The fatty acid compositions of phospholipid and triacylglycerol fractions of total lipids prepared from eggs, nymphs, new-generation, aestivating, and diapausing adults of the wheat stink bug Aelia rostrata Boheman (Heteroptera: Pentatomidae) were analyzed by gas chromatography-mass spectrometry. The major components were C16 and C18 saturated and unsaturated fatty acid ubiquitous to most animal species. In addition to these components, several odd-chain (C13:0, C15:0, and C17:0) and prostaglandin-precursor fatty acids were found. The fatty acid profiles of phospholipids and triacyglycerols were substantially different. Generally, the phospholipids were higher than triacyglycerols in polyunsaturated fatty acids. The unsaturation/saturation ratio for phospholipid was higher than calculated for triacylglycerol. There were substantial differences in fatty acid compositions from different development stages. In phospholipid fractions, the fatty acid profiles from eggs and nymph were not the same, with decreased palmitoleic acid proportions in nymphs. Eggs also differed from the adult stage, with lower proportions of myristic and higher proportions of palmitoleic and eicosenoic acids. Percentages of linoleic acid increased significantly at the expense of palmitic acid from new-generation adult compared to other nymphal stages. In triacylglcerol fraction, the content of oleic acid in nymphs and most adults stages decreased relative to eggs. In both fractions, polyunsaturated fatty acids contents were higher in female than in male. The proportion of unsaturation/saturation ratio was significantly increased in phospholipid and triacylglycerol, apparently because of increases in major monounsaturated oleic acid at the expense of saturated palmitic acid during diapause. Thus, temperature and development stages seem to play an important role of lipid metabolism in the wheat stink bug.