subalba

G. subalba Braun

Adult Characteristics

Wing expanse 11-16 mm. Forewing uniformly white (male) to yellowish white (female). Hindwind light gray, somewhat darker than the forewing.

Comparison with similar species

Occasional males of G. solenobiella may very rarely be so light as to cause confusion. The two species show very little, if any, overlap in current range. Tetragma gei coexists with the species in some areas, and is superficially similar; differences are listed under that species.

Hosts, oviposition, and larval feeding habits

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

Female ovipositing into Lomatium dissectum fruit.

Geographic distribution

Known from drier portions of southern British Columbia and Alberta in Canada. It is common in interior Washington and Oregon, northern Idaho, and western Montana, and may occur as far south as southwestern Oregon.

Habitat

In dry, forb-rich steppe with Lomatium. Elevational range, 200-1650 m.

Typical habitat with Lomatium grayi, in Nez Perce Co., Idaho.

Ecological notes

Thompson (1986, 1987) used G. subalba and a braconid parasitoid as a model system to explore the evolution of egg dispersal strategies in herbivores using discrete food patches and evolution of host search behavior in their natural enemies.

References

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.
Thompson, J.N. 1986. Oviposition behaviour and searching efficiency in a natural 
          population of a braconid parasitoid. J. Anim. Ecol. 55:351-360.
Thompson, J.N. 1987. Variance in number of eggs per patch: oviposition 
          behaviour and population dispersion in a seed parasitic 
          moth. Ecol. Entom. 12:311-320.

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 Whitman Co., Washington, USA.