The impact of predation on prey populations has long been a focus of ecologists, but a firm understanding of the factors influencing prey selection, a key predictor of that impact, remains elusive. High levels of variability observed in prey selection may reflect true differences in the ecology of different communities but might also reflect a failure to deal adequately with uncertainties in th...

Body composition traits have potential use in fish breeding programs as indicator traits for selective improvement of feed efficiency. Moreover, feed companies are increasingly replacing traditional fish meal (FM) based ingredients in feeds for carnivorous farmed fish with plant protein ingredients. Therefore, genetic relationships of composition and feed utilization traits need to be quantifie...

Comparative studies have shown that diet, life history, and phylogeny interact to determine microbial community structure across mammalian hosts. However, these studies are often confounded by numerous factors. Selection experiments offer unique opportunities to validate conclusions and test hypotheses generated by comparative studies. We used a replicated, 15-generation selection experiment on...

Here, we simultaneously examine both content and efficacy-based sources of selection on the visual and seismic multimodal courtship display of the wolf spider Schizocosa retrorsa. Immature field-collected S. retrorsa were reared in the laboratory on either high-quantity diet (HD) or low-quantity diet (LD) treatments. On maturation, females of each diet treatment were run in simultaneous mate ch...

The heritability of diet selection for mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana [Rydb] Beetle) by grazing sheep was estimated from fecal samples collected from 549 Rambouillet ewes. Fecal samples were collected in September and October during 1996 and 1997 from free-grazing ewes on intermountain sagebrush-bunchgrass rangelands at the U.S. Sheep Experiment Station in Idah...

Feeding is the set of behaviors whereby organisms acquire and process the energy required for survival and reproduction. Thus, feeding system morphology is presumably subject to selection to maintain or improve feeding performance. Relationships among feeding system morphology, feeding behavior, and diet not only explain the morphological diversity of extant primates, but can also be used to re...

The adaptive benefits of maternal investment into individual offspring (inherited environmental effects) will be shaped by selection on mothers as well as their offspring, often across variable environments. We examined how a mother's nutritional environment interacted with her offspring's nutritional and social environment in Xiphophorus multilineatus, a live-bearing fish. Fry from mothers rea...

The short-term consumption of foods that differed in energy density (ED) and/or NaHCO3 supplementation, on subsequent food intake and diet selection in sheep were measured. Thirty sheep weighing 35.9 (sd 2.89) kg were used. Two foods were formulated: H had 11 and L had 8 MJ metabolizable energy/kg fresh matter. Four further foods were formulated by adding either 40 g NaHCO3/kg or 16.5 g NaCl/kg...

It has been reported that morphine causes a selective increase in the intake of dietary fat. Because we have noted considerable variability among rats in their preferences for carbohydrate and fat, we reasoned that the effect of morphine on diet selection may differ in fat-preferring vs. carbohydrate-preferring rats. Male Sprague-Dawley rats were given ad lib access to separate sources of carbo...

As a starting point for investigating the mechanisms of diet selection it is worth considering the function of diet selection. First, it is clear that the animal must select from the available foods a diet which can satisfy its nutritional requirements. Second, in doing this it must avoid ingesting harmful substances. Third, it must exploit resources efficiently: for many animals food supplies ...