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...

Causes of interspecific variation in growth rates within and among geographic regions remain poorly understood. Passerine birds represent an intriguing case because differing theories yield the possibility of an antagonistic interaction between nest predation risk and food delivery rates on evolution of growth rates. We test this possibility among 64 Passerine species studied on three continent...

Both predators and parasitoids can have significant effects on species' life history traits, such as longevity or clutch size. In the case of gall inducers, sporadically there is evidence to suggest that both vertebrate predation and insect parasitoid attack may shape the optimal gall size. While the effects of parasitoids have been studied in detail, the influence of vertebrate predation is le...

Question: Does nest predation influence egg colour appearance among North American and European passerine birds? Analyses of species that lay their eggs directly on the ground provide support for such a contention, but it is less obvious in shrub and canopy nesters. We hypothesized that if predators locate nests by egg colour, nest predation could select for eggs with a less conspicuous backgro...

A small or sparse population may suffer a reduction in fitness owing to Allee effects. Here, we explored effects of plant density on pollination, reproduction and predation in the alpine herb Pedicularis rex over two years. We did not detect a significant difference in the pollination rate or fecundity (fruit set and the initial seed set) before predation between sparse and dense patches in eit...

Omnivorous Heteroptera constitute an important component of predatory guilds with high potential for biological control. Understanding the relative effects of plant feeding on the suppression of prey by omnivores could be an important element for improving biological control strategies. In the current paper, the effects of different plant food sources on the predation rate of the omnivorous pre...

Dispersal theory generally predicts kin competition, inbreeding, and temporal variation in habitat quality should select for dispersal, whereas spatial variation in habitat quality should select against dispersal. The effect of predation on the evolution of dispersal is currently not well-known: because predation can be variable in both space and time, it is not clear whether or when predation ...

Based on a cyclic predator-prey model of three species, spiral waves on global level of the system are obtained. It is found that the predation intensity greatly affects on the behaviors of spiral waves. The wavelength of spiral waves alter with the mobility in the form of λ ∼ D. Values of θ are determined by predation rates between species. It indicates the behaviors of spiral waves varying wi...

Predation by small mammals has been reported as an important mortality factor for the cocoons of sawfly species. However, it is difficult to provide an accurate estimate of newly spun cocoons and subsequent predation rates by small mammals for several reasons. First, all larvae do not spin cocoons at the same time. Second, cocoons are exposed to small mammal predation immediately after being sp...