Pontania sp.

an undescribed species near P pacifica that occurs on the same host plant

[Photos of the galls appear on page 5 of the pdf. Matching Smith's type-iv leaf galls, with thin walls and projecting entirely from the lower side of the leaf]

The Pontania sp. leaf-galler on arroyo willow in northern Arizona appeared to be P. pacifica Marlatt based on morphological criteria, but the galls, life history, and gall growth patterns were different, suggesting that the Pontania sp. leaf-galler in Arizona is an undescribed species that occurs on the same host plant (H. Goulet, personal communication).

The galls formed by Pontania sp. in Arizona were spherical, thin walled, and hung from the underside of the leaf midrib (Fig. 5 and 6). The galls formed by P. pacifica in California were thick walled and protruded through both sides of the leaf (Caltagirone 1964, Smith 1970).

Other aspects of Pontania sp. biology distinguished it from P. pacifica. In California, P. pacifica was multivoltine and bred year-round on S. lasiolepis, which is evergreen in sheltered places, and produced at least a few new leaves every month (Smith 1970). Pontania sp. in Arizona is primarily univoltine. The eggs and larvae of Pontania sp. were distinctly smaller than P. pacifica eggs and larvae (Caltagirone 1964). Larval development for Pontania sp. was > 2.5-fold longer than for P. pacifica (Caltagirone 1964). Pontania sp. leaf galls in Arizona continued to grow long after the leaf had stopped growing, and the presence of a sawfly larva in the gall was required in most cases for the gall to attain maximum growth. P. pacifica galls grew only as long as the leaf grew, and galls without a live sawfly larva attained normal size (Caltagirone 1964)

Range: northern AZ

- Karen Clancy, Peter Price, Timothy Craig: (1986) Life history and natural enemies of an undescribed sawfly near Pontania pacifica (Hymenoptera: Tenthredinidae) that forms leaf galls on arroyo willow, Salix lasiolepis^©