By Cheryl Conley
Lake Creek Nature Preserve
Board of Directors
About mid-August I take out my hummingbird feeders, mix up a batch of hummingbird food, and wait. They are certainly amazing little birds. But occasionally, upon closer inspection, I see that it’s not a hummingbird at all. It’s actually a hummingbird moth.
Hummingbirds and hummingbird moths are an example of what’s called convergent evolution. This is when two unrelated species develop similar traits because they live in similar environments. Over the course of millions of years, both organisms independently evolved toward the same highly efficient biological design.
Let’s explore the similarities between the bird and the insect. While most moths fly at night, hummingbird moths are active during the day. The food source for both is nectar from flowers, which they drink while suspended in the air. Both can hover and can fly backwards and sideways. Both also have long mouthparts that are used to drink nectar—hummingbirds have an incredibly long tongue, while the moth has a long, coiled proboscis. A proboscis is a straw-like mouthpart that uncoils when the moth feeds. Both feed frequently throughout the day, and both help sustain a healthy ecosystem through pollination.
So how do they differ? About half of a hummingbird’s diet is nectar, while the other half is made up of small insects and spiders. The adult hummingbird moth feeds on nectar. A hummingbird is covered in feathers, while the moth is covered in fuzzy hairs. Hummingbirds have a beak; the moth has antennae. Hummingbirds have two legs, which are often difficult to see during flight, while moths have six. And, of course, hummingbirds are much larger. Hummingbird moths typically have a wingspan of only about 1. to 2. inches.
Hummingbird moths belong to the sphinx or hawk moth family, a group known for its strong, fast-flying members. Their plump bodies, rapidly beating wings, and ability to hover in front of flowers are what make them so easy to mistake for tiny birds. Some species even have mostly transparent wings, adding to their unusual appearance.
Like other moths, they go through complete metamorphosis: egg, caterpillar, pupa, and adult. The female lays her eggs on plants that will later provide food for the caterpillars. After hatching, the caterpillars feed and grow through several stages before eventually pupating. In warmer southern climates, hummingbird moths may have more than one generation each year. Many overwinter in the pupal stage and emerge as adults when temperatures warm again.
The caterpillar stage may look nothing like the graceful adult moth it eventually becomes. Hummingbird moth caterpillars are often called hornworms because many have a noticeable horn-like projection on the rear of the body. They can grow quite large and may be brightly patterned in shades of green, yellow, or white. Although the caterpillar and adult look completely different, they are simply two stages of the same remarkable insect.
Once the adult emerges, it begins visiting flowers for nectar and, in the process, transferring pollen from one flower to another. This makes hummingbird moths valuable pollinators. Native flowering plants are especially important because they provide nectar for adults and food plants for caterpillars.
So the next time you see what appears to be a tiny hummingbird darting from flower to flower, take a second look. If it has antennae, six legs, and a fuzzy little body, you may be watching one of nature’s best impersonators. With its hovering flight and hummingbird-like appearance, it’s easy to see how this moth earned its name.
