小菜蛾的飞行能力及飞行过程中的能源利用模式

Flight capacity and energy utilization mode in the diamondback moth,Plutella xylostella(Lepidoptera:Plutellidae)during flight

【目的】明确小菜蛾Plutella xylostella成虫的飞行能力及飞行过程中的能源利用模式。【方法】利用飞行磨吊飞测定小菜蛾不同日龄未交配雌雄成虫的飞行能力;田间种群在室内继代饲养3代(F3)和20代(F20)后比较各种群飞行能力的差异;用酶联免疫试剂盒测定1日龄未交配成虫吊飞0,2,6,12和24 h后胸部和腹部中甘油三酯和可溶性糖含量以及3-磷酸甘油醛脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)、海藻糖酶(trehalase,TRE)、3-磷酸甘油脱氢酶(glycerol 3-phosphate dehydrogenase,GPD)、乳酸脱氢酶(lactate dehydrogenase,LDH)、3-羟酰辅酶A脱氢酶(3-hydroxyacyl-CoA dehydrogenase,HOAD)和柠檬酸合酶(citrate synthase,CS)6种能量代谢关键酶活性的变化。【结果】根据吊飞的累计飞行时间(accumulative flight duration,AFD)可将小菜蛾种群划分为短飞型(AFD≤4.5 h)、中间型(4.5 h<AFD≤8.5 h)和长飞型(AFD>8.5 h)3种类型。小菜蛾不同日龄未交配雌成虫以及相同日龄雌雄成虫之间的吊飞能力没有显著差异;未交配1日龄雄成虫的累计飞行时间显著低于3-6日龄雄成虫的。F3和F20代种群的平均飞行速度和累计飞行距离显著低于田间种群的;F20代种群的累计飞行时间和长飞型个体比例较田间种群显著下降。吊飞24 h内,1日龄未交配雌、雄成虫胸部和腹部中甘油三酯含量呈逐渐升高趋势;胸部中可溶性糖含量在静息状态下显著低于飞行状态,腹部中可溶性糖含量先降低后升高并于吊飞6 h时出现最低值。吊飞过程中6种能量代谢关键酶活性均随吊飞时间呈现逐渐升高的变化趋势,其中GAPDH,GPD和HOAD活性一直处于较高的水平,LDH和CS活性处于相对较低的水平;GAPDH︰HOAD活性比略高于1.0,且在吊飞2 h时出现最大值。【结论】小菜蛾成虫有较强的飞行能力;飞行过程中其能源利用类型为混合型,但在飞行初始阶段(前2 h)利用糖类的能力比利用脂类的能力强;飞行中雌雄成虫均可以进行高速有氧代谢,也具备一定的无氧代谢能力。

【Aim】To clarify the flight capacity and energy utilization mode in adults of the diamondback moth(Plutella xylostella)during flight.【Methods】The flight capacities of the unmated female and male adults of P.xylostella at different day-old ages were examined by tethered flight on a computerized flight mill.After the field population was reared for three(F3)and twenty(F20)generations in laboratory,the differences in flight capacity were compared among various populations.The changes in contents of triglyceride and soluble sugar,and the activities of six key enzymes related to energy metabolism,including glyceraldehyde-3-phosphate dehydrogenase(GAPDH),trehalase(TRE),glycerol 3-phosphate dehydrogenase(GPD),lactate dehydrogenase(LDH),3-hydroxyacyl-CoA dehydrogenase(HOAD)and citrate synthase(CS),in the thorax and abdomen of the unmated 1-day-old adults at 0,2,6,12 and 24 h after tethered flight were assayed by ELISA kit.【Results】Based on the accumulative flight duration(AFD),the population of P.xylostella could be divided into three types:short-flight type(AFD≤4.5 h),intermediate-flight type(4.5 h<AFD≤8.5 h)and long-flight type(AFD>8.5 h).No significant differences in tethered flight capacity were observed among the unmated adults of P.xylostella at different day-old and between female and male adults at the same day-old.The accumalative flight duration of the unmated 1-day-old males was significantly lower than that of the 3-6-day-old males.The average flight velocity and accumulative flight distance of the F3 and F20 populations were significantly lower than those of the field population,and the accumalative flight duration and the proportion of long-flight type individuals in F20 decreased significantly as compared to those of the field population.Within the 24-h tethered flight,the triglyceride contents in the thorax and abdomen of the 1-day-old female and male adults gradually increased;the soluble sugar content in the thorax in resting state was lower than that during tethered flight,while that in the abdomen was decreased first and then increased,and reached the lowest value at 6 h after tethered flight.The activities of six key enzymes related to energy metabolisn in the thorax and abdomen of the 1-day-old female and male adults showed similar change trend,gradually increasing with tethered flight duration.Furthermore,the activities of GAPDH,GPD and HOAD were always at high levels,while those of LDH and CS were relatively low.The activity ratio of GAPDH to HOAD was slightly higher than 1.0,and reached the peak at 2 h after tethered flight.【Conclusion】P.xylostella adults have strong flight capacity.Their energy utilization mode during flight is a mixed type,whereas the ability to utilize carbohydrates in the initial phase of flight within 2 h is stronger than that to utilize lipids.In the process of flight,both female and male adults are capable of high-speed aerobic metabolism,and also possess a certain capacity for anaerobic metabolism.