Gynaephora rossii

(Curtis, 1835)

Ross' tussock moth

Gynaephora rossii is a cold-adapted tussock distributed across the Holarctic tundra and alpine regions. The is notable for its extended larval development period of 7–11 years and its ability to survive freezing temperatures. are active during daylight hours in summer, with males actively searching for females while females are largely sedentary. The caterpillars feed primarily on Saxifraga species and certain willows.

Gynaephora rossii by (c) Doug Macaulay, some rights reserved (CC BY), uploaded by Doug Macaulay. Used under a CC-BY license.

Pronunciation

How to pronounce Gynaephora rossii: //ˌɡaɪniˈfɔːrə ˈrɒsaɪ//

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Identification

Distinguished from the sympatric Gynaephora groenlandica by: more patterned forewings in ; presence of a broad dark band along the hindwing margin (absent in G. groenlandica); and caterpillars with finer, feather-like () hairs versus the stiffer, unbranched (spinulose) hairs of G. groenlandica. Cocoons are single-layered versus double-layered in G. groenlandica. May be confused with Polia richardsoni in British Columbia, which differs in wing pattern, presence of hair on , and much thinner .

Images

Habitat

Arctic and subarctic tundra, rocky alpine tundra on high mountains, and muskeg with scattered trees. Occurs from sea level to at least 2,400 m elevation. Survives extreme environments including temperatures that freeze caterpillars solid.

Distribution

Holarctic: North America (Alaska, Canada, Rocky Mountains, Appalachians), Russia (Siberian Arctic from Urals to Chukchi Peninsula, Buryatia, Kamchatka, Magadan Oblast), and Japan (Hokkaido). Includes isolated alpine in Colorado, Wyoming, New Hampshire, and Maine.

Seasonality

active May to August in North America; primarily July in northern British Columbia. Large emergences occur for one to two days in June on Somerset Island, Nunavut. Caterpillars observed making cocoons in August in northwestern Chukotka.

Diet

Caterpillars feed on Saxifraga tricuspidata, S. oppositifolia, Salix arctica, Dryas, and potentially Potentilla. Also recorded on Rubus acaulis. Laboratory rearing successful on Rubus idaeus, Rosa, and Taraxacum. In Northern Yakutia, reported on Salix polaris, S. boganidensis, and S. pulchra.

Host Associations

Saxifraga tricuspidata - primary food plantMain food plant on Somerset Island
Saxifraga oppositifolia - primary food plantMain food plant on Somerset Island
Salix arctica - food plant
Dryas - food plant
Rubus acaulis - food plant
Salix polaris - food plantNorthern Yakutia
Salix boganidensis - food plantNorthern Yakutia
Salix pulchra - food plantNorthern Yakutia
Chetogena gelida - Tachinid fly, appears -specific to G. rossii

Life Cycle

Extended development with caterpillar stage lasting 7–11 years. Caterpillars survive freezing and can resume activity after thawing. occurs in silk cocoons. has been documented in females from eastern Yakutia and northwestern Chukotka, producing viable offspring without mating; however, this was not observed on Ellesmere Island.

Behavior

activity. Females have fully developed wings but rarely fly, instead remaining stationary and emitting to attract males. Males fly rapidly during daylight searching for females. Caterpillars and pupae practice behavioral by basking in sunshine to elevate body temperature. Caterpillars show avoidance responses to bat sounds despite absence of bats in their range. On Ellesmere Island, females typically lay in masses on or inside their cocoon; in Hokkaido, females fly and deposit eggs on upright woody stems.

Ecological Role

Herbivore in tundra . Serves as for flies including Chetogena gelida. Prey for birds including small foraging birds that tear open cocoons to consume masses.

Human Relevance

Named for John Ross, leader of the Arctic expedition during which the was discovered. Subject of physiological research on cold and freezing survival. MONA (Hodges) number 8290.

Similar Taxa

Gynaephora groenlandicaSympatric in Arctic Canada and Wrangel Island; distinguished by less patterned wings, absence of hindwing marginal band, spinulose (not ) caterpillar hairs, and double-layered cocoons.
Polia richardsoniSimilar wing coloration and period in British Columbia; distinguished by different wing pattern, hairy , and much thinner .

More Details

Taxonomic history

Originally described as Laria rossii by John Curtis in 1835. Transferred through Dasychira and Byrdia before placement in Gynaephora. include G. r. rossii (North America) and G. r. relictus (Asia), with G. r. daisetsuzana and G. r. lugens sometimes recognized.

Conservation notes

Recorded as common historically on Somerset Island (1832) but appears rare in Hokkaido (only two specimens collected 1920s–1950s). Present in multiple protected areas including Rocky Mountain National Park, Kenai National Wildlife , and Sirmilik National Park.