Meeting Abstract
P2.37 Saturday, Jan. 5 Effects of variation at mitochondrial and nuclear genes on mitochondrial enzyme function and locomotor performance of a leaf beetle ZAVALA, N. A.*; RANK, N. E.; DAHLHOFF, E. P.; Santa Clara University; Sonoma State University; Santa Clara University nzavala@scu.edu
Organisms experiencing stressful thermal conditions can experience reduced performance and reproductive success. Genetic differences at loci associated with temperature adaptation may mitigate these effects, and metabolic enzyme function may mediate the relationship between genetic variation and performance. Sierra Nevada populations of the leaf beetle Chrysomela aeneicollis are distributed along elevation and latitudinal temperature gradients and are polymorphic at the glycolytic enzyme locus phosphoglucose isomerase (pgi) and mitochondrial gene cytochrome oxidase II (COII); latitudinal variation at pgi and COII are concordant. Prior studies have shown that effects of temperature on thermal tolerance, performance and reproduction differ among (pgi) genotypes; however, Cytochrome c Oxidase (CytOx), an enzyme partially coded for by COII critical for aerobic metabolism, has not been investigated. To quantify the relationship between genotype, CytOx function, and performance, beetles were collected along elevation gradients in drainages differing in thermal regime; COII haplotype and pgi genotype was determined. In nature, CytOx activity differs between sites and drainages, being highest in coolest drainages and at high elevation. To investigate this further, beetles were collected from genetically intermediate localities, acclimated to common garden conditions in the laboratory, and effects of heat stress (36°C, 3 h) versus controls (20°C) on running speed between pgi genotypes/COII haplotypes was measured. Beetles exposed to 36°C ran faster than controls, males faster than females. Genetic analyses are underway. Variability at enzymes critical for metabolism may contribute to enhanced performance in the face of environmental change.
