扶桑绵粉蚧寄主选择行为及其与寄主叶片生化物质含量的相关性

Host selection behavior of Phenacoccus solenopsis Tinsley and its correlation with the contents of biochemical substances in host leaves

【目的】研究扶桑绵粉蚧的寄主选择行为及其取食选择行为与寄主叶片部分生化物质含量的相关性,为预测该害虫在广西的发生为害趋势及综合防控提供参考依据。【方法】采用自由选择法,测定接虫24、48和72 h后不同虫龄(1、2和3龄若虫)或虫态(雌成虫)扶桑绵粉蚧在7种寄主植物(朱槿、棉花、悬铃花、马铃薯、番茄、红薯和三叶鬼针草)上的虫口数量,比较同一时间不同寄主间虫口百分率的差异;测定寄主植物叶片生化物质(可溶性糖、可溶性蛋白和单宁酸)的含量,分析扶桑绵粉蚧寄主选择行为与生化物质含量的相关性。【结果】不同虫龄或虫态扶桑绵粉蚧喜食寄主存在一定差异,1龄若虫3个时段(接虫24、48和72 h)在同一寄主上的虫口百分率较接近,其偏好三叶鬼针草、棉花、悬铃花和马铃薯;2龄若虫在同一寄主上的虫口百分率随接虫时间而改变,且在不同寄主上的虫口百分率差异显著(P<0.05,下同),总体上偏好棉花、悬铃花、三叶鬼针草和番茄;3龄若虫和雌成虫的喜食寄主基本相同,为棉花、悬铃花、朱槿和三叶鬼针草。朱槿、棉花和马铃薯叶片中可溶性糖含量较高,三叶鬼针草、马铃薯和红薯叶片中可溶性蛋白含量较高,棉花、红薯和朱槿叶片中单宁酸含量相对较高。2龄若虫的取食选择行为与寄主叶片可溶性蛋白含量显著负相关,与单宁酸含量显著正相关;雌成虫取食选择行为与寄主叶片可溶性糖含量显著正相关;多数虫龄的取食选择行为与寄主叶片生化物质含量无显著相关性(P>0.05)。【结论】棉花、悬铃花和三叶鬼针草为扶桑绵粉蚧喜食寄主;不同寄主叶片生化物质含量大多存在显著差异,扶桑绵粉蚧多数虫龄或虫态的寄主选择行为与寄主叶片生化物质含量无显著相关性。

【Objective】In the present study,the feeding preference of Phenacoccus solenopsis Tinsley to different hosts,the correlations between the contents of biochemical substances in host leaves and host selection were studied to provide reference for prediction of the occurrence tendency and comprehensive prevention of the pest in Guangxi.【Method】The number of the P. solenopsis at different stages or instars(first-instar nymph,second-instar nymph,thirdinstar nymph and adult female)in seven host plants(Hibiscus rosa-chinensis,Gossypium hirsutum,Malvaviscus arboreus, Solanum tuberosum,Lycopersicon esculentum,Ipomoea batatas and Bidens pilosa)was measured by free choice test after infected 24,48 and 72 h,and the population proportion of P. solenopsis among different hosts at the same time was compared. The contents of biochemical substances(soluble sugar,soluble protein and tannin)in host plants leaves were determined,the further correlations between the host selection of the P. solenopsis and the contents of biochemical substances were analyzed.【Result】Every different stage or instar of P. solenopsis had their own preferred host. The population proportions of first-instar nymph in the three periods(infected 24,48 and 72 h)on the same host were close,their preferred hosts were B. pilosa,G. hirsutum,M. arboreus and S. tuberosum. The population proportions of second-instar nymph on the same host varied with infected time,and the population proportions on different hosts were significantly different( P<0.05,the same as below). Overall,the preferred hosts of second-instar nymph were G. hirsutum,B. pilosa,M. arboreus and L. esculentum. Third-instar nymph and adult female shared the similar preferred hosts: G. hirsutum,B. pilosa, H. rosa-chinensis and M. arboreus. The contents of soluble sugar were high in the leaves of H. rosa-chinensis,G. hirsutum and S. tuberosum. The soluble protein contents were high in the leaves of B. pilosa,S. tuberosum and I. batatas. The tannin contents were high in the leaves of G. hirsutum,I. batatas and H. rosa-chinensis. There was a significant negative correlation between the feeding selection behavior of second-instar nymph and the content of soluble protein in host leaves,while tannin content was significantly positively correlative with the feeding selection behavior of second-instar nymph. Feeding selection behavior of adult females was significantly positively correlated with soluble sugar content in host leaves,whereas,there was no significant correlation between the feeding selection behavior of most stages and the contents of biochemi-cal substances in the host leaves(P>0.05).【Conclusion】G. hirsutum,M. arboreus and B. pilosa are the preferred hosts of P. solenopsis. The contents of biochemical substances in leaves among different hosts are significantly different. There are no significant correlations between the host selection of most P. solenopsis instars and the contents of biochemical substances in host leaves.