Diversity in membrane composition is associated with variation in thermoregulatory capacity in hymenopterans

Thermoregulatory capacity varies widely among bees and wasps, but the cellular physiology required to support such thermogenic ability remains unclear. Studies conducted on ectothermic species living in varying temperature show that cellular membrane composition is adjusted to remain functional, a process named homeoviscous adaptation. We show that the fatty acid composition of flight muscle membranes varies with thermogenic capacity in species of bees and wasps. The relative abundance of palmitate (16:0) and linoleate (18:2) decreased, while oleate (18:1) increased with increasing thoracic temperature. Species selected for the study varied over ten-fold in body mass, which in turn affected species thoracic temperature and their fatty acids profile. Nevertheless, all analyses conducted show that thoracic temperature is the main driver of flight muscle membrane composition in hymenopterans with diverse thermoregulatory capacity. These findings are in line with the predictions based on the homeoviscous adaptation hypothesis and further show that thermogenic strategy used by insect species impacts cellular membrane composition.