机构地区:[1]南京农业大学植物保护学院,农作物生物灾害综合治理教育部重点实验室,南京210095 [2]新疆师范大学生命科学学院,乌鲁木齐830054
出 处:《昆虫学报》2015年第9期997-1004,共8页Acta Entomologica Sinica
基 金:国家自然科学基金项目(30960055);国家公益性行业(农业)科研专项(201103002)
摘 要:【目的】为明确新疆棉田棉蚜Aphis gossypii捕食性天敌之间的集团内捕食效应及其对蚜虫数量的控制作用。【方法】本研究以优势天敌昆虫大草蛉Chrysopa pallens和七星瓢虫Coccinella septempunctata为对象,以棉蚜为猎物,在温室中利用盆栽棉花,首先观察了2种天敌昆虫之间各虫态及虫龄配对的19个处理在无蚜植株上共存24 h后的存活数,然后观察了2种天敌昆虫配对处理下棉苗上棉蚜数量随时间的变化趋势。【结果】在无蚜棉株上2种捕食性天敌昆虫共存24 h后的存活结果表明:(1)在发育阶段相同的配对组合中,若是成虫则均存活,若是1龄幼虫则大草蛉存活较多,若是末龄幼虫则七星瓢虫存活较多;(2)在有卵的组配中,除七星瓢虫卵不被大草蛉成虫所捕食外,其他5个组配处理中卵均被捕食;(3)在有蛹的配对组合中,除七星瓢虫蛹被大草蛉末龄幼虫捕食外,其他处理下蛹均不被捕食;(4)在成虫与幼虫的配对组合中,七星瓢虫成虫捕食较多的大草蛉1龄幼虫,但不捕食大草蛉末龄幼虫,而大草蛉成虫与七星瓢虫1龄或末龄幼虫之间不发生捕食;(5)在不同龄期幼虫的配对组合中,大草蛉末龄幼虫捕食七星瓢虫1龄幼虫,而七星瓢虫末龄幼虫捕食大草蛉1龄幼虫。在有蚜植株上2种捕食性天敌共存对棉蚜数量具有不同的控制作用:(1)2种捕食昆虫的幼虫各自单独存在(对照)下,蚜虫密度随时间而降低;(2)大草蛉幼虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而增大;(3)大草蛉成虫与七星瓢虫幼虫或成虫配对处理下,棉蚜密度随时间而减小。【结论】研究结果说明,大草蛉与七星瓢虫之间存在集团内捕食,但2种天敌共存对棉蚜的控制作用取决于大草蛉虫态,若大草蛉为幼虫,可使蚜虫密度增大,若为成虫,则使蚜虫密度减小。【Aim 】 This study aims to investigate intra-guild predation in aphidophagous predaceous insects and their control effects of the cotton aphid,Aphis gossypii,in Xinjiang,West China. 【Methods】We conducted experiments in greenhouse to examine intraguild predation between the seven-spotted ladybird beetle,Coccinella septempunctata,and the green lacewing,Chrysopa pallens,by pairing them at different life stages on potted cotton seedlings in the absence of the prey aphid A. gossypii. In addition,we manipulated the two predators at larval and adult stages as pairing treatments to investigate their effects on A. gossypii density on potted cotton seedlings. 【Results】In the absence of aphids,intraguild predation between two predators on cotton plants for 24 h showed the following results. In pairing treatments of two predators at comparable life stages,no intraguild predation occurred at adult stage; Ch. pallens survived more than C. septempunctata at the 1st larval instar; but C. septempunctata survived more than Ch.pallens at the last larval instars. In pairing treatments involved with eggs,the eggs were preyed on in all pairings except that C. septempunctata eggs were not preyed on by Ch. pallens adults. In pairing treatments including pupae,the pupae were not preyed on except that C. septempunctata pupae were preyed on by the last instar larvae of Ch. pallens. In pairing treatments between larvae and adults,C.septempunctata adults preyed on the 1st instar larvae of Ch. pallens,but not on the last instar larvae,and no intraguild predation occurred between Ch. pallens adults and the 1st instar or 4th instar larvae of C.septempunctata. In pairing treatments between different instar larvae,the last instar larvae of Ch. pallens preyed on the 1st instar larvae of C. septempunctata but its 1st instar larvae was preyed on by the 4th instar larvae of C. septempunctata. Experiments to examine effects on A. gossypii density of the two predator pairings showed that whereas two predator larvae each alone decreased A. go
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