Figure 1

Representative metabolic rate ($\dot{V}\mathbf{C}{\mathbf{O}}_{\mathbf{2}}$) tracings from larvae with different Hsp70 gene copy numbers before, during, and after 36°C exposure. Metabolic rate was measured as the volume of CO₂ (μL hr^-1) produced by pools of five larvae before, during and after exposure to the Hsp70-inducible temperature of 36°C. A. Larvae left at 22°C never had a rise in metabolic rate, as observed at 36°C. B, C and D. The increase in metabolic rate due to the Q₁₀ effect of increased temperature is readily apparent when 3-copy (B), 6-copy (C) and 12-copy (D) larvae are moved from 22°C to 36°C. All genotypes exhibited a transient increase in metabolic rate above the 36°C RMR that always occurred within the first 30 minutes of 36°C exposure. The metabolic rate of larvae with 12 copies of Hsp70 rises above and beyond that of other genotypes. Shown are tracings representative of the average and maximum rise in metabolic rate observed for each genotype. Different placement of tracings on the y-axis represents differences in overall metabolic rate due to mass effects, but mass did not differ among genotypes (F=2.66, P=0.078), nor did the 22°C or 36°C RMRs (Table 1 and Additional file 2: Table S1). Variation in the Q₁₀ among different samples of larvae is also apparent; however, Q₁₀ also did not differ among genotypes (F=0.76, P=0.384). Tracings begin five minutes after larvae are placed at 22°C.