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At least 991 records · Page 55Linked to original sources
PubMed2004

Foraging behaviour in domestic pigs (Sus scrofa): remembering and prioritizing food sites of different value.

This experiment investigated whether domestic pigs can remember the locations of food sites of different relative value, and how a restricted retrieval choice affects their foraging behaviour. Nine juvenile female pigs were trained to relocate two food sites out of a possible eight in a spatial memory task. The two baited sites contained different amounts of food and an obstacle was added to the smaller amount to increase handling time. On each trial, a pig searched for the two baited sites (search visit). Once it had found and eaten the bait, it returned for a second (relocation) visit, in which the two same sites were baited. Baited sites were changed between trials. All subjects learnt the task. When allowed to retrieve both baits, the subjects showed no preference for retrieving a particular one first (experiment 1). When they were allowed to retrieve only one bait, a significant overall preference for retrieving the larger amount emerged across subjects (experiment 2). To test whether this preference reflected an avoidance of the obstacle with the smaller bait, 15 choice-restricted control trials were conducted. In control trials obstacles were present with both baits. Pigs continued to retrieve the larger bait, indicating they had discriminated between the two food sites on the basis of quantity or profitability and adjusted their behaviour accordingly when the relocation choice was restricted. This suggests for the first time that domestic pigs have the ability to discriminate between food sites of different relative value and to remember their respective locations.

Animals↗
PubMed2005

Hybrid disadvantage in the larval foraging behaviour of the two neotropical species of Drosophila pavani and Drosophila gaucha.

Flies from two populations of the Chilean endemic neotropical species Drosophila pavani and two populations of its sibling species Drosophila gaucha were crossed reciprocally to obtain intra- and interspecific hybrids. The developmental pathways of locomotor activity and feeding rate were analysed for eleven of twelve possible genotype groups. The hybrids showed reduced fitness indicated by a decrease in the measured traits. Hybrid disadvantage was strongest in interspecific hybrids, especially with respect to feeding behaviour. This evidence supports the contention that D. pavani and D. gaucha have evolved different coadapted gene pools controlling the developmental pathways for behavioural traits expressed during larval foraging; but genetic divergence affecting these behaviours has also taken place between locally adapted populations within each species.

Animals↗
PubMed2005

Characterization of condensed tannins purified from legume forages: chromophore production, protein precipitation, and inhibitory effects on cellulose digestion.

To identify simple screening tools for selecting condensed tannin (CT)-containing forages as candidate sources for further study, CT were isolated from nine legumes, and their molecular weights (MW), chromophore production, capacity to precipitate bovine serum albumin (BSA) and Fraction 1 protein (Rubisco) isolated from alfalfa, and inhibition of filter paper digestion were compared. Sources were as follows: leaves of sericea lespedeza (Lespedeza cuneata Dum.-Cours.), crown vetch (Coronilla varia L.), and sainfoin (Onobrychis viciifolia Scop.); stems of hedysarum (Hedysarum alpinum L.); seeds of alfalfa (Medicago sativa L.); and whole plants of birdsfoot trefoil (Lotus corniculatus var. corniculatus L.) and three varieties of big trefoil (Lotus pedunculatus Cav.), viz., Lotus uliginosus Schkuhr, L. uliginosus var. glabriusculus, and L. uliginosus var. villosus. Molecular weights and sizes (degrees of polymerization) of the CT varied considerably within and among plant species. Average MW ranged from 3036 Da (crown vetch) to 7143 Da (lespedeza). All CT exhibited greater capacity (w/w basis) to bind alfalfa Rubisco than BSA. Relative astringencies (microg CT required to precipitate 1 mg protein) against BSA ranged from 262.5 for CT from lespedeza to 435.5 for CT from L. corniculatus, and against Rubisco, from 49.6 (sainfoin) to 108.2 (alfalfa seed). Including CT at 300 microg/ml in cultures of Fibrobacter succinogenes reduced digestion of cellulose filter paper by 19.8% (sainfoin) to 92.4% (crown vetch) and increased the specific activity of cell-associated endoglucanase. There were no correlations between inhibitory effects of CT on filter paper digestion and (1) chromophore formation during CT assay by butanol-HCl, vanillin-HCl, or H2SO4; (2) precipitation of BSA or alfalfa Rubisco; and (3) MW of CT. The most inhibitory CT for cellulose digestion included those with broad and with narrow MW distributions. Sainfoin was the most desirable source of CT, as it had the highest capacity to bind alfalfa protein and was least inhibitory to cellulose digestion by F. succinogenes. This study suggests that these properties are not easily defined via chemical means, and that biological assays using rumen bacteria may help identify those CT with properties of nutritional interest.

1-Butanol↗
PubMed2006

Foraging behavior of Anastrepha Ludens, A. obliqua, and A. serpentina in response to feces extracts containing host marking pheromone.

Following oviposition, females of many Tephritid flies deposit host marking pheromones (HMPs) to indicate that the host fruit has been occupied. We describe the foraging behavior of these three economically important species (Anastrepha ludens and A. obliqua from the fraterculus species group and A. serpentina from the serpentina species group) when they encounter an artificial fruit (green agar spheres wrapped in Parafilm) marked with intra- and interspecific feces extracts that contain, among other substances, host marking pheromone. When flies encountered fruit treated with either 1 or 100 mg/ml feces extract, there were drastic and statistically significant reductions in tree residence time, mean time spent on fruit, and in the number of oviposition attempts or actual ovipositions when compared to the control treatment (clean fruit). These responses were almost identical irrespective of extract origin (i.e., fly species), indicating complete interspecific HMP cross-recognition by all three Anastrepha species tested. We discuss the ecological and practical implications of our findings.

Animals↗
PubMed2006

Volatile foraging kairomones in the littoral zone: attraction of an herbivorous freshwater gastropod to algal odors.

Volatile organic compounds (VOCs) produced by algae and cyanobacteria are primarily responsible for odors in fresh waters. Among other functions, VOCs may serve as important infochemicals in biofilms of benthic primary producers. VOCs liberated by benthic, mat-forming cyanobacteria can be used as habitat-finding cues by insects, nematodes, and possibly other organisms. We developed a new gastropod behavioral assay that allows detection of food preference without offering food, thus allowing the distinction between taste, which requires direct contact with the food source, and the detection of odorous infochemicals, which work over distance. We demonstrated that VOCs released from disintegrated cells of a benthic, mat-forming, green alga (Ulothrix fimbriata) are food-finding cues ("foraging kairomones") that attract the herbivorous freshwater snail Radix ovata. A mixture of three C5 lipoxygenase compounds and 2(E),4(E)-heptadienal that mimic the major VOCs released by U. fimbriata attracted the snails, whereas neither the mixture of C5 compounds nor 2(E),4(E)-heptadienal were effective when given alone. This study suggests that VOCs can play a steering role as infochemicals in freshwater benthic habitats, as has been established for many organismic interactions in terrestrial ecosystems.

Adsorption↗
PubMed1990

Corticosterone, foraging behavior, and metabolism in dark-eyed juncos, Junco hyemalis.

Male, dark-eyed juncos, Junco hyemalis, were held in captivity under conditions simulating winter temperature and photoperiod. Birds were administered corticosterone (B), metapyrone (MET), or control (empty) implants in silastic tubing. B implants resulted in higher plasma levels of B, especially on the first day following implantation. After 4 days, B-implanted birds had significant atrophy of the flight muscles and increased storage of fat in the furcular and abdominal adipose depots. Despite the increased fat deposition, no differences in adipose tissue lipoprotein lipase (LPL) activity or plasma levels of glycerol or free fatty acid were observed after 4 days of treatment. There were no differences in muscle LPL activity when enzyme activity was expressed per tissue. However, when enzyme activity was expressed per gram of tissue, muscle LPL was significantly greater in the B-treated birds. Therefore, despite the atrophy of muscle tissue, the LPL enzyme had been preserved. No differences were observed in either foraging behavior or food consumption, even in light of the dramatic changes in fat and muscle masses in B-treated birds. These data are discussed in light of the chronic effects of B which may be applicable to the advanced stage of stress in birds.

Adipose Tissue↗
PubMed1990

Conflict between the need to forage and the need to avoid competition: persistence of two-species model.

We consider a model in which the need to forage and the need to avoid a competitor are in conflict. The model is composed of two Lotka-Volterra patches. The system has two competitors; one can diffuse between two patches, but the other is confined to one of the patches and cannot diffuse. It is proved that the system can be made persistent under appropriate diffusion conditions that ensure the instability of boundary equilibria, even if the competitive patch is not persistent without diffusion. Further it is shown that the system is globally stable for any diffusion rate if the competition between the two species is weak.

Animals↗
PubMed1985

Influence of food and water deprivation on the behavior of the white rat foraging in a hostile environment.

Rats were trained to feed 2 hr per day, the food offered being placed at 16 m from a warm refuge and the ambient temperature being - 15 degrees C. They were food deprived for 0, 12, 22, 46, 70 and 94 hr prior to the six feeding sessions. Speed of feeding and meal duration were not influenced by food deprivation. The amount eaten, the number of meals, the time spent at the feeder, the speed of running to the feeder and the number of foraging rats increased from 0 hr fast to 22 hr then plateaued for the 46, 70 and 96 hr fasts. The same experiment was carried out after water deprivation for 0, 12, 22, 46 and 70 hr. Rats could find, at -15 degrees C, water kept at 30-40 degrees C and at 16 m from their warm refuge. The speed of running to water and the rate of drinking were not influenced by water deprivation. The amount drunk, drinking-bout duration, the number of drinking-bouts, total drinking time and the number of rats drinking increased monotonically from 0 to 70 hr deprivation. Two main conclusions are drawn from these data: (1) in the rat, up to 70 hr deprivation, the motivation to feed seems to be stronger than the motivation to drink; (2) to satisfy hunger or thirst, the nervous system uses several different motor subsystems of behavior.

Animals↗
PubMed1989

Age-specific optimal diets and optimal foraging tactics: a life-historic approach.

By linking optimal foraging theory and optimal life history theory, we demonstrate that optimal diets, in general, may depend on the individual's age even when everything else remains the same. Older individuals (i.e., individuals with lower reproductive values) are predicted to have diets composed of highly nutritious food types that are possibly dangerous to pursue.

Aging↗
PubMed1985

Determination of cobalt in forages by Zeeman electrothermal atomic absorption spectrophotometry without preliminary extraction.

A simple and rapid method, avoiding preliminary extraction, is described for the determination of Co in plant samples. The factors influencing the mineralization steps and the interference of major elements are investigated. The described method gives a recovery in the range 100-110%. Use of the standard addition method avoids interference from Ca and Fe. In the range 0.1-1 ppm (dry basis), Co can be determined with a precision of 5%. The detection limit of the method is 0.02 ppm of Co in forages.

Animal Feed↗
PubMed1979

Variables associated with peripartum traits in dairy cows. I. Effect of dietary forages and disorders on voluntary intake of feed, body weight and milk yield.

Daily voluntary intakes of feed by each of 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. Diets designed to meet NRC requirements and which contained either chopped hay (29 cows), hay crop silage (HCS; 30 cows) or corn silage (CS; 30 cows) were compared prepartum (27 to 0 days), peripartum (1 day before to 3 days after calving) and postpartum (days 4 to 30 postpartum). Mixed rations, fed during lactation, were 60% forage and 40% concentrate dry matter (DM). Cow management was similar to commercial operations. The experimental hypothesis was that pre-disposition for partum and postpartum disorders (abnormal) could be related either to voluntary intake of different diets or to physical traits. Intakes (DM or estimated net energy) across diets decreased 30% between days 7 and 1 prepartum and averaged 18% and 20% lower peripartum and postpartum, respectively, in abnormal cows than in control cows. Seasonal effects on intakes were significant. In general, changes in body weight and condition and differences in udder edema and milk yield reflected intakes. The results support the original hypothesis.

Journal Article↗
PubMed1988

Rumen fungi: morphological types from Georgia cattle and the attack on forage cell walls.

Fungal colonies developing in anaerobic media from zoospores in rumen fluid from cows eating Cynodon dactylon or Medicago sativa included types showing monocentric and polycentric growth. High energy supplements added to diets of Sorghum bicolor silage increased fungal numbers in the rumen, but increases were also affected by the history and predisposition of the animal. Mixed fungal types in rumen fluid and pure cultures of isolates showing monocentric and polycentric growth degraded and weakened lignocellulosic tissues and penetrated the cuticle of C. dactylon leaf blades. By weakening or degrading recalcitrant structures in forages, rumen fungi may alter physical parameters of plants that influence utilization of fibre by ruminants.

Anaerobiosis↗
PubMed2006

Evolutionary and anthropological perspectives on optimal foraging in obesogenic environments.

The nutrition transition has created an obesogenic environment resulting in a growing obesity pandemic. An optimal foraging approach provides cost/benefit models of cognitive, behavioral and physiological strategies that illuminate the causes of caloric surfeit and consequent obesity in current environments of abundant food cues; easy-access and reliable food patches; low processing costs and enormous variety of energy-dense foods. Experimental and naturalistic observations demonstrate that obesogenic environments capitalize on human proclivities by displaying colorful advertising, supersizing meals, providing abundant variety, increasing convenience, and utilizing distractions that impede monitoring of food portions during consumption. The globalization of fast foods propels these trends.

Advertising↗
PubMed2005

Adaptive changes in a radial maze task: Efficient selection of baited arms with reduced foraging in senescent hooded rats.

Qualitative differences in strategy selection during foraging in a partially baited maze were assessed in young and old rats. The baited and non-baited arms were at a fixed position in space and marked by a specific olfactory cue. The senescent rats did more re-entries during the first four-trial block but were more rapid than the young rats in selecting the reinforced arms during the first visits. Dissociation between the olfactory spatial cue reference by rotating the maze revealed that only few old subjects relied on olfactory cues to select the baited arms and the remainder relied mainly on the visuo-spatial cues.

Adaptation, Psychological↗
PubMed2006

Dominance behaviour and regulation of foraging in the primitively eusocial wasp Ropalidia marginata (Lep.) (Hymenoptera: Vespidae).

Ropalidia marginata is a primitively eusocial, polistine wasp widely distributed in peninsular India. In spite of its primitively eusocial status, queens of R. marginata are surprisingly docile and behaviourally non-dominant (except during the first week or so of their careers as queens). Yet they successfully maintain reproductive monopoly throughout their careers, probably through the use of pheromones. Workers exhibit dominance-subordinate interactions but these behaviours are not involved in regulating reproductive competition among the workers because workers with high dominance ranks are not necessarily the ones who replace lost queens. We have speculated and provided correlational evidence before that dominance-subordinate interactions among the workers have been co-opted in this species for the workers to regulate each other's foraging. Here, we provide experimental evidence in support of the speculation, by reducing demand for food and showing that this results in a significant decrease in the frequency of dominance-subordinate interactions among the workers.

Agonistic Behavior↗
PubMed2006

Contextual control of rats' foraging behaviour in a radial maze.

This study demonstrated that with experience rats were able to discriminate the background contextual cues in order to foraging correctly in an eight-arm radial maze if the background contexts signaled to the rats which of two bait patterns was in effect in that context. Four of the eight arms were context-dependent: two arms were baited in the "night" context, while the other two were baited in the "daytime" context. The remaining four arms were context-independent: three of them were never baited, while the remaining one was baited in both contexts. The rats gradually began to avoid the arms that were uniquely baited in the other context, suggesting a contextual or conditional control of arm selection. Interestingly, these rats also showed better performance in avoiding the never-baited arms, compared with control rats. Namely, disambiguating the incentive values of the four arms by contextual cues collaterally facilitated the context-independent arm performance. Another interesting finding of the present study is that the rats did not visit the always-baited arm earlier than the arms uniquely baited in that context.

Animals↗
PubMedDate not supplied

Coupled computational simulation and empirical research into the foraging system of Pharaoh's ant (Monomorium pharaonis).

The Pharaoh's ant (Monomorium pharaonis), a significant pest in many human environments, is phenomenally successful at locating and exploiting available food resources. Several pheromones are utilized in the self-organized foraging of this ant but most aspects of the overall system are poorly characterised. Agent-based modelling of ants as individual complex X-machines facilitates study of the mechanisms underlying the emergence of trails and aids understanding of the process. Conducting simultaneous modelling, and simulation, alongside empirical biological studies is shown to drive the research by formulating hypotheses that must be tested before the model can be verified and extended. Integration of newly characterised behavioural processes into the overall model will enable testing of general theories giving insight into division of labour within insect societies. This study aims to establish a new paradigm in computational modelling applicable to all types of multi-agent biological systems, from tissues to animal societies, as a powerful tool to accelerate basic research.

Animals↗
PubMed2004

Control of glycerol production by rainbow smelt (Osmerus mordax) to provide freeze resistance and allow foraging at low winter temperatures.

The rainbow smelt (Osmerus mordax) is a small anadromous fish that actively feeds under the ice at temperatures as low as the freeze point of seawater. Freezing is avoided through the production of both non-colligative antifreeze protein (AFP) and glycerol that acts in a colligative manner. Glycerol is constantly lost across the gills and skin, thus glycerol production must continue on a sustained basis at low winter temperatures. AFP begins to accumulate in early fall while water temperatures are still high. Glycerol production is triggered when water temperatures decrease to about 5 degrees C. Glycerol levels rapidly increase with carbon flow from dihydroxyacetone phosphate (DHAP) to glycerol 3-phosphate (G3P) to glycerol. Glucose/glycogen serves as the initial carbon source for glycerol accumulation with amino acids contributing thereafter. The period of glycerol accumulation is associated with increases in GPDH mRNA and PEPCK mRNA followed by elevations in protein synthesis and enzyme activities. Plasma glycerol levels may reach in excess of 500 mM in winter. The high freeze resistance allows rainbow smelt to invade water of low temperature and forage for food. The lower the temperature, the higher the glycerol must be, and the higher the glycerol the greater the loss to the environment through diffusion. During the winter, rainbow smelt feed upon protein rich invertebrates with glycerol production being fueled in part by dietary amino acids via the gluconeogenic pathway. At winter temperatures, glycerol is quantitatively more important than AFP in providing freeze resistance of blood; however, the importance of AFPs to other tissues is yet to be assessed. Glycerol levels rapidly plummet in the spring when water temperature is still close to 0 degrees C. During this period, freeze resistance must be provided by AFP alone. Overall, the phenomenon of glycerol production by rainbow smelt reveals an elegant connection of biochemistry to ecology that allows this species to exploit an otherwise unavailable food resource.

Animals↗