Differences in critical thermal maxima (<i>CT</i>_max) in the stonefly <i>Dinocras cephalotes</i> at three different levels of oxygen (a), the relationship between <i>CT</i>_max of the stonefly nymphs and their thermal sensitivity in oxygen consumption (b) and their body mass (c).

<p>Differences in <i>CT</i>_max were consistent with the mechanism of oxygen limitation: hypoxia lowered <i>CT</i>_max, while hyperoxia increased <i>CT</i>_max (a) and thermal maxima were lower for individuals which strongly increased their oxygen consumption rates at higher temperatures (high Q₁₀ values). Each bar represents the average (± s.e.) of 15 nymphs. Letters indicate significant differences (<i>P<0.05</i>; Tukey HSD post hoc test following an anova including only oxygen treatment: F_2,41 = 44·06, P<0·001).