نتایج جستجو برای: predation
تعداد نتایج: 12312 فیلتر نتایج به سال:
1. There is growing interest in the causes and consequences of animal temperaments. Temperament behaviours often have heritable components, but ecological variables can also affect them. Numerous variables are likely to differ between habitats, and these may interact to influence temperament behaviours. 2. Temperament behaviours may be correlated within populations (behavioural syndromes), alth...
Intraguild predation, the killing of species that use similar resources, has been largely overlooked in raptor investigations. To help fill this gap in knowledge, we conducted a literature review, focusing on studies that tested the behavioural and demographic impact of intraguild predation on individuals, populations, and assemblages of diurnal and nocturnal raptorial species. Overall, data we...
Populations of the native ninespotted lady beetle, Coccinella novemnotata Herbst, have undergone precipitous declines in North America following the establishment of the exotic sevenspotted lady beetle, Coccinella septempunctata L. Recent volunteer efforts have made it possible to establish colonies of the now-rare C. novemnotata and test mechanisms contributing to its decline. We evaluated the...
The integration of infectious disease epidemiology with community ecology is an active area of research. Recent studies using SI models without acquired immunity have demonstrated that predation can suppress infectious disease levels. The authors recently showed that incorporating immunity (SIR models) can produce a "hump"-shaped relationship between disease prevalence and predation pressure; t...
Ecologists often assume that dispersing individuals experience increased predation risk owing to increased exposure to predators while moving. To test the hypothesis that predation risk is a function of movement distance or rate of movement, we used radio-telemetry data collected from 193 ruffed grouse (Bonasa umbellus) during 1996– 1999 in southeastern Ohio. Cox’s proportional hazards model wa...
Predation by protists is top-down pressure that regulates prokaryotic abundance, community function, structure, and diversity in natural and artificial ecosystems. Although the effects of predation by protists have been studied in aerobic ecosystems, they are poorly understood in anoxic environments. We herein studied the influence of predation by Metopus and Caenomorpha ciliates-ciliates frequ...
Visual predation by nocturnal zooplanktivorous fish is assumed to be sufficiently limited to allow the evolution of vertical migration as means for predation avoidance by zooplankton. However, in situ measurements of predation rates by nocturnal fish are lacking. Most of our knowledge of this predation is based on stomach contents and laboratory experiments. Our objectives were to measure the i...
Correspondence: T. Stankowich, Psychology Department, Young Hall, One Shields Avenue, University of California, Davis, CA 95616, U.S.A. (email: [email protected]). Biologists have studied group dynamics and attempted to define the benefits of gregariousness across diverse taxa for several decades. The relative costs and benefits of group living (reviewed in Krause & Ruxton 2002) may diffe...
Predation is a major source of mortality for many avian species. Species that face more predators, and those with less effective anti-predator responses, are presumably likely to die from predation over time. rate, as measure susceptibility predation, difficult in the field. Radio-tracking studies, however, allow researchers determine time cause death marked individuals, making it possible esti...
We use microsatellite loci to detail the multiple paternity patterns in broods from 10 wild populations of the guppy (Poecilia reticulata) found in Northern Trinidad. The populations span two major drainages comprising the Caroni and the Oropouche, and include sites that are characterized by either high or low predation. Across the populations the frequency of multiple paternity is high with 95...
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