Hemaris thetis

Boisduval, 1855

Rocky Mountain Clearwing, California Clearwing

Hemaris thetis is a day-flying sphinx moth in the Sphingidae, commonly known as the Rocky Mountain clearwing or California clearwing. The exhibits clearwing with reduced wing scaling, resembling a bumblebee in . are active from May to August and feed on nectar from various flowers. The species was first described by Jean Baptiste Boisduval in 1855 and occurs in mountainous regions of western North America.

Hemaris thetis, female, upperside. United States, Colorado, Jefferson, Golden by The Trustees of the Natural History Museum, London. Used under a CC BY 3.0 license.

Hemaris thetis, male, underside. United States, Colorado, Jefferson, Golden by The Trustees of the Natural History Museum, London. Used under a CC BY 3.0 license.

Hemaris senta BMNHE274287 male up by Robert Young. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Hemaris thetis: /hɛˈmɛərɪs ˈθiːtɪs/

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

Identification

Distinguished from other Hemaris by geographic range and subtle morphological differences. Hemaris thetis overlaps with H. diffinis (snowberry clearwing) in some areas but tends to occur at higher elevations and more western localities. H. thysbe (hummingbird clearwing) is generally more eastern and has different wing scaling patterns. Accurate identification often requires examination of geographic provenance combined with wing venation and body coloration details. The species lacks the extensive dark scaling on the wings seen in some other clearwing moths.

Images

Appearance

have partially transparent wings with reduced scaling, dark borders along the wing edges, and a robust, furry body. The clearwing appearance results from sparse scaling on the central wing . Body coloration typically includes greenish or brownish tones with pale or yellowish markings. The wingspan is moderate for the . Like other Hemaris , the has a streamlined body adapted for rapid, hovering .

Habitat

Streamsides and meadows in mountainous areas. Occurs in montane and subalpine zones, often associated with riparian corridors and open grassy at elevation.

Distribution

Western North America from Colorado, New Mexico, Montana, Idaho, Wyoming and Utah westward to California, and north to British Columbia. The range spans the Rocky Mountains and associated ranges west to the Pacific Coast.

Seasonality

are on wing from May to August. The probably has one per year.

Diet

feed on nectar of various flowers including Arctostaphylos uva-ursi (bearberry) and Lupinus . Larvae feed on Symphoricarpos species (snowberries and related shrubs).

Host Associations

Symphoricarpos - larval food plantLarvae feed on in this
Arctostaphylos uva-ursi - nectar source visit for nectar
Lupinus - nectar source visit for nectar

Life Cycle

Probably one per year. are laid on plants. Larvae are caterpillars, typical of Sphingidae, feeding on Symphoricarpos. occurs in soil or leaf litter. emerge in spring and summer.

Behavior

are and hover at flowers while feeding on nectar, resembling hummingbirds or bumblebees in . This hovering and rapid wing movement are characteristic of the . The clearwing and coloration likely serve as protective mimicry of stinging Hymenoptera.

Ecological Role

may act as of the flowers they visit. The is part of the montane pollinator in western North America. Larvae are herbivores that consume leaves of Symphoricarpos shrubs.

Human Relevance

Not a significant pest or beneficial from a human perspective. are sometimes mistaken for hummingbirds or bees due to their and appearance. The species may be encountered by hikers and naturalists in mountain meadows and along streams.

Similar Taxa

Hemaris diffinisOverlapping range in western areas; H. diffinis (snowberry clearwing) tends to occur at lower elevations and has different wing scaling patterns
Hemaris thysbeSimilar appearance and ; H. thysbe (hummingbird clearwing) is generally more eastern in distribution with different wing scaling details
Sesiidae (clearwing moths) of with similar clearwing and -mimicry, but belong to different superfamily and have different wing venation and body structure

More Details

Taxonomic history

Originally described as Macroglossa thetis by Boisduval in 1855, later transferred to Hemaris. The has been subject to taxonomic revision along with other members of the .

Conservation status

Not formally assessed; appears to be locally common within its range but dependent on montane meadow and riparian that may be affected by climate change and land use.