The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoi...The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds （3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene） were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.展开更多
Aphid species can be polyphagous, feeding on multiple host plants across genera. As host plant species can have large variation in their phloem composition, this can affect aphid fitness and honeydew composition. Prev...Aphid species can be polyphagous, feeding on multiple host plants across genera. As host plant species can have large variation in their phloem composition, this can affect aphid fitness and honeydew composition. Previous research showed significant intraspecific genotype variation in the composition of the honeydew carbohydrates of the black bean aphid Aphis fabae, with the ant attractant trisaccharide melezitose showing especially large variation across different genotypes. In this study, we test if variation in melezitose and carbohydrate composition of aphid honeydew could be linked to the adap- tation of specific aphid genotypes to particular host plants. To this end, 4 high and 5 low melezitose secreting genotypes of the black bean aphid Aphisfabae were reared on 4 com- mon host plants： broad bean, goosefoot, beet, and poppy. The carbohydrate composition, and in particular melezitose secretion, showed important aphid genotype and host plant in- teractions, with some genotypes being high melezitose secreting on 1 host plant but not on another. However, the interaction effects were not paralleled in the fitness measurements, even though there were significant differences in the average fitness across the different host plants. On the whole, this study demonstrates that aphid honeydew composition is influenced by complex herbivore-plant interactions. We discuss the relevance of these findings in the context of ant-aphid mutualisms and adaptive specialization in aphids.展开更多
Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temper...Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temperate forest in Hidalgo, Mexico some oak trees were heavily infested by honeydew-producing insects （family Margarodidae, tribe Xylococcini, genus Strigmacoccus） and the honeydew was consumed by hummingbirds. Here using survival analysis we investigate how the honey- dew produced by dense populations of these margarodids is temporally and spatially partitioned by hummingbirds. We also measured the availability and quality of honeydew exudates, and then we recorded the time until a bird visited and used such re- sources. Four hummingbird species consumed this resource （Atthis eloisa, Hylocharis leucotis, Colibri thalassinus and Eugenes fulgens）. Data from 294 hours of observation on seven focal trees suggested temporal and spatial segregation among visiting birds according to body size and territorial behavior during the most honeydew-limited time. Hummingbird species differed in the dally times they foraged, as well as in the location where honeydew-producing insects were visited on the trees. Temporal and spatial segregation among hummingbird species is interpreted as an adaptation to reduce the risk of aggressive encounters. This may facilitate multispecies coexistence and allow these birds to exploit honeydew more effectively展开更多
为建立水蜜桃多酚氧化酶(PPO)高效分离纯化方法,并明确该酶的酶学特性,本研究采用柱层析法对该酶进行分离纯化,对其反应特性及稳定性进行研究。结果表明,Phenyl-Sepharose CL-4B疏水柱层析法对水蜜桃PPO的纯化倍数与硫酸铵分级沉淀法相...为建立水蜜桃多酚氧化酶(PPO)高效分离纯化方法,并明确该酶的酶学特性,本研究采用柱层析法对该酶进行分离纯化,对其反应特性及稳定性进行研究。结果表明,Phenyl-Sepharose CL-4B疏水柱层析法对水蜜桃PPO的纯化倍数与硫酸铵分级沉淀法相近,但其得率为89%远高于后者;采用PhenylSepharose CL-4B、DEAE Sepharose Fast Flow和Sephaoryl HR S-200三级柱层析联用的方法对PPO分离纯化,获得PPO总纯化倍数为12.40倍,总得率为20%;该PPO组分经SDS-聚丙烯酰胺凝胶电泳分析得到单一蛋白条带,其分子量为81 k Da。纯化后的水蜜桃PPO对(+)-儿茶素和(-)-表儿茶素的米氏常数分别为0.14 m M和0.12 m M,最适反应p H值为7.0,最适反应温度为40℃。纯化后的水蜜桃PPO对热以及低p H值都很不稳定。本研究结果为进一步研究PPO酶促褐变机制提供了理论指导,同时也为其他果蔬中PPO的分离纯化提供参考。展开更多
文摘The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds （3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene） were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.
文摘Aphid species can be polyphagous, feeding on multiple host plants across genera. As host plant species can have large variation in their phloem composition, this can affect aphid fitness and honeydew composition. Previous research showed significant intraspecific genotype variation in the composition of the honeydew carbohydrates of the black bean aphid Aphis fabae, with the ant attractant trisaccharide melezitose showing especially large variation across different genotypes. In this study, we test if variation in melezitose and carbohydrate composition of aphid honeydew could be linked to the adap- tation of specific aphid genotypes to particular host plants. To this end, 4 high and 5 low melezitose secreting genotypes of the black bean aphid Aphisfabae were reared on 4 com- mon host plants： broad bean, goosefoot, beet, and poppy. The carbohydrate composition, and in particular melezitose secretion, showed important aphid genotype and host plant in- teractions, with some genotypes being high melezitose secreting on 1 host plant but not on another. However, the interaction effects were not paralleled in the fitness measurements, even though there were significant differences in the average fitness across the different host plants. On the whole, this study demonstrates that aphid honeydew composition is influenced by complex herbivore-plant interactions. We discuss the relevance of these findings in the context of ant-aphid mutualisms and adaptive specialization in aphids.
文摘Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temperate forest in Hidalgo, Mexico some oak trees were heavily infested by honeydew-producing insects （family Margarodidae, tribe Xylococcini, genus Strigmacoccus） and the honeydew was consumed by hummingbirds. Here using survival analysis we investigate how the honey- dew produced by dense populations of these margarodids is temporally and spatially partitioned by hummingbirds. We also measured the availability and quality of honeydew exudates, and then we recorded the time until a bird visited and used such re- sources. Four hummingbird species consumed this resource （Atthis eloisa, Hylocharis leucotis, Colibri thalassinus and Eugenes fulgens）. Data from 294 hours of observation on seven focal trees suggested temporal and spatial segregation among visiting birds according to body size and territorial behavior during the most honeydew-limited time. Hummingbird species differed in the dally times they foraged, as well as in the location where honeydew-producing insects were visited on the trees. Temporal and spatial segregation among hummingbird species is interpreted as an adaptation to reduce the risk of aggressive encounters. This may facilitate multispecies coexistence and allow these birds to exploit honeydew more effectively
文摘为建立水蜜桃多酚氧化酶(PPO)高效分离纯化方法,并明确该酶的酶学特性,本研究采用柱层析法对该酶进行分离纯化,对其反应特性及稳定性进行研究。结果表明,Phenyl-Sepharose CL-4B疏水柱层析法对水蜜桃PPO的纯化倍数与硫酸铵分级沉淀法相近,但其得率为89%远高于后者;采用PhenylSepharose CL-4B、DEAE Sepharose Fast Flow和Sephaoryl HR S-200三级柱层析联用的方法对PPO分离纯化,获得PPO总纯化倍数为12.40倍,总得率为20%;该PPO组分经SDS-聚丙烯酰胺凝胶电泳分析得到单一蛋白条带,其分子量为81 k Da。纯化后的水蜜桃PPO对(+)-儿茶素和(-)-表儿茶素的米氏常数分别为0.14 m M和0.12 m M,最适反应p H值为7.0,最适反应温度为40℃。纯化后的水蜜桃PPO对热以及低p H值都很不稳定。本研究结果为进一步研究PPO酶促褐变机制提供了理论指导,同时也为其他果蔬中PPO的分离纯化提供参考。
