FIGURE 1.

Thermal sensitivity of mitochondrial oxygen consumption rate (OCR) measured from 6 to 45°C in permeabilized thoraces of the three insect species. (A) A. mellifera carnica (n = 7–10), (B) D. melanogaster (n = 5–10) and (C) L. decemlineata (n = 5–10). OCRs were measured with pyruvate + malate (+glutamate in honeybees) +ADP (CI-OXPHOS), +proline (CI + ProDH-OXPHOS), +succinate (CI + ProDH + CII-OXPHOS), +G3P (CI + ProDH + CII + mtG3PDH-OXPHOS). OCRs are reported as mean ± s.e.m. and were compared within each species between assay temperatures using a one-way ANOVA followed by a HSD (Honest Significant Difference) Tukey’s test. Dissimilar letters indicate significant differences between OCRs. For CI + ProDH + CII-OXPHOS in beetles, one-way ANOVA conditions were not met, and a non-parametric test (Kruskall-Wallis) followed by a Dunn’s test were performed. When assessing respiration levels for L. decemlineata, OCRs at 30 and 42°C did not stabilize after proline addition (CI + ProDH-OXPHOS), not allowing the estimation of a reliable respiration rate. In this case, the respiration rate was taken 10 min after the start of the O₂ consumption decrease (represented with hatched bars) and another one was taken just prior to the addition of the next substrate, succinate. In this case, only the second rate was used for the calculations and the comparisons.