Energy metabolism pathways of the flight muscle of hymenopteran species such as the bumblebee Bombus impatiens and the wasp Vespula vulgaris. AAT, alanine aminotransferase; ETS, electron transfer system; GPDH, glycerol-3-phosphate dehydrogenase; MDH, malate dehydrogenase; ME, malic enzyme; ProDH, proline dehydrogenase; Q, ubiquinone; TCA, tricarboxylic acid.