suffusca

G. suffusca Davis and Pellmyr

Adult Characteristics

Wing expanse 12.5-20 mm. Forewing brown with heavy irroration of white scales; female generally darker and more patterened. Pattern consists of pale streaks and undulating lines between costa and hind margin. Pattern may be altogether absent in male, save for a subtornal patch. Hindwing uniformly gray.

Comparison with similar species

The species is quite similar to many forms of the polymorphic G. solenobiella. Greya suffusca is on average a larger and darker moth. The two species can coexist at habitat edges, and are readily told apart based on behavioral traits: G. suffusca will remain within meters of patches of its host Osmorhiza brachypoda, and it flies at a height about 30-100 cm (the height of Osmorhiza inflorescences) with slow wing beats visible to the naked eye. By comparison, solenobiella flies 5-25 cm above the ground, and particularly the female has such fast wingbeats that single strokes are not discernible. In flight, solenobiella appears white, whereas suffusca appears to be brown; this difference becomes especially apparent at low light levels.

Host, oviposition, and larval feeding habits

Feeds exclusively on Osmorhiza brachypoda (Apiaceae). The female cuts into young fruits, and the single larva feeds on the developing seeds for the first one or two instars. The life history of later stages is unknown.

Female ovipositing into an Osmorhiza fruit.

Geographic distribution

So far only known from Sierra Nevada near Sequoia National Park, California.

Habitat

In oak and mixed oak-conifer forest with understory dominated by Osmorhiza brachypoda. Other common dominants are Galium sp. and Toxicodendrum diversilobum.

Phylogenetic notes

In a phylogenetic analysis based on mitochondrial DNA sequence data, G. suffusca was nested within G. solenobiella (Brown et al 1994), appearing as the sister taxon of a G. solenobiella collected at the type locality for suffusca. It is evident that speciation of G. suffusca occurred so recently that the mitochondrial lineages have not yet been assorted. Greya suffusca reflects speciation based on a host shift, and obvious behavioral changes are associated with this shift.

References

Brown, J.M., O. Pellmyr, J.N. Thompson & R.G. Harrison. 1994. 
          Phylogeny of Greya (Lepidoptera: Prodoxidae), based 
          on nucleotide sequence variation in mitochondrial cytochrome 
          oxidase I and II: congruence with morphological data. 
          Mol. Biol. Evol. 11:128-141.
Davis, D.R., O. Pellmyr & J.N. Thompson. 1992. Biology and systematics 
          of Greya Busck and Tetragma n. gen. (Lepidoptera: Prodoxidae). 
          Smiths. Contrib. Zool. 524:1-88.

Holotype in USNM.

About this page

Olle Pellmyr
E-mail: pellmyr@ctrvax.vanderbilt.edu.
Dept of Biology, Vanderbilt University, Box 1812-B Nashville, TN 37235, USA

Title illustrations: Male and female from type locality in Tulare Co., California.