Sheep predation by coyotes (Canis latrans) is a major problem for sheep producers in North America. Solutions are facilitated by a basic understanding of the trophic dynamic context of this problem, one that likely varies geographically in important qualitative ways. Little is known about vertebrate trophic dynamics in Mediterranean ecosystems, where prey are diverse and their biomass is strong...

Intraspecific variation in body pigmentation is an ecologically and evolutionary important trait; however, the pigmentation related trade-offs in marine zooplankton are poorly understood. We tested the effects of intrapopulation phenotypic variation in the pigmentation of the copepod Eurytemora affinis on predation risk, foraging, growth, metabolic activity and antioxidant capacity. Using pigme...

Amphipod abundance and biomass were determined in soft-bottom substrates (SBS), monospecific Thalassia testudinum patches and T. testudinum with attached macroalgae (SAV) from Términos Lagoon. Amphipods were absent in SBS, and their density and biomass were higher in SAV (3351 individualsm(-2), 1718 mg AFDWm(-2)) than in T. testudinum (1220 indm(-2), 625 mg AFDWm(-2)). Although macroalgae and s...

BACKGROUND Predation may potentially lead to negative effects on both prey (directly via predators) and predators (indirectly via human persecution). Predation pressure studies are, therefore, of major interest in the fields of theoretical knowledge and conservation of prey or predator species, with wide ramifications and profound implications in human-wildlife conflicts. However, detailed work...

We model the population of the Blue Crab in the Chesapeake Bay by using differential equations. Blue crabs are inherently cannibalistic of juveniles, while also in competition with juvenile blue crabs for resources. These differential equations describe the intraguild predation consistent in the blue crab food web, as well as the cannibalistic nature of the blue crab. We introduce an aging and ...

Journal Club Every so often, a hypothesis comes along that contains an idea that makes you wonder why no one has thought of it before. A recent paper by T.E. Martin et al. 1 contains such a conceptual leap. In 1949, A.F. Skutch provided an original hypothesis regarding the evolution of parental care behaviour in birds. The hypothesis was that nest predation should increase with increasing paren...

Urban domestic cat (Felis catus) populations can attain exceedingly high densities and are not limited by natural prey availability. This has generated concerns that they may negatively affect prey populations, leading to calls for management. We enlisted cat-owners to record prey returned home to estimate patterns of predation by free-roaming pets in different localities within the town of Rea...

Models for organisms with complex life cycles predict decreased size at, and altered time to, metamorphosis for organisms experiencing greater mortality rate during the larval stages. We tested this prediction by exposing larvae of the tree hole mosquito, Aedes triseriatus, to predation by the mosquito Toxorhynchites rutilus in a series of five experiments. Populations both sympatric and allopa...

Growth is a critical ecological trait because it can determine population demography, evolution, and community interactions. Predation risk frequently induces decreased foraging and slow growth in prey. However, such strategies may not always be favored when prey can outgrow a predator's hunting ability. At the same time, a growing gape-limited predator broadens its hunting ability through time...

We conducted field experiments in 2002 and 2003 to determine whether the functional response of white-footed mice (Peromyscus leucopus ) to gypsy moth (Lymantria dispar ) pupae is decelerating (e.g. type 2) or accelerating (e.g. type 3) at low pupal density. In both experiments, live gypsy moth pupae were deployed in June (prior to the appearance of natural pupae) at densities of approximately ...