1. Organisms may internally or behaviourally regulate their body temperatures or conform to the ambient air temperatures. Previous studies are inconclusive on whether pigmentation influences thermoregulation in various odonates. 2. We investigated the thermal response of sympatric North American Calopteryx aequabilis and Calopteryx maculata with a thermal imaging study across a 25 °C ambient temperature range. 3. We found that regressions of thorax temperature on ambient temperature had similar slopes for male and female C. maculata, but females were consistently 1.5 °C warmer than males. 4. In contrast, the sexes of C. aequabilis differed in slope, with C. aequabilis females having a slope less than 1.0 and males having a slope greater than 1.0. 5. Given that C. aequabilis is strongly sexually dimorphic in pigment, but C. maculata is not, our findings suggest that pigmentation does influence thermal response rate in sympatric populations of both species.