mitellae

G. mitellae Davis and Pellmyr

Adult Characteristics

Wing expanse 10-15 mm. This is arguably the most sexually dimorphic species of the genus. It also represents a reversal of the unusual size dimorphism in the genus. Forewings of the larger female are stramineous, and in the smaller male brown to dark yellow and slight purple iridescence in fresh specimens; both sexes marked with small, dark brown spots, usually fewer in number on the female. Hindwings medium to dark gray.

Comparison with similar species

Males are unmistakable, whereas females possibly can be mistaken for small indidivuals of the allopatric G. punctiferella. Greya punctiferella is a larger moth with lighter yellow ground color, narrower wings, and smeared spots.

Host, oviposition, and larval feeding habits

The species feeds exclusively on Mitella stauropetala (Saxifragaceae). Eggs are laid most commonly in leaf stalks, but also in the peduncle and in the floral calyx. The larvae evidently mine in vegetative tissue, but nothing is known about later instars.

G. mitellae nectaring and accidentally pollinating a Mitella flower; notice pollen adhering to proboscis.

Geographic distribution

Northwestern Idaho and the Blue Mountains of southeastern Washington. Further extension eastward of the host suggests that the moth may have a wider range as well.

Habitat

In moist coniferous or mixed forest, particularly in light gaps where the host tends to flower more luxuriantly. Elevational range 800-1300 m. The species often co-occurs with G. obscuromaculata.

Typical habitat in Latah Co., Idaho.

Ecological notes

Greya mitellae drinks nectar from the flowers of its host, and experimental studies show that pollen adheres to the proboscis and that the moth causes passive pollination of the flowers. Because few other flower visitors are observed in the habitat of M. stauropetala, this moth may be a very important pollinator to the plant (Pellmyr et al. 1996).

Phylogenetic notes

In a phylogenetic analysis based on mitochondrial DNA sequence data, G. mitellae was nested within G. piperella (Brown et al 1994). It is evident that speciation of G. mitellae has occurred so recently that the mitochondrial lineages have not yet been assorted. Greya mitellae reflects speciation based on a simultaneous habitat and host shift, and there has been striking morphological evolution particularly in the male.

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.
Pellmyr, O., J.N. Thompson, J. Brown & R.G. Harrison. 1996. Evolution 
          of pollination and mutualism in the yucca moth lineage. 
          Amer. Nat. 148:827-847.

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 Latah Co. and Nez Perce Co., Idaho, respectively.