White-Lined Sphinx Moths: Pollinators, Hornworms, and Hummingbird Lookalikes

White-lined Sphinx Moths are common pollinators across the southwest. They're so big, people mistake them for hummingbirds.

Spring in San Diego means wildflowers, warm evenings, and the return of one of our most charismatic nighttime pollinators: the White-lined Sphinx Moth (Hyles lineata). I get texts and shared stories every year from mesmerized friends and clients who've run into these moths in their yards, on the trails, or even walking around their neighborhoods in the evening.

It's a Bird! It's a Bat! It's a... Moth?

If you have ever spotted something hovering at a flower and thought, "wait, was that a hummingbird?" there is a good chance you were actually looking at one of these moths. White-lined Sphinx Moths look like hummingbirds because they're enormous, and they feed the same way — hovering in front of blooms, beating their wings rapidly, and darting from flower to flower with surprising speed and precision. Both daytime and nighttime fliers, they are also called hummingbird moths or hawk moths.

White-lined Sphinx Moths are big, beautiful, and wonderfully strange. Their caterpillars, called hornworms, are thick little chonkers, while the adults can grow to nearly three inches across, making them among the most noticeable moths in Southern California. Though these moths are hefty, their typical adult lifespan is only a few weeks.

What do White-lined Sphinx Moths Pollinate?

These moths are important pollinators. White-lined Sphinx Moths use a two- to three-inch long straw-like tongue, called a proboscis, to reach nectar inside the deepest flowers. As they feed, the moths transfer pollen between blooms and help support both native plants and flowering landscapes.

Sphinx Moths tend to be generalists, which means they aren't picky eaters and will visit many different flowers depending on where in the world they're foraging. Columbines and thistles are favorites, but here in San Diego, they are especially associated with Sacred Datura (Datura wrightii). Datura is a dramatic native plant with enormous white flowers. It's highly toxic to mammals, but has a tight ecological relationship with Sphinx Moths, who are one of the plant's most successful pollinators. Watching a Sphinx visit Datura at dusk is one of those quiet nature moments that feels almost unreal.

Two Carolina Sphinx Moths visiting Sacred Datura at night — one diving deep, the other in flight.

Sacred Datura is part of the nightshade family, which also includes tomatoes, peppers, potatoes, and eggplants. This explains why some Sphinx Moths, like tomato hornworms, are less beloved by gardeners.

Where Can You Find Sphinx Moths in Southern California?

Anywhere! Everywhere! These moths are found nearly anywhere there are plants and flowers. From the desert to the coastline and the mountains in between, White-lined Sphinxes are some of the most widely dispersed Sphingid moths in our region. Others, like the gorgeous Pacific Green Sphinx (Proserpinus lucidus), are found only in our mountains in winter. Peak season for the White-lined Sphinx is March — precisely when everyone starts asking me about them. 🙂

Do Sphinx Moths Have Cultural Importance?

Sphinx Moths likely have different cultural significances wherever they are found, but locally, it is the Cahuilla Band of Indians (AKA Qawishpa Cahuillangna) that is most known for using Sphinx Moths as food. In spring, they would harvest and eat White-lined Sphinx caterpillars after removing the head and viscera. According to one anthropological account, they would then dry any leftovers and grind the hornworms into a nutritious flour.

Though their remaining territory is much smaller today, the Cahuilla historically occupied and stewarded the northernmost desert in our county. To this day, the desert in spring is one of the best places to see huge quantities of hornworms munching away on native plants.

San Diego's Favorite Moth?

White-lined Sphinx Moths are not all beauty and grace. Sometimes their fast, frantic flightpaths collide with our heads. Get one stuck inside a well-lit room and things get chaotic quick. Meanwhile the caterpillars can do serious damage to certain crops and gardens.

Still, the adults are hard not to admire. They hover like tiny aircraft, zoom through the evening air, and make spring and summer evenings a little more magical. And those pink underwings! My heart! San Diego has around twenty species of Sphinx Moth, but the White-lined Sphinx is the most commonly observed — and one of the most likely to catch your eye.

To learn more about Sphinx Moths and other insects, consider signing up for my bi-monthly newsletter or follow me on Instagram. These are where I announce my bug-blacklighting parties, which almost always attract Sphingids and many other moth species.

Update: In 2024, I felt so inspired by these moths that I created my own White-lined Sphinx Moth costume for Halloween! My ever-supportive partner went as a lamp. 😭