棉花花外蜜主要组分对异色瓢虫捕食豆蚜能力的影响

Effects of main components in cotton extrafloral nectar on the predation of multicolored Asian lady beetle Harmonia axyridis feeding on groundnut aphid Aphis craccivora

为明确棉花花外蜜主要组分糖和氨基酸对异色瓢虫Harmonia axyridis捕食豆蚜Aphis craccivora能力的影响,选取蔗糖、葡萄糖、果糖3种糖以及谷氨酰胺、组氨酸、缬氨酸3种氨基酸,测定糖混合液、氨基酸混合液以及糖+氨基酸混合液处理后异色瓢虫对豆蚜24 h和连续7 d的捕食能力。结果表明,糖混合液处理组、糖+氨基酸混合液处理组异色瓢虫4龄幼虫在较高猎物密度(40~100头豆蚜)下,雌雄成虫在各猎物密度下对豆蚜24 h捕食量均显著低于对照组。不同处理异色瓢虫对豆蚜捕食量的总体趋势为对照组>氨基酸混合液组>糖+氨基酸混合液组>糖混合液组。不同处理异色瓢虫1~4龄幼虫和成虫对豆蚜的捕食功能反应均符合HollingⅡ功能反应模型,糖混合液、氨基酸混合液和糖+氨基酸混合液处理均降低了异色瓢虫对豆蚜的捕食能力,其中糖混合液的作用最明显,异色瓢虫4龄幼虫、雌成虫和雄成虫对豆蚜的捕食能力分别降低了72.47%、53.29%和42.55%;其次是糖+氨基酸混合液处理,异色瓢虫4龄幼虫、雌成虫和雄成虫对豆蚜的捕食能力分别降低了62.37%、47.61%和38.74%。糖混合液、氨基酸混合液及糖+氨基酸混合液显著降低了异色瓢虫成虫对豆蚜连续7 d的捕食量。表明棉花花外蜜主要组分糖、氨基酸均可显著影响异色瓢虫对豆蚜的捕食能力。

To clarify the influence of different components in cotton extrafloral nectar on the predatory ability of multicolored Asian lady beetle Harmonia axyridis,sugars,amino acids and their mixture were simulated according to their concentrations in cotton extrafloral nectar.Sucrose,glucose and fructose were used for sugar treatment,while glutamine,histidine and valine were used for amino acid treatment in the experiments.The predation amounts of H.axyridis on groundnut aphid Aphis craccivora were assayed under treatments with sugars,amino acids and sugars+amino acids for 24 h or seven consecutive days to evaluate their effects on the predatory ability of H.axyridis.The results showed that the predation amounts of the 4th instar larvae under high prey density conditions(40-100 A.craccivora)and female/male adults of H.axyridis on A.craccivora in the treatment groups with sugars or sugars+amino acids for 24 h were significantly lower than those in the control group.The predation amounts of H.axyridis on A.craccivora from high to low were as followed:control group,amino acids group,sugars+amino acids group and sugars group.The predatory functional responses of the 1st-4th instar larvae and adult of H.axyridis to A.craccivora under different treatments fitted with HollingⅡfunctional response model.The predatory ability of H.axyridis treated with sugars,amino acids and sugars+amino acids against A.craccivora decreased significantly,and the effect of sugars was the most obvious.The predatory ability of the 4th instar larva,female and male of H.axyridis treated with sugars decreased by 72.47%,53.29%and 42.55%,respectively,followed by the treatment with sugars+amino acids(62.37%,47.61%and 38.74%,respectively).The treatments with sugars,amino acids and sugars+amino acids could significantly reduce the predation of female and male adults of H.axyridis on A.craccivora for seven consecutive days.The results indicated that the main components of cotton extrafloral nectar,sugars and amino acids could significantly affect the predatory ability of H.axyridis againstA.craccivora.