Search Results - "Letourneau, D.K"

Impacts of groundcover management systems on yield, leaf nutrients, weeds, and arthropods of tart cherry in Michigan, USA by Sirrine, JR, Letourneau, D.K., Shennan, C., Sirrine, D., Fouch, R., Jackson, L., Mages, A.

“…Three different assemblages of cover crops were planted, fertilizer and herbicide input reduced, and mulch side-delivered in a northern Michigan tart cherry…”
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Experimental test in lowland tropical forest shows top-down effects through four trophic levels by Letourneau, D. K., Dyer, L. A.

“…Approximately 50% of the variation in productivity in lakes is hypothesized to depend upon the cascading effects of top predators. A relative paucity of…”
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The role of food retailers in improving resilience in global food supply by Macfadyen, Sarina, Tylianakis, Jason M., Letourneau, Deborah K., Benton, Tim G., Tittonell, Pablo, Perring, Michael P., Gómez-Creutzberg, Carla, Báldi, András, Holland, John M., Broadhurst, Linda, Okabe, Kimiko, Renwick, Anna R., Gemmill-Herren, Barbara, Smith, Henrik G.

“…We urgently need a more resilient food supply system that is robust enough to absorb and recover quickly from shocks, and to continuously provide food in the…”
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Pest Damage and Arthropod Community Structure in Organic vs. Conventional Tomato Production in California by Letourneau, D. K., Goldstein, B.

“…1. To test common assumptions that the reduction in agrochemicals on organic farms allows (i) the conservation of biodiversity but (ii) has some cost in terms…”
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Ecological causes and consequences of variation in defensive chemistry of a neotropical shrub by Dyer, L. A., Letourneau, D. K., Dodson, C. D., Tobler, M. A., Stireman, J. O., Hsu, A.

“…Prominent models of herbivore regulation focus on predators, low plant biomass, or poor resource quality as factors that limit herbivore populations. We…”
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Synergistic effects of three Piper amides on generalist and specialist herbivores by Dyer, L.A, Dodson, C.D, Stireman, J.O. III, Tobler, M.A, Smilanich, A.M, Fincher, R.M, Letourneau, D.K

“…The tropical rainforest shrub Piper cenocladum, which is normally defended against herbivores by a mutualistic ant, contains three amides that have various…”
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Ants, stem-borers, and fungal pathogens: experimental tests of a fitness advantage in Piper ant-plants by Letourneau, Deborah K.

“…This study tests experimentally the hypothesis that Pheidole bicornis ants increase the fitness of Piper ant-plants (Piperaceae) in Costa Rican forests. In two…”
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Fundamental differences between conventional and organic tomato agroecosystems in California by Drinkwater, L. E., Letourneau, D. K., Workneh, F., van Bruggen, A. H. C., Shennan, C.

“…In an integrated, multidisciplinary study we compared ecological characteristics and productivity of commercial farms categorized as either organic (ORG) or…”
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Determinants of Lichen Diversity in a Rain Forest Understory by Dyer, L. A., Letourneau, D. K.

“…Change in lichen diversity is often used as a bioindicator to estimate effects of atmospheric pollution, but natural variation in lichen cover and species…”
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Trade-offs in antiherbivore defenses in Piper cenocladum: ant mutualists versus plant secondary metabolites by Dyer, L.A, Dodson, C.D, Beihoffer, J, Letourneau, D.K

“…Ant-plant mutualisms may provide indirect evidence for costs of antiherbivore defenses when plants demonstrate trade-offs between allocating resources and…”
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Indirect effects of a top predator on a rain forest understory plant community by Letourneau, D.K, Dyer, L.A, Vega C, G

“…Tropical rain forests, some of the most diverse natural communities, have been characterized either as inherently stable or as extremely fragile…”
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Ants, stem borers, and pubescence in Endospermum in Papua New Guinea by Letourneau, D.K, Barbosa, P

“…The stems of the ant-plant, Endospermum labios Schodde, serve as colonization sites for the ant, Camponotus quadriceps F. Smith. They are also subject to…”
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Density patterns of Piper ant-plants and associated arthropods: top-predator trophic cascades in a terrestrial system? by Letourneau, D.K. (University of California, Santa Cruz.), Dyer, L.A

“…Top-predator (fourth-trophic-level) controlled trophic cascades are thought to be uncommon in terrestrial systems, but actual quantitative tests and…”
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Effects of soil management on crop nitrogen and insect damage in organic vs. conventional tomato fields by Letourneau, D.K., Drinkwater, L.E., Shennan, C.

“…To detect if different soil management practices had an impact on the crop in terms of tissue nitrogen, and thereby influenced herbivore damage, tomato plants…”
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Associational susceptibility: effects of cropping pattern and fertilizer on Malawian bean fly levels by Letourneau, Deborah K.

“…Subsistence farmers with little access to costly pesticides must rely on cultural practices to enhance biological control, reduce crop apparency or suitability…”
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Parasitism rates and sex ratios of a parasitoid wasp: effects of herbivore and plant quality by Fox, L.R, Letourneau, D.K, Eisenbach, J, Nouhuys, S.V

“…We studied interactions among collards, Brassica oleracea var. acephala, the diamondback moth (DBM), Plutella xylostella (Lepidoptera: Yponomeutidae) and its…”
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The enemies hypothesis: tritrophic interactions and vegetational diversity in tropical agroecosystems by Letourneau, Deborah K.

“…The effects of vegetational diversity on the abundance of natural enemies of herbivores were studied in a traditional agroecosystem in tropical Mexico…”
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A commensalism between Piper marginatum Jacq. (Piperaceae) and a coccinellid beetle at Barro Colorado Island, Panama by Dyer, Lee A., Letourneau, Deborah K., Williams, Wyatt, Dodson, Craig

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Code of ant-plant mutualism broken by parasite by Letourneau, D.K. (University of California, Santa Cruz, CA)

“…Newly discovered Phyllobaenus beetles are parasites of a mutualism. Piper ant-plants in tropical forests provide lipid and protein-rich food cells and shelter…”
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Passive aggression: an alternative hypothesis for the Piper-Pheidole association by Letourneau, D.K

“…Myrmecophytic Piper spp. were re-examined in view of what has become a common expectation in studies of mutualistic ant-plant associations: overtly aggressive…”
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