Hemileuca eglanterina

Boisduval, 1852

Sheep Moth, Common Sheep Moth

Species Guides

Hemileuca eglanterina shastaensis(Mount Shasta Sheep Moth)

Hemileuca eglanterina, commonly known as the sheep moth or common sheep moth, is a day-flying saturniid native to western North America. The exhibits remarkable geographic variation in coloration, ranging from nearly black to pink/yellow to the typical orange with black markings. are short-lived and lack functional mouthparts, relying entirely on fat reserves accumulated during the larval stage. The species has been documented in coevolutionary dynamics with Argiope spiders, which appear to lure male moths using chemical mimicry of female moth .

Hemileuca eglanterina by no rights reserved, uploaded by Andreas Manz. Used under a CC0 license.

Hemileuca eglanterina1 by J Schmidt. Used under a Public domain license.

C.1957. Hemileuca eglanterina adult in resting position on bitterbrush. Collected by Robert L. Furniss. Steens Mountain, Oregon. (40832349124) by R6, State & Private Forestry, Forest Health Protection. Used under a Public domain license.

Pronunciation

How to pronounce Hemileuca eglanterina: /ˌhɛmɪˈljuːkə ˌɛɡlænˈtɛrɪnə/

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

Identification

Highly variable coloration across geographic range; typical form shows orange wings with black markings, but range from nearly black to pink/yellow. Day-flying habit distinguishes it from most saturniid . Males have broad wings and streamlined bodies with feathery for detecting female . lack functional mouthparts. Similar to other Hemileuca but distinguished by geographic range west of the Sierran crest in California and specific plant associations.

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Habitat

Grassland and shrub-dominated in western North America; males typically fly well above vegetation . Associated with habitats containing plants Ceanothus, Rhamnus, and Rosa. In California, occurs west of the Sierran crest and in mountains of Southern California, ranging near to the coast.

Distribution

Western North America; California west of the Sierran crest, mountains of Southern California, and coastal regions. studied across southern and western United States where range overlaps with Argiope aurantia spiders.

Seasonality

appear in summer; day-flying active during daylight hours.

Diet

Larvae feed exclusively on plants of three : Ceanothus, Rhamnus (including coffeeberry), and Rosa. lack functional feeding mouthparts and incomplete ; adults do not feed and rely entirely on fat reserves accumulated as larvae.

Host Associations

Ceanothus - larval food plant
Rhamnus - larval food plantincluding coffeeberry
Rosa - larval food plant

Life Cycle

are short-lived; mate location accomplished through volatile . Males engage in circular locating (500 m to 1 km diameter) when detecting female , then follow gradient to locate calling female. Females invest most energy in production and rarely stray far from site; once mated, fly to appropriate trees to deposit eggs. Even unmated females deposit eggs in large quantities. Both sexes live only a few days.

Behavior

Males fly in large circles through where females likely occur; when plume detected, paths become smaller diameter to geospatially map pheromone concentrations and follow gradient to emitting female. Males rarely fly below 1.5 m except to court females. Day-flying activity pattern. -level variation in response to Argiope spider pheromone lures suggests ongoing coevolutionary dynamics.

Ecological Role

Prey for Argiope spiders; subject to via chemical mimicry of mating by female Argiope aurantia. Potential coevolutionary arms race with involving pheromone-based attraction. Larvae function as herbivores on woody shrubs; serve as food source for visually-hunting predators.

Human Relevance

Collected for scientific study and museum collections; subject of research on -prey and chemical . Misinformation on internet incorrectly associates with feeding on sheep wool—this is false, as larvae feed only on plants. Popular among moth enthusiasts and at museum open houses due to colorful appearance and day-flying habit.

Similar Taxa

Hemileuca heraSimilar geographic variation in coloration; distinguished by specific range and associations
Hemileuca nuttalliRelated in same clade but shows no attraction to Argiope lures, unlike some H. eglanterina
Hemileuca maiaRelated buck moth ; males show no attraction to Argiope lures
Hemileuca nevadensisRelated ; males show no attraction to Argiope lures

Misconceptions

Internet misinformation falsely claims sheep moth larvae feed on sheep wool or that wooly bear caterpillars feed on sheep hair. These are false—Hemileuca eglanterina larvae feed exclusively on plants (Ceanothus, Rhamnus, Rosa). The "sheep moth" does not indicate any association with sheep as a .

More Details

Population Variation in Predator Response

Hemileuca eglanterina exhibits within- variation in attraction to Argiope aurantia spider lures, with responses ranging from strong to weak to no attraction depending on the . This variation, mapped onto the Hemileuca , suggests a complex coevolutionary history involving measures and countermeasures between and prey.

Museum Collections

The Bohart Museum of Entomology at UC Davis houses approximately 400-500 specimens of this across around 10 drawers, representing significant geographic variation. Many specimens were collected by Mike Smith, a U.S. Air Force veteran who raised hundreds of Hemileuca from caterpillars and to study geographic variability.

Sex Pheromone Biology

Female emit -specific volatile mixtures to attract males. Male moths use sensitive to detect these pheromones and may travel a mile or more to locate females. This system appears to be exploited by Argiope spiders through chemical mimicry.