【目的】观察研究黑带食蚜蝇Episyrphus balteatus De Geer成虫复眼形态、小眼结构和不同光暗条件对小眼结构的影响,以明确其光视觉的结构基础和调光机制。【方法】利用组织切片法和扫描电镜等技术。【结果】1.复眼位于头部两侧,正面观...【目的】观察研究黑带食蚜蝇Episyrphus balteatus De Geer成虫复眼形态、小眼结构和不同光暗条件对小眼结构的影响,以明确其光视觉的结构基础和调光机制。【方法】利用组织切片法和扫描电镜等技术。【结果】1.复眼位于头部两侧,正面观呈半球形,占据除额颜外大部分头部。雄虫与雌虫单个复眼分别有约7 180个、7 230个小眼。各小眼面呈整齐排列的规则六边形。2.小眼由角膜及伪晶锥组成的屈光器、不同水平面分布的8个小网膜细胞及其特化形成的离散型视杆、屏蔽色素细胞和基膜等组成。小眼自远端至近端由主色素细胞和12个附属色素细胞围绕。3.随光暗条件的改变小眼内的附属色素细胞色素和基细胞细胞核沿小眼纵轴移动。光适应时,附属色素细胞色素颗粒沿小眼纵轴均匀分布,基细胞细胞核位于基膜上方。暗适应时,附属色素细胞色素颗粒向伪晶锥近端压缩,基细胞细胞核亦向远端移动,到达视杆中段。【结论】黑带食蚜蝇复眼精密的小眼排列形式和内部结构均显示了其强大的生理功能;屏蔽色素颗粒的移动是其复眼适应外界光环境变化的重要机制。本试验为进一步探究黑带食蚜蝇视觉结构和光调节机制,以及与其飞行行为间的关系提供了一定的理论基础。展开更多
To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are th...To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.展开更多
Intraguild predation （IGP） can be an important factor influencing the effective- ness of aphid natural enemies in biological control. In particular, aphid parasitoid foraging could be influenced by the presence of p...Intraguild predation （IGP） can be an important factor influencing the effective- ness of aphid natural enemies in biological control. In particular, aphid parasitoid foraging could be influenced by the presence of predators. This study investigated the effect of larvae of the predatory hoverfly Episyrphus balteatus DeGeer （Diptera： Syrphidae） and the multicolored Asian ladybird Harmonia axyridis Pallas （Coleoptera： Coccinellidae） on the foraging behavior of the aphid parasitoid, Aphidius ervi Haliday （Hymenoptera： Aphidiidae） in choice experiments using a leaf disc bioassay. Wasp response to chemical tracks left by those predator larvae was also tested. Parasitoid behavior was recorded using the Observer （Noldus Information Technology, version 5.0, Wageningen, the Netherlands）. The experiments were conducted under controlled environmental conditions using leaves of the broad bean plant, Viciafaba L. （Fabaceae） with Myzus persicae Sulzer （Homoptera： Aphididae） as the host complex. A. ervi females avoided aphid patches when larvae of either predator were present. A similar avoidance response was shown by A. ervi to aphid patches with E. balteatus larval tracks, whereas no significant response was observed to tracks left by H. axyridis larvae. It was concluded that IG predator avoidance shown by the aphid parasitoid A. ervi may be a factor affecting their distribution among host patches.展开更多
Phenology shifts and range expansions cause organisms to experience novel day length-temperature correlations.Depending on the temporal niche,organisms may benefit or suffer from changes in day length,thus potentially...Phenology shifts and range expansions cause organisms to experience novel day length-temperature correlations.Depending on the temporal niche,organisms may benefit or suffer from changes in day length,thus potentially affecting phenological adaptation. We assessed the impact of day length changes on larvae of Chrysoperla carnea (Stephens) and Episyrphus balteatus (De Geer),both of which prey on aphids.Larvae ofE.balteatus are night-active,whereas those of C.carnea appear to be crepuscular.We subjected both species in climate chambers to day lengths of 16 :8 L :D and,to circumvent diapause responses,20 :4 L :D.We recorded development times and predation rates of both species. E.balteatus grew 13%faster in the 16 :8 L :D treatment and preyed on significantly more aphids.In contrast,C.carnea grew 13% faster in the 20 :4 L :D treatment and higher predation rates in 20 :4 L :D were marginally significant.Our results show that day length affects development and predation,but that the direction depends on species. Such differences in the use of day length may alter the efficiency ofbiocontrol agents in a changing climate.展开更多
文摘To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.
文摘Intraguild predation （IGP） can be an important factor influencing the effective- ness of aphid natural enemies in biological control. In particular, aphid parasitoid foraging could be influenced by the presence of predators. This study investigated the effect of larvae of the predatory hoverfly Episyrphus balteatus DeGeer （Diptera： Syrphidae） and the multicolored Asian ladybird Harmonia axyridis Pallas （Coleoptera： Coccinellidae） on the foraging behavior of the aphid parasitoid, Aphidius ervi Haliday （Hymenoptera： Aphidiidae） in choice experiments using a leaf disc bioassay. Wasp response to chemical tracks left by those predator larvae was also tested. Parasitoid behavior was recorded using the Observer （Noldus Information Technology, version 5.0, Wageningen, the Netherlands）. The experiments were conducted under controlled environmental conditions using leaves of the broad bean plant, Viciafaba L. （Fabaceae） with Myzus persicae Sulzer （Homoptera： Aphididae） as the host complex. A. ervi females avoided aphid patches when larvae of either predator were present. A similar avoidance response was shown by A. ervi to aphid patches with E. balteatus larval tracks, whereas no significant response was observed to tracks left by H. axyridis larvae. It was concluded that IG predator avoidance shown by the aphid parasitoid A. ervi may be a factor affecting their distribution among host patches.
文摘Phenology shifts and range expansions cause organisms to experience novel day length-temperature correlations.Depending on the temporal niche,organisms may benefit or suffer from changes in day length,thus potentially affecting phenological adaptation. We assessed the impact of day length changes on larvae of Chrysoperla carnea (Stephens) and Episyrphus balteatus (De Geer),both of which prey on aphids.Larvae ofE.balteatus are night-active,whereas those of C.carnea appear to be crepuscular.We subjected both species in climate chambers to day lengths of 16 :8 L :D and,to circumvent diapause responses,20 :4 L :D.We recorded development times and predation rates of both species. E.balteatus grew 13%faster in the 16 :8 L :D treatment and preyed on significantly more aphids.In contrast,C.carnea grew 13% faster in the 20 :4 L :D treatment and higher predation rates in 20 :4 L :D were marginally significant.Our results show that day length affects development and predation,but that the direction depends on species. Such differences in the use of day length may alter the efficiency ofbiocontrol agents in a changing climate.
