Understanding predator-prey interactions has a pivotal role in biological control programs. This study evaluated the functional response of three larval instars of the green lacewing, Chrysoperla carnea （Stephens）, ...Understanding predator-prey interactions has a pivotal role in biological control programs. This study evaluated the functional response of three larval instars of the green lacewing, Chrysoperla carnea （Stephens）, preying upon eggs and first instar larvae of the cotton bollworm, Helicoverpa armigera Hubner. The first and second instar larvae of C. carnea exhibited typeⅡ functional responses against both prey stages. However, the third instar larvae of C. carnea showed a type II functional response to the first instar larvae of H. armigera, but a typeⅢ functional response to the eggs. For the first instar larvae of C. carnea, the attack rate on H. armigera eggs was significantly higher than that on the larvae, whereas the attack rate of the second instar C. carnea on H. armigera larvae was significantly higher than that on the eggs. For the third instar larvae of C. carnea, the attack rate on the larvae was 1.015±0.278/h, and the attack coefficient on the eggs was 0.036 ±0.005. The handling times of the third instar larvae on larvae and eggs were 0.087 ± 0.009 and 0.071 ± 0.001 h, respectively. The highest predation rate was found for the third instar larvae of C. carnea on H. armigera eggs. Results of this study revealed that the larvae of C. carnea, especially the third instar, had a good predation potential in controlling H. armigera eggs and larvae. However, for a comprehensive estimation of the bio- control abilities of C. carnea toward H, armigera, further field-based studies are needed.展开更多
The sweetpotato whitefly, Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae）, is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator （Coccinella undecimpu...The sweetpotato whitefly, Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae）, is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator （Coccinella undecimpunctata L. [Coleoptera： Coccinellidae]）, a common green lacewing predator （Chrysoperla carnea Stephen [Neuroptera： Chrysopidae]）, and a mirid predator （Macrolophus caliginosus [Wagner] [Hemiptera： Miridae]） were independently made in three vegetable crops （cabbage [Brassica oleracea var. capitata L.], cucumber [Cucumis sativus L.], and squash [Cucurbita pepo L.]） for the management of the sweetpotato whitefly. Approximately 1 million to 2.5 million larvae or nymphs of each predator were released in the vegetable crops during 20 weeks. Whitefly populations were reduced by ≈ 25%-45% during most of the season in each crop where each predator was released. The effect of each predator was similar on whitefly population reduction. Late in the season （October） when whitefly populations were low, generally no benefit was obtained from releasing the predators. Numbers of predators recovered during sampling in all crops were greatest for C. carnea, but this corresponded with the fact that more individuals of this predator were released than any other predator in the experiment. These results help define the utility of these natural enemies for managing B. tabaci in vegetable crops.展开更多
Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea （S.） （Neuroptera： Chrysopidae） on the cereal aphids, Rhopalosiphum ...Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea （S.） （Neuroptera： Chrysopidae） on the cereal aphids, Rhopalosiphum padi （L.）, and Sitobion avenae （F.） at varying nitrogen fertilizer levels was calculated under laboratory conditions. Wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the C. carnea. Aphid densities of 10, 30, and 90 were offered to first, second, and third instar larvae of green lacewing. Increased nitrogen application improved nitrogen contents of the plants and also the body weight of cereal aphids feeding on them. Aphid consumption by green lacewings was reduced with the increase in nitrogen content in the host plants of aphids. Predation of both aphid species by first, second, and third instars larvae of C. carnea was highest on aphids reared on plants with the lowest rate of fertilization, suggesting a compensatory consumption to overcome reduced biomass （lower aphid size）. Total biomass devoured by C. carnea on all nitrogen fertilizer treatments was not statistically different. Additionally, the heavier host prey influenced by the plant nutrition had an effect on the life history characteristics of green lacewings. The larval duration, pupal weight, pupal duration, fecundity, and male and female longevity were significantly affected by the level of nitrogen fertilization to the aphid＇s host plants, except for pupal duration when fed on S. avenae. This study showed that quantity of prey supplied to the larvae affects the prey consumption and thereafter the life history characteristics of green lacewings.展开更多
文摘Understanding predator-prey interactions has a pivotal role in biological control programs. This study evaluated the functional response of three larval instars of the green lacewing, Chrysoperla carnea （Stephens）, preying upon eggs and first instar larvae of the cotton bollworm, Helicoverpa armigera Hubner. The first and second instar larvae of C. carnea exhibited typeⅡ functional responses against both prey stages. However, the third instar larvae of C. carnea showed a type II functional response to the first instar larvae of H. armigera, but a typeⅢ functional response to the eggs. For the first instar larvae of C. carnea, the attack rate on H. armigera eggs was significantly higher than that on the larvae, whereas the attack rate of the second instar C. carnea on H. armigera larvae was significantly higher than that on the eggs. For the third instar larvae of C. carnea, the attack rate on the larvae was 1.015±0.278/h, and the attack coefficient on the eggs was 0.036 ±0.005. The handling times of the third instar larvae on larvae and eggs were 0.087 ± 0.009 and 0.071 ± 0.001 h, respectively. The highest predation rate was found for the third instar larvae of C. carnea on H. armigera eggs. Results of this study revealed that the larvae of C. carnea, especially the third instar, had a good predation potential in controlling H. armigera eggs and larvae. However, for a comprehensive estimation of the bio- control abilities of C. carnea toward H, armigera, further field-based studies are needed.
文摘[目的]研究普通草蛉卵低温储存的有效时间.[方法]低温储存普通草蛉卵,分析比较不同储存时间对孵化率、幼虫历期、化蛹率、蛹期及羽化率的影响.[结果]普通草蛉卵在（6±1）℃、RH（60±5）％的环境下低温储存7～13 d,其孵化率、幼虫历期、化蛹率、蛹期、羽化率等各处理间无显著差异.低温储存时间超过15 d,其孵化率、幼虫历期、化蛹率、羽化率出现显著差异.[结论]普通草蛉卵在（6±1）℃、RH（60±5）％的环境下,低温储存天数不宜超过13 d.
文摘The sweetpotato whitefly, Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae）, is a global pest on numerous crops, including vegetables. Weekly inundative releases of a coccinellid predator （Coccinella undecimpunctata L. [Coleoptera： Coccinellidae]）, a common green lacewing predator （Chrysoperla carnea Stephen [Neuroptera： Chrysopidae]）, and a mirid predator （Macrolophus caliginosus [Wagner] [Hemiptera： Miridae]） were independently made in three vegetable crops （cabbage [Brassica oleracea var. capitata L.], cucumber [Cucumis sativus L.], and squash [Cucurbita pepo L.]） for the management of the sweetpotato whitefly. Approximately 1 million to 2.5 million larvae or nymphs of each predator were released in the vegetable crops during 20 weeks. Whitefly populations were reduced by ≈ 25%-45% during most of the season in each crop where each predator was released. The effect of each predator was similar on whitefly population reduction. Late in the season （October） when whitefly populations were low, generally no benefit was obtained from releasing the predators. Numbers of predators recovered during sampling in all crops were greatest for C. carnea, but this corresponded with the fact that more individuals of this predator were released than any other predator in the experiment. These results help define the utility of these natural enemies for managing B. tabaci in vegetable crops.
文摘Plant quality can directly and indirectly affect the third trophic level. The predation by all the instars of green lacewing, Chrysoperla carnea （S.） （Neuroptera： Chrysopidae） on the cereal aphids, Rhopalosiphum padi （L.）, and Sitobion avenae （F.） at varying nitrogen fertilizer levels was calculated under laboratory conditions. Wheat plants were grown on four nitrogen fertilizer levels and aphids were fed on these plants and subsequently offered as food to the C. carnea. Aphid densities of 10, 30, and 90 were offered to first, second, and third instar larvae of green lacewing. Increased nitrogen application improved nitrogen contents of the plants and also the body weight of cereal aphids feeding on them. Aphid consumption by green lacewings was reduced with the increase in nitrogen content in the host plants of aphids. Predation of both aphid species by first, second, and third instars larvae of C. carnea was highest on aphids reared on plants with the lowest rate of fertilization, suggesting a compensatory consumption to overcome reduced biomass （lower aphid size）. Total biomass devoured by C. carnea on all nitrogen fertilizer treatments was not statistically different. Additionally, the heavier host prey influenced by the plant nutrition had an effect on the life history characteristics of green lacewings. The larval duration, pupal weight, pupal duration, fecundity, and male and female longevity were significantly affected by the level of nitrogen fertilization to the aphid＇s host plants, except for pupal duration when fed on S. avenae. This study showed that quantity of prey supplied to the larvae affects the prey consumption and thereafter the life history characteristics of green lacewings.
