十一星瓢虫对枸杞棉蚜的捕食作用研究

Study on predation of Coccinella undecimpunctata Linnaeus on Aphis gossypii Glover

十一星瓢虫Coccinella undecimpunctata Linnaeus是青海省柴达木地区的一种重要捕食性天敌。为明确其对枸杞棉蚜Aphis gossypii Glover和枸杞木虱Poratrioza sinica Yang et Li.两种主要枸杞害虫的嗜好性,开展了捕食选择性试验,发现当两种害虫共存时,瓢虫成虫更喜食棉蚜。为进一步探究十一星瓢虫对枸杞棉蚜的捕食能力,测定了瓢虫各龄幼虫和成虫在不同棉蚜密度下的捕食量、寻找效应以及种内干扰、自身密度对捕食作用的影响。结果表明:十一星瓢虫各虫态对棉蚜的捕食功能反应均符合Holling-Ⅱ功能反应模型,种内干扰、自身密度对捕食量的影响分别符合Hassell干扰效应模型和Watt模型。十一星瓢虫1~4龄幼虫及成虫对枸杞棉蚜的日最大理论捕食量分别为18.94、44.29、81.57、145.27和126.48头;在一定空间、相同瓢蚜比条件下,瓢虫同一虫态个体间存在种内干扰效应,以1龄幼虫受干扰最大,干扰常数为1.1803。此外,瓢虫自身密度对其捕食作用产生一定的影响,4龄幼虫和成虫影响更为明显,竞争参数分别为0.7948和0.6848。本研究可为今后更高效地利用青海高原本地十一星瓢虫资源提供理论依据。

Coccinella undecimpunctata Linnaeus is an important predatory natural enemy in Qaidam Region of Qinghai Province.In order to clarify the ladybug’s prey preference to nymph of Aphis gossypii Glover and Poratrioza sinica Yang et Li.which severely jeopardized Lycium barbarum Linnaeus,experiment of prey selection was carried out,and the result showed that adult ladybugs preferred A.gossypii when the two kinds of insects coexisted.To understand the natural control ability of ladybugs to aphids,the predatory capacity of larvae and adults under different density of aphids,searching efficiency,the impact of intraspecific interference and density of ladybugs on their feeding effect were determined.Results showed that the predation functional responses of each stages all fitted as mathematical model of Holling-II,and the effect of intraspecific interference and density of ladybugs on predation was consistent with the Hassell interference effect model and Watt model,separately.Their maximum theoretical predation of 1st,2nd,3rd,4th larvae and adults in one day were 18.94,44.29,81.57,145.27 and 126.48 aphids,respectively.In a certain space and the same proportion of prey being conditions,there was influence of intraspecific interference between individuals.Among them,the 1st larvae were most disturbed,its interference constant was 1.1803.In addition,the ladybugs’population density made a difference to their feeding effect,especially the 4th instar larvae and adult,whose competition parameter was 0.7948,0.6848.This study can provide a theoretical basis for more efficient utilization of native ladybug resources in Qinghai plateau.