Sphinx canadensis

Boisduval, 1875

Canadian sphinx

Sphinx canadensis, the Canadian sphinx, is a in the Sphingidae first described by Jean Baptiste Boisduval in 1875. It is an ash- whose larvae feed exclusively on black ash (Fraxinus nigra). are notable for flying later in the year than most other sphinx moth species, with peak activity in late July and early August. The species is frequently confused with the hermit sphinx (Sphinx eremitus) in areas where their ranges overlap.

Sphinx canadensis, female, upperside. United States, Maine, Cumberland, North Bridgton by The Trustees of the Natural History Museum, London. Used under a CC BY 3.0 license.

Sphinx canadensis, female, underside. United States, Maine, Cumberland, North Bridgton by The Trustees of the Natural History Museum, London. Used under a CC BY 3.0 license.

Sphinx canadensis – Canadian Sphinx Moth by Andy Reago & Chrissy McClarren. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Sphinx canadensis: /ˈsfɪŋks ˌkænəˈdɛnsɪs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from the hermit sphinx (Sphinx eremitus) by the absence of a white spot on the forewing—a feature consistently present in S. eremitus. The combination of gray-brown forewings with black streaks along and white marginal lines, plus black-and-white banded hindwings, provides diagnostic field marks. The black lateral patches on larvae are thought to mimic the curled leaves of black ash.

Images

Appearance

have a wingspan of 70–85 mm. The forewing is gray-brown with black streaks along the , interrupted by white lines along the outer margin. The hindwing displays a pattern of black and white bands. Unlike the similar Sphinx eremitus, this lacks a white spot on the forewing. Larvae have distinctive black patches on their sides.

Habitat

Associated with swamp edges and moist where black ash (Fraxinus nigra) grows. The larval plant occurs at wetland margins and in riparian zones.

Distribution

Northeastern United States and Canada, ranging north to Newfoundland and Labrador. Present in Vermont and throughout the northeastern region.

Seasonality

fly predominantly in very late July and early August, notably later than most other sphinx moth .

Diet

Larvae feed exclusively on black ash (Fraxinus nigra). nectar on Phlox and bouncing bet (Saponaria officinalis).

Host Associations

Fraxinus nigra - larval sole confirmed larval plant; grows at swamp edges
Fraxinus americana - larval previously thought to be used but recent observations refute this
Vaccinium - larval previously thought to be used but recent observations refute this
Phlox - nectar sourcepreferred nectar source
Saponaria officinalis - nectar sourcepreferred nectar source; bouncing bet

Life Cycle

Complete with , larva, pupa, and stages. Larvae burrow into soil to pupate. Adults emerge in late summer. Specific details of stage and number of per year are not documented in available sources.

Behavior

are or in activity pattern. Larvae display cryptic coloration with black lateral patches that appear to mimic curled black ash leaves. Adults fly later in the season than , suggesting possible temporal isolation from related .

Ecological Role

herbivore dependent on black ash, making it vulnerable to ash tree decline from emerald ash borer and other threats. As an ash-specialist, it contributes to nutrient cycling in wetland forest and serves as prey for and other natural enemies.

Human Relevance

Subject of ecological concern due to dependence on ash trees threatened by emerald ash borer (Agrilus planipennis). Used as a study for understanding impacts of ash decline on dependent Lepidoptera. Occasionally attracted to lights.

Similar Taxa

Sphinx eremitusOverlapping range and similar appearance; distinguished by presence of white spot on forewing in S. eremitus (absent in S. canadensis)

Misconceptions

Previously believed to have broader plant range including white ash and blueberry, but recent observations confirm exclusive specialization on black ash.

More Details

Taxonomic history

First described by Jean Baptiste Boisduval in 1875. The epithet canadensis reflects its northern distribution in Canada.

Conservation context

As an ash-dependent , this potential impacts from widespread ash mortality caused by emerald ash borer invasion across North America.