With the arrival of summer, the diversity of pollinators in and around my garden is on an exponential upswing. Near my patio is a singular butterfly bush now thoroughly ravaged and almost completely defoliated by Asiatic garden beetles we met in a previous episode (Midnight marauders: Asiatic garden beetles, Maladera castanea, July 21, 2014). On the few remaining blossoms I spied what appeared to be a small hummingbird zipping around the florets. It looked like a hummingbird, but not exactly. This curious animal was actually a moth and a relative of the tomato hornworm that we met in a previous episode of Bug of the Week (“Horning in on your tomatoes”, September 26, 2005).
At 70 beats per second, wings of the hummingbird moth almost appear motionless.
Hummingbird moths are beautiful insects as both adults and larvae. Adults fly very rapidly with wings beating at a rate of 70 times per second. When it reaches a blossom, a long straw-like proboscis probes each floret and withdraws nectar in just a few seconds, then away flies the moth to the next feeding station. Some of its favorite flowers are honeysuckle, snowberry, lilac, phlox, bee balm, trumpet vine, vetch, butterfly bush, and thistles.
In addition to feeding like a hummingbird, some say that the greenish hairs on the back of the moth resemble the feathers of a ruby throated hummingbird. The flight and feeding behaviors, in conjunction with the unusual coloration, might be enough to confuse a hungry predator. While a tasty moth might make a fine meal, a predator might think twice about eating a feisty hummingbird.
Hummingbird moths are found throughout the United States and venture as far north as Alaska. Hemaris thysbe has two generations in southern states and one in the northern part of its range. After feeding and mating, females lay eggs on the leaves of small shrubs and vines. Honeysuckles, snowberries, viburnums, hawthorns, and cherries are favored for egg laying by this magnificent moth.
From the eggs hatch caterpillars that munch on the leaves. Like many species of hawk and sphinx moths, the caterpillars of hummingbird moths have a rather dramatic horn on the upper surface of their rear end and are commonly called hornworms. After consuming leaves for several weeks, the caterpillars disperse from their food source and move to the ground to form rather nondescript pupae.
When hummingbirds and their insect look-alikes are gone from our gardens this year, planting annuals and perennials with tubular flowers in the spring will ensure a return of these marvelous insects next year.
It’s easy to see the similarity between the hummingbird moth and the bird from which it gets its name.
Bug of the Week thanks Dr. Shrewsbury for providing the inspiration for this episode. David Wagner’s wonderful book “Caterpillars of Eastern North America” was used as a reference, as were the interesting web sites listed below. To learn more about hummingbird moths, please visit the following web sites: