Seasonal changes of phospholipids in last instar larvae of rice stem borer Chilo suppressalis Walker (Lepidoptera: Pyralidae)
Article first published online: 23 DEC 2009
© 2009 The Entomological Society of Japan
Volume 12, Issue 4, pages 376–381, December 2009
How to Cite
IZUMI, Y., KATAGIRI, C., SONODA, S. and TSUMUKI, H. (2009), Seasonal changes of phospholipids in last instar larvae of rice stem borer Chilo suppressalis Walker (Lepidoptera: Pyralidae). Entomological Science, 12: 376–381. doi: 10.1111/j.1479-8298.2009.00336.x
- Issue published online: 23 DEC 2009
- Article first published online: 23 DEC 2009
- Received 12 November 2008; accepted 21 April 2009.
- cold hardiness;
- homeoviscous adaptation;
- seasonal adaptation
Phospholipids of the cell membrane have been studied from the viewpoint of how overwintering insects inhabiting temperate zones adapt to low temperature. The transition of cell membrane phospholipids from a liquid crystalline phase to a gel phase is a crucial cause of cold or freezing injuries. We determined the qualitative and quantitative changes of phospholipids in the last instar larvae of the rice stem borer in summer and winter. We found that the total amount of their phospholipids did not change significantly between summer and winter and that the sum of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) comprised about 85% of their total phospholipids. In summer, the ratio of their PE to PC was almost one, while from autumn to mid-winter it increased and reached three in February. The fatty acid compositions of PC hardly changed, and the percentage of unsaturated fatty acids did not exceed 50%. In contrast, the percentage of unsaturated fatty acids of PE in overwintering larvae increased up to 80% as ambient temperatures fell and oleic acid mainly contributed to the high percentage of unsaturation. In the present study, the relationship between the quantitative and qualitative changes of phospholipids and adaptation of the rice stem borer to cold winter climate are discussed.