The difficulty of directly observing predatory events hinders a complete understanding of how predation structures food webs. Indirect approaches such as PCR-based and isotopic analyses clarify patterns of resource consumption but fail to distinguish predation from scavenging. Given that facultative scavenging is a ubiquitous and phylogenetically widespread foraging strategy, an improved abilit...

Trophic structure and interconnectedness have important implications for diversity and stability in ecosystems. While it is generally difficult to determine trophic structure and the specific prey of predators in ancient ecosystems, analysis of stable isotope ratios in tooth enamel can be used to exclude taxa from a predator’s diet. This study analyzes δC v-pdb and δO v-pdb values in a canine o...

The effects of seasonal and regional differences in diet composition on the food requirements of Steller sea lions (Eumetopias jubatus) were esti­ mated by using a bioenergetic model. The model considered differences in the energy density of the prey, and dif­ ferences in digestive efficiency and the heat increment of feeding of different diets. The model predicted that Steller sea lions in sou...

Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats. This study inve...

BACKGROUND & OBJECTIVES The predatory potential of the larvivorous fishes can be affected by the presence of alternative preys. In the present study the predation pattern of the sewage dwelling Poecilia reticulata (Peters 1872) on the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae) was evaluated in the presence of alternative preys. METHODS The predation of Cx. quinquefasciatus...

A study was conducted to examine the influence of the hunger level on the prey consumption of Macrolophus pygmaeus Rambur (Hemiptera Miridae) at varying densities of Myzus persicae Sulzer (Hemiptera Aphididae) through laboratory functional response experiments. Newly emerged adult females of the predator were subjected to 24 or 48 h of prey deprivation on pepper plant, as well as to 48 h only o...

The interaction of prey distribution patterns and predator behavior can mediate predator–prey dynamics. Inter-patch distance (lag) may be especially important in the interacting effects of aggregation and interference among predators on their search and prey-handling ability. Interactions of blue crabs Callinectes sapidus preying upon thin-shelled clams Macoma balthica in Chesapeake Bay provide...

We study a reaction-diffusion-advection model for the dynamics of populations under biological control. A control agent is assumed to be a predator species that has the ability to perceive the heterogeneity of pest distribution. The advection term represents the predator density movement according to a basic prey taxis assumption: acceleration of predators is proportional to the prey density gr...

Past evaluations of pesticide exposure have been conducted with substantial uncertainty regarding avian consumption of contaminated food items. One question is whether birds consume invertebrates that are killed by a chemical application and that may present an increasing chemical concentration as they desiccate. We addressed the research question in two phases. First, a laboratory study was co...

Laboratory experiments were conducted to determine how larval and juvenile yellow perch Perca flavescens respond to changes in prey density when exposed to different levels and types of turbidity (phytoplanktonic or sedimentary). Across prey densities, consumption by P. flavescens tended to be less in phytoplanktonic turbidity compared with sedimentary turbidity. For larvae, this effect was dep...