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Nephaspisoculatus (Blatchley)属毛瓢虫亚科的小毛瓢虫族 ,专食粉虱。它源于中美洲 ,自七十年代初就在美国佛州被发现 ,是柑橘和蔬菜上白粉虱的重要天敌。本研究确定了该瓢虫各幼虫龄期和雌雄成虫在青菜 (col lard)叶上捕食银叶白粉虱BemisiaargentifoliiBellows&Perring卵在 6个密度的捕食功能反应及其成虫对 5种寄主植物的选择。结果表明 ,该瓢虫捕食率与白粉虱卵的密度呈线性相关。除第四龄幼虫其相关系数 (r2 )仅为0 .6 33外 ,其它各虫态的相关系数高达 0 .82 7～ 0 .94 4。根据该瓢虫各龄幼虫和雌雄成虫捕食量和白粉虱卵密度的关系 ,其捕食功能反应符合Holling圆盘方程的第二种反应模式。随着龄期的增加 ,幼虫捕食白粉虱卵的量也随之增加。第四龄幼虫捕食白粉虱卵量最多可达 312粒 ,其次为第三龄幼虫 2 2 9粒 ,第二龄幼虫 73粒 ,而第一龄幼虫捕食量仅为 34粒。雌成虫捕食白粉虱卵量 (32 1粒 )明显高于雄成虫 (2 37粒 )。雌成虫特别喜欢在青菜上活动、取食和产卵 ,而不喜欢番茄 ,大豆 ,茄子和甘薯。有 4 4 .9%的雌成虫在青菜上活动 ,只有 9.9% - 17.1%的雌成虫在其它植物上活动。雌成虫在青菜 ,甘薯和茄子上的产卵量占总产卵量的比率依次为 95 .8% ,2 .8%和 1.4 % ,而无任何卵产在番茄和大豆上。
Nephaspisoculatus (Blatchley) is a small ladybug family belonging to the genus Coccinella. It originated in Central America and was found in Florida of the United States since the early 1970s. It is an important natural enemy of whitefly on citrus and vegetables. In this study, the predation function responses of Bemisia arborescensiolii Bellell & Perring eggs at each larvae stage and the male and female adults on the col lard leaf of the ladybug were studied. The results showed that the ladybug predation rate and the whiteflies egg density was linearly correlated. Except for the fourth instar larvae, the correlation coefficient (r2) was only 0.636, and the correlation coefficients of all the other larvae reached as high as 0.82 7 ~ 0.944. According to the relationship between the predation rate of the larvae and the male and female adults and the eggshell density of the whitefly, the predation functional response accorded with the second reaction mode of the Holling disc equation. With the increase of age, larvae feeding on the amount of whitefly eggs also increased. The fourth-instar larvae fed on the largest amount of whitefly eggs up to 312, followed by 299 larvae of the third instar larvae and 73 larvae of the second instar larvae, while the first-instar larvae fed only 34 larvae. Female adult eggs feeding on whiteflies (32 1) were significantly higher than male adults (2 37). Female adults particularly like activities on vegetables, feeding and spawning, but do not like tomatoes, soybeans, eggplants and sweet potatoes. Forty-four to nine percent of female adults were active on vegetables and only 9.9% to 17.1% of female adults were active on other plants. Female adults in the vegetables, sweet potatoes and eggplant on the total fecundity of the ratio of 95.8%, 2.8% and 1.4%, without any eggs on tomatoes and soybeans.