寄主植物-蚜虫-捕食性瓢虫三营养层相互作用关系的分析-analysis of the interactions between host plants, aphids and predatory ladybug in the third feeding layer.docx

variegata (Goeze) to A.gossypii were studied. At the most prey densities, for the first to third instar larvae of H.variegata, the amount of consumption to aphids reared on C. moschata and C.sativus was higher than that on L. siceraria and C. melo. For the fourth larvae and adults, the amount of consumption on C. moschata and C. sativus was higher when the prey density was lower whereas higher on L.siceraria and C.pepo. The functional responses of all instar larvae and adults were of Holling-II type. The handling times decreased, and the instantaneous attack rates and maximum of predation increased with the increase of instar. The handling times of adults were longer than those of the fourth larvae whereas the instantaneous attack rates and maximum of predation were lower. All three above parameters were different when the predators predated the aphids reared on different Host plants.Utilization was assessed with measures of consumption index (CI), relative growth rate (RGR), approximate digestibility (AD), efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI). The Host plants have significant effects on the consumption and utilization of fourth-instar and female H. variegate. Consumption by instars and females was highest for aphids reared on C. moschata and lowest on L. siceraria. For instars, RGR, ECI and ECD values were highest and CI was higher when fed aphids from C. melo. For females, RGR, ECI and ECD values were highest and CI was higher when fed aphids reared on C. sativus. Thus, aphids reared on C. melo were more suitable prey for fourth instar H. variegata, whereas aphids reared on C. sativus were more suitable prey for female adults.Behavioral responses of H.variegata were influenced significantly by volatiles from five different plants after feeding by aphis. Whether removing aphis from Host plants or not, volatiles of the plants after feeding aphis attracted H.variegata apparently, whereas the health plants