采用气相色谱法测定了不同时期麦红吸浆虫Sitodiplosis mosellana(Gehin)幼虫脂肪酸的变化.结果表明:幼虫脂肪酸组分有10～16种,其中主要以棕榈酸(C16:0)、油酸(C18:1)和亚油酸(C18:2)3种组分为主,占全部脂肪酸总量的95%以上;其次是硬脂酸(C18:0)含量较高,约占2%～3.5%;其它组分脂肪酸含量很少,均在1%以下.从5月中下旬麦红吸浆虫幼虫离穗入土进入越夏至翌年4月化蛹羽化前,脂肪酸组分表现了由少到多的变化趋势.越夏、越冬幼虫及越冬后未进入活动状态的圆茧其脂肪酸组分中不含花生酸(C20:0),而且饱和脂肪酸含量明显少于越冬后进入活动状态的幼虫和麦穗幼虫;而越冬后进入活动状态的幼虫和麦穗幼虫脂肪酸组分中含有一定量的花生酸,不饱和脂肪酸含量明显少于越夏、越冬幼虫及越冬后未进入活动状态的圆茧,故花生酸的有无及饱和脂肪酸与不饱和脂肪酸含量的比例变化可作为判断麦红吸浆虫幼虫活动状态,特别是滞育不同深度的生化指标之一.%The changes of fatty acids in larvae of the wheat blossom midge, Sitodiplosis mosellana (Gehin) at different periods were examined by gas choromatography. There were 10-16 kinds of fatty acids, of which the predominant ingredients were palmitic (C16:0), oleic (C18:1) and linoleic (C18:2) acids which were more than 95% in total fatty acids, stearic acid ( C18:0 ) about 2 % -3.5 % and any of the others was less than 1%. The fatty acid compositions increased from mid-May, when larvae of the wheat blossom midge left the wheat-ears and fallen on the ground, to April of next year before pupating and emerging. No arachidic acid (C20:0) was discovered in over-summering, over-wintering as well as inactive over-wintered larvae. The content of saturated fatty acids in over-summering, overwintering as well as inactive over-wintered larvae were less than those of in active over-wintered larvae and wheat-ear larvae. Therefore, changes of the arachidic acid and the proportions of saturated fatty acids/unsaturated fatty acids could be used as one of the biochemical criteria to determine the active state and the degree of diapause in larvae of the wheat blossom midge.
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