INFLUENCE OF TEMPERATURE AND ACTIVITY ON THE METABOLIC-RATE OF ADULT DROSOPHILA-MELANOGASTER

We measured metabolic rates of adult male Drosophila melanogaster allo wed to evolve in the laboratory at 18 and 25 degrees C and compared th ese with measurements of metabolic rates of flies collected along a la titudinal gradient in Australia. Metabolic rates of flies that had evo lved in the laboratory at low temperature were 5-7% higher than those of flies allowed to evolve at high temperature. Metabolic rates of fie ld collected increased with latitude when measured at 18 degrees C but not at higher temperature (25 degrees C) and were about 9% greater in high latitude (similar to 41'00) flies than low latitude (16'53) flie s. Metabolic rate was strongly influenced by measurement temperature; estimated Q(10)s ranged from 1.79 to 2.5 for measurements made at 18 a nd 25 degrees C. Metabolic rate scaled isometrically with body mass; t he estimated slope of a In-in regression of metabolic rate and body ma ss was 1.03 +/- 0.1. We used our measures of metabolic rate and activi ty to estimate the minimum cost of transport (MCOT) while walking. The estimates of MCOT have high standard errors (lab, 34.30 +/- 14.2 mi O -2/g/km; and field, 38.0 +/- 17.0 mi O-2/g/km); however, they differ b y only 3-9% from predicted values based on allometric relationships re ported in the literature. (C) 1997 Elsevier Science Inc.