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1.
The effects of weed strips on aphids and aphidophagous predators in an apple orchard 总被引:1,自引:0,他引:1
Eric Wyss 《Entomologia Experimentalis et Applicata》1995,75(1):43-49
Selected weeds were used to attract antagonists of apple aphids in an apple orchard near Berne, Switzerland. In the year before
the experiment, in 1991, the apple aphidsDysaphis plantaginea (Pass.) andAphis pomi (DeGeer) and aphidophagous predators were homogenously distributed in the orchard. In April 1992, weed strips were sown between
tree rows and along the border parallel to the first and the last row of trees in one part (the other part served as control).
In both parts of the orchard, randomly chosen tress were controlled visually in weekly intervals in 1992 and 1993. During
flowering of weeds more aphidophagous predators were observed on the apple trees within the strip-sown area than in the control
area. The most abundant and permanent aphidophagous predators were spiders, predaceous Heteroptera, Coccinellidae, and Chrysopidae.
Both species of aphids were significantly less abundant in the area with weed strips than in the control area during the vegetation
period. The effects of the weed strips on aphidophagous predators, and those of predators on aphids, are discussed. 相似文献
2.
用电内渗不同(0、0.03、0.08、0.20mr)的琼脂糖制成凝胶或电极缓冲液凝胶条,观察对电泳行为的影响.结果表明等电聚焦电泳必须使用无电内渗琼脂糖.不同电内渗的琼脂糖制成的电极缓冲液凝胶条对SDS电泳无显著影响,但对常规聚丙烯酰胺凝胶电泳有不同程度的影响,电内渗越高,越不利于电泳的进行. 相似文献
3.
Cerulenin has been used to investigate the mechanism by which leaf strips of Centranthus ruber (L.) Lam et D.C. increase their capacity for solute uptake during a period of incubation in CaSO4 (aging). -Aminoisobutyric acid was used to assess uptake capability. The leaf strips developed their uptake capacity for at least 8–10 h after excision. Cerulenin, if added to the aging medium immediately after cutting or at any time during the aging process, almost completely halted this development, but did not bring about loss of the uptake capacity already achieved. That cerulenin was specifically interfering with fatty-acid biosynthesis was indicated by the fact that it drastically depressed incorporation of labelled acetate into the lipid fraction but did not affect the incorporation of labelled alanine. Cycloheximide strongly inhibited the development of uptake capacity, but sensitivity to actinomycin D was not evident for at least 2 h. The results are consistent with the concept that slicing leads to immediate damage to tissue membranes and that aging is a process of membrane repair, involving renewed synthesis of membrane lipids and membrane proteins.The damage to membranes associated with cutting may involve wound ethylene. This is indicated by the following findings: Treatment of aged leaf strips with Ethrel (2-chloroethylphosphonic acid) resulted in drastic loss of their acquired uptake capacity. The strips recovered from such Ethrel-induced loss of uptake capacity while aging in CaSO4 as they can after cutting. Cerulenin halted recovery of uptake capacity after ethrel treatment just as it did after cutting. Treatment of leaves before cutting with amino-ethoxyvinylglycine somewhat improved the uptake performance of leaf strips immediately after excision. 相似文献
4.
Matthias Albrecht David Kleijn Neal M. Williams Matthias Tschumi Brett R. Blaauw Riccardo Bommarco Alistair J. Campbell Matteo Dainese Francis A. Drummond Martin H. Entling Dominik Ganser G. Arjen de Groot Dave Goulson Heather Grab Hannah Hamilton Felix Herzog Rufus Isaacs Katja Jacot Philippe Jeanneret Mattias Jonsson Eva Knop Claire Kremen Douglas A. Landis Gregory M. Loeb Lorenzo Marini Megan McKerchar Lora Morandin Sonja C. Pfister Simon G. Potts Maj Rundlf Hillary Sardias Amber Sciligo Carsten Thies Teja Tscharntke Eric Venturini Eve Veromann Ines M.G. Vollhardt Felix Wckers Kimiora Ward Andrew Wilby Megan Woltz Steve Wratten Louis Sutter 《Ecology letters》2020,23(10):1488-1498
Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future. 相似文献
5.
6.
Diab Al Hassan Ewen Georgelin Thomas Delattre Franoise Burel Manuel Plantegenest Pavel Kindlmann Alain Butet 《Agricultural and Forest Entomology》2013,15(1):24-33
- 1 We investigated, over the course of 2 years, the spatial distribution and abundance of two species of aphid, Metopolophium dirhodum and Sitobion avenae, and predatory species of carabid. This was undertaken in 24 wheat fields in ‘coarse‐grain’ and ‘fine‐grain’ landscapes in western France. A greater percentage of the latter landscape was covered by hedgerows and grassland and the total area covered by fields and the average size of the fields were smaller.
- 2 The effects on aphid abundance of the distance from field margins, the presence of grassy strips and carabid abundance were determined in both landscapes.
- 3 Both aphid species were more abundant in the ‘fine‐grain’ landscape, which may have been a result of the higher density of semi‐natural elements. In both types of landscape, the total numbers of aphids were negatively correlated with the distance from the field margin. This may have been because aphids were dispersing from overwintering sites in field margins. The abundance of M. dirhodum was strongly negatively correlated with the presence of grassy strips in the ‘coarse‐grain’ landscape, although there were no such significant correlations for either of the aphid species in the ‘fine‐grain’ landscape.
- 4 Aphid and carabid abundances were negatively correlated in the ‘fine‐grain’ and positively in ‘coarse‐grain’ landscape.
- 5 The results obtained in the present study emphasize the importance of semi‐natural areas in agricultural landscapes in shaping the spatial distribution of aphids and carabid beetles, their natural enemies, at different spatial scales.
7.
8.
Symbiotic bacteria in herbivorous insects can have strong beneficial impacts on their host's survival, including conferring resistance to natural enemies such as parasitoid wasps or pathogens, while also imposing energetic costs on the host, resulting in cost‐benefit trade‐offs. Whether these trade‐offs favour the hosting of symbionts depends on the growth environment of the herbivore. Long‐term experimental grassland studies have shown that increasing plant species richness leads to an increased diversity of associated herbivores and their natural enemies. Such a change in natural enemy diversity, related to changes in plant diversity, could also drive changes in the community of symbionts hosted by the herbivorous insects. Aphids are one model system for studying symbionts in insects, and effects of host‐plant species and diversity on aphid‐symbiont interactions have been documented. Yet, we still understand little of the mechanisms underlying such effects. We review the current state of knowledge of how biodiversity can impact aphid‐symbiont communities and the underlying drivers. Then, we discuss this in the framework of sustainable agriculture, where increased plant biodiversity, in the form of wildflower strips, is used to recruit natural enemies to crop fields for their pest control services. Although aphid symbionts have the potential to reduce biological control effectiveness through conferring protection for the host insect, we discuss how increasing plant and natural enemy biodiversity can mitigate these effects and identify future research opportunities. Understanding how to promote beneficial interactions in ecological systems can help in the development of more sustainable agricultural management strategies. 相似文献
9.
Ten urine chemistry parameters were measured on 74 voided urine samples from 34 wild chimpanzees (Pan troglodytes). Multi-reagent urine dipstick tests were performed and results determined using colorimetric scales. Urine pH measured between 8 and 9 units in 91% of the chimpanzees. Test pads detected protein, erythrocytes, leukocyte esterase activity, and nitrites, ketones and bilirubin in 47, 32, 29, and <10% of the chimpanzees, respectively. No apparent association between positive test results for blood in adult females and reproductive status was found. Overall, 17 of the 34 chimpanzees had positive urine test results for protein, hemoglobin, erythrocytes, leukocytes, nitrites, ketones, and/or bilirubin. Dipstick urinalysis alone is an unreliable method for assessing health and physiological status of wild chimpanzees. However, if combined with other diagnostics it could prove to be a valuable health-monitoring tool. Limitations associated with this methodology need to be considered when interpreting urinary dipstick test results. 相似文献
10.
Fredy D.A. Silva Ilka M. Vasconcelos Marina D.P. Lobo Patrícia G. de Castro Vladimir G. Magalhães Cléverson D.T. de Freitas Célia R.R.S. Carlini Paulo M. Pinto Leila M. Beltramini José H.A. Filho Eduardo B. Barros Luciana M.R. Alencar Thalles B. Grangeiro José T.A. Oliveira 《Biochimica et Biophysica Acta (BBA)/General Subjects》2012