Sphinx Moths

Sphinx Moths in Your Butterfly Garden

What is that large creature hovering over my flowers drinking nectar? It is the size and shape of a hummingbird but birds don’t have antennae. It not a butterfly with that plump hairy body and short sweptback wings. Thus, the observant butterfly gardener realizes that sphinx moths are also participants in a butterfly garden.

Barnstorming Pollinators!

The sphinx or hawk moth ranks second only to dragonflies as aviators with the ability to hover, fly backwards and sustain flight speeds over 30 mph. At least 50 species of these large (up to 6” wingspan) furry moths live in our area, but most have no tongue and abstain from drinking. As butterfly gardeners, our interest centers on the nectar drinkers, especially the three largest species often called hummingbird moths. Since bees and butterflies go to bed at dusk, night blooming flowers depend on the hummingbird moths as their primary pollinators, especially since their hairy bodies pick up pollen almost as efficiently as bees. Proportionally they have the longest tongues of any insect; the Carolina hummingbird moth has a ten-inchlong tongue!

Hornworms

All sphinx moth caterpillars have jaunty tails or “horns” on their butts and are commonly lumped together as “hornworms.” Like butterfly children, most of the caterpillars are host plant specific. Two of the 50 species have earned the ire of humans by eating tomato vines. THE tomato hornworm has a black horn and white V markings on its green or dark brown body. It metamorphosizes into the five-spotted hawk moth. The Carolina hummingbird moth is the parent of the far more common tobacco hornworm, which has a red horn and markings of single white lines rather than Vs on its green body. Angry vegetable gardeners call both “Tomato Hornworms” and may murder them on sight.

A pandorus hornworm would never eat tomatoes; grape leaves are on its menu.

Photos by Lenora Larson.

Bumblebee clearwing moths nectar during the day. As a caterpillar, it eats leaves in the honeysuckle family.

White-lined sphinx moths nectar both night and day. Unlike most caterpillars, it eats many species of plants, but never tomatoes. The Carolina hummingbird moth nectars on datura using its 10” tongue. The tobacco hornworm is the child of the Carolina hummingbird moth. Don’t kill it!

Strategies for Co-existence

How can you preserve these spectacular pollinators without losing your tomato crop? Easy, plant a “sacrificial” indeterminate tomato vine to reserve for the hornworms. Choose a grape tomato variety such as the Super 100 series, use high nitrogen fertilizer and remove all flower buds to promote abundant leaves. This healthy-looking plant will usually be the mother’s choice for egg-laying, but any hornworms found on “your” tomato vines can be relocated to their vine. Another solution is to plant an inedible caterpillar food plant from the Tomato (Nightshade) family such as datura or flowering tobacco.

Attracting Hummingbird Moths

Butterflies will not be seen unless their specific host plants are present. Likewise, moths need their host plants to be present in the area. The adults are then drawn to hover over their favorite nectar-rich tubular blooms. You and the moths will delight in heavily scented flowers like honeysuckle, datura, nicotiana, heirloom petunias and cleome.

LENORA LARSON Butterfly Maven

A Marais des Cygnes Master Gardener, Lenora is a member of the Idalia Butterfly Society and Kansas Native Plant Society. She gardens in the clay soil and cruel winds of Paola, KS. She may be contacted at lenora.longlips@gmail.com.