Meeting Abstract

90.6  Sunday, Jan. 6  Variation in nuclear and mitochondrial genes important for energy metabolism along a climatic gradient in montane populations of a leaf beetle RANK, NE*; MARDULYN, PM; ROBERTS, KR; HEIDL, S; SMILEY, JT; DAHLHOFF, EP; Sonoma State University (SSU); University of Brussels; SSU; SSU; White Mountain Research Center; Santa Clara University rank@sonoma.edu

Many montane organisms live in fragmented populations that are especially vulnerable to climate change. The ability of small populations to persist depends partly on whether they possess genetic variation in their capacity to respond and adapt physiologically to altered environments. In the Sierra Nevada Mountains of California, the willow leaf beetle Chrysomela aeneicollis occurs at high elevations just below tree line (2400-3600 m). Variation at genetic marker loci [5 allozymes, 5 microsatellites, and a 550 bp region of mitochondrial cytochrome II oxidase (COII)] shows significant differentiation among montane drainages along a 75 km transect from the King’s River in the southwestern Sierra to Rock Creek in the central Sierra. Geographic variation along this transect is much greater for the allozyme phosphoglucose isomerase (PGI) than for other nuclear loci. In prior studies, we described functional, physiological, and reproductive differences among PGI genotypes that correspond to differences in frequency over a latitudinal transect. Here we show that PGI variation and environmental variability jointly affected persistence of local populations over the past decade. In addition, we found that latitudinal variation in frequencies of mitochondrial COII haplotypes is concordant to variation in PGI frequencies previously observed. Natural selection may act on COII and PGI. Genetic variability at loci, such as COII and PGI, which are critical to energy metabolism, may contribute to population persistence in the face of rapid environmental change.