pupating, and butterflies that have died of natural causes. Ants may also feed on pupa, especially those of moths that tend to bury themselves in the ground. The photo below shows ants feasting on a sphinx moth pupa.

Wasps. Paper wasps are especially known to feed on caterpillars. Many gardeners consider them beneficial in eliminating caterpillar pests like cutworms or tomato hornworms, but they will eat butterfly caterpillars too. The paper wasp below is dining on a monarch caterpillar; in some areas, paper wasps are major predators of these larvae.

Birds. Many insect-eating birds eat both caterpillars and adult butterflies and moths. In defense, many of these butterflies have evolved to be toxic, or at least foul-tasting, but some birds have found their way around this difficulty: Orioles slit open the abdomen of the butterfly before eating them to avoid a heavy dose of the toxins.

Parasites. Some butterfly predators are much smaller than you'd expect. Many other insects use caterpillars and pupae as hosts for their own young. For instance, the chalcid wasp lays its eggs in newly-formed pupae that haven't had a chance to harden yet, or even through the skin of a caterpillar preparing to pupate. The eggs hatch and the wasp larvae eat the chrysalis from the inside out. When they're full-grown, they eat a small hole through the pupal case and escape to mate and continue the cycle. Several hundred Chalcid wasps can emerge from a single pupa, as shown below with infected monarch chrysalids. (Learn more about chalcid wasps here.)

Bats. Though most butterflies have settled down long before dusk falls, moths are just getting ready to get up and about. What else emerges at dusk? Bats, of course! Not surprisingly, bats are big predators of moths. Silk moths can make an especially nutritious treat due to their large bodies full of fat.

Humans. In some parts of the world, caterpillars are an important food source. In South Africa, the larva of a moth called Gonimbrasia belina is one of the main sources of protein for the indigenous people. In countries like China silkworm pupae have been eaten for centuries, and in the US Pacific Northwest, members of the Native American tribe Paiute historically ate Piagi (other sources call it Piuga), the caterpillars of the Pandora Pinemoth (Coloradia pandora). Learn more about entomophagy (the consumption of insects as food) by clicking here.