تاثیر دیاپوز بر میزان اسیدهای چرب غشاء فسفولیپیدی در کرم خوشه خوار انگور Lobesia botrana (Lepidoptera: Tortricidae)

The European grapevine moth, Lobesia botrana (Denis and Schiffermueller) (Lepidoptera: Tortricidae), is one of the major pests of vineyard across multiple countries, including Iran. Previous research has shown that this particular insect enters a diapause period during the pupal stage in response to shorter daylight duration. Therefore, the aim of this study was to investigate the induction of diapause and its effects on phospholipid fatty acid compositions. The larvae were reared on an artificial diet under non-diapause conditions for six generations, maintaining a constant temperature of 23 ± 0.5 ºC, relative humidity of 75%, and a light-dark cycle of 16:8 h (L:D). Subsequently, one-day-old eggs were exposed to a photoperiod of 12:12 h (L:D) under the same temperature and humidity conditions to induce diapause. The experiment was done in three replications, and each replicate included five pupae. Sixteen fatty acids were identified in the laboratory. The results revealed that pupal diapause was accompanied by a significant increase in unsaturated fatty acids (UFAs). Unsaturated fatty acids: myristoletic acid (C14:1), palmitoleic acid (C16:1), cis-10- heptadecenoic acid (C17:1), oleic acid (C18:1n:9c), linoleic acid (C18:2n6c), Gamma-linolenic acid (C18:3n6) and cis-13-16-docosadinoic acid (C22:2) significantly increased. Specifically, the ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) was higher in pupae that entered diapause. However, there was no significant difference in the fatty acid composition between diapausing and non-diapausing pupae. These findings show that this insect increases the amount of unsaturated fatty acids needed to cope with the cold season by simply understanding the short day length. Findings led to the conclusion that phospholipid fatty acids play an essential role in the diapause of L. botrana.