Quantitative genetic variation of metabolism in the nymphs of the sand cricket, Gryllus firmus, inferred from an analysis of inbred-lines

ABSTRACT

Compared with morphological and life history traits, quantitative genetic variation of metabolic and related traits in animals has been poorly studied. We used flow-through VC0(2) respirometry and simultaneous activity measurement on nymphs of the sand cricket {Gryllus firmus) from inbred lines to estimate broad-sense heritability of four metabolic variables. In addition, we measured a number of linear dimensions in the adults from the same inbred lines. There were significant multivariate effects of inbred lines for all traits and broad-sense heritability for physiological traits was 4.5 percent, 5.2 percent, 10.3 percent and 8.5 percent for average, resting, minimum and maximum C0(2) production in nymphs, respectively. Though the MANOVA indicated significant genetic variation among inbred lines in adult morphology, the broad-sense heritabilities were relatively low ranging from 0-18 percent. Our results indicate that the heritabilities of metabolic measures are large enough to potentially respond to selection.