Type

Native

Exotic, but established

Exotic

Taxonomy

Rhyacionia Hübner (Tortricidae: Olethreutinae: Eucosmini)

Overview

Rhyacionia contains 43 described species distributed in the Holarctic region; 23 native species occur in the United States in addition to one introduced European species (R. buoliana). The global distribution of the genus closely matches the distribution of Pinus (Pinaceae), its sole host plant. The genus reaches its greatest diversity in the western and southwestern US. The Nearctic fauna was most recently reviewed by Powell & Miller (1978)Miller (1978):
Miller, W. E. 1978. Petrova pitch-blister moths of North America and Europe: two new species and synopsis (Olethreutidae). Annals of the Entomological Society of America. 71: 329-340., from which most of the following account is drawn.

Species of Rhyacionia are known as pine tip moths in the economic literature due to the damage larvae cause while feeding in young shoots and buds of pine (Pinus spp.). Remarkably, of the species of Rhyacionia for which host data is known, only a single species feeds on pines in the subgenus Strobus, the white and soft pines. The rest all feed on members of the subgenus Pinus, the yellow and hard pines. Several species are considered economically significant pests in pine plantations.

There is a single generation per year for most species, but a few eastern species are facultatively bivoltine. One species, R. frustrana, can have up to six generation per year in the southernmost portion of its range. Eggs are laid singly or in small clusters of up to 11 on or between pine needles, on needle sheaths, bud scales, or on nearby twigs. Eggs hatch in between 6 to 21 days depending on temperature and species. Larvae of most species initially mine a single needle before moving on to sheaths or buds and finally inside growing shoots to complete development by mid-summer or fall. With the exception of the introduced R. buoliana, all species occurring in North America overwinter in the pupal stage, either in the larval feeding gallery or on the ground.

MacKay (1959) described the larval chaetotaxychaetotaxy:
the arrangement of setae (in reference to Lepidoptera larvae), often depicted on a "setal map"
for three species of Rhyacionia. Species identification of adults is difficult when based solely on wing pattern, which is remarkably uniform across the genus. This, compounded with dramatic intraspecific variation in size, makes examination of the genitalia crucial for a correct identification. Rhyacionia have a rather narrow forewing with a red or orange ground color and narrow, vertical silver or white fasciaefasciae:
plural of "fascia"
. Males lack a costal fold, which separates them from the similar-looking Eucopina, which also feed on Pinaceae.

Male genitalia are characterized by a large, thumb-like projection on the cuculluscucullus:
the distal portion of the male valva
, the size and shape of which is taxonomically useful. Female genitalia are characterized by a variably-shaped plate like sterigmasterigma:
the sclerotized region surrounding the female ostium bursae
and two short, tack-like signasigna:
plural of "signum"
in the corpus bursaecorpus bursae:
a dilated membranous sac at the anterior end of the bursa copulatrix
.

Host plant table (embedded)

View full screen host table here

Links

Additional photos and distribution maps for species in the United States and Canada are available at Moth Photographers Group.