Gnorimoschema octomaculella

(Chambers, 1875)

Rabbitbrush stem gall moth

A small gelechiid described by Vactor Tousey Chambers in 1875. The larvae are gall-formers on rabbitbrush (Acamptopappus sphaerocephalus). Known from California and Washington.

Gnorimoschema octomaculella by (c) Tim Messick, some rights reserved (CC BY), uploaded by Tim Messick. Used under a CC-BY license.

Gnorimoschema octomaculella by (c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda. Used under a CC-BY license.

Pronunciation

How to pronounce Gnorimoschema octomaculella: /ɡnɒrɪmoʊˈskɛmə ɒktoʊˌmækjʊˈlɛlə/

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

Identification

Distinguished from similar Gnorimoschema by the specific arrangement of forewing markings: the large rust-red discal spot before the middle that contacts the brown costal spot, combined with the rusty-red spot at the end of the disc and the paired dusting patches before the cilia. The association with Acamptopappus sphaerocephalus provides additional diagnostic context.

Images

Appearance

Forewings with a brown spot on the margin near the base, a large rust-red spot on the disc before the middle touching a brown costal spot placed just before it, another rusty-red spot at the end of the disc, and dense small patches of dusting before both the costal and dorsal cilia. Hindwings pale grayish fuscus.

Habitat

Associated with rabbitbrush (Acamptopappus sphaerocephalus) in dry, open where this plant occurs.

Distribution

Recorded from California and Washington in western North America.

Diet

Larvae feed on Acamptopappus sphaerocephalus (rabbitbrush), inducing gall formation in stems.

Host Associations

Acamptopappus sphaerocephalus - plantlarval food plant; gall-forming

Life Cycle

Larvae form stem galls on the plant. Specific details of and timing are not documented.

Behavior

are attracted to ultraviolet light. Larvae are gall-formers, inducing abnormal stem growth on the plant.

Ecological Role

As a gall-former, modifies plant tissue to create protected larval chambers. The galls may accumulate soil contaminants at higher concentrations than surrounding plant tissues, though this has been demonstrated for congeneric G. gallaesolidaginis rather than this specifically.

Human Relevance

No direct economic or medical significance documented. Contributes to biodiversity of western North American fauna.

Similar Taxa

Gnorimoschema gallaesolidaginisAlso a gall-forming Gnorimoschema , but associated with goldenrod (Solidago) rather than rabbitbrush, and produces elongate stem galls rather than the stem galls of G. octomaculella. Forewing pattern differs.
Other Gnorimoschema speciesMany congeneric share similar size and general appearance; reliable separation requires examination of forewing spot pattern and plant association.

More Details

Taxonomic history

Originally described as Gelechia octomaculella by Chambers in 1875, later transferred to Gnorimoschema.

Gall formation

Like other members of the , larvae induce gall formation on their plant. The specific of galls produced by this on Acamptopappus sphaerocephalus has not been described in detail in available literature.