In recent years, an important decline of honey bee populations is observed, in part due to environmental variations caused by climate change. Particularly, increased temperatures during winter and spring bring forth new challenges, as the transition from winter to summer is crucial for the colony's survival. We have recently demonstrated that honey bee mitochondria undergo drastic changes between the winter and summer seasons, which is attributed to their different roles within the hive. Specifically, winter bees have lower CI-linked respiration but increased mtG3PDH- and CII-linked respiration. However we do not know whether and how this affects ATP and reactive oxygen species (ROS) production. Further, the regulation mechanisms behind this drastic change in phenotype is unknown. In this study, we investigated the seasonal differences in mitochondrial oxygen consumption, ATP production, and site-specific ROS production in honey bees (Apis mellifera). We also evaluated supercomplex assembly to determine if this could explain the changes observed in the mitochondrial parameters measured. Our results demonstrate that even though CI-linked respiration is diminished in winter bees, ATP production by CI is increased, suggesting that CI is more efficient in winter. Differences were also detected in terms of ROS production, with summer bees producing less ROS than all other season. In terms of supercomplex assembly, we are currently performing the analyses, which has never been done in honey bees, and will be included in this talk. We hypothesize that supercomplex assembly could shed light on the results described above, explaining the contrasting mitochondrial phenotypes observed between seasons.