Royal Alberta Museum: Invertebrate Zoology - Bug Facts

[Caterpillars and Other Immature Insects]

Fact Sheets: Commonly Observed and Asked About Insects and Spiders Found in Alberta

Waved Sphinx (Ceratomia undulosa)

Waved Sphinx
Photo CD 0023 3291 1601, Image #05 - Credit: Terry Thormin

Waved Sphinx, caterpillar
Credit: Terry Thormin

INTRODUCTION

There are about 21 species of sphinx moths in Alberta. The Waved Sphinx has recently moved into central Alberta and is often observed. The large green caterpillar is often seen when it comes down out of the trees and shrubs and goes looking for a place to pupate.

IDENTIFICATION

The adults have brownish-grey front wings with black wavy or zigzag lines. The hind wings have a less defined pattern. Wingspread is from 75 to 110 mm. The larvae are green with a pink horn near the back end, and six or seven pale yellow diagonal stripes on the sides of the body. The larvae can get up to about 75 mm.

DISTRIBUTION

In Alberta the Willow Sphinx is found primarily in Edmonton, and has probably moved in because of the introduction of ornamentals like black ash and lilac, both of which are food plants for the larvae. Eventually it may be common in all major cities in the province. It is common in eastern North America.

TIME OF YEAR

Adults appear from mid-June to early July. Larvae are present from late July through late August, but are not usually seen until they are fully grown and ready to pupate. They overwinter in the pupal stage.

HABITAT AND HABITS

Larvae feed on leaves of black ash, lilac, hawthorn, oak and privet. Because of their colouring, they are very difficult to see in the green foliage. When they are ready to pupate, they leave the bush or tree they are in and come down to the ground. At this stage the caterpillars are often easy to see as they roam around looking for a place to pupate. They pupate in the soil, usually within 2 to 3 cm of the surface, but occasionally as deep as 12 cm. Adults are nocturnal, and thus not often seen. They are attracted to lights, and do occasionally turn up on the wall of a house beside a porch light.

SIMILAR SPECIES

Although there are 21 species of sphinx moths in Alberta, most look quite different in colour from the Waved Sphinx. The Vashti Sphinx is the most similar species with very similar front wings. The hind wings, however, are banded black and white and the overall size is considerably smaller. There are several caterpillars that are similar and these can be tough to identify, in some cases requiring rearing them to adulthood to confirm the identification.

COMMENTS

This species is never abundant enough to be considered an important pest. When people do find them, either the adult moth or the caterpillar, they are amazed at the size and curious to know what the insect is.

For information on how to over-winter pupae of this species, see How to over-winter butterfly and moth pupae

For more information on the Waved Sphinx you can visit the University of Alberta’s entomology collection species page.

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Last update: December 10 2004