Host associations and taxonomy of Nearctic conifer cone moths in the genusEucosma(Lepidoptera: Tortricidae)

Abstract

The genus Eucosma includes more than 150 described species in North America. Whereas larvae of most evidently are root and stem borers in plants such as woody Compositae, a small group of closely related species feeds in cones of coniferous trees. Diagnostic features, descriptions, host ranges, and geographical distributions for the ten members of this complex are given in the present paper. Four species are previously undescribed. One species, Eucosma tocullionana Heinrich, in eastern North America, has been reared from various conifers—pine (Pinus), fir (Abies), spruce (Picea), and hemlock (Tsuga). Two other species, E. monitorana Heinrich and E. cocana Kearfott, of the eastern United States and Canada, are associated with pines. Of seven species that occur in western North America, three feed in pines and one in fir. Hosts are unknown for the remaining three. Records in California indicate that specificity in host selection has resulted in isolation among populations on different conifer species. Thus, E. bobana Kearfott, which feeds on pinyon pines, is sympatric with E. ponderosa Powell in areas where Jeffrey pine occurs with the pinyons, while the latter moth is in turn broadly sympatric with the lodgepole pine-feeding E. rescissiorana Heinrich; yet each retains its identity in zones of overlap. Eucosma siskiyouana (Kearfott) has formerly been confused with another tortricid, Barbara colfaxiana (Kearfott), Although both feed in fir cones as larvae, they are generically distinct moths.