Journal articles on the topic 'Fourth trophic level'
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Nair, Abhilash, Toby Fountain, Suvi Ikonen, Sami P. Ojanen, and Saskya van Nouhuys. "Spatial and temporal genetic structure at the fourth trophic level in a fragmented landscape." Proceedings of the Royal Society B: Biological Sciences 283, no. 1831 (May 25, 2016): 20160668. http://dx.doi.org/10.1098/rspb.2016.0668.
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A fragmented habitat becomes increasingly fragmented for species at higher trophic levels, such as parasitoids. To persist, these species are expected to possess life-history traits, such as high dispersal, that facilitate their ability to use resources that become scarce in fragmented landscapes. If a specialized parasitoid disperses widely to take advantage of a sparse host, then the parasitoid population should have lower genetic structure than the host. We investigated the temporal and spatial genetic structure of a hyperparasitoid (fourth trophic level) in a fragmented landscape over 50 × 70 km, using microsatellite markers, and compared it with the known structures of its host parasitoid, and the butterfly host which lives as a classic metapopulation. We found that population genetic structure decreases with increasing trophic level. The hyperparasitoid has fewer genetic clusters ( K = 4), than its host parasitoid ( K = 15), which in turn is less structured than the host butterfly ( K = 27). The genetic structure of the hyperparasitoid also shows temporal variation, with genetic differentiation increasing due to reduction of the population size, which reduces the effective population size. Overall, our study confirms the idea that specialized species must be dispersive to use a fragmented host resource, but that this adaptation has limits.
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Rand, Tatyana A., F. J. Frank van Veen, and Teja Tscharntke. "Landscape complexity differentially benefits generalized fourth, over specialized third, trophic level natural enemies." Ecography 35, no. 2 (February 2012): 97–104. http://dx.doi.org/10.1111/j.1600-0587.2011.07016.x.
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Araj, Salah-Eddin, Steve Wratten, Alison Lister, and Hannah Buckley. "Adding floral nectar resources to improve biological control: Potential pitfalls of the fourth trophic level." Basic and Applied Ecology 10, no. 6 (September 2009): 554–62. http://dx.doi.org/10.1016/j.baae.2008.12.001.
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Buitenhuis, R., L. E. M. Vet, G. Boivin, and J. Brodeur. "Foraging behaviour at the fourth trophic level: a comparative study of host location in aphid hyperparasitoids." Entomologia Experimentalis et Applicata 114, no. 2 (February 2005): 107–17. http://dx.doi.org/10.1111/j.1570-7458.2005.00234.x.
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Chen, Cong, Rieta Gols, Arjen Biere, and Jeffrey A. Harvey. "Differential effects of climate warming on reproduction and functional responses on insects in the fourth trophic level." Functional Ecology 33, no. 4 (January 28, 2019): 693–702. http://dx.doi.org/10.1111/1365-2435.13277.
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Nahrung, Helen F., and Michael P. Duffy. "Exploring the fourth trophic level: do hyperparasitoids infl uence biocontrol of a forestry pest in a native system?" New Zealand Entomologist 31, no. 1 (February 2008): 59–66. http://dx.doi.org/10.1080/00779962.2008.9722167.
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Gorbatenko, K. M., and I. V. Melnikov. "TROPHODYNAMICS OF MARINE ORGANISMS IN THE EPIPELAGIC LAYER OF THE OKHOTSK SEA IN 2000S." Izvestiya TINRO 198 (October 2, 2019): 143–63. http://dx.doi.org/10.26428/1606-9919-2019-198-143-163.
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New data on matter and energy transfer between major components of the Okhotsk Sea ecosystem are obtained on the base of trophodynamic modeling, taking into consideration their production and food consumption rates. The main trophodynamic relationships in the pelagic and bottom communities are determined from observations on zooplankton and nekton abundance, organic carbon content, food habits of marine organisms, and their isotope composition in 2000–2014. The total zooplankton production in the entire Okhotsk Sea in these years is assessed as 2616 . 106 t in raw weight, including 2275 . 106 t for non-predatory plankton, and 341 . 106 t for predatory plankton. So high total production of zooplankton is conditioned by favorable environmental conditions and dominance of high-productive species. Taking into account the rate of zooplankton consumption by predators, only 22.4 % of the total annual zooplankton production was consumed annually, with 16.2 % grazed by predatory plankton and 6.2 % by nekton. In carbon units, 831.0 . 106 tC was produced annually in the Okhotsk Sea at the first trophic level, 177.4 . 106 tC at the second trophic level, 18.1 . 106 tC at the third trophic level, 0.74 . 106 tC at the fourth trophic level, and 0.016 . 106 tC at the fifth trophic level. Pelagic nekton consumed 159 . 106 tC annually. The nekton prey included 85.5 % of zooplankton, 12.8 % of nekton, and 1.7 % of zoobenthos, by biomass. The main part of zooplankton consumed by nekton (50.7 %) was grazed by walleye pollock, 18.9 % by herring, 16.6 % by squids, 7.6 % by capelin, 5.3 % by deep-sea smelt, and 0.9 % by salmons. The total annual production of organisms in the epipelagic layer of the Okhotsk Sea exceeded 109 tons of C (1027.4 . 106 tC/year equal to the biomass of 17.85 . 109 t in wet weight). Primary production is estimated as 67.60 % of gross production in carbon units, microheterotrophic organisms produce 13.30 %, dominant zooplankton groups — 18.60 % (copepods 11.40 %, euphausiids 5.50 %, sagittas 1.20 %, and hyperiids 0.50 %), the portion of nekton production is estimated as 0.13 % of gross production.
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Jonsson, M., S. D. Wratten, K. A. Robinson, and S. A. Sam. "The impact of floral resources and omnivory on a four trophic level food web." Bulletin of Entomological Research 99, no. 3 (December 9, 2008): 275–85. http://dx.doi.org/10.1017/s0007485308006275.
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AbstractOmnivory is common among arthropods, but little is known about how availability of plant resources and prey affects interactions between species operating at the third and fourth trophic level. We used laboratory and field cage experiments to investigate how the provision of flowers affects an omnivorous lacewing, Micromus tasmaniae (Hemerobiidae) and its parasitoid Anacharis zealandica (Figitidae). The adult lacewing is a true omnivore that feeds on both floral resources and aphids, whereas the parasitoid is a life-history omnivore, feeding on lacewing larvae in the larval stage and floral nectar as an adult. We showed that the effect of floral resources (buckwheat) on lacewing oviposition depends on prey (aphid) density, having a positive effect only at low prey density and that buckwheat substantially increases the longevity of the adult parasitoid. In field cages, we tested how provision of flowering buckwheat affects the dynamics of a four trophic level system, comprising parasitoids, lacewings, pea aphids and alfalfa. We found that provision of buckwheat decreased the density of lacewings in the first phase of the experiment when the density of aphids was high. This effect was probably caused by increased rate of parasitism by the parasitoid, which benefits from the presence of buckwheat. Towards the end of the experiment when the aphid populations had declined to low levels, the effect of buckwheat on lacewing density became positive, probably because lacewings were starving in the no-buckwheat treatment. Although presence of buckwheat flowers did not affect aphid populations in the field cages, these findings highlight the need to consider multitrophic interactions when proposing provision of floral resources as a technique for sustainable pest management.
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Schulz, Ashley N., Rima D. Lucardi, and Travis D. Marsico. "Successful Invasions and Failed Biocontrol: The Role of Antagonistic Species Interactions." BioScience 69, no. 9 (August 7, 2019): 711–24. http://dx.doi.org/10.1093/biosci/biz075.
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Abstract Understanding the successes and failures of nonnative species remains challenging. In recent decades, researchers have developed the enemy release hypothesis and other antagonist hypotheses, which posit that nonnative species either fail or succeed in a novel range because of the presence or absence of antagonists. The premise of classical biological control of invasive species is that top-down control works. We identify twelve existing hypotheses that address the roles that antagonists from many trophic levels play during plant and insect invasions in natural environments. We outline a unifying framework of antagonist hypotheses to simplify the relatedness among the hypotheses, incorporate the role of top-down and bottom-up influences on nonnative species, and encourage expansion of experimental assessments of antagonist hypotheses to include belowground and fourth trophic level antagonists. A mechanistic understanding of antagonists and their impacts on nonnative species is critical in a changing world.
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Härri, Simone A., Jochen Krauss, and Christine B. Müller. "Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection." Proceedings of the Royal Society B: Biological Sciences 275, no. 1651 (August 5, 2008): 2627–32. http://dx.doi.org/10.1098/rspb.2008.0594.
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Complex biotic interactions shape ecological communities of plants, herbivores and their natural enemies. In studies of multi-trophic interactions, the presence of small, invisible micro-organisms associated with plants and those of a fourth above-ground trophic level have often been neglected. Incorporating these neglected factors improves our understanding of the processes within a multi-trophic network. Here, we ask whether the presence of a fungal endosymbiont, which alters plant quality by producing herbivore-toxic substances, trickles up the food chain and affects the performance and host-selection behaviour of aphid secondary parasitoids. We simultaneously offered hosts from endophyte-free and endophyte-infected environments to secondary parasitoids. Older and more experienced parasitoid females discriminated against hosts from the endophyte-infected environment. Developing in lower quality hosts from the endophyte-infected environment reduced the lifespan of secondary parasitoids. This indicates that aphid secondary parasitoids can perceive the disadvantage for their developing offspring in parasitoids from the endophyte environment and can learn to discriminate against them. In the field, this discrimination ability may shift the success of primary parasitoids to endophyte-infected plants, which co-occur with endophyte-free plants. Ultimately, the control of aphids depends on complex interactions between primary and secondary parasitoids and their relative sensitivity to endophytic fungi.
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Zeng, W. J., J. H. Li, J. X. Wang, Y. Wang, L. Bao, L. J. Liao, X. F. Guo, Y. X. Guo, B. L. Wu, and J. S. Zhang. "Research on response of water quality to land use pattern in nine plateau lake watersheds of Yunnan Province, China." Water Supply 20, no. 8 (July 24, 2020): 3739–51. http://dx.doi.org/10.2166/ws.2020.139.
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Abstract To study how water quality responds to land use types is of great significance in realizing effective control of non-point source pollution. This study built a response model of water quality to land use. The research results are as follows. First, the proportion of farmland is positively correlated to the total phosphorus (TP) value and biochemical oxygen demand (BOD) value, which indicates that the water quality deteriorates as the area of farmland increases. Second, the proportion of woodland is negatively correlated to the permanganate index, the trophic state index, total nitrogen (TN) value, TP value and BOD value, which means the water quality improves as the area of woodland increases. Third, the proportion of grassland is negatively correlated to the water quality indices and the correlation coefficient is large, which indicates that the water quality improves as the area of grassland increases. Fourth, the proportion of land used for buildings is positively correlated to the trophic state index and the chemical oxygen demand (COD) value at the 0.05 significance level, which means that the water quality deteriorates as the area of land for buildings increases. This study is expected to provide a basis for optimization of the land use and effective pollution control in the nine plateau lake watersheds.
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Chaplygina, A. B., O. Y. Pakhomov, and V. V. Brygadyrenko. "Trophic links of the song thrush (Turdus philomelos) in transformed forest ecosystems of North-Eastern Ukraine." Biosystems Diversity 27, no. 1 (March 9, 2019): 51–55. http://dx.doi.org/10.15421/011908.
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The diet spectrum of the song thrush (Turdus philomelos Brehm, 1831; Passeriformes, Turdidae) was studied with the aim of supporting the population of the species in transformed forests of North-Eastern Ukraine. Four forest ecosystems were surveyed: three model sites in oak woodlands with different stages of recreational digression, and the fourth model site in a pine-oak forest. A total of 45 invertebrate taxa with the dominance of Insecta (64.6%, n = 1321), Oligochaеta (16.7%), and Gastropoda (12.0%) were revealed in the diet of the song thrush. At the level of orders, Lepidoptera (66.2%) was dominant. In the qualitative structure of the song thrush nestling diet, the highest number of taxa (40.5–59.1%) was represented by phytophages. Phytophagous species also comprised the majority of the consumed prey items (44.7–80.3%). Environmental conditions are an important factor, affecting the diet composition of birds. The most favourable foraging conditions for the thrushes were revealed in natural protected areas. The analysis has shown a fairly even foraging efficiency of the thrushes in all the studied sites. The highest biodiversity indices were found in a protected area of the National Nature Park “Homilshanski Forests”. The results of the research indicate an important role of T. philomelos in the population management of potentially dangerous agricultural pests.
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Santos, Terezinha Monteiro dos, and Arlindo Leal Boiça Jr. "Biological aspects and predatory capacity of Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) fed on Alabama argillacea (Hübner) (Lepidoptera: Noctuidae) reared on cotton genotypes." Scientia Agricola 59, no. 4 (December 2002): 671–75. http://dx.doi.org/10.1590/s0103-90162002000400008.
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Host plants may influence indirectly biological characteristics of predators, on a positive or negative way, poiting out the importance of studies evaluating the effect of cultivars on the third trophic level. This study evaluates the biological aspects and predatory capacity of Podisus nigrispinus adults fed Alabama argillacea larvae reared on cotton genotypes. The predator was fed daily with fourth instar larvae reared on leaves of the following genotypes CNPA Precoce 1 (hirsute), CNPA 9211-31 (high gossypol level), CNPA 9211-41 (medium gossypol level) and GL2 GL3 (gossypol glandless). The pre-oviposition, oviposition and post-oviposition periods and the oviposition capacity of P. nigripinus were not affected when preyed on cotton leafworms reared on the listed cotton genotypes. Mean weight of predator females was higher (126.2 mg) when they fed on A. argillacea reared on GL2 GL3 cotton leaves, in comparison to the observed weight (96.2mg) of P. nigripinus females fed on larvae reared on CNPA 9211-41. Longevity of P. nigrispinus ranged 30.7 to 31.5 days for females and 38.0 to 66.3 days for males. P. nigrispinus females preyed 125.2 to 184.0 A. argillacea larvae during its adult stage, while adult males preyed 135.7 to 205.0 leafworms. Using plant resistance in association with P. nigrispinus is viable to control A. argillacea, because resistant genotypes do not influence negatively the biological characteristics of the predator.
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Sukovatykh, Boris Semenovich, Elvin Eynulla Feyziev, Alexander Sergeevich Belous, Elena Vladimirovna Trubnikova, Mikhail Borisovich Sukovatykh, and Anzhelika Yurievna Orlova. "Experimental Modeling of the Ultra-Necrotic Stage of Critical Ischemia of the Lower Limbs." Journal of Experimental and Clinical Surgery 14, no. 2 (June 22, 2021): 107–11. http://dx.doi.org/10.18499/2070-478x-2021-14-2-107-111.
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Objective. So far, no experimental model of the necrotic ulcerative stage of critical limb ischemia has been created. Aim. Development of a method for modeling the necrotic ulcerative stage of critical lower limb ischemia.Materials and methods. The experimental study was carried out on 120 rats - males of the "Wistar" line, divided into 4 groups of 30 animals each. In the first group (intact), the level of microcirculation in the muscles of the hind limb was determined. In the second (sham-operated) group, ischemia was not simulated, but the neurovascular bundle of the thigh was isolated and the wound was sutured. In the third group (comparison), the modeling of chronic ischemia of the leg muscles was performed by removing the femoral, popliteal, anterior and posterior tibial arteries. In the fourth (experimental) group, to simulate chronic critical ischemia of the leg muscles, the femoral, popliteal, anterior and posterior tibial arteries and veins were removed, and the peripheral nerve was damaged.In the postoperative period, the dynamics of symptoms of limb ischemia was monitored. Animals were taken out of the experiment, 10 animals in each group by an overdose of anesthesia on the 10th, 21st and 28th days. Before hatching, the level of microcirculation was determined using laser Doppler flowmetry. To study the morphological picture at the same time in the third and fourth groups, the ischemic gastrocnemius muscle of the leg was excised and a standard histological examination was performed.Results. Trophic disorders in animals of the third group developed in 13.3%, and in the experimental group - in 100%. In the experimental group, the level of microcirculation at all periods was significantly less than in the comparison group: on the 10th and 21st by 1.3 times, on the 28th day by 1.2 times, and the area of muscle necrosis was greater by the same days by 21.2%, by 8.2% and by 6.8%.Conclusion. The developed experimental model corresponds to the necrotic ulcerative stage of critical ischemia in humans.
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Armstrong, D. G. "Ornithine decarboxylase activity in small ovarian follicles from the laying hen (Gallus domesticus): a comparison of follicles from several regions of the ovary." Journal of Endocrinology 112, no. 2 (February 1987): 183–87. http://dx.doi.org/10.1677/joe.0.1120183.
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ABSTRACT Small non-atretic follicles (1·5–250 mg) were collected from four distinct areas of the ovary of the laying hen. These were as follows: (1) the stalks of the two largest preovulatory follicles; (2) the stalks of the third largest preovulatory follicle; (3) the stalks of the fourth and fifth largest preovulatory follicle and (4) zona parenchymatosa. There was an increase in the proportion of small follicles in the size range 1·5–10 mg collected from the stalks of the large yellow yolky preovulatory follicles approaching ovulation, with a corresponding decrease in the number of small follicles in the size group 10–250 mg. In addition, the ornithine decarboxylase activity in follicles collected from regions 1 and 2 was significantly greater than that in small follicles collected from region 4. Since the level of ornithine decarboxylase activity is critically dependent on the degree of hormonal stimulation and growth rate of the tissue, it is suggested, on the basis of the differences in their ornithine decarboxylase activity, that small follicles located on the stalks of the large yolky preovulatory follicles are stimulated by trophic hormones and growth factors to a greater degree than similarly sized follicles located elsewhere in the ovary. It is proposed that this increased stimulation may increase the chances of these small follicles being recruited into the hierarchy. J. Endocr. (1987) 112, 183–187
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von Burg, Simone, Frank J. F. van Veen, Fernando Álvarez-Alfageme, and Jörg Romeis. "Aphid–parasitoid community structure on genetically modified wheat." Biology Letters 7, no. 3 (January 19, 2011): 387–91. http://dx.doi.org/10.1098/rsbl.2010.1147.
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Since the introduction of genetically modified (GM) plants, one of the main concerns has been their potential effect on non-target insects. Many studies have looked at GM plant effects on single non-target herbivore species or on simple herbivore–natural enemy food chains. Agro-ecosystems, however, are characterized by numerous insect species which are involved in complex interactions, forming food webs. In this study, we looked at transgenic disease-resistant wheat ( Triticum aestivum ) and its effect on aphid–parasitoid food webs. We hypothesized that the GM of the wheat lines directly or indirectly affect aphids and that these effects cascade up to change the structure of the associated food webs. Over 2 years, we studied different experimental wheat lines under semi-field conditions. We constructed quantitative food webs to compare their properties on GM lines with the properties on corresponding non-transgenic controls. We found significant effects of the different wheat lines on insect community structure up to the fourth trophic level. However, the observed effects were inconsistent between study years and the variation between wheat varieties was as big as between GM plants and their controls. This suggests that the impact of our powdery mildew-resistant GM wheat plants on food web structure may be negligible and potential ecological effects on non-target insects limited.
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Drozdenko, Tatyana, Sergey Fedorov, and Irina Kek. "SEASONAL DYNAMICS OF PHYTOPLANKTON AND SOME HYDROCHEMICAL INDICATORS OF THE PEIPSI-PSKOV LAKE." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 16, 2021): 50–54. http://dx.doi.org/10.17770/etr2021vol1.6557.
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The Peipsi-Pskov Lake is the largest freshwater body in Europe, ranking fourth in area and fifth in volume. It is characterized by shallow water and a high level of trophy. The water in the lake is poorly mineralized and has little transparency due to suspended sediments and the development of plankton. Phytoplankton acts as a primary link in trophic chains, quickly reacts to changes in the aquatic environment and serves as a convenient object in monitoring studies.The average concentrations of total nitrogen in the lake during the observation period were in the range of 525-818 µg/dm3. The content of ammonium, nitrate, and nitrite nitrogen in the samples was mostly below the detection limits. The values of total phosphorus varied from 20 µg/dm3 to 54 µg/dm3, and its concentrations were lower than the sensitivity of the method during the flood recession.The maximum values of total nitrogen and phosphorus were recorded in August: in Lake Peipsi - 1.12 mg/dm3 and 0.09 mg/dm3, in Lake Pskov - 1.59 mg/dm3 and 0.14 mg/dm3, respectively. BOD5 values ranged from 1.96 mg/dm3 in autumn to 4.26 mg/dm3 in summer.During the growing season of 2020, 244 species taxa of phytoplankton from 8 phylums were identified in the Peipsi-Pskov Lake: Chlorophyta, Bacillariophyta, Cyanobacteria, Chrysophyta, Euglenophyta, Cryptophyta, Dinophyta and Xanthophyta. Floristic complex was characterized as сhlorophyta-diatom-cyanobacterial.The number of phytoplankton varied between 2.1 and 16.2 million cells/l depending on the season. The average number was 7.6 million cells/l. The biomass values ranged from 0.9 g/m3 to 3.6 g/m3. The average biomass was 2.3 g/m3.According to the ecological and geographical characteristics of the lake, widespread freshwater forms of microalgae predominated, preferring stagnant-flowing, slightly alkaline waters.Saprobiological analysis showed that the waters of the Peipsi-Pskov Lake were classified as moderately polluted, class III of water purity quality.
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Hawkins, Bradford A. "Species Diversity in the Third and Fourth Trophic Levels: Patterns and Mechanisms." Journal of Animal Ecology 57, no. 1 (February 1988): 137. http://dx.doi.org/10.2307/4769.
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Zahn, Matthias, and Richard P. Allan. "Climate Warming–Related Strengthening of the Tropical Hydrological Cycle." Journal of Climate 26, no. 2 (January 15, 2013): 562–74. http://dx.doi.org/10.1175/jcli-d-12-00222.1.
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Abstract The authors estimate climate warming–related twenty-first-century changes of moisture transports from the descending into the ascending regions in the tropics. Unlike previous studies that employ time and space averaging, here homogeneous high horizontal and vertical resolution data from an Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) climate model are used. This allows for estimating changes in much greater detail (e.g., the estimation of the distribution of ascending and descending regions, changes in the vertical profile, and separating changes of the inward and outward transports). Low-level inward and midlevel outward moisture transports of the convective regions in the tropics are found to increase in a simulated anthropogenically warmed climate as compared to a simulated twentieth-century atmosphere, indicating an intensification of the hydrological cycle. Since an increase of absolute inward transport exceeds the absolute increase of outward transport, the resulting budget is positive, meaning that more water is projected to converge in the moist tropics. The intensification is found mainly to be due to the higher amount of water in the atmosphere, while the contribution of weakening wind counteracts this response marginally. In addition the changing statistical properties of the vertical profile of the moisture transport are investigated and the importance of the substantial outflow of moisture from the moist tropics at midlevels is demonstrated.
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Chen, Chun-Xia, Erzhong Wu, Yi-Zhong Yang, and Hong-Hua Su. "The transfer of Bt insecticidal protein to higher tropic levels via a transgenic cotton, then beet armyworm (Lepidoptera: Noctuidae) and their natural enemies." Canadian Entomologist 146, no. 1 (October 10, 2013): 1–7. http://dx.doi.org/10.4039/tce.2013.41.
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AbstractIn order to determine the transference of Bacillus thuringiensis Berliner (Bacillaceae) (Bt) insecticidal protein in the food chain, enzyme-linked immunosorbent assay was used to detect Bt insecticidal protein levels in transgenic Bt cotton (GK12, New variety 33B and SGK321), Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) fed on the Bt cotton varieties, and two natural enemies of S. exigua, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) and Microplitis pallidipes Szépligeti (Hymenoptera: Braconidae). The results showed that Bt insecticidal protein was found not only in cotton leaves, but also in the body and excrement of S. exigua and the bodies of both C. carnea and M. pallidipes. Bt toxin was detected in S. exigua larvae of all the examined instars (second, third, fourth, and fifth) that fed on transgenic cotton varieties and the Bt toxin level was the highest in the body of the second instar. In addition, the Bt toxin content in the excrement of the second instar was lower than that in the older ones. After the natural enemies C. carnea and M. pallidipes preyed/parasitised the S. exigua larvae that fed on transgenic cotton, Bt toxin was found in both the predator and parasite. This research indicates that Bt protein can be transferred through the food chain and to natural enemies of various predatory habits.
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Winter, WH, JJ Mott, and RW McLean. "Evaluation of management options for increasing the productivity of tropical savanna pastures. 3. Trees." Australian Journal of Experimental Agriculture 29, no. 5 (1989): 631. http://dx.doi.org/10.1071/ea9890631.
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The effect of killing trees upon the production and quality of native perennial grasses, Themeda triandra, Chrysopogon fallax, Sehima nervosum, and Sorghum plumosum, and oversown legumes from the genus Stylosanthes, was studied over 4 years at Katherine, in the semi-arid tropics of northwestern Australia. The pastures were either unfertilised or received low inputs of superphosphate, and for each fertility level were grazed at 3 stocking rates. At no time were legume yields affected by killing the trees but, in the first 3 years, the amount of grass was approximately twice as much when the trees were killed. During this period the mean grass yields declined 4-5 fold from about 2.2 t/ha. By the fourth year the advantage from tree killing upon grass yield was apparent only at the lowest stocking rates at each fertility level. Nitrogen concentrations of the grasses and legumes, with the exception of S. hamata, were increased 7 and 10% respectively above the mean annual values of 0.89 and 1.75% where the trees were killed, while the phosphorus and sulfur concentrations were not affected. Tree killing had no effect upon wet season liveweight gains during the last 2 years of the experiment. However, there were some benefits during the dry season when weight losses were lower for most treatments during the early dry season (June-September) and also lower for the lowest stocking rate treatment without fertiliser during the late dry season (October-November).
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Govindappa, M., and K. Elavarasan. "Shade Cum Fruit Yielding Avocado under Coffee Ecosystem." International Letters of Natural Sciences 27 (October 2014): 61–66. http://dx.doi.org/10.18052/www.scipress.com/ilns.27.61.
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Avocado is one of the most commonly preferred shades grown tree crop under Coffee ecosystem. In view of that, Peninsula of Nicoya and Cost Rica farmer was rated avocado (Persea americana L. Mill) is a primary shade tree crop under coffee plantation at the level of 66.3 per cent and it ranked as a fourth position after the Inga spp., Guazumala ulmiflora and Cardia alliodoara. Hence, the avocado is a commercially important shade cum fruit yielding tree under coffee ecosystem which has cultivating both in humid tropic as well as subtropical climates of throughout the world. The tree is basically grown as the forest species but later on as a shade growing tree under coffee cultivation because of high nutritional and medicinal values of fruit and it makes for wider diversity. Thereafter it was entered into the other parts of the world from Central America and Mexico. The tree is of multipurpose in nature and also helps to avoid the soil and water erosion by way of its wider spread canopy. Generally, Avocado leafs reduce the beating action of rain drops which in-turn minimize the soil erosion. The soil enrichment by adding the leaf litter continuously is an advantage in the coffee plantations. It yields in the additional economic returns after three to five years of establishment. Hence, the establishment of shade tree under coffee ecosystem will give additional income to the coffee growers, which mainly helps on lean period of coffee cultivation.
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Cordero, E. C., and P. M. de F. Forster. "Stratospheric variability and trends in models used for the IPCC AR4." Atmospheric Chemistry and Physics 6, no. 12 (November 29, 2006): 5369–80. http://dx.doi.org/10.5194/acp-6-5369-2006.
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Abstract. Atmosphere and ocean general circulation model (AOGCM) experiments for the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) are analyzed to better understand model variability and assess the importance of various forcing mechanisms on stratospheric trends during the 20th century. While models represent the climatology of the stratosphere reasonably well in comparison with NCEP reanalysis, there are biases and large variability among models. In general, AOGCMs are cooler than NCEP throughout the stratosphere, with the largest differences in the tropics. Around half the AOGCMs have a top level beneath ~2 hPa and show a significant cold bias in their upper levels (~10 hPa) compared to NCEP, suggesting that these models may have compromised simulations near 10 hPa due to a low model top or insufficient stratospheric levels. In the lower stratosphere (50 hPa), the temperature variability associated with large volcanic eruptions is absent in about half of the models, and in the models that do include volcanic aerosols, half of those significantly overestimate the observed warming. There is general agreement on the vertical structure of temperature trends over the last few decades, differences between models are explained by the inclusion of different forcing mechanisms, such as stratospheric ozone depletion and volcanic aerosols. However, even when human and natural forcing agents are included in the simulations, significant differences remain between observations and model trends, particularly in the upper tropical troposphere (200 hPa–100 hPa), where, since 1979, models show a warming trend and the observations a cooling trend.
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Cordero, E. C., and P. M. de F. Forster. "Stratospheric variability and trends in IPCC model simulations." Atmospheric Chemistry and Physics Discussions 6, no. 4 (August 9, 2006): 7657–95. http://dx.doi.org/10.5194/acpd-6-7657-2006.
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Abstract. Atmosphere and Ocean General Circulation Model (AOGCM) experiments for the Intergovernmental Panel on Climate Change Fourth Assessment Report are analyzed using both 20th and 21st century model output to better understand model variability and assess the importance of various forcing mechanisms on stratospheric trends. While models represent the climatology of the stratosphere reasonably well in comparison with NCEP reanalysis, there are biases and large variability among models. In general, AOGCMs are cooler than NCEP throughout the stratosphere, with the largest differences in the tropics. Around half the AOGCMs have a top level beneath ~2 hPa and show a significant cold bias in their upper levels (~10 hPa) compared to NCEP, suggesting that these models may have compromised simulations near 10 hPa due to a low model top or insufficient stratospheric levels. In the lower stratosphere (50 hPa), the temperature variability associated with large volcanic eruptions is either absent (in about half of the models) or the warming is overestimated in the models that do include volcanic aerosols. There is general agreement on the vertical structure of temperature trends over the last few decades, differences between models are explained by the inclusion of different forcing mechanisms, such as stratospheric ozone depletion and volcanic aerosols. However, even when human and natural forcing agents are included in the simulations, significant differences remain between observations and model trends, particularly in the upper tropical troposphere (200 hPa–100 hPa), where, since 1979, models show a warming trend and the observations a cooling trend.
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Rozputnyi, O., V. Herasymenko, I. Pertsovyi, and M. Saveko. "Migration of 137Cs and 90Sr from black soil into vegetable of the Central part of the Forest-steppe zone of Ukraine." Agrobìologìâ, no. 2(142) (December 22, 2018): 90–98. http://dx.doi.org/10.33245/2310-9270-2018-142-2-90-98.
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Regardless of the time after the Chernobyl disaster, the problem of radioactive contamination is very urgent. At present, 6.7 million hectares of our country remain contaminated, of which 1.2 million hectares of land are contaminated with 137Cs with a density of 42 to 589 kBq/m2 (1–15 Ci/km2). There are 2,161 settlements in the radioactively contaminated territories, where there are about 3 million inhabitants. For the inhabitants of rural areas of these settlements, the main part of food products belongs to the products obtained from the land, so the definition of plant contamination by artificial radionuclides 137Cs and 90Sr on the lands affected by radioactive contamination. The Chernobyl accident is relevant, since the internal dose of radiation is formed due to consumed products, grown in private plots. Reducing the transition of radionuclides 137Cs and 90Sr from soil to crop production is one of the main tasks of agricultural production on contaminated radionuclide lands. The realization of these researchers will clarify the current state of migration of data of radionuclides in the soil-vegetation link in the agro eco systems of the Central Forest-steppe of Ukraine. From the moment of the Chernobyl accident, leading scientists conducted a sufficiently large number of scientific studies on the migration of 137Cs and 90Sr in agricultural production facilities, their accumulation in food products and the assessment of human exposure doses. The focus of the scholars focused on the territory of Polissya. Preferably migration of 137Cs and 90Sr in separate links and systems of the trophic chain. In addition, somewhat more attention is paid to 137Cs, which is the main dose-forming radionuclide. In addition, in forest-steppe areas that are radioactively contaminated, a significant proportion of pollution occurs at 90Sr, whose migration rate, according to scientists, will gradually increase. All these data led to the need for a detailed study of the state of migration of 137Cs and 90Sr in the soil-vegetation chain of agro eco systems of agricultural enterprises and private parts of the central forest-steppe affected by radioactive contamination because of the Chornobyl accident in the remote period. The purpose of these studies was to study the migration of 137Cs and 90Sr in the chain of soil plants in the villages Yosypivka and Tarasivka of the Kyiv region of the central forest-steppe of Ukraine, as well as the determination of the coefficients of transition of 137Cs and 90Sr from typical black soil to vegetable products for the next prognostication. The investigated areas of the Bila Tserkva district are located in the north-eastern part of the right-bank forest-steppe region of Ukraine and are represented mainly by typical low-humus black soil in the forests within the boundary plains. In order to achieve this goal, selection of samples of crop production and soil was carried out on private plots of peasants of Yosypivska and Tarasivska villages of the Bila Tserkva district of Kyiv region according to generally accepted methods. The territory of these settlements fell into the zone of the "southern trace of radioactive contamination" and is associated with the third and fourth zones of radioactive contamination. After preparation of samples, the activity of 137Cs and 90Sr was determined in the life safety department of the Bila Tserkva National Agrarian University at the USK Gamma Plus spectrometric complex according to the methodology for this device. To determine 90Sr, selective radiochemical separation was performed by precipitation of oxalates. The 90Sr determination was performed on the USC Gamma Plus beta spectrometric path. These studies were processed using the statistical method using the Microsoft Excel program. The main vegetable crops grown on private plots were carrots, cucumbers, potatoes, cabbage, tomatoes, zucchini, onions, peppers and radish. These studies were conducted during 2016-2018. From the data of the research it is clear that the least activity of 137Cs was in potatoes, onions and cucumbers. In zucchini and pepper, it appeared twice, carrots and tomatoes – almost four times, beets and radish – almost in 8, and beans – 11 times higher. Our studies show that there is a direct proportional relationship between the activity of 137Cs and 90Sr in the yield of vegetable crops and the level of the soil contamination. The research results make it possible, on the basis of the explained coefficient of transfer of 137Cs and 90Sr, to predict the contamination by plant radionuclides that will be grown in radioactive contaminated territories of the Central Forest-steppe of Ukraine. The coefficients of transition of 137Cs from soil (typical black soil) to vegetable crops grown in the III zone of radioactive contamination accumulate from 0.01 to 0.09 and 90Sr – from 0.01 to 0.30. The lowest coefficient of transition of 137Cs in potatoes, onions and cucumbers (0.01). In cabbage, squash and pepper, the transition factor is twice as high (0.03), and in carrots and tomatoes it is three times higher (0.04), in beets – 5 times, radish – 6 and beans – in 9 times higher. The lowest transfer coefficient of 90Sr in onions (0.01), in tomatoes and cucumbers it is 2 times higher (0.02), in pepper – 4 times higher (0.04), potatoes and cabbage – nine times higher (0.09), and in beets, radishes, carrots and beans in 27–30 times higher. The research conducted by us proves that the studied vegetable production, obtained in the settlements of Yosypivka and Tarasivka, does not exceed DR-2006, that is, it is quite suitable for use. The coefficients of the transition of radionuclides 137Cs and 90Sr from the soil (in this case, this typical black soil) to crop production grown on peasants’ plots have been determined, which will allow to predict in the future the contamination of 137Cs and 90Sr of vegetable products on the radically contaminated territories of the Central Forest-Steppe data. The content of radionuclide contamination of vegetable products after 33 years of the Chernobyl disaster proves that the problem of monitoring, studying and forecasting of products is still very relevant. Key words: 137Cs and 90Sr radionuclides, pollution density, transition coefficient.
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Duflot, Valentin, Jean-Luc Baray, Guillaume Payen, Nicolas Marquestaut, Francoise Posny, Jean-Marc Metzger, Bavo Langerock, et al. "Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): system description, instrumental performance and result comparison with ozone external data set." Atmospheric Measurement Techniques 10, no. 9 (September 15, 2017): 3359–73. http://dx.doi.org/10.5194/amt-10-3359-2017.
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Abstract. In order to recognize the importance of ozone (O3) in the troposphere and lower stratosphere in the tropics, a DIAL (differential absorption lidar) tropospheric O3 lidar system (LIO3TUR) was developed and installed at the Université de la Réunion campus site (close to the sea) on Reunion Island (southern tropics) in 1998. From 1998 to 2010, it acquired 427 O3 profiles from the low to the upper troposphere and has been central to several studies. In 2012, the system was moved up to the new Maïdo Observatory facility (2160 m a.m.s.l. – metres above mean sea level) where it started operation in February 2013. The current system (LIO3T) configuration generates a 266 nm beam obtained with the fourth harmonic of a Nd:YAG laser sent into a Raman cell filled up with deuterium (using helium as buffer gas), generating the 289 and 316 nm beams to enable the use of the DIAL method for O3 profile measurements. The optimal range for the actual system is 6–19 km a.m.s.l., depending on the instrumental and atmospheric conditions. For a 1 h integration time, vertical resolution varies from 0.7 km at 6 km a.m.s.l. to 1.3 km at 19 km a.m.s.l., and mean uncertainty within the 6–19 km range is between 6 and 13 %. Comparisons with eight electrochemical concentration cell (ECC) sondes simultaneously launched from the Maïdo Observatory show good agreement between data sets with a 6.8 % mean absolute relative difference (D) between 6 and 17 km a.m.s.l. (LIO3T lower than ECC). Comparisons with 37 ECC sondes launched from the nearby Gillot site during the daytime in a ±24 h window around lidar shooting result in a 9.4 % D between 6 and 19 km a.m.s.l. (LIO3T lower than ECC). Comparisons with 11 ground-based Network for Detection of Atmospheric Composition Change (NDACC) Fourier transform infrared (FTIR) spectrometer measurements acquired during the daytime in a ±24 h window around lidar shooting show good agreement between data sets with a D of 11.8 % for the 8.5–16 km partial column (LIO3T higher than FTIR), and comparisons with 39 simultaneous Infrared Atmospheric Sounding Interferometer (IASI) observations over Reunion Island show good agreement between data sets with a D of 11.3 % for the 6–16 km partial column (LIO3T higher than IASI). ECC, LIO3TUR and LIO3T O3 monthly climatologies all exhibit the same range of values and patterns. In particular, the Southern Hemisphere biomass burning seasonal enhancement and the ozonopause altitude decrease in late austral winter–spring, as well as the sign of deep convection bringing boundary layer O3-poor air masses up to the middle–upper troposphere in late austral summer, are clearly visible in all data sets.
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JM, Segura León, Medina i. Mirapeix F., and Valera Garrido F. "Adverse effects of percutaneous needle electrolysis in carpal tunnel syndrome." Revista Fisioterapia Invasiva / Journal of Invasive Techniques in Physical Therapy 02, no. 02 (December 2019): 130. http://dx.doi.org/10.1055/s-0039-3402508.
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Abstract Background Percutaneous needle electrolysis is a physical therapy technique which has shown to be useful for the treatment of nerve entrapments. The aim of the present study was to analyze the possible adverse effects and the follow-up pattern after the application of percutaneous needle electrolysis in carpal tunnel syndrome. Material and Methods A descriptive observational study conducted at the Traumatology Service of the Ciudad Real Hospital, in patients with a medical diagnosis of carpal tunnel syndrome confirmed by electromyography (gold standard).Percutaneous needle electrolysis was applied under ultrasound guidance in the superficial and deep interphase of the median nerve in its passage through the carpal tunnel, applied with a frequency of once every seven days over four weeks.The week after each intervention, the follow-up pattern of the adverse effects variables was gathered, grouped in the following categories: type of adverse effect, moment of appearance, prevalence period, impact and causality.At 1.5 weeks and 6 weeks after the last intervention, the following variables were gathered: presence of painful or hypertrophic scar, stiffness at the level of the wrist, hand or fingers, infection of the wound, alteration of reflex sympathetic trophism, symptoms related with a nerve lesion, symptoms related with a tendon lesion, post intervention effusion. The McNemar test was used for comparative measures between the first, second, third and fourth intervention, without significant variations (p < 0.05). Results 30 cases participated in the study, of which one subject had to abandon the treatment after the first application because of apprehension in relation to following through with treatment.Of the 117 intervention applied, one vegetative reaction was recorded, which was transitory and without consequences. Pain appeared during the intervention in 96.5% of the interventions, after the intervention pain was present in 56%, whereas pain experienced days after the intervention occurred in 28.4%. No cases required further medical intervention, and there were no irreversible cases, independent of the cause. For the remaining variables, the records were negative in all interventions.No adverse effects were described for any cases at the follow up at 1.5 and 6 weeks post-intervention. Conclusions No adverse effects were described at the end of the intervention in the short to mid term. Regarding the follow-up pattern, the pain followed a highly homogeneous course, there were no irreversible adverse effects requiring intervention, and no relationship was found with any cause on behalf of the patient.
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Miranda, Gonzalo Francisco, and Luciana del Pilar Rafael. "Non-Tropical Diabetic Hand Syndrome in Peru: A Case Report." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A394. http://dx.doi.org/10.1210/jendso/bvab048.802.
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Abstract Background: The diabetic foot is the most studied spectrum in relation to musculoskeletal complications in diabetic patients but upper extremities may be affected, producing from superficial hand injuries to multiorganic failure due to sepsis. Tropical diabetic hand syndrome has been used to describe a potentially dangerous infection in the hand, generally diagnosed in areas of the tropics. Nevertheless, cases have been seen in non-tropical areas in marginal urban areas which are part of the spectrum of Non tropical diabetic hand syndrome. Clinical Case: A 52-year-old woman, from marginal urban area of Lima- Peru with type 2 diabetes mellitus (T2DM) of 6 years in poor metabolic control. She was admitted to the emergency room with two weeks of volume increase, erythema, purulent secretion, flogosis in the fifth finger of the left hand and fever. Initial tests confirmed mild diabetic ketoacidosis and sepsis (pH: 7.29; Glucose: 320 mg / dl, Bicarbonate: 15 mEq/L, Ketone bodies - urine (+), leukocytes 14360 cells/mm3, CRP: 180). Intravenous antibiotic was started. A surgical debridement and amputation of the fifth finger of the left hand was decided. Patient with unfavorable evolution, on the eight day, was admitted to new surgical debridement without clinical improvement. Arterial Doppler Ultrasound and CT angiography confirmed distal arterial insufficiency due to monophasic flow in the left ulnar artery with the presence of collateral circulattion. A third surgical debridement and amputation of the fourth finger of the left hand was done with favorable postoperative clinical evolution. Non tropical diabetic hand syndrome affects predominantly women, between 50 to 60 years, with low socio-cultural level and deficient glycemic control, as in case presented. Other factors include body mass index < 20kg/m2, DM 1 and diabetic neuropathy. Diabetic neuropathy is the most common risk factor in Non tropical diabetic hand syndrome cases, with a prevalence of 88%, while peripheral arterial disease was present in 11% of cases. In this report, neuropathy and peripheral arterial disease were present. Conclusion: Non tropical diabetic hand syndrome is uncommon and underdiagnosed complication of Diabetes Mellitus that has an important clinical repercussion as an important cause of disability. Detailed physical examination of the hands in a patient with diabetes for detection of these cases is highlighted because an early diagnosis and treatment improves prognosis.
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Levinson, D. H., and J. H. Lawrimore. "ABSTRACT." Bulletin of the American Meteorological Society 89, no. 7s (July 1, 2008): 10–179. http://dx.doi.org/10.1175/1520-0477-89.7s.10.
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The combined land and ocean surface temperature in 2007 fell within the 10 highest on record, while the average land temperature was the warmest since global records began in 1880. In the low to midtroposphere, the annual global mean temperature was among the five warmest since reliable global records began in 1958, but still cooler than the record warmest year of 1998. For the fourth consecutive year, the annual precipitation averaged over global land surfaces was above the long-term mean, although the anomaly was significantly less than in 2006 when the annual value was the eighth wettest since 1901. The globally averaged concentration of carbon dioxide (CO2) continued to increase in 2007, having risen to 382.7 ppm at the Mauna Loa Observatory in Hawaii. The average rate of rise of CO2 has been 1.6 ppm yr−1 since 1980; however, since 2000 this has increased to 1.9 ppm yr−1. In addition, both methane (CH4) and carbon monoxide (CO) concentrations were also higher in 2007. Over the oceans, global SST during 2007 showed significant departures from the 1971–2000 climatology. Annual average upper-ocean heat content anomalies declined between 2006 and 2007 in the eastern equatorial Pacific and increased in off-equatorial bands in that ocean basin. These changes were consistent with the transition from an El Niño in 2006 to a La Niña in 2007. The global mean sea level anomaly (SLA) in 2007 was I.I mm higher than in 2006, which is about one standard deviation below what would be expected from the 15-yr trend value of 3.4 mm yr−1. In the tropics, the Atlantic hurricane season was near normal in 2007, although slightly more active than in 2006. In the north and south Indian Ocean Basins, both the seasonal totals and intensity of tropical cyclones (TC) were significantly above average, and included two Saffir-Simpson category 5 TCs in the north Indian Ocean and a world record rainfall amount of 5510 mm over a 3–8-day period on the island of Reunion in the south Indian Ocean. In the polar regions 2007 was the warmest on record for the Arctic, and continued a general, Arctic-wide warming trend that began in the mid-1960s. An unusually strong high pressure region in the Beaufort Sea during summer contributed to a record minimum Arctic sea ice cover in September. Measurements of the mass balance of glaciers and ice caps indicate that in most of the world, glaciers are shrinking in mass. The Greenland ice sheet experienced records in both the duration and extent of the summer surface melt. From the continental scale, as a whole the Antarctic was warmer than average in 2007, although the Antarctic Peninsula was considerably cooler than average. The size of the ozone hole was below the record levels of 2006, and near the average of the past 15 yr, due to warmer springtime temperatures in the Antarctic stratosphere.
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Pr�tz, Gernot, Andreas Brink, and Konrad Dettner. "Transgenic insect-resistant corn affects the fourth trophic level: effects of Bacillus thuringiensis-corn on the facultative hyperparasitoid Tetrastichus howardi." Naturwissenschaften 91, no. 9 (August 24, 2004). http://dx.doi.org/10.1007/s00114-004-0558-0.
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Zawisza, Edyta, Anna Filbrandt-Czaja, and Alexander Correa-Metrio. "Subfossil Cladocera and pollen as indicators of natural and anthropogenic trophic changes of Lake Jelonek (Tuchola Forest, N Poland) during the Holocene." Advances in Oceanography and Limnology 1, no. 1S (December 9, 2016). http://dx.doi.org/10.4081/aiol.2016.6234.
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<p class="Tre">Lake Jelonek is a small lake located in central northern Poland, in the Tuchola Forest. The sediments of the lake represent a natural archive that offers insights into the natural history of the region from the Late Glacial to present. In winter 2002, a 1330 cm long sediment core was recovered from the deepest part of lake. Using a multiproxy approach (cladocerans, pollen and basic geochemistry), we reconstructed trophic status changes through the last ~15,000 years. Special attention was devoted to the evaluation of nutrient contributions to the lake from natural and anthropogenic sources. The Cladocera analyses yielded a total of 29 species belonging to five families (Bosminidae, Daphniidae, Leptodoridae, Chydoridae, Sididae), with planktonic species representing more than 60% of Cladocera relative abundance throughout the core. The pollen results suggested four periods of increased human activity, so-called settlement phases. The first traces of human activity in the basin of Lake Jelonek appeared in the Atlantic period and were related with Mesolithic and Neolithic settlements. The second (Bronze Age) and the third (Iron Age) settlement phases are well marked by the paleolimnological proxies studied. This time period clearly manifested on the lake waters as an increasing trophy level probably caused by human-associated discharges of nutrients to the lake. After the third settlement phase cladoceran data indicated a significant decrease in the lake trophic level and the pollen data showed a recovery of forest cover. The fourth period of human economic activity during the early Middle Age was characterized by deforestation associated with land reclamation for grazing and cultivation of cereals, and the subsequent nutrient enrichment of lake waters. According to our results, the biological development of Lake Jelonek was determined by climate changes from Late Glacial up to the Atlantic period. Contrastingly, the most important driver for the lake development though the middle and late Holocene has been human activity within the lake catchment. The recovery of the lake trophic level during the last century, which is primarily related to extensive afforestation of the lake catchment, highlighted the importance of land use in the conservation of healthy water bodies.</p>
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Robert, Christelle AM, Xi Zhang, Ricardo AR Machado, Stefanie Schirmer, Martina Lori, Pierre Mateo, Matthias Erb, and Jonathan Gershenzon. "Sequestration and activation of plant toxins protect the western corn rootworm from enemies at multiple trophic levels." eLife 6 (November 24, 2017). http://dx.doi.org/10.7554/elife.29307.
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Highly adapted herbivores can phenocopy two-component systems by stabilizing, sequestering and reactivating plant toxins. However, whether these traits protect herbivores against their enemies is poorly understood. We demonstrate that the western corn rootworm Diabrotica virgifera virgifera, the most damaging maize pest on the planet, specifically accumulates the root-derived benzoxazinoid glucosides HDMBOA-Glc and MBOA-Glc. MBOA-Glc is produced by D. virgifera through stabilization of the benzoxazinoid breakdown product MBOA by N-glycosylation. The larvae can hydrolyze HDMBOA-Glc, but not MBOA-Glc, to produce toxic MBOA upon predator attack. Accumulation of benzoxazinoids renders D. virgifera highly resistant to nematodes which inject and feed on entomopathogenic symbiotic bacteria. While HDMBOA-Glc and MBOA reduce the growth and infectivity of both the nematodes and the bacteria, MBOA-Glc repels infective juvenile nematodes. Our results illustrate how herbivores combine stabilized and reactivated plant toxins to defend themselves against a deadly symbiosis between the third and the fourth trophic level enemies.