نتایج جستجو برای: predators and gorgan

تعداد نتایج: 16828322  

Journal: :The Journal of animal ecology 2015
Hanna ten Brink Abul Kalam Azad Mazumdar Joseph Huddart Lennart Persson Tom C Cameron

Coexistence of predators that share the same prey is common. This is still the case in size-structured predator communities where predators consume prey species of different sizes (interspecific prey responses) or consume different size classes of the same species of prey (intraspecific prey responses). A mechanism has recently been proposed to explain coexistence between predators that differ ...

1999
JAY A. ROSENHEIM DAVID D. LIMBURG RAMANA G. COLFER

Generalist predators in terrestrial arthropod communities have traditionally been viewed as predators whose dynamics are less tightly coupled to any particular prey species, but whose ecological roles are in other respects analogous to those of specialist predators. Biological-control theory for predator–prey interactions has been based upon a model of communities composed of three discrete tro...

Journal: :The American naturalist 2011
Vincent Hin Tim Schellekens Lennart Persson André M de Roos

In basic intraguild predation (IGP) systems, predators and prey also compete for a shared resource. Theory predicts that persistence of these systems is possible when intraguild prey is superior in competition and productivity is not too high. IGP often results from ontogenetic niche shifts, in which the diet of intraguild predators changes as a result of growth in body size (life-history omniv...

2016
Maggie M. Hantak Daniel J. Paluh Ralph A. Saporito

Defensive chemicals in anuran skin secretions function in protection against potential predators. Although studies have demonstrated that particular chemicals are effective against certain predators, very little is known about how different chemicals from different species function against the same predators. Understanding how different chemicals function as a defence against similar predators ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده کشاورزی 1388

چکیده به منظور بررسی اثر تنوع گیاهی و نوع منبع تغذیه ای بر تنوع و تراکم علفهای هرز و حشرات، کارایی مصرف نهاده ها ( نور، آب، عناصر غذایی) و عملکرد و خصوصیات کیفی چند گونه زراعی، آزمایشی به صورت کرتهای خردشده بر پایه طرح بلوکهای کامل تصادفی با سه تکرار در دو سال زراعی 1385-1384 و 1386-1385 در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد به اجرا درآمد. تیمارهای مورد بررسی دو منبع کود دامی و...

Journal: :Journal of medical entomology 2010
Shin-Ya Ohba Hitoshi Kawada Gabriel O Dida Duncan Juma Gorge Sonye Noboru Minakawa Masahiro Takagi

Polymerase chain reaction analysis was performed to determine whether mosquito predators in wetland habitats feed on Anopheles gambiae sensu lato (s.l.) larvae. Aquatic mosquito predators were collected from six wetlands near Lake Victoria in Mbita, Western Kenya. This study revealed that the whole positive rate of An. gambiae s.l. from 330 predators was 54.2%. The order of positive rate was th...

Journal: :تولید گیاهان زراعی 0

environmental issues have attracted many concerns in recent years. life cycle assessment (lca) is a method that evaluates all environmental effects of a product during its life cycle. the objective of this study was to introduce lca [to persian researchers] and to use it in assessment of environmental impact of wheat production in gorgan, ne iran compared to european counties. first, data were ...

ژورنال: Medical Laboratory Journal 2008
Aslani, M, Bagheri, H, Dadgar, T, Ghaemi, A, Livani, S, Mozafari, N,

Abstract Background and objectives: Diarrhea is one of the main cases of morbidity and mortality among children in developing countries. Enteroaggregative Escherichia coli (EAggEC) is an emerging diarrheal pathogen that has been associated characteristically with persistent diarrhea among infants, particularly in the developing Counties. Therefore, we decided to study the prevalence of enteroag...

2017
Frank Johansson Peter Halvarsson Dirk J Mikolajewski Jacob Höglund

Presence or absence of predators selects for different kind of morphologies. Hence, we expect variation in traits that protect against predators to vary over geographical areas where predators vary in past and present abundance. Abdominal larval spines in dragonfly larvae provide protection against fish predators. We studied geographical variation in larval spine length of the dragonfly Leucorr...

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