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Sample records for esox lucius foraging

  1. Trophic flexibility and opportunism in pike Esox lucius.

    PubMed

    Pedreschi, D; Mariani, S; Coughlan, J; Voigt, C C; O'Grady, M; Caffrey, J; Kelly-Quinn, M

    2015-10-01

    The first comprehensive investigation of pike Esox lucius trophic ecology in a region (Ireland) where they have long been thought to be a non-native species is presented. Diet was investigated across habitat types (lake, river and canal) through the combined methods of stable-isotope and stomach content analyses. Variations in niche size, specialization and the timing of the ontogenetic dietary switch were examined, revealing pronounced opportunism and feeding plasticity in E. lucius, along with a high occurrence of invertivory (up to 60?cm fork length, LF ) and a concomitant delayed switch to piscivory. Furthermore, E. lucius were found to primarily prey upon the highly available non-native roach Rutilus rutilus, which may alleviate predation pressure on brown trout Salmo trutta, highlighting the complexity of dynamic systems and the essential role of research in informing effective management. PMID:26351044

  2. Morphological study of the northern pike (Esox lucius) tongue.

    PubMed

    Sadeghinezhad, Javad; Rahmati-holasoo, Hooman; Fayyaz, Sahel; Zargar, Ashkan

    2015-09-01

    The northern pike (Esox lucius) is a fresh water species belonging to the Esocidae family. It is a carnivorous fish feeding mostly on invertebrates and fishes. Due to the scantiness of relevant literature regarding the morphology of the tongue in fish we carried out this study with the aim of providing information on the dorsal surface morphology and histological structures of the tongue in E. lucius. The tongues of five E. lucius were examined using light- and scanning electron- microscopy (SEM) techniques. The SEM studies revealed the presence of numerous teeth, longitudinal mucosal strands and scattered taste buds spread on the tongue surface. Histological studies using hematoxylin and eosin and Masson's trichrome staining showed that the musculature was not visible in the tongue of E. lucius. The tongue is composed of mucosa, and submucosa supported by osteocartilagionous skeleton. The mucosa consists of several layers of unicellular mucous cells interrupted by numerous teeth. The derivation of teeth from the underlying bronchial skeleton was visible in longitudinal section. The scattered taste buds with a typical onion shape were also present. Overall, the morphological features of the E. lucius tongue together suggested its mechanical and sensory roles. The findings of this study together with morphological and physiological data from other fishes contribute to the knowledge of the nutrition and feeding behavior in aquaculture species. PMID:25205560

  3. Northern pike (Esox lucius) are common sport fish in the northern United States and Canada. In

    E-print Network

    ). Anglers traditionally want "quality" angling opportunities, which usually means more large- sized fish6 Northern pike (Esox lucius) are common sport fish in the northern United States and Canada. In South Dakota, northern pike and muskellunge (Esox masquinongy) ranked second in total number of fishing

  4. Northern pike (Esox lucius) collagen: Extraction, characterization and potential application.

    PubMed

    Kozlowska, J; Sionkowska, A; Skopinska-Wisniewska, J; Piechowicz, K

    2015-11-01

    Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the scales of northern pike (Esox lucius) were extracted and characterized. It was the first time that this species was used as sources of collagen. FT-IR and amino acid analysis results revealed the presence of collagen. Glycine accounts for one-third of its amino acid residues and specific for collagen amino acid - hydroxyproline - is present in isolated protein. The content of imino acid: proline and hydroxyproline in ASC and PSC was similar (12.5% Pro and 6.5% Hyp). Both ASC and PSC were type I collagen. The denaturation temperature of ASC and PSC were 28.5 and 27°C, respectively. Thin collagen films were obtained by casting of collagen solution onto glass plates. The surface properties of ASC and PSC films were different - the surface of ASC collagen film was more polar and less rough than PSC and we can observe the formation of collagen fibrils after solvent evaporation. ASC films showed much higher tensile properties than PSC. The obtained results suggest that northern pike scales have potential as an alternative source of collagen for use in various fields. PMID:26254247

  5. Mercury elimination rates for adult northern pike Esox lucius: evidence for a sex effect

    USGS Publications Warehouse

    Madenjian, Charles P.; Blanchfield, Paul J.; Hrenchuk, Lee E.; Van Walleghem, Jillian L. A.

    2014-01-01

    We examined the effect of sex on mercury elimination in fish by monitoring isotope-enriched mercury concentrations in the muscle tissue of three adult female and three adult male northern pike Esox lucius, which had accumulated the isotope-enriched mercury via a whole-lake manipulation and were subsequently moved to a clean lake. Mercury elimination rates for female and male northern pike were estimated to be 0.00034 and 0.00073 day?1, respectively. Thus, males were capable of eliminating mercury at more than double the rate than that of females. To the best of our knowledge, our study represents the first documentation of mercury elimination rates varying between the sexes of fish. This sex difference in elimination rates should be taken into account when comparing mercury accumulation between the sexes of fish from the same population. Further, our findings should eventually lead to an improved understanding of mechanisms responsible for mercury elimination in vertebrates.

  6. Hematological parameters associated with parasitism in pike, Esox lucius caught from Anzali wetland.

    PubMed

    Fallah, Farzin Jamalzad; Khara, Hossein; Rohi, Javad Daghigh; Sayadborani, Mohammad

    2015-06-01

    This study involved 120 pike, Esox lucius, captured from Anzali wetland. Parasite fauna were identified in captured fish. Also, changes of haematological parameters were compared both infected and uninfected fish. Parasitological inspections revealed the following infestations: Skin: Lernea cyprinacea, Argulus foliaceus (Crustacean) and Tricodina sp. (Ciliatea). Gill: Dactylogyrus sp. (Digenea) and Tetraonchus monenteron (Monogenea). Eye: Diplostomum spathaceum (Digenea). Gut: Eustrongylides exises, Rhipdocotyle illense, Raphidascaris acus (Nematode), Corynosoma Strumosum (Acanthocephala). Most prevalence and intensity were related to Eustrongylides exises and Rhipdocotyle illense. Following haematological parameters were evaluated: haematocrit, haemoglobin concentration, erythrocyte and leukocyte counts, mean cell volume (MCV), mean cell haemoglobin, mean cell haemoglobin concentration lymphocytes, monocytes and eosinophils. Significant difference was found for MCV between infected and uninfected fish. PMID:26064009

  7. 'Soft' harness for external attachment of large radio transmitters to northern pike (Esox lucius)

    USGS Publications Warehouse

    Herke, S.W.; Moring, J.R.

    1999-01-01

    We developed a 'soft' harness for dorsally attaching large, external radio transmitters to northern pike (Esox lucius). The key harness component was a soft, flexible, thick-walled tubing that prevented tissue abrasion by the attachment lines which passed through the tubing. Six field-tagged fish (1.5-7.5 kg) were monitored for 45-115 days before tracking was terminated. Tracking patterns of fish indicated no apparent effect of these large, external transmitters on movement behavior; further, the transmitters did not appear to entangle the fish in vegetation. One fish with its transmitter still secure was recaptured after 54 days, and there was minimal tissue erosion under the transmitter. With minor improvements for the attachment lines and the transmitter saddle, the method is suitable for externally attaching large telemetry transmitters to fish.

  8. Age and growth of pike (Esox lucius) in Chivyrkui Bay, Lake Baikal

    USGS Publications Warehouse

    Owens, Randall W.; Pronin, Nikolai M.

    2000-01-01

    The purpose of this study was to describe age and growth of pike (Esox lucius) in Lake Baikal. Pike were collected with gill nets and by angling in Chivyrkui Bay in late July-early August 1993 and by gill nets in June 1995. Total length (mm), weight (g), and sex were recorded and scales and cleithra were collected for aging. In 1993, pike, ages 1 to 3, ranged in length from 331 to 810 mm and in 1995 , pike, ages 2 to 10, ranged in length from 365 to 1,111 mm but only three percent were age 7 or older. Most growth in length occurred during the first two years of life. The length-weight relation for pike from Chivyrkui Bay was similar to that of pike from the St. Lawrence River. Calculated total length of pike from Lake Baikal equalled or exceeded the lengths of pike from lakes Erie or Ontario. Good agreement was found between ages from cleithra and from scales. Lengths at age in June 1995 (N=108) varied widely among pike. Females were generally larger than males at a given age among fish age-3 and older. When compared with the circumpolar growth standard, based on the von Bertalanffy growth curve, growth of Lake Baikal pike exceeded all other Asian populations, and equalled or exceeded many other northern hemisphere populations.

  9. Genetic structure of pike (Esox lucius) reveals a complex and previously unrecognized colonization history of Ireland

    PubMed Central

    Pedreschi, Debbi; Kelly-Quinn, Mary; Caffrey, Joe; O’Grady, Martin; Mariani, Stefano; Phillimore, Albert

    2014-01-01

    Aim We investigated genetic variation of Irish pike populations and their relationship with European outgroups, in order to elucidate the origin of this species to the island, which is largely assumed to have occurred as a human-mediated introduction over the past few hundred years. We aimed thereby to provide new insights into population structure to improve fisheries and biodiversity management in Irish freshwaters. Location Ireland, Britain and continental Europe. Methods A total of 752 pike (Esox lucius) were sampled from 15 locations around Ireland, and 9 continental European sites, and genotyped at six polymorphic microsatellite loci. Patterns and mechanisms of population genetic structure were assessed through a diverse array of methods, including Bayesian clustering, hierarchical analysis of molecular variance, and approximate Bayesian computation. Results Varying levels of genetic diversity and a high degree of population genetic differentiation were detected. Clear substructure within Ireland was identified, with two main groups being evident. One of the Irish populations showed high similarity with British populations. The other, more widespread, Irish strain did not group with any European population examined. Approximate Bayesian computation suggested that this widespread Irish strain is older, and may have colonized Ireland independently of humans. Main conclusions Population genetic substructure in Irish pike is high and comparable to the levels observed elsewhere in Europe. A comparison of evolutionary scenarios upholds the possibility that pike may have colonized Ireland in two ‘waves’, the first of which, being independent of human colonization, would represent the first evidence for natural colonization of a non-anadromous freshwater fish to the island of Ireland. Although further investigations using comprehensive genomic techniques will be necessary to confirm this, the present results warrant a reappraisal of current management strategies for this species. PMID:25435649

  10. Biomarkers of contaminant exposure in northern pike (Esox lucius) from the Yukon River Basin, Alaska

    USGS Publications Warehouse

    Hinck, J.E.; Blazer, V.S.; Denslow, N.D.; Myers, M.S.; Gross, T.S.; Tillitt, D.E.

    2007-01-01

    As part of a larger investigation, northern pike (n = 158; Esox lucius) were collected from ten sites in the Yukon River Basin (YRB), Alaska, to document biomarkers and their correlations with organochlorine pesticide (total p,p'-DDT, total chlordane, dieldrin, and toxaphene), total polychlorinated biphenyls (PCBs), and elemental contaminant (arsenic, cadmium, copper, lead, total mercury, selenium, and zinc) concentrations. A suite of biomarkers including somatic indices, hepatic 7-ethoxyresorufin O-deethylase (EROD) activity, vitellogenin concentrations, steroid hormone (17B- ustradiol and 16-kebtestosteront) concentrations, splenic macrophage aggregates (MAs), oocyte atresia, and other microscopic anomalies in various tissues were documented in YRB pike. Mean condition factor (0.50 to 0.68), hepatosomatic index (1.00% to 3.56%), and splenosomatic index (0.09% to 0.18%) were not anomalous at any site nor correlated with any contaminant concentration. Mean EROD activity (0.71 to 17.51 pmol/min/mg protein) was similar to basal activity levels previously measured in pike and was positively correlated with selenium concentrations (r = 0.88, P 0.01 mg/mL in male pike from multiple sites indicated exposure to estrogenic compounds. Mean steroid hormone concentrations and percent oocyte atresia were not anomalous in pike from any YRB site. Few site differences were significant for mean MA density (1.86 to 6.42 MA/mm2), size (812 to 1481 ??m2), and tissue occupied (MA-%; 0.24% to 0.75%). A linear regression between MA-% and total PCBs was significant, although PCB concentrations were generally low in YRB pike (???63 ng/g), and MA-% values in female pike (0.24% to 0.54%) were lower than in male pike (0.32% to 0.75%) at similar PCB concentrations. Greater numbers of MAs were found as zinc concentrations increased in YRB female pike, but it is unlikely that this is a causative relationship. Histological abnormalities observed in gill, liver, spleen, and kidney tissues were not likely a result of contaminant exposure but provide information on the general health of YRB pike. The most common histologic anomalies were parasitic infestations in various organs and developing nephrons and nephrocalcinosis in posterior kidney tissues. Overall, few biomarker responses in YRB pike were correlated with chemical contaminant concentrations, and YRB pike generally appeared to be healthy with no site having multiple anomalous biomarker responses. ?? 2007 Springer Science+Business Media, LLC.

  11. Fish Community Responses to the Establishment of a Piscivore, Northern Pike (Esox lucius), in a Nebraska Sandhill Lake

    USGS Publications Warehouse

    DeBates, T.J.; Paukert, C.P.; Willis, D.W.

    2003-01-01

    Northern pike (Esox lucius) was first documented in West Long Lake, Nebraska, in 1998 when two pike <380 mm were collected. In 2002, a Peterson mark-recapture population estimate on northern pike revealed density and standing stock (i.e., biomass) estimates of 35.8 fish/ha (95% CI= ?? 8.8) and 22.0 kg/ha (95% CI= ?? 5.4), respectively. Consequently, West Long Lake was sampled in 2002 to compare relative abundance, size structure, and growth of bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), and yellow perch (Perca flavescens) prior to and after the establishment of a high-density northern pike population. Bluegill, largemouth bass, and yellow perch relative abundances were significantly lower in 2002 than 1998. Similarly, size structures of all three species were significantly different between years. Size structure declined for both bluegill and yellow perch, and increased for largemouth bass. Growth was significantly higher for bluegill, largemouth bass, and yellow perch in 2002 than 1998. While the fish community changes were expected with the establishment of northern pike, they occurred in a relatively short time period (i.e., four years).

  12. {sup 32}P-postlabeling analysis of DNA adducts in wild perch (Perca fluviatilis) and northern pike (Esox lucius)

    SciTech Connect

    Ericson, G.; Liewenborg, B.; Balk, L.

    1995-12-31

    Several previous studies have demonstrated a correlation between high concentrations of sediment-associated contaminants and elevated levels of aromatic/hydrophobic DNA adduct levels in the liver of benthic fish species. In the present study DNA adducts was analyzed in coastal populations of perch (Perca fluviatilis) and northern pike (Esox lucius). Fish were sampled from four different sites in a gradient from a heavily industrialized area at the Swedish Baltic coast. For comparison, fish were also caught in a reference area with no main industries and comparatively low levels of contaminants of anthropogenic origin. DNA was extracted from liver and several extrahepatic tissues and DNA adducts were analyzed by the nuclease PI version of the {sup 32}P-postlabeling assay. The autoradiograms derived from DNA of fish from the contaminated sites showed several adduct spots not visible on the autoradiograms derived from fish from the reference area. Total adduct levels were significantly elevated in several tissues in fish from contaminated sites compared to the reference area. Species and tissue-specific differences in adduct levels and the use of {sup 32}P-postlabeling analysis of DNA adducts as a biomarker to monitor the presence and effects of genotoxic chemicals in the aquatic environment are discussed.

  13. Post-glacial dispersal patterns of Northern pike inferred from an 8800 year old pike (Esox cf. lucius) skull from interior Alaska

    NASA Astrophysics Data System (ADS)

    Wooller, Matthew J.; Gaglioti, Benjamin; Fulton, Tara L.; Lopez, Andres; Shapiro, Beth

    2015-07-01

    The biogeography of freshwater fish species during and after late-Pleistocene glaciations relate to how these species are genetically organized today, and the management of these often disjunct populations. Debate exists concerning the biogeography and routes of dispersal for Northern pike (Esox lucius) after the last glaciation. A hypothesis to account for the relatively low modern genetic diversity for E. lucius is post-glacial radiation from refugia, including lakes from within the un-glaciated portions of eastern Beringia. We report the remains of a Northern pike (E. cf. lucius) skull, including bones, teeth, bone collagen and ancient DNA. The remains were preserved at a depth of between 440 and 446 cm in a 670 cm long core of sediment from Quartz Lake, which initiated at ˜11,200 cal yr BP in interior Alaska. A calibrated accelerator mass spectrometer (AMS) radiocarbon age of the collagen extracted from the preserved bones indicated that the organism was dated to 8820 cal yr BP and is bracketed by AMS values from analyses of terrestrial plant macrofossils, avoiding any potential aquatic reservoir effect that could have influenced the radiocarbon age of the bones. Scanning electron microscope images of the specimen show the hinged tooth anatomy typically of E. lucius. Molar C:N (3.5, 1? = 0.1) value of the collagen from the specimen indicated well-preserved collagen and its mean stable nitrogen isotope value is consistent with the known predatory feeding ecology of E. lucius. Ancient DNA in the bones showed that the specimen was identical to modern E. lucius. Our record of E. lucius from interior Alaska is consistent with a biogeographic scenario involving rapid dispersal of this species from glacial refugia in the northern hemisphere after the last glaciation.

  14. Landscape variability explains spatial pattern of population structure of northern pike (Esox lucius) in a large fluvial system.

    PubMed

    Ouellet-Cauchon, Geneviève; Mingelbier, Marc; Lecomte, Frédéric; Bernatchez, Louis

    2014-10-01

    A growing number of studies have been investigating the influence of contemporary environmental factors on population genetic structure, but few have addressed the issue of spatial patterns in the variable intensity of factors influencing the extent of population structure, and particularly so in aquatic ecosystems. In this study, we document the landscape genetics of northern pike (Esox lucius), based on the analysis of nearly 3000 individuals from 40 sampling sites using 22 microsatellites along the Lake Ontario - St. Lawrence River system (750 km) that locally presents diverse degrees of interannual water level variation. Genetic structure was globally very weak (F ST = 0.0208) but spatially variable with mean level of differentiation in the upstream section of the studied area being threefold higher (F ST = 0.0297) than observed in the downstream sector (F ST = 0.0100). Beside interannual water level fluctuation, 19 additional variables were considered and a multiple regression on distance matrices model (R (2)  = 0.6397, P < 0.001) revealed that water masses (b = 0.3617, P < 0.001) and man-made dams (b = 0.4852, P < 0.005) reduced genetic connectivity. Local level of interannual water level stability was positively associated to the extent of genetic differentiation (b = 0.3499, P < 0.05). As water level variation impacts on yearly quality and localization of spawning habitats, our study illustrates how temporal variation in local habitat availability, caused by interannual water level fluctuations, may locally decrease population genetic structure by forcing fish to move over longer distances to find suitable habitat. This study thus represents one of the rare examples of how environmental fluctuations may influence spatial variation in the extent of population genetic structure within a given species. PMID:25614787

  15. Landscape variability explains spatial pattern of population structure of northern pike (Esox lucius) in a large fluvial system

    PubMed Central

    Ouellet-Cauchon, Geneviève; Mingelbier, Marc; Lecomte, Frédéric; Bernatchez, Louis

    2014-01-01

    A growing number of studies have been investigating the influence of contemporary environmental factors on population genetic structure, but few have addressed the issue of spatial patterns in the variable intensity of factors influencing the extent of population structure, and particularly so in aquatic ecosystems. In this study, we document the landscape genetics of northern pike (Esox lucius), based on the analysis of nearly 3000 individuals from 40 sampling sites using 22 microsatellites along the Lake Ontario – St. Lawrence River system (750 km) that locally presents diverse degrees of interannual water level variation. Genetic structure was globally very weak (FST = 0.0208) but spatially variable with mean level of differentiation in the upstream section of the studied area being threefold higher (FST = 0.0297) than observed in the downstream sector (FST = 0.0100). Beside interannual water level fluctuation, 19 additional variables were considered and a multiple regression on distance matrices model (R2 = 0.6397, P < 0.001) revealed that water masses (b = 0.3617, P < 0.001) and man-made dams (b = 0.4852, P < 0.005) reduced genetic connectivity. Local level of interannual water level stability was positively associated to the extent of genetic differentiation (b = 0.3499, P < 0.05). As water level variation impacts on yearly quality and localization of spawning habitats, our study illustrates how temporal variation in local habitat availability, caused by interannual water level fluctuations, may locally decrease population genetic structure by forcing fish to move over longer distances to find suitable habitat. This study thus represents one of the rare examples of how environmental fluctuations may influence spatial variation in the extent of population genetic structure within a given species. PMID:25614787

  16. Development of new microsatellite loci and multiplex reactions for muskellunge (Esox masquinongy)

    USGS Publications Warehouse

    Sloss, Brian L.; Franckowiak, R.P.; Murphy, E.L.

    2008-01-01

    The muskellunge (Esox masquinongy) is a valued fisheries species throughout its native range. Numerous studies have documented performance and phenotypic differences among muskellunge populations, but genetic markers for assessment have been lacking. We characterized 14 microsatellite loci and developed five multiplex polymerase chain reactions. Successful amplification of northern pike (Esox lucius) was observed for seven loci. These microsatellites will be useful for analysing population structure, performance characteristics of propagated strains, and helping to develop and monitor hatchery management guidelines for muskellunge. ?? 2008 Blackwell Publishing Ltd.

  17. Molecular and Phenotypic Evidence of a New Species of Genus Esox (Esocidae, Esociformes, Actinopterygii): The Southern Pike, Esox flaviae

    PubMed Central

    Lucentini, Livia; Puletti, Maria Elena; Ricciolini, Claudia; Gigliarelli, Lilia; Fontaneto, Diego; Lanfaloni, Luisa; Bilò, Fabiana; Natali, Mauro; Panara, Fausto

    2011-01-01

    We address the taxonomic position of the southern European individuals of pike, performing a series of tests and comparisons from morphology, DNA taxonomy and population genetics parameters, in order to support the hypothesis that two species of pike, and not only one, exist in Europe. A strong relationship emerged between a northern genotype supported by COI, Cytb, AFLP and specific fragments, and a phenotype with round spot skin colour pattern and a large number of scales in the lateral line, clearly separated from a southern genotype with other skin colour pattern and a low number of scales in the lateral line. DNA taxonomy, based on a coalescent approach (GMYC) from phylogenetic reconstructions on COI and Cytb together with AFLP admixture analysis, supported the existence of two independently evolving entities. Such differences are not simply due to geographic distances, as northern European samples are more similar to Canadian and Chinese samples than the southern Europe ones. Thus, given that the differences between the two groups of European pike are significant at the phenotypic, genotypic and geographical levels, we propose the identification of two pike species: the already known northern pike (Esox lucius) and the southern pike (E. flaviae n.sp.). The correct identification of these two lineages as independent species should give rise to a ban on the introduction of northern pikes in southern Europe for recreational fishing, due to potential problems of hybridisation. PMID:22164201

  18. Fine-scale oscillatory banding in otoliths from arctic charr (Salveninus alpinus) and pike (Esox lucius)

    SciTech Connect

    Meldrum, A.; Halden, N.M.

    1997-12-31

    Transmission electron microscopy of otoliths from the inner ear of arctic charr and pike has revealed the presence of fine banding on the scale of several nanometers. The thickness of the bands was observed to vary in different portions of the sample, and some areas were not banded. EDS analysis could not detect chemical differences within the bands, but electron diffraction showed that the crystallographic orientation of the bands is related by a lattice mismatch. Previously, banding on the scale of 50 to 100 microns was observed by SEM in otoliths from arctic charr and was attributed to seasonal variations in growth. The fine-scale banding observed in this study, however, is unlikely to represent a daily variation. Electron diffraction from the pike samples shows that the material is composed of CaCO{sub 3} having the both the vaterite and aragonite structure, and hydrous CaCO{sub 3} was also observed. The large-scale banding previously identified by SEM was not observed in the TEM despite attempts to intersect the boundaries of the micron-sized layers. The interaction of the electron beam with the sample material was investigated by conducting several electron-irradiation experiments. The electron beam was observed to interact strongly with the sample and caused the precipitation of cubic CaO from the calcium carbonate matrix. Bright-field imaging showed the development of fine grained ({approximately} 5 nm) randomly oriented crystallites which accumulated with increasing electron dose. These initial results suggest that the precipitation of CaO is not driven by electron-beam beating. Previously, a similar phase-change phenomenon has been observed in hydroxyapatite from dental enamel. Other Ca-bearing biominerals may therefore also be expected to be sensitive to electron irradiation.

  19. OCCURRENCE OF 'ESOX NIGER' IN SANTA ROSA SOUND, FLORIDA

    EPA Science Inventory

    This is the first report of Esox niger collected from the normally saline portion of the lower Pensacola estuary. A 109 mm standard length chain pickerel was seined on 7 August 1975 from Santa Rosa Sound, in Santa Rosa County, Florida, from Thalassia beds about 300 m W. of the N....

  20. Complete mitochondrial genome of Esox reichertii (Amur pike).

    PubMed

    Liu, Yu; Yang, Jun

    2015-12-01

    The whole mitochondrial genome of Esox reichertii (fish) was first sequenced and characterized. It was determined to be 16,909?bp long, which contains the control region (CR), the origin of light-strand replication (OL), 22 transfer RNA genes, 2 ribosomal genes and 13 protein-coding genes. Overall base composition of the complete mitochondrial DNA was 28.65% A, 28.67% T, 27.28% C and 15.41% G, with 57.32%AT. PMID:24409891

  1. The effects of season on fatty acid composition and ?3/?6 ratios of northern pike ( Esox lucius L., 1758) muscle lipids

    NASA Astrophysics Data System (ADS)

    Mert, Ramazan; Bulut, Sait; Konuk, Muhsin

    2015-01-01

    In the present study, the effects of season on fatty acid composition, total lipids, and ?3/?6 ratios of northern pike muscle lipids in Kizilirmak River (Kirikkale, Turkey) were investigated. A total of 35 different fatty acids were determined in gas chromatography. Among these, palmitic, oleic, and palmitoleic acids had the highest proportion. The main polyunsaturated fatty acids (PUFAs) were found to be docosahexaenoic acid, eicosapentaenoic acid, and arachidonic acid. There were more PUFAs than monounsaturated fatty acids (MUFA) in all seasons. Similarly, the percentages of ?3 fatty acids were higher than those of total ?6 fatty acids in the fatty acid composition. ?3/?6 ratios were calculated as 1.53, 1.32, 1.97, and 1.71 in spring, summer, autumn and winter, respectively. Overall, we found that the fatty acid composition and ?3/?6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.

  2. The Genome and Linkage Map of the Northern Pike (Esox lucius): Conserved Synteny Revealed between the Salmonid Sister Group and the Neoteleostei

    PubMed Central

    Rondeau, Eric B.; Minkley, David R.; Leong, Jong S.; Messmer, Amber M.; Jantzen, Johanna R.; von Schalburg, Kristian R.; Lemon, Craig; Bird, Nathan H.; Koop, Ben F.

    2014-01-01

    The northern pike is the most frequently studied member of the Esociformes, the closest order to the diverse and economically important Salmoniformes. The ancestor of all salmonids purportedly experienced a whole-genome duplication (WGD) event, making salmonid species ideal for studying the early impacts of genome duplication while complicating their use in wider analyses of teleost evolution. Studies suggest that the Esociformes diverged from the salmonid lineage prior to the WGD, supporting the use of northern pike as a pre-duplication outgroup. Here we present the first genome assembly, reference transcriptome and linkage map for northern pike, and evaluate the suitability of this species to provide a representative pre-duplication genome for future studies of salmonid and teleost evolution. The northern pike genome sequence is composed of 94,267 contigs (N50?=?16,909 bp) contained in 5,688 scaffolds (N50?=?700,535 bp); the total scaffolded genome size is 878 million bases. Multiple lines of evidence suggest that over 96% of the protein-coding genome is present in the genome assembly. The reference transcriptome was constructed from 13 tissues and contains 38,696 transcripts, which are accompanied by normalized expression data in all tissues. Gene-prediction analysis produced a total of 19,601 northern pike-specific gene models. The first-generation linkage map identifies 25 linkage groups, in agreement with northern pike's diploid karyotype of 2N?=?50, and facilitates the placement of 46% of assembled bases onto linkage groups. Analyses reveal a high degree of conserved synteny between northern pike and other model teleost genomes. While conservation of gene order is limited to smaller syntenic blocks, the wider conservation of genome organization implies the northern pike exhibits a suitable approximation of a non-duplicated Protacanthopterygiian genome. This dataset will facilitate future studies of esocid biology and empower ongoing examinations of the Atlantic salmon and rainbow trout genomes by facilitating their comparison with other major teleost groups. PMID:25069045

  3. Balancing Forage Demand with Forage Supply 

    E-print Network

    Troxel, Tom R.; White, Larry D.

    1995-09-25

    Ranchers must achieve a balance between stocking rate and forage supply for effective conversion of range forage to animal production. This publication can help ranchers evaluate current forage conditions, make timely forage inventories, plan stock...

  4. Muskie Lunacy: does the lunar cycle influence angler catch of muskellunge (Esox masquinongy)?

    PubMed

    Vinson, Mark R; Angradi, Ted R

    2014-01-01

    We analyzed angling catch records for 341,959 muskellunge (Esox masquinongy) from North America to test for a cyclic lunar influence on the catch. Using periodic regression, we showed that the number caught was strongly related to the 29-day lunar cycle, and the effect was consistent across most fisheries. More muskellunge were caught around the full and new moon than at other times. At night, more muskellunge were caught around the full moon than the new moon. The predicted maximum relative effect was ?5% overall. Anglers fishing exclusively on the peak lunar day would, on average, catch 5% more muskellunge than anglers fishing on random days. On some lakes and at night, the maximum relative effect was higher. We obtained angler effort data for Wisconsin, Mille Lacs (MN), and Lake Vermilion (MN). For Lake Vermilion there was a significant effect of the lunar cycle on angler effort. We could therefore not conclude that the lunar effect on catch was due to an effect on fish behavior alone. Several factors affected the amount of variation explained by the lunar cycle. The lunar effect was stronger for larger muskellunge (>102 cm) than for smaller fish, stronger in midsummer than in June or October, and stronger for fish caught at high latitudes (>48°N) than for fish caught further south. There was no difference in the lunar effect between expert and novice muskellunge anglers. We argue that this variation is evidence that the effect of the lunar cycle on catch is mediated by biological factors and is not due solely to angler effort and reflects lunar synchronization in feeding. This effect has been attributed to variation among moon phases in lunar illumination, but our results do not support that hypothesis for angler-caught muskellunge. PMID:24871329

  5. Muskie Lunacy: Does the Lunar Cycle Influence Angler Catch of Muskellunge (Esox masquinongy)?

    PubMed Central

    Vinson, Mark R.; Angradi, Ted R.

    2014-01-01

    We analyzed angling catch records for 341,959 muskellunge (Esox masquinongy) from North America to test for a cyclic lunar influence on the catch. Using periodic regression, we showed that the number caught was strongly related to the 29-day lunar cycle, and the effect was consistent across most fisheries. More muskellunge were caught around the full and new moon than at other times. At night, more muskellunge were caught around the full moon than the new moon. The predicted maximum relative effect was ?5% overall. Anglers fishing exclusively on the peak lunar day would, on average, catch 5% more muskellunge than anglers fishing on random days. On some lakes and at night, the maximum relative effect was higher. We obtained angler effort data for Wisconsin, Mille Lacs (MN), and Lake Vermilion (MN). For Lake Vermilion there was a significant effect of the lunar cycle on angler effort. We could therefore not conclude that the lunar effect on catch was due to an effect on fish behavior alone. Several factors affected the amount of variation explained by the lunar cycle. The lunar effect was stronger for larger muskellunge (>102 cm) than for smaller fish, stronger in midsummer than in June or October, and stronger for fish caught at high latitudes (>48°N) than for fish caught further south. There was no difference in the lunar effect between expert and novice muskellunge anglers. We argue that this variation is evidence that the effect of the lunar cycle on catch is mediated by biological factors and is not due solely to angler effort and reflects lunar synchronization in feeding. This effect has been attributed to variation among moon phases in lunar illumination, but our results do not support that hypothesis for angler-caught muskellunge. PMID:24871329

  6. Fish, FADs and Forage (and Foraging Behavior)

    E-print Network

    Hawai'i at Manoa, University of

    Fish, FADs and Forage (and Foraging Behavior) Kim Holland, David Itano, Laurent Dagorn, Dean Grubbs, Marianne Robert #12;Contributing PFRP Programs · Trophic ecology of structure associated tropical tuna Oahu #12;#12;#12;#12;#12;Movements of fish #109H0 YFT #109H0 (54 cm) 0 5 10 15 20 25 30 Days CO FAD R

  7. Heat Damaged Forages: Effects on Forage Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditionally, heat damage in forages has been associated with alterations in forage protein quality as a result of Maillard reactions, and most producers and nutritionists are familiar with this concept. However, this is not necessarily the most important negative consequence of spontaneous heating...

  8. Forages for Beef Cattle 

    E-print Network

    Bade, David H.; Dorsett, Donald J.

    2002-09-05

    Pasture forages for beef cattle are of five types--warm-season perennials, warm-season annuals, cool-season annuals, cool-season perennials and legumes. This publication discusses the five types and proposes a year-round forage management system...

  9. Defining Forage Quality 

    E-print Network

    Muir, James; Lambert, Barry; Newman, Yoana

    2007-01-18

    and Extension Cen- ter, respectively, The Texas A&M University System. L-5481 01/07 Yoana C. Newman, Barry Lambert and James P. Muir* ? animal production of forage-based diets depends on the nutritive value of forage consumed ? the crude protein concentration...

  10. Understanding Forage Quality Analysis 

    E-print Network

    Stokes, Sandra R.; Prostko, Eric P.

    1998-03-23

    Sandra R. Stokes and Eric P. Prostko* L-5198 3-98 M any dairy producers in Texas do not have the land to grow their own forages. Consequent- ly, they rely on both local and out-of-state farmers for supplies. This gives Texas forage produc- ers...

  11. FORAGES - CHAPTER 19

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water use by forage crops is an important component of water management in the western United States where it constitutes a significant proportion of the irrigated land. Forage crops account for 57 percent of the total irrigated area in the eight western states of Colorado, Idaho, Montana, Nevada, ...

  12. OPTIMAL FORAGING BEHAVIOR: GROUP VS. SOLITARY FORAGING UNDER

    E-print Network

    Antonovics, Janis

    OPTIMAL FORAGING BEHAVIOR: GROUP VS. SOLITARY FORAGING UNDER DIFFERENT FOOD DISTRIBUTION PATTERNS experimental data to test hypotheses about optimal foraging behavior (flock or solitary) in environments patterns of food distribution · Understand optimal foraging theory better by collecting data on their own

  13. Forage Quality Photo Guide 

    E-print Network

    Lyons, Robert K.; Machen, Richard V.; Stuth, Jerry W.

    2000-08-18

    and energy to the diet, is not required for mature cows. Forage, which cre- ates droppings like this, should support 1 pound to 1.5 pounds average daily gain on heifers and steers. This dropping indicates a forage crude protein level between 6 percent and 9... such as small grains or ryegrass. Nutrient (protein and energy) availability exceeds the cattle?s require- ments for maintenance, growth or lactation. This dropping indicates a forage crude protein level between 10 percent and about 17 percent and a...

  14. Redefining Honeybee Foraging Cognition

    E-print Network

    Najera, Daniel Arnulfo

    2009-04-28

    The research in this manuscript was designed to investigate all of the facets of current honeybee foraging knowledge. In order to do so, we constructed new methodologies to provide more accurate data for a finer level of ...

  15. Foraging Experiences with Children

    ERIC Educational Resources Information Center

    Russell, Helen Ross

    1976-01-01

    Provided are foraging experiences and wild foods information for utilization in the urban school curriculum. Food uses are detailed for roses, dandelions, wild onions, acorns, cattails, violets and mints. (BT)

  16. Small Grains for Forage

    E-print Network

    Holt, Ethan C.

    1959-01-01

    may 1)e nccrr sary or desirable to utilize some forage during critical fall and early winter periods. I Growth studies with oats have shown a direct relationship of growth to temperature. Winter tempel. atures generally are mild enough south... of rainfall occur frequently in most of the areas; therefore, moisture frequently may be a lim iting factor. Excessive rainfall for maximum growth may occur, especially in the coastal area. A number of varieties, especially of oats, are adapted for forage...

  17. Foraging search: Prototypical intelligence

    NASA Astrophysics Data System (ADS)

    Mobus, George

    2000-05-01

    We think because we eat. Or as Descartes might have said, on a little more reflection, "I need to eat, therefore I think." Animals that forage for a living repeatedly face the problem of searching for a sparsely distributed resource in a vast space. Furthermore, the resource may occur sporadically and episodically under conditions of true uncertainty (nonstationary, complex and non-linear dynamics). I assert that this problem is the canonical problem solved by intelligence. It's solution is the basis for the evolution of more advanced intelligence in which the space of search includes that of concepts (objects and relations) encoded in cortical structures. In humans the conscious experience of searching through concept space we call thinking. The foraging search model is based upon a higher-order autopoeitic system (the forager) employing anticipatory processing to enhance its success at finding food while avoiding becoming food or having accidents in a hostile world. I present a semi-formal description of the general foraging search problem and an approach to its solution. The latter is a brain-like structure employing dynamically adaptive neurons. A physical robot, MAVRIC, embodies some principles of foraging. It learns cues that lead to improvements in finding targets in a dynamic and nonstationary environment. This capability is based on a unique learning mechanism that encodes causal relations in the neural-like processing element. An argument is advanced that searching for resources in the physical world, as per the foraging model, is a prototype for generalized search for conceptual resources as when we think. A problem represents a conceptual disturbance in a homeostatic sense. The finding of a solution restores the homeostatic balance. The establishment of links between conceptual cues and solutions (resources) and the later use of those cues to think through to solutions of quasi-isomorphic problems is, essentially, foraging for ideas. It is a quite natural extension of the fundamental foraging model.

  18. Redesigning forages with condensed tannins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maximizing protein content in forages and minimizing protein loss during silage fermentation and rumen digestion are concerns for livestock and dairy producers. Substantial amounts of forage protein undergo proteolysis (breakdown) during the ensiling process and during rumen fermentation, transforme...

  19. Do You Have Enough Forage

    E-print Network

    White, Larry D.

    1999-02-12

    To limit the impact of a forage crisis, a rancher must be able to recognize forage shortfalls and make timely decisions for the good of the livestock and the enterprise. This publication discusses strategies that help ranchers determine exactly how...

  20. Foraging Behavior Some Basic Ideas

    E-print Network

    Brown, Christopher A.

    or handle prey). Optimal Foraging Theory Developed in late 1960's-early 1970's to address animal decisions is to maximize (or optimize) energy intake Some disagreement over terminology: optimize vs. maximize Forager may1 Foraging Behavior Some Basic Ideas Two individuals involved: predator and prey Predator eats prey

  1. Optimal Foraging in Semantic Memory

    ERIC Educational Resources Information Center

    Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

    2012-01-01

    Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

  2. New Developments in Forage Varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage crops harvested for hay or haylage or grazed support dairy, beef, sheep and horse production. Additional livestock production from reduced forage acreage supports the need for forage variety improvement. The Consortium for Alfalfa Improvement is a partnership model of government, private no...

  3. Breeding Objectives in Forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All breeding programs share one common objective – to improve a species for use within a target population of environments and a particular agricultural context. Beyond this common goal, the objectives of forage breeding programs are as varied as the species upon which they are based and the breeder...

  4. DISSOLVED OXYGEN, TEMPERATURE, SURVIVAL OF YOUNG AT FISH SPAWNING SITES

    EPA Science Inventory

    Fluctuations of dissolved oxygen concentrations and water temperatures in their natural spawning sites were measured during embryo through larva stages of northern pike (Esox lucius), and during embryo and sac larva stages of bluegills (Lepomis macrochirus) and pumpkinseeds (Lepo...

  5. The decay of similarity with geographical distance in parasite communities of vertebrate hosts

    E-print Network

    Poulin, Robert

    commersoni and Esox lucius) from continental North America. Methods Distances between localities of similarity is plotted against untransformed distance, the slopes obtained for the two fish species are lower

  6. Foraging Swarms: From Biology to Engineering

    E-print Network

    optimizes foraging #12;7 OHIO STATE T . H . E UNIVERSITY Group of predators Forager Nutient patch Search/foraging strategies, use dynamic programming to find "optimal policies." Social foraging: Costs, but get "collective? A good engineering optimization method? · See: "Biomimicry of Bacterial Foraging for Distributed

  7. Optimal Foraging by Zooplankton

    NASA Astrophysics Data System (ADS)

    Garcia, Ricardo; Moss, Frank

    2007-03-01

    We describe experiments with several species of the zooplankton, Daphnia, while foraging for food. They move in sequences: hop-pause-turn-hop etc. While we have recorded hop lengths, hop times, pause times and turning angles, our focus is on histograms representing the distributions of the turning angles. We find that different species, including adults and juveniles, move with similar turning angle distributions described by exponential functions. Random walk simulations and a theory based on active Brownian particles indicate a maximum in food gathering efficiency at an optimal width of the turning angle distribution. Foraging takes place within a fixed size food patch during a fixed time. We hypothesize that the exponential distributions were selected for survival over evolutionary time scales.

  8. Learning foraging thresholds for lizards

    SciTech Connect

    Goldberg, L.A.; Hart, W.E.; Wilson, D.B.

    1996-01-12

    This work gives a proof of convergence for a randomized learning algorithm that describes how anoles (lizards found in the Carribean) learn a foraging threshold distance. This model assumes that an anole will pursue a prey if and only if it is within this threshold of the anole`s perch. This learning algorithm was proposed by the biologist Roughgarden and his colleagues. They experimentally confirmed that this algorithm quickly converges to the foraging threshold that is predicted by optimal foraging theory our analysis provides an analytic confirmation that the learning algorithm converses to this optimal foraging threshold with high probability.

  9. The Dynamics of Foraging Ants

    NASA Astrophysics Data System (ADS)

    Baxter, G. William

    2009-03-01

    We experimentally study the foraging of small black ants, Formicinae lasius flavus, in order to describe their foraging behavior mathematically. Individual ants are allowed to forage on a two-dimensional surface in the absence of any food sources. The position of the ant as a function of time is determined using a high-resolution digital camera. Analysis of the average square displacements of many ants suggests that the foraging strategy is a non-reversing random walk. Moreover, the ants do not retrace their steps to return home but instead continue the random walk until it brings them back near their starting point.

  10. Rainfall Effects on Wilting Forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Given the uncertainty of the weather and inherent differences between forage crops, specific recommendations for managing potential rain damage to wilting forages are difficult. However, there are a number of principles that can be applied to best manage the potential for rain damage. These science-...

  11. Pasture forages for small ruminants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small ruminant producers in Appalachia have many questions about forage management. Forage management decisions need to be keyed to the specific needs of the small ruminant t species to be grazed. Sheep and goats are different from each other and both are very different from cattle. Important con...

  12. Forage Breeding and New Varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At Agriculture and Agri-Food Canada, the focus of the forage breeding program is to identify and develop novel germplasm and cultivars. The main objective is to produce cultivars with superior persistence, nutritive value and forage yield. This program also emphasizes two other objectives, namely:...

  13. NONSTRUCTURAL CARBOHYDRATES IN OAT FORAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nonstructural carbohydrates (NSC) fractions found in forage may play a role in equine diseases that involve carbohydrate intolerance, such as laminitis. Sugars in forage may adversely affect equines with dysfunctions of glucose metabolism. Insulin resistance has been associated with laminitis in e...

  14. Forage breeding and new varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At Agriculture and Agri-Food Canada, the focus of the forage breeding program is to identify and develop novel germplasm and cultivars. The main objective is to produce cultivars with superior persistence, nutritive value and forage yield. This program also emphasizes two other objectives, namely:...

  15. Behavior of fish predators and their prey: habitat choice between open water and dense vegetation

    USGS Publications Warehouse

    Savino, Jacqueline F.; Stein, Roy A.

    1989-01-01

    Behavior of largemouth bass, Micropterus salmoides , and northern pike, Esox lucius, foraging on fathead minnows, Pimephales promelas, or bluegills, Lepomis macrochirus, was quantified in pools with 50% cover (half the pool had artificial stems at a density of 1000 stems n-2). Both predators spent most of their time in the vegetation. Largemouth bass searched for bluegills and ambushed minnows, whereas the relatively immobile northern pike ambushed all prey. Minnows were closer to predators and were captured more frequently than bluegills. Even when minnows dispersed, they moved continually and eventually wandered within striking distance of a predator. Bluegills dispersed in the cover with predators. Bass captured the few bluegills that strayed into the open and pike captured those that approached too closely in the cover. The ability of predators to capture prey while residing in habitats containing patches of dense cover may explain their residence in areas often considered to be poor ones for foraging.

  16. THEORETICAL NOTE Optimal Foraging in Semantic Memory

    E-print Network

    Jones, Michael

    THEORETICAL NOTE Optimal Foraging in Semantic Memory Thomas T. Hills University of Warwick Michael their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging recalled more items. Keywords: optimal foraging, memory search, category fluency, semantic space models

  17. Forage Crops in Northwest Texas. 

    E-print Network

    Conner, A. B. (Arthur Benjamin)

    1908-01-01

    and at different dates to get information as to the best methods to secure maximum yields. The forage crop experiments at Amarillo, Texas, during the season of 1906 and 1907 have been conducted with the assistance of Mr. A. H. Leidigh, Superintendent... planted too thinly in the drill to give the maxi- mum yields of forage of the best quality. From the plantings made April 25, 1907, at different rates from one to sixteen inches in the drill it was found that the heaviest yields of forage were secured...

  18. Root Foraging Influences Plant Growth Responses to Earthworm Foraging

    PubMed Central

    Cameron, Erin K.; Cahill, James F.; Bayne, Erin M.

    2014-01-01

    Interactions among the foraging behaviours of co-occurring animal species can impact population and community dynamics; the consequences of interactions between plant and animal foraging behaviours have received less attention. In North American forests, invasions by European earthworms have led to substantial changes in plant community composition. Changes in leaf litter have been identified as a critical indirect mechanism driving earthworm impacts on plants. However, there has been limited examination of the direct effects of earthworm burrowing on plant growth. Here we show a novel second pathway exists, whereby earthworms (Lumbricus terrestris L.) impact plant root foraging. In a mini-rhizotron experiment, roots occurred more frequently in burrows and soil cracks than in the soil matrix. The roots of Achillea millefolium L. preferentially occupied earthworm burrows, where nutrient availability was presumably higher than in cracks due to earthworm excreta. In contrast, the roots of Campanula rotundifolia L. were less likely to occur in burrows. This shift in root behaviour was associated with a 30% decline in the overall biomass of C. rotundifolia when earthworms were present. Our results indicate earthworm impacts on plant foraging can occur indirectly via physical and chemical changes to the soil and directly via root consumption or abrasion and thus may be one factor influencing plant growth and community change following earthworm invasion. More generally, this work demonstrates the potential for interactions to occur between the foraging behaviours of plants and soil animals and emphasizes the importance of integrating behavioural understanding in foraging studies involving plants. PMID:25268503

  19. Caffeinated Forage Tricks Honeybees into Increasing Foraging and Recruitment Behaviors.

    PubMed

    Couvillon, Margaret J; Al Toufailia, Hasan; Butterfield, Thomas M; Schrell, Felix; Ratnieks, Francis L W; Schürch, Roger

    2015-11-01

    In pollination, plants provide food reward to pollinators who in turn enhance plant reproduction by transferring pollen, making the relationship largely cooperative; however, because the interests of plants and pollinators do not always align, there exists the potential for conflict, where it may benefit both to cheat the other [1, 2]. Plants may even resort to chemistry: caffeine, a naturally occurring, bitter-tasting, pharmacologically active secondary compound whose main purpose is to detract herbivores [3-6], is also found in lower concentrations in the nectar of some plants, even though nectar, unlike leaves, is made to be consumed by pollinators [5, 7, 8]. A recent laboratory study showed that caffeine may lead to efficient and effective foraging by aiding honeybee memory of a learned olfactory association [4], suggesting that caffeine may enhance bee reward perception. However, without field data, the wider ecological significance of caffeinated nectar remains difficult to interpret. Here we demonstrate in the field that caffeine generates significant individual- and colony-level effects in free-flying worker honeybees. Compared to a control, a sucrose solution with field-realistic doses of caffeine caused honeybees to significantly increase their foraging frequency, waggle dancing probability and frequency, and persistency and specificity to the forage location, resulting in a quadrupling of colony-level recruitment. An agent-based model also demonstrates how caffeine-enhanced foraging may reduce honey storage. Overall, caffeine causes bees to overestimate forage quality, tempting the colony into sub-optimal foraging strategies, which makes the relationship between pollinator and plant less mutualistic and more exploitative. VIDEO ABSTRACT. PMID:26480843

  20. SEMANTIC MEMORY AND OPTIMAL FORAGING 1 Running head: SEMANTIC MEMORY AND OPTIMAL FORAGING

    E-print Network

    Jones, Michael

    SEMANTIC MEMORY AND OPTIMAL FORAGING 1 Running head: SEMANTIC MEMORY AND OPTIMAL FORAGING Optimal to replicate our work may be found at http://www.indiana.edu/~clcl/Optimal_Foraging/ Contact information 524 225 email: t.t.hills@warwick.ac.uk #12;SEMANTIC MEMORY AND OPTIMAL FORAGING 2 Abstract Do humans

  1. 7 CFR 1437.401 - Forage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...eligibility requirements, CCC will consider other factors, such as, water sources and available fencing, and adequate fertilization to determine small grain forage eligibility, yields, and production. (f) CCC will establish forage losses of...

  2. 7 CFR 1437.401 - Forage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...eligibility requirements, CCC will consider other factors, such as, water sources and available fencing, and adequate fertilization to determine small grain forage eligibility, yields, and production. (f) CCC will establish forage losses of...

  3. 7 CFR 1437.401 - Forage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...eligibility requirements, CCC will consider other factors, such as, water sources and available fencing, and adequate fertilization to determine small grain forage eligibility, yields, and production. (f) CCC will establish forage losses of...

  4. 7 CFR 1437.401 - Forage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...eligibility requirements, CCC will consider other factors, such as, water sources and available fencing, and adequate fertilization to determine small grain forage eligibility, yields, and production. (f) CCC will establish forage losses of...

  5. 7 CFR 1437.401 - Forage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...eligibility requirements, CCC will consider other factors, such as, water sources and available fencing, and adequate fertilization to determine small grain forage eligibility, yields, and production. (f) CCC will establish forage losses of...

  6. Evolution of foraging strategies on resource gradients

    E-print Network

    Dieckmann, Ulf

    -based theory of optimal foraging to continuous resource gradients following the traditional assumptions free distribution, interference competition, optimal foraging, resource dynamics, resource gradientEvolution of foraging strategies on resource gradients Mikko Heino 1,2,3 , Kalle Parvinen 4 and Ulf

  7. Ant Foraging Revisited Liviu Alexandru Panait1

    E-print Network

    Luke, Sean

    Ant Foraging Revisited Liviu Alexandru Panait1 and Sean Luke1 1. Department of Computer Science: lpanait@cs.gmu.edu Abstract Previous artificial (non-biological) ant foraging models have to date relied ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

  8. Forage characteristics affecting meat goat preferences for forage chicory cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concentration of bitter sesquiterpene lactones (SL), lactucin, lactucopicrin, and 8-deoxylactucin, has been associated with low soil phosphorus fertility and reduced livestock preference for forage chicory (Cichorium intybus L.). We evaluated the effect of cultivar and available soil P (ASP) on mea...

  9. Foraging Decisions, Patterns, and Strategies

    E-print Network

    Chittka, Lars

    of behavioral ecology as a discipline (Krebs and Davies 1993; Owens 2006). However, despite the considerable and Krebs 1986), when to abandon a foraging patch (Kacelnik and Krebs 1985; Cuthill et al. 1990), how (10­15% of all work- ers) at regular intervals during the colony cycle. Interestingly, they found

  10. Breeding for increased forage quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage crops have a large number of benefits to society, including ecosystem services such as soil and water conservation, wildlife habitat, and diversification of the agricultural landscape. However, their principal function can only be realized when they are processed through livestock to produce ...

  11. How anthropogenic noise affects foraging.

    PubMed

    Luo, Jinhong; Siemers, Björn M; Koselj, Klemen

    2015-09-01

    The influence of human activity on the biosphere is increasing. While direct damage (e.g. habitat destruction) is relatively well understood, many activities affect wildlife in less apparent ways. Here, we investigate how anthropogenic noise impairs foraging, which has direct consequences for animal survival and reproductive success. Noise can disturb foraging via several mechanisms that may operate simultaneously, and thus, their effects could not be disentangled hitherto. We developed a diagnostic framework that can be applied to identify the potential mechanisms of disturbance in any species capable of detecting the noise. We tested this framework using Daubenton's bats, which find prey by echolocation. We found that traffic noise reduced foraging efficiency in most bats. Unexpectedly, this effect was present even if the playback noise did not overlap in frequency with the prey echoes. Neither overlapping noise nor nonoverlapping noise influenced the search effort required for a successful prey capture. Hence, noise did not mask prey echoes or reduce the attention of bats. Instead, noise acted as an aversive stimulus that caused avoidance response, thereby reducing foraging efficiency. We conclude that conservation policies may seriously underestimate numbers of species affected and the multilevel effects on animal fitness, if the mechanisms of disturbance are not considered. PMID:26046451

  12. Switchgrass for forage and bioenergy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass is a native warm-season grass that has been used for hay, forage, and conservation purposes for decades and switchgrass research in Nebraska has been ongoing since 1936. Recently, switchgrass has been identified as a model perennial grass for bioenergy in the Great Plains and Midwest. Si...

  13. Squirrel Foraging Preferences: Gone Nuts?

    ERIC Educational Resources Information Center

    Darling, Randi A.

    2007-01-01

    This field exercise examines the feeding preferences of Gray Squirrels ("Sciurus carolinensis"). Students present squirrels with a variety of food types in a cafeteria-style arrangement in order to test hypotheses about foraging preferences. This exercise, which is appropriate for introductory biology, ecology, and animal behavior classes, is…

  14. The Laurentian Great Lakes strain (MI03) of the viral haemorrhagic septicaemia virus is highly pathogenic for juvenile muskellunge, Esox masquinongy (Mitchill).

    PubMed

    Kim, R K; Faisal, M

    2010-06-01

    The Great Lakes strain of viral haemorrhagic septicaemia virus (VHSV) isolated from adult subclinical muskellunge, Esox masquinongy (Mitchill), in Lake St. Clair, MI, USA was shown to be highly pathogenic in juvenile muskellunge through intraperitoneal (i.p.) injection and waterborne challenge. Mortality began as early as 3 days after exposure in waterborne challenged fish, whereas fish infected by the i.p. route experienced the first mortality by 5 days post-infection (p.i.). The median lethal intraperitoneal injection dose (IP-LD(50)) was approximately 2.21 plaque forming units (PFU) as opposed to the median lethal immersion challenge dose (IM-LD(50)) of 1.7 x 10(4) PFU mL(-1). A high, medium and low dose of infection caused acute, subacute and chronic progression of the disease, respectively, as was evident by the cumulative mortality data. Clinical signs of disease observed in dead and moribund fish were very pale gills, dermal petechial haemorrhages along the flanks, severe nuchal haemorrhages, intramuscular haemorrhages at the fin-muscle junction and focal haemorrhaging on the caudal peduncle. Internal lesions included livers that were pale, discoloured and friable, and kidneys that were either congested or degenerative in appearance, and petechial to ecchymotic haemorrhages on the swim bladder wall. Histopathologic examination demonstrated massive haemorrhages in the swimbladder wall and muscle, severe vacuolation and multifocal necrosis of the liver, multifocal necrosis of the gills and depletion of lymphoid tissues within the spleen. Kidney tissues also exhibited a mixed pattern of degeneration that included tubular necrosis, interstitial oedema and congestion. Virus was recovered from kidney and spleen tissues through tissue culture and reverse transcriptase-polymerase chain reaction (RT-PCR). PMID:20367742

  15. Age, growth, and food of northern pike in eastern Lake Ontario

    USGS Publications Warehouse

    Wolfert, David R.; Miller, Terence J.

    1978-01-01

    Northern pike (Esox lucius) from eastern Lake Ontario were sampled with gill nets and trap nets in 1972-1973. Fish of age-groups IV, V, and VI were predominant in the catch. Although males were slightly longer after the 1st yr of life, females gained a 25-mm advantage in the 2nd yr and a 30-mm advantage in the 3rd yr. In later years, the increments of growth of males and females were similar. All males were mature after 2 yr and females after 3 yr. The stomachs of northern pike contained only fish; the alewife (Alosa pseudoharengus) was the principal forage species consumed. Electivity indexes for alewives, white perch (Morone americana), and yellow perch (Perca flavescens), the three most common species in the diet, indicated a positive selection for alewives that increased from June to October during a period when the relative abundance of alewives steadily decreased.

  16. Behavioural interaction between fish predators and their prey: effects of plant density

    USGS Publications Warehouse

    Savino, Jacqueline F.; Stein, Roy A.

    1989-01-01

    Prey-specific anti-predatory behaviour under different degrees of structural complexity determines foraging success of predators. The behaviour of piscivorous fish (largemouth bass, Micropterus salmoides and northern pike, Esox lucius) and their prey (bluegills, Lepomis macrochirus, and fathead minnows, Pimephales promelas) were quantified in 60-min experiments in laboratory pools (2 multiplied by 4 m in diameter, 0 multiplied by 5 m deep) with artificial vegetation at densities of 0, 50, 250, and 1000 stems/m2. Largemouth bass switched predatory tactics from searching to ambushing as plant density increased whereas northern pike always used ambushing. At high plant density, both predators captured minnows, but not bluegills. Bluegills modified their behaviour more than minnows in response to predators, thereby avoiding predation at high plant densities. Structural complexity alone did not always provide refuge for prey; prey must use the structure to avoid predators. Predators may seek vegetated areas if appropriate, vulnerable prey are present.

  17. BREEDING SOYBEANS FOR FORAGE PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At Chazy, NY yields of forage soybeans varied from 14.3 Mg ha-1 to 5.6 Mg ha-1 over three years with CP ranging from 169 g kg-1 to 116 g kg-1 and NDF ranging from 513 g kg-1 to 445 g kg-1. At Ames, IA, IVDMD declined from 700 g kg-1 46 days after planting then increased at seasons end as seed incre...

  18. Optimal foraging in semantic memory.

    PubMed

    Hills, Thomas T; Jones, Michael N; Todd, Peter M

    2012-04-01

    Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared structure of the search problems-searching in patchy environments-and recent evidence supporting a domain-general cognitive search process. To investigate these questions directly, we asked participants to recover from memory as many animal names as they could in 3 min. Memory search was modeled over a representation of the semantic search space generated from the BEAGLE memory model of Jones and Mewhort (2007), via a search process similar to models of associative memory search (e.g., Raaijmakers & Shiffrin, 1981). We found evidence for local structure (i.e., patches) in memory search and patch depletion preceding dynamic local-to-global transitions between patches. Dynamic models also significantly outperformed nondynamic models. The timing of dynamic local-to-global transitions was consistent with optimal search policies in space, specifically the marginal value theorem (Charnov, 1976), and participants who were more consistent with this policy recalled more items. PMID:22329683

  19. Individual honey bee (Apis cerana) foragers adjust their fuel load to match variability in forage reward

    PubMed Central

    Tan, Ken; Latty, Tanya; Dong, Shihao; Liu, Xiwen; Wang, Chao; Oldroyd, Benjamin P.

    2015-01-01

    Animals may adjust their behavior according to their perception of risk. Here we show that free-flying honey bee (Apis cerana) foragers mitigate the risk of starvation in the field when foraging on a food source that offers variable rewards by carrying more ‘fuel’ food on their outward journey. We trained foragers to a feeder located 1.2?km from each of four colonies. On average foragers carried 12.7% greater volume of fuel, equivalent to 30.2% more glucose when foraging on a variable source (a random sequence of 0.5, 1.5 and 2.5?M sucrose solution, average sucrose content 1.5?M) than when forging on a consistent source (constant 1.5?M sucrose solution). Our findings complement an earlier study that showed that foragers decrease their fuel load as they become more familiar with a foraging place. We suggest that honey bee foragers are risk sensitive, and carry more fuel to minimize the risk of starvation in the field when a foraging trip is perceived as being risky, either because the forager is unfamiliar with the foraging site, or because the forage available at a familiar site offers variable rewards. PMID:26549746

  20. Individual honey bee (Apis cerana) foragers adjust their fuel load to match variability in forage reward.

    PubMed

    Tan, Ken; Latty, Tanya; Dong, Shihao; Liu, Xiwen; Wang, Chao; Oldroyd, Benjamin P

    2015-01-01

    Animals may adjust their behavior according to their perception of risk. Here we show that free-flying honey bee (Apis cerana) foragers mitigate the risk of starvation in the field when foraging on a food source that offers variable rewards by carrying more 'fuel' food on their outward journey. We trained foragers to a feeder located 1.2?km from each of four colonies. On average foragers carried 12.7% greater volume of fuel, equivalent to 30.2% more glucose when foraging on a variable source (a random sequence of 0.5, 1.5 and 2.5?M sucrose solution, average sucrose content 1.5?M) than when forging on a consistent source (constant 1.5?M sucrose solution). Our findings complement an earlier study that showed that foragers decrease their fuel load as they become more familiar with a foraging place. We suggest that honey bee foragers are risk sensitive, and carry more fuel to minimize the risk of starvation in the field when a foraging trip is perceived as being risky, either because the forager is unfamiliar with the foraging site, or because the forage available at a familiar site offers variable rewards. PMID:26549746

  1. Boa constrictor (Boa constrictor): foraging behavior

    USGS Publications Warehouse

    Sorrell, G.G.; Boback, M.S.; Reed, R.N.; Green, S.; Montgomery, Chad E.; DeSouza, L.S.; Chiaraviglio, M.

    2011-01-01

    Boa constrictor is often referred to as a sit-and-wait or ambush forager that chooses locations to maximize the likelihood of prey encounters (Greene 1983. In Janzen [ed.], Costa Rica Natural History, pp. 380-382. Univ. Chicago Press, Illinois). However, as more is learned about the natural history of snakes in general, the dichotomy between active versus ambush foraging is becoming blurred. Herein, we describe an instance of diurnal active foraging by a B. constrictor, illustrating that this species exhibits a range of foraging behaviors.

  2. BIODIVERSITY Fidelity to foraging sites, consistency of

    E-print Network

    Hays, Graeme

    BIODIVERSITY RESEARCH Fidelity to foraging sites, consistency of migration routes and habitat the identification of priority marine protected areas beyond the core breeding site. Keywords Biodiversity scale

  3. Optimal Foraging Strategy: Angle Matters

    NASA Astrophysics Data System (ADS)

    Erdmann, Udo; Göller, Sebastian; Sokolov, Igor M.; Schimansky-Geier, Lutz

    2006-03-01

    We report a theory to describe the motion of zooplankton. In contrast to move just randomly like a classical Brownian particle, zooplankters like Daphnia or Copepods pick their turning angle from a distribution which is far from being Gaussian or equally distributed. This leads to different behavior in the motion compared to normal diffusion. The question which can be asked here is: Is there an evolutionary reason to forage for food in the aforementioned manner? The talk is planned to give an answer into that direction.

  4. Feedout losses from forage storage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant losses of forage can occur as forage is removed from storage and fed. Hay losses are affected by the type of feeder used. Losses from silage are also affected by the bulk density of the silage, feedout rate, smoothness of the removal face and the amount of loosened silage that is not fed...

  5. Palatability of Forage Chicory Cultivars for Goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sesquiterpene lactones (SL) in forage chicory (Cichorium intybus L.) may have anthelmintic activity against gastrointestinal parasites in sheep and goats, but have been implicated in poor palatability of forage. We used three levels of soil P fertilization to influence SL concentrations in three cu...

  6. PERENNIAL FORAGES AS SECOND GENERATION BIOENERGY CROPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The lignocellulose in forage crops represents a second generation of biomass feedstock for conversion into energy-related end products. Some of the most extensively studied species for cellulosic feedstock production include forages such as switchgrass (Panicum virgatum L.), reed canarygrass (Phalar...

  7. Optimal forager against ideal free distributed prey.

    PubMed

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior. PMID:26098343

  8. DEMONSTRATION BULLETIN: FORAGER™ SPONGE TECHNOLOGY - DYNAPHORE, INC.

    EPA Science Inventory

    The Forager™ Sponge is an open-celled cellulose sponge incorporating an amine-containing chelating polymer that has selective affinity for dissolved heavy metals in both cationic and anionic states. The Forager™ Sponge technology can be utilized to remove and concentrate heavy me...

  9. Harvesting and Drying Selected Forage Crops. 

    E-print Network

    Sorenson, J. W. Jr. (Jerome Wallace); Person, Nat K. Jr. (Nat Kimbrough)

    1967-01-01

    Harvesting and Drying Selected Forage Crops ' TEXAS A&M UNIVERSITY 1 Texas Agricultural Experiment Station I H. 0. Kunkel, Acting Director, College Station, Texas . Contents Summary... ---.--.--------.--.----.-------.------.---...-....................--.-----..- 2 Introduction ..................................................................... 4 Review of Literatme .--.--..--------..--...-.---.-------------...--.--. 4 Pliysical Properties of Forage Plants Related to Drying...

  10. Potential of energy production from conserved forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forages have a potential role in meeting the demand for energy. Perennial forages are attractive for various reasons. One, both the monetary and energy cost of planting is spread over many years. Two, we already have the equipment for harvesting, storing and transporting this source of biomass. Thre...

  11. NON-TRADITIONAL FORAGES FOR CENTRAL APPALACHIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small ruminant forage research at AFSRC is designed to improve forage and pasture management for small ruminants, especially as related to control of gastrointestinal nematode (GIN) parasites. Alfalfa pasture produced better meat goat weight gains than orchardgrass, but red clover pasture was diff...

  12. Heating effects on the quality of forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The negative consequences of baling forages before they are dried adequately are widely known to hay producers. Generally, these responses include molding, spontaneous heating, losses of DM, and other changes in forage quality that are usually quite undesirable. Many changes in nutritive value are r...

  13. Optimal Foraging by Birds: Experiments for Secondary & Postsecondary Students

    ERIC Educational Resources Information Center

    Pecor, Keith W.; Lake, Ellen C.; Wund, Matthew A.

    2015-01-01

    Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. We describe three experiments designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These experiments can be used alone or in combination and can…

  14. 7 CFR 457.117 - Forage production crop insurance provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Cutting. The severance of the forage plant from its roots. Direct marketing. Sale of the forage crop... broker. An example of direct marketing is selling directly to other producers. Fall planted. A forage... be sold by direct marketing unless you have records verifying that the forage was direct...

  15. 7 CFR 457.117 - Forage production crop insurance provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... Cutting. The severance of the forage plant from its roots. Direct marketing. Sale of the forage crop... broker. An example of direct marketing is selling directly to other producers. Fall planted. A forage... be sold by direct marketing unless you have records verifying that the forage was direct...

  16. 2008 Forage Trials Report Cool-Season Grasses 13

    E-print Network

    Guiltinan, Mark

    2008 Forage Trials Report CONTENTS Alfalfa 3 Cool-Season Grasses 13 Forage Grazing Trial 16 Rock-season (forage) grass trials established at the Russell E. Larson Agricultural Research Center at Rock Springs established at the Haller Grazing Research Farm near State College. Both cool-season (forage) grasses

  17. 2007 Forage Trials Report Cool-Season Grasses 13

    E-print Network

    Guiltinan, Mark

    2007 Forage Trials Report CONTENTS Alfalfa 3 Cool-Season Grasses 13 Forage Grazing Trial 16 Rock-season (forage) grass trials established at the Russell E. Larson Agricultural Research Center at Rock Springs established at the Haller Grazing Research Farm near State College. Both cool-season (forage) grasses

  18. 2009 Forage Trials Report Cool-Season Grasses 13

    E-print Network

    Guiltinan, Mark

    2009 Forage Trials Report CONTENTS Alfalfa 3 Cool-Season Grasses 13 Forage Grazing Trial 17 Rock-season (forage) grass trials established at the Russell E. Larson Agricultural Research Center at Rock Springs established at the Haller Grazing Research Farm near State College. Both cool-season (forage) grasses

  19. Perennial Forages as Second Generation Bioenergy Crops

    PubMed Central

    Sanderson, Matt A.; Adler, Paul R.

    2008-01-01

    The lignocellulose in forage crops represents a second generation of biomass feedstock for conversion into energy-related end products. Some of the most extensively studied species for cellulosic feedstock production include forages such as switchgrass (Panicum virgatum L.), reed canarygrass (Phalaris arundinacea L.), and alfalfa (Medicago sativa L.). An advantage of using forages as bioenergy crops is that farmers are familiar with their management and already have the capacity to grow, harvest, store, and transport them. Forage crops offer additional flexibility in management because they can be used for biomass or forage and the land can be returned to other uses or put into crop rotation. Estimates indicate about 22.3 million ha of cropland, idle cropland, and cropland pasture will be needed for biomass production in 2030. Converting these lands to large scale cellulosic energy farming could push the traditional forage-livestock industry to ever more marginal lands. Furthermore, encouraging bioenergy production from marginal lands could directly compete with forage-livestock production. PMID:19325783

  20. Metabolic rate during foraging in the honeybee.

    PubMed

    Balderrama, N M; Almeida, L O; Núñez, J A

    1992-01-01

    The metabolic rate of free-flying honeybees, Apis mellifera ligustica, was determined by means of a novel respirometric device that allowed measurement of CO2 produced by bees foraging under controlled reward at an artificial food source. Metabolic rate increased with reward (sugar flow rate) at the food source. In addition, there was no clear-cut dependence of metabolic rate on load carried during the visit, neither as crop load nor as supplementary weights attached to the thorax. The hypothesis that metabolic rate, as well as foraging and recruiting activities, depend on the motivational state of the foraging bee determined by the reward at the food source is discussed. PMID:1401337

  1. An economic model of the limits to foraging range in central place foragers with numerical solutions for

    E-print Network

    optimality criteria to discriminate between foraging sites at different distances from the forager's central considered in optimal foraging theory with respect to the economics of territoriality (Dill, 1978), dietary assumptions to consider the optimal spatial distribution of foragers sharing a nesting site, but the economics

  2. Interactions Increase Forager Availability and Activity in Harvester Ants

    PubMed Central

    Pinter-Wollman, Noa; Crow, Sam; Allen, Kelsey; Mathur, Maya B.; Gordon, Deborah M.

    2015-01-01

    Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated. PMID:26539724

  3. Japanese Sugar Cane as a Forage Crop. 

    E-print Network

    Leidigh, A. H. (Arthur Henry); McNess, George Thomas; Laude, H. H. (Hilmer Henry)

    1916-01-01

    DIVISION OF AGRONOMY JAPANESE SUGAR CANE AS A FORAGE CROP .".: . COLLEGE POSTOFFICE: COLLEGE STATION,. BRAZOS COUNTY, TEXAS AUSTIN, TEXAS VON BOECKMANN-JONES CO 1916 [Blank Page in Original Bulletin] TEXAS AGRICULTURAL EXPERIMENT STAT10 N... BULLETIN NO. 195 AUGUST, 1916 DIVISION OF AGRONOMY JAPANESE SUGAR CANE AS A FORAGE CROP BY A. H. LEIDIGH, B. S., Agronomist, IN CONSULTATION WITH G. T. McNESS, Superintendent, Substation No. 11, Nacogdoches, and H. H. LAUDE, B. S., Superintendenr...

  4. How Much Forage Do You Have? 

    E-print Network

    Hanselka, C. Wayne; McGinty, Allan

    2006-06-21

    grazing manage- ment decisions. The only materials required are a range site map (aerial photograph), plot frame, grass shears, paper sacks, drying oven, camera, weigh scales, notepad (data sheet), pencil and calculator. A sample photo guide... October-early November. A March evaluation is needed in all regions to document the forage lost over the winter because of grazing and weathering. Forage remaining in March might have to last until mid-summer if spring rainfall is less than normal...

  5. Fishing amplifies forage fish population collapses

    PubMed Central

    Essington, Timothy E.; Moriarty, Pamela E.; Froehlich, Halley E.; Hodgson, Emma E.; Koehn, Laura E.; Oken, Kiva L.; Siple, Margaret C.; Stawitz, Christine C.

    2015-01-01

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches. PMID:25848018

  6. Aggressive and foraging behavioral interactions among ruffe

    USGS Publications Warehouse

    Savino, Jacqueline F.; Kostich, Melissa J.

    2000-01-01

    The ruffe, Gymnocephalus cernuus, is a nonindigenous percid in the Great Lakes. Ruffe are aggressive benthivores and forage over soft substrates. Laboratory studies in pools (100 cm in diameter, 15 cm water depth) were conducted to determine whether fish density (low = 2, medium = 4, high = 6 ruffe per pool) changed foraging and aggressive behaviors with a limited food supply of chironomid larvae. All fish densities demonstrated a hierarchy based on aggressive interactions, but ruffe were most aggressive at low and high fish densities. Time spent in foraging was lowest at the low fish density. The best forager at the low fish density was the most aggressive individual, but the second most aggressive fish at the medium and high fish density was the best forager and also the one chased most frequently. A medium fish density offered the best energetic benefits to ruffe by providing the lowest ratio of time spent in aggression to that spent foraging. Based on our results, ruffe should grow best at an intermediate density. With high ruffe densities, we would also expect disparity in size as the more aggressive fish are able to garner a disproportionate amount of the resources. Alternatively, as the Great Lakes are a fairly open system, ruffe could migrate out of one area to colonize another as populations exceed optimal densities.

  7. EFFECTS OF VARIABLE FIRE SEVERITY ON FORAGE PRODUCTION AND FORAGING BEHAVIOR OF MOOSE IN WINTER

    E-print Network

    EFFECTS OF VARIABLE FIRE SEVERITY ON FORAGE PRODUCTION AND FORAGING BEHAVIOR OF MOOSE IN WINTER primary goal was to examine how wildfire affects production and distribution of winter for- age for moose offtake (kg/ha) by moose. Under the assumption of homogenous effects of fire severity on regeneration, we

  8. EFFECTS OF FORAGE SPECIES ON RIB COMPOSITION, COLOR, AND PALATABILITY IN FORAGE-FINISHED BEEF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forty-seven Angus-crossbred steers were used to evaluate the effects of forage species grazed in the last 41 d of the finishing period on rib composition, color, and palatability in forage-finished beef and compared to traditional high concentrate finished. Steers grazed naturalized pastures (bluegr...

  9. Tillage and forage system effects on forage yields and nutrient uptake under broiler litter amended soils.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting and harvesting high yielding forage grasses may remove phosphorus (P), copper (Cu) and zinc (Zn) from surface soils with a long history of broiler litter application. A study was conducted in Alabama’s Sand Mountain region from 1998 to 2000 to determine tillage and forage systems best suite...

  10. Macronutrient modifications of optimal foraging theory: an approach using indifference curves applied to some modern foragers

    SciTech Connect

    Hill, K.

    1988-06-01

    The use of energy (calories) as the currency to be maximized per unit time in Optimal Foraging Models is considered in light of data on several foraging groups. Observations on the Ache, Cuiva, and Yora foragers suggest men do not attempt to maximize energetic return rates, but instead often concentration on acquiring meat resources which provide lower energetic returns. The possibility that this preference is due to the macronutrient composition of hunted and gathered foods is explored. Indifference curves are introduced as a means of modeling the tradeoff between two desirable commodities, meat (protein-lipid) and carbohydrate, and a specific indifference curve is derived using observed choices in five foraging situations. This curve is used to predict the amount of meat that Mbuti foragers will trade for carbohydrate, in an attempt to test the utility of the approach.

  11. Social foragers adopt a riskier foraging mode in the centre of their groups

    PubMed Central

    Beauchamp, Guy

    2013-01-01

    Foraging in groups provides many benefits that are not necessarily experienced the same way by all individuals. I explore the possibility that foraging mode, the way individuals exploit resources, varies as a function of spatial position in the group, reflecting commonly occurring spatial differences in predation risk. I show that semipalmated sandpipers (Calidris pusilla), a social foraging avian species, tended to adopt a riskier foraging mode in the central, more protected areas of their groups. Central birds effectively used the more peripheral group members as sentinels, allowing them to exploit a wider range of resources within the same group at the same time. This finding provides a novel benefit of living in groups, which may have a broad relevance given that social foraging species often exploit a large array of resources. PMID:24108674

  12. Evolution of foraging behavior in Drosophilid larvae

    NASA Astrophysics Data System (ADS)

    Rivera-Alba, Marta; Kabra, Mayank; Branson, Kristin; Mirth, Christen

    2015-03-01

    Drosophilids, like other insects, go through a larval phase before metamorphosing into adults. Larvae increase their body weight by several orders of magnitude in a few days. We therefore hypothesized that foraging behavior is under strong evolutionary pressure to best fit the larval environment. To test our hypothesis we used a multidisciplinary approach to analyze foraging behavior across species and larval stages. First, we recorded several videos of larvae foraging for each of 47 Drosophilid species. Then, using a supervised machine learning approach, we automatically annotated the video collection for the foraging sub-behaviors, including crawling, turning, head casting or burrowing. We also computed over 100 features to describe the posture and dynamics of each animal in each video frame. From these data, we fit models to the behavior of each species. The models each had the same parametric form, but differed in the exact parameters. By simulating larva behavior in virtual arenas we can infer which properties of the environments are better for each species. Comparisons between these inferred environments and the actual environments where these animals live will give us a deeper understanding about the evolution of foraging behavior in Drosophilid larvae.

  13. 7 CFR 457.117 - Forage production crop insurance provisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...stand . A population of live forage plants that equals or exceeds the minimum required number of plants per square foot as shown in the Special...Cutting. The severance of the forage plant from its roots. Direct marketing. Sale...

  14. 7 CFR 457.117 - Forage production crop insurance provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...stand —A population of live forage plants that equals or exceeds the minimum required number of plants per square foot as shown in the Special...Cutting. The severance of the forage plant from its roots. Direct marketing. Sale...

  15. 7 CFR 457.117 - Forage production crop insurance provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...stand —A population of live forage plants that equals or exceeds the minimum required number of plants per square foot as shown in the Special...Cutting. The severance of the forage plant from its roots. Direct marketing. Sale...

  16. Evidence of Lvy walk foraging patterns in human huntergatherers

    E-print Network

    Pontzer, Herman

    Evidence of Lévy walk foraging patterns in human hunter­gatherers David A. Raichlena,1 , Brian M patterns in human foraging. Here, we show that human hunter­gatherers, the Hadza of northern Tanzania/'hoansi hunter­gather

  17. Optimal Lévy-flight foraging in a finite landscape

    PubMed Central

    Zhao, Kun; Jurdak, Raja; Liu, Jiajun; Westcott, David; Kusy, Branislav; Parry, Hazel; Sommer, Philipp; McKeown, Adam

    2015-01-01

    We present a simple model to study Lévy-flight foraging with a power-law step-size distribution in a finite landscape with countable targets. We find that different optimal foraging strategies characterized by a wide range of power-law exponent ?opt, from ballistic motion (?opt ? 1) to Lévy flight (1 < ?opt < 3) to Brownian motion (?opt ? 3), may arise in adaptation to the interplay between the termination of foraging, which is regulated by the number of foraging steps, and the environmental context of the landscape, namely the landscape size and number of targets. We further demonstrate that stochastic returning can be another significant factor that affects the foraging efficiency and optimality of foraging strategy. Our study provides a new perspective on Lévy-flight foraging, opens new avenues for investigating the interaction between foraging dynamics and the environment and offers a realistic framework for analysing animal movement patterns from empirical data. PMID:25631566

  18. A properly adjusted forage harvester can save time and money

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A properly adjusted forage harvester can save fuel and increase the realizable milk per ton of your silage. This article details the adjustments necessary to minimize energy while maximizing productivity and forage quality....

  19. A DIGITAL PHOTOGRAPHIC TECHNIQUE FOR ASSESSING FORAGE UTILIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in forage utilization have been difficult to measure nondestructively without some level of subjectivity. This subjectivity, combined with a lack of reproducibility of visual estimates, has made forage utilization measurement techniques a topic of considerable discussion. The objective of ...

  20. Spatiotemporal chemotactic model for ant foraging

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Subramanian; Laurent, Thomas; Kumar, Manish; Bertozzi, Andrea L.

    2014-12-01

    In this paper, we present a generic theoretical chemotactic model that accounts for certain emergent behaviors observed in ant foraging. The model does not have many of the constraints and limitations of existing models for ants colony dynamics and takes into account the distinctly different behaviors exhibited in nature by ant foragers in search of food and food ferrying ants. Numerical simulations based on the model show trail formation in foraging ant colonies to be an emergent phenomenon and, in particular, replicate behavior observed in experiments involving the species P. megacephala. The results have broader implications for the study of randomness in chemotactic models. Potential applications include the developments of novel algorithms for stochastic search in engineered complex systems such as robotic swarms.

  1. Metabolomics of forage plants: a review

    PubMed Central

    Rasmussen, Susanne; Parsons, Anthony J.; Jones, Christopher S.

    2012-01-01

    Background Forage plant breeding is under increasing pressure to deliver new cultivars with improved yield, quality and persistence to the pastoral industry. New innovations in DNA sequencing technologies mean that quantitative trait loci analysis and marker-assisted selection approaches are becoming faster and cheaper, and are increasingly used in the breeding process with the aim to speed it up and improve its precision. High-throughput phenotyping is currently a major bottle neck and emerging technologies such as metabolomics are being developed to bridge the gap between genotype and phenotype; metabolomics studies on forages are reviewed in this article. Scope Major challenges for pasture production arise from the reduced availability of resources, mainly water, nitrogen and phosphorus, and metabolomics studies on metabolic responses to these abiotic stresses in Lolium perenne and Lotus species will be discussed here. Many forage plants can be associated with symbiotic microorganisms such as legumes with nitrogen fixing rhizobia, grasses and legumes with phosphorus-solubilizing arbuscular mycorrhizal fungi, and cool temperate grasses with fungal anti-herbivorous alkaloid-producing Neotyphodium endophytes and metabolomics studies have shown that these associations can significantly affect the metabolic composition of forage plants. The combination of genetics and metabolomics, also known as genetical metabolomics can be a powerful tool to identify genetic regions related to specific metabolites or metabolic profiles, but this approach has not been widely adopted for forages yet, and we argue here that more studies are needed to improve our chances of success in forage breeding. Conclusions Metabolomics combined with other ‘-omics’ technologies and genome sequencing can be invaluable tools for large-scale geno- and phenotyping of breeding populations, although the implementation of these approaches in forage breeding programmes still lags behind. The majority of studies using metabolomics approaches have been performed with model species or cereals and findings from these studies are not easily translated to forage species. To be most effective these approaches should be accompanied by whole-plant physiology and proof of concept (modelling) studies. Wider considerations of possible consequences of novel traits on the fitness of new cultivars and symbiotic associations need also to be taken into account. PMID:22351485

  2. 7 CFR 407.13 - Group risk plan for forage.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows:...

  3. Allometric scaling of ant foraging trail networks Joseph Jun,

    E-print Network

    Gillooly, Jamie

    2/3 . Since the cost of foraging increases linearly with F, the model predicts an optimal number, foraging, optimal networks, social insects. INTRODUCTION A major transition in organic evolution with the number of foragers. The model also implies that there is an optimal colony size that maximizes the rate

  4. Monitoring the presence of ergot alkaloids in forage animal samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Novel Aspect Initial liquid chromatography tandem mass spectrometry method development for metabolite profiling of ergot alkaloids consumed by forage animals Introduction The presence of ergot alkaloids in forages has been reported to produce acute toxicity when consumed by forage animals. A meth...

  5. Factors influencing the field germination of forage kochia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage kochia is a drought and salt tolerant perennial, semi-shrub that has proven to be valuable forage in the western U.S., but also difficult to establish. This study evaluated the effects that age of seed, subspecies, and planting date have on forage kochia seed germination in the field. Seed ...

  6. 7 CFR 407.13 - Group risk plan for forage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Group risk plan for forage. 407.13 Section 407.13..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.13 Group risk plan for forage. The provisions of the Group Risk Plan for Forage for the 2000 and succeeding crop years are as follows:...

  7. EFFECTS OF FORAGE MANAGEMENT ON PASTURE PRODUCTIVITY AND PHOSPHORUS CONTENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of the current study were to determine the amounts of above- and below-ground plant biomass production, phosphorus (P) uptake by forage, and P concentration of cool-season grass forage as influenced by management and season. Five forage management treatments were evaluated over three...

  8. Biomimicry of Foraging for Optimization, Control, and Automation

    E-print Network

    UNIVERSITY Outline · Philosophy, foraging theory · Chemotactic behavior (foraging strategy) of E. coli (Foraging) Behavior of E. coli · E. coli: Diameter: 1µm, Length: 2µm Figure 4: E. coli bacterium (from [2]). · Can reproduce (split) in 20 min. #12;9 OHIO STATE T . H . E UNIVERSITY 5 E. coli in action... (from C

  9. Symmetry breaking in collective honeybee foraging: A simulation study

    E-print Network

    de Vries, Han

    . All runs were made with a forager pool of 200 bees, a patch size of 40 for all sources generator. All runs were made with a forager pool of 200 bees, a patch size of 40 for all sources on patch size and potential forager pool Emergence of symmetry breaking happens through the haphazard

  10. VARIABILITY IN RELATIONSHIPS AMONG FORAGE INTAKE, DIGESTIBILITY, NDF, AND ADF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confusion exists about forage quality and in methods to measure or predict forage quality. The conventional wisdom is that there are close relationships between voluntary forage dry matter intake (DMI) and digestible dry matter (DDM) concentration, DMI and NDF, and DDM and ADF. Correlation coeffic...

  11. Ant Foraging Revisited Liviu A. Panait and Sean Luke

    E-print Network

    Turk, Greg

    Ant Foraging Revisited Liviu A. Panait and Sean Luke George Mason University, Fairfax, VA 22030 lpanait@cs.gmu.edu, sean@cs.gmu.edu Abstract Most previous artificial ant foraging algorithms have to date the artificial ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

  12. Ant Foraging Revisited Liviu A. Panait and Sean Luke

    E-print Network

    Luke, Sean

    Ant Foraging Revisited Liviu A. Panait and Sean Luke George Mason University, Fairfax, VA 22030 lpanait@cs.gmu.edu, sean@cs.gmu.edu Abstract Most previous artificial ant foraging models have to date re the artificial ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

  13. Advances in the Assessment of the Nutritive Value of Forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The consumption of forages, which are primary producers, results in ‘value added’ animal products as meat, milk and fiber, and in some cases, recreation. How a forage might support the value added product of interest has been a concern since the mid-1800’s. The characteristic of a forage that compos...

  14. Alexander Creek in the Susitna Basin

    USGS Multimedia Gallery

    Researchers with the Alaska Fish and Game travel along Alexander Creek in the Susitna Basin of south-central Alaska. The team is on their way to a back country base-camp for a study examining the preferred diet of invasive northern pike (Esox lucius).  ...

  15. WINTER MOVEMENTS OF FOUR FISH SPECIES NEAR A THERMAL PLUME IN NORTHERN MINNESOTA (JOURNAL VERSION)

    EPA Science Inventory

    During winter 1975, 17 yellow perch (Perca flavescens), 6 northern pike (Esox lucius), 3 walleyes (Stizostedion vitreum), and 2 largemouth bass (Micropterus salmoides) were equipped with radio frequency transmitters to compare their winter movements near the thermal plume of a po...

  16. BLUE WHALE-SIZED MOUTHFULS MAKE FORAGING

    E-print Network

    Martin, Paul R.

    Inside JEB i BLUE WHALE-SIZED MOUTHFULS MAKE FORAGING SUPER EFFICIENT When a blue whale dives from the University of British Columbia, Canada, explains that blue whales may be able to dive. Explaining that the whales feed by lunging repeatedly through deep shoals of krill, engulfing their own body

  17. Field and Forage Crop Pests. MEP 310.

    ERIC Educational Resources Information Center

    Morgan, Omar, D.; And Others

    As part of a cooperative extension service series by the University of Maryland, this publication introduces the identification and control of common agricultural pests that can be found in field and forage crops. The first of the five sections defines "pest" and "weed" and generally introduces different kinds of pests in the categories of…

  18. Scholarly Foraging and Network Discovery Tools.

    ERIC Educational Resources Information Center

    Cronin, Blaise; Hert, Carol A.

    1995-01-01

    Parallels between subsistence foraging and scholarly information seeking are described in the context of the World Wide Web. Suggests that the prevailing information retrieval paradigm does not capture the complex of behavior and stimuli that drives scholars' quests for new ideas and insights. Research questions are suggested by extended use of…

  19. Human memory retrieval as Lévy foraging

    NASA Astrophysics Data System (ADS)

    Rhodes, Theo; Turvey, Michael T.

    2007-11-01

    When people attempt to recall as many words as possible from a specific category (e.g., animal names) their retrievals occur sporadically over an extended temporal period. Retrievals decline as recall progresses, but short retrieval bursts can occur even after tens of minutes of performing the task. To date, efforts to gain insight into the nature of retrieval from this fundamental phenomenon of semantic memory have focused primarily upon the exponential growth rate of cumulative recall. Here we focus upon the time intervals between retrievals. We expected and found that, for each participant in our experiment, these intervals conformed to a Lévy distribution suggesting that the Lévy flight dynamics that characterize foraging behavior may also characterize retrieval from semantic memory. The closer the exponent on the inverse square power-law distribution of retrieval intervals approximated the optimal foraging value of 2, the more efficient was the retrieval. At an abstract dynamical level, foraging for particular foods in one's niche and searching for particular words in one's memory must be similar processes if particular foods and particular words are randomly and sparsely located in their respective spaces at sites that are not known a priori. We discuss whether Lévy dynamics imply that memory processes, like foraging, are optimized in an ecological way.

  20. Optimal search behavior and classic foraging theory

    NASA Astrophysics Data System (ADS)

    Bartumeus, F.; Catalan, J.

    2009-10-01

    Random walk methods and diffusion theory pervaded ecological sciences as methods to analyze and describe animal movement. Consequently, statistical physics was mostly seen as a toolbox rather than as a conceptual framework that could contribute to theory on evolutionary biology and ecology. However, the existence of mechanistic relationships and feedbacks between behavioral processes and statistical patterns of movement suggests that, beyond movement quantification, statistical physics may prove to be an adequate framework to understand animal behavior across scales from an ecological and evolutionary perspective. Recently developed random search theory has served to critically re-evaluate classic ecological questions on animal foraging. For instance, during the last few years, there has been a growing debate on whether search behavior can include traits that improve success by optimizing random (stochastic) searches. Here, we stress the need to bring together the general encounter problem within foraging theory, as a mean for making progress in the biological understanding of random searching. By sketching the assumptions of optimal foraging theory (OFT) and by summarizing recent results on random search strategies, we pinpoint ways to extend classic OFT, and integrate the study of search strategies and its main results into the more general theory of optimal foraging.

  1. ALFALFA: FORAGE CROP OF THE FUTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alfalfa hay and silage support dairy, beef, sheep, and horse production in the U.S., as well as a growing export market. Alfalfa is relatively low in fiber and high in protein compared to other forages and typically results in high intakes and levels of milk production. In addition to its excellent...

  2. Forage analysis can help you determine

    E-print Network

    different management and fertilization practices, and areas with different types of grass should be sampled, sealable plastic bags (only if dry) and small paper sacks (fertilizer and feed sacks are not appropriate will be harvested, the forage height after grazing, and differences in fertil- ization from one area of the pasture

  3. Improving Efficiency in Breeding Forage Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic gains in yield of forage crops have lagged far behind gains made in yield of grain crops. Inefficient breeding procedures are one reason for the lag in yield gains. Efficiency of breeding procedures for increased yield can be improved by sowing families into sward plots to accurately measure...

  4. Investigating Optimal Foraging Theory in the Laboratory

    ERIC Educational Resources Information Center

    Harden, Siegfried; Grilliot, Matthew E.

    2014-01-01

    Optimal foraging theory is a principle that is often presented in the community ecology section of biology textbooks, but also can be demonstrated in the laboratory. We introduce a lab activity that uses an interactive strategy to teach high school and/or college students about this ecological concept. The activity is ideal because it engages…

  5. WINTER TRITICALE: A FORAGE FOR ALL SEASONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter Triticale (X Triticosecale Wittmack) is usually planted in late summer or early fall, grows vegetatively prior to vernalization by cold winter temperatures and develops reproductively the following spring. Earlier establishment could increase production of high quality forage by extending the...

  6. Nitrates and Prussic Acid in Forages 

    E-print Network

    Provin, Tony; Pitt, John L.

    2003-01-06

    When nitrates and prussic acid accumulate in forage, the feed may not be safe for livestock consumption. Learn the symptoms of nitrate and prussic acid poisoning and which plants are most likely to pose a risk to livestock. Also learn sampling...

  7. Purslane: A Potential Forage for Small Ruminants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable small ruminant production on small-acreage farms in Appalachia depends upon use of various plant resources to meet nutritional and health requirements of animals and provide meat products that satisfy consumer desires and expectations. While traditional forage species can supply nutrien...

  8. Simplifying Cyber Foraging Rajesh Krishna Balan

    E-print Network

    trademarks mentioned in this dissertation are properties of their respective owners. The viewsSimplifying Cyber Foraging Rajesh Krishna Balan May 2006 CMU­CS­06­120 School of Computer Science Computer Science Department Carnegie Mellon University Pittsburgh, PA Submitted in partial fulfillment

  9. Simplifying Cyber Foraging Rajesh Krishna Balan

    E-print Network

    trademarks mentioned in this dissertation are properties of their respective owners. The viewsSimplifying Cyber Foraging Rajesh Krishna Balan May 2006 CMU-CS-06-120 School of Computer Science Computer Science Department Carnegie Mellon University Pittsburgh, PA Submitted in partial fulfillment

  10. Diving Patterns and Foraging Locations of

    E-print Network

    Diving Patterns and Foraging Locations of Female Northern Fur Seals Michael E. Goebel John L 98 J J5-0070 Abstract.-Nine lactating north- ern fur seals Callo7'hinus ursinus from St. Paul Island water. An analysis of the occurrence of food in stomachs of lactating fur seals collected in the eastern

  11. Calibrating your forage harvester's yield monitor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With some attention to the details, you will have a harvester that should be able to produce yield maps that will allow the same precision management that is expected in cereal crops. Forage yield maps, coupled with site-specific technologies in application of soil amendments, fertilizers, and pesti...

  12. The Dynamics of Infant Visual Foraging

    ERIC Educational Resources Information Center

    Robertson, Steven S.; Guckenheimer, John; Masnick, Amy M.; Bacher, Leigh F.

    2004-01-01

    Human infants actively forage for visual information from the moment of birth onward. Although we know a great deal about how stimulus characteristics influence looking behavior in the first few postnatal weeks, we know much less about the intrinsic dynamics of the behavior. Here we show that a simple stochastic dynamical system acts…

  13. DIEL FORAGING ACTIVITY OF AMERICAN EELS,

    E-print Network

    DIEL FORAGING ACTIVITY OF AMERICAN EELS, ANGUILLA ROSTRATA (LESUEUR), IN A RHODE ISLAND ESTUARY Although the American eel, Anguilla rostrata (LeSueur), is abundant and commercially exploited along Veen et aI. 1976; Westin and Nyman 1979), that American eel locomotor activity is noc- turnal

  14. Effects of rain damage on wilting forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most common problems faced by hay or silage producers is how to manage production schedules around unfavorable weather. Inevitably, some wilting forage crops are damaged by unexpected rainfall events each year, and producers often inquire about the effects of unexpected rain damage, and w...

  15. Forage harvest representation in RUSLE2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Revised Universal Soil Loss Equation (RUSLE and RUSLE2) has long been used by USDA and others for management planning based on soil erosion and sediment delivery estimates. It has worked well for normal annual agronomic crops, but proved to be awkward for forage crops. This is partly because RU...

  16. Measuring and budgeting available forage in pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We modeled two farms that differed in size, grazing management, and feeding strategy. We first modeled the optimal management and performance conditions for each farm with the assumption that forage on pasture was measured accurately and budgeted optimally. We also established an economically optimu...

  17. SWITCHGRASS FOR BIOFUEL, FORAGE, AND MUSHROOMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.), a native perennial warm-season grass, is used as a forage and conservation plant in the eastern USA. During the last 15 years switchgrass has received much attention as a model energy crop. Attributes of switchgrass desirable for bioenergy cropping include its demo...

  18. The hidden cost of information in collective foraging

    PubMed Central

    Dechaume-Moncharmont, François-Xavier; Dornhaus, Anna; Houston, Alasdair I; McNamara, John M; Collins, Edmund J; Franks, Nigel R

    2005-01-01

    Many animals nest or roost colonially. At the start of a potential foraging period, they may set out independently or await information from returning foragers. When should such individuals act independently and when should they wait for information? In a social insect colony, for example, information transfer may greatly increase a recruit's probability of finding food, and it is commonly assumed that this will always increase the colony's net energy gain. We test this assumption with a mathematical model. Energy gain by a colony is a function both of the probability of finding food sources and of the duration of their availability. A key factor is the ratio of pro-active foragers to re-active foragers. When leaving the nest, pro-active foragers search for food independently, whereas re-active foragers rely on information from successful foragers to find food. Under certain conditions, the optimum strategy is totally independent (pro-active) foraging because potentially valuable information that re-active foragers may gain from successful foragers is not worth waiting for. This counter-intuitive outcome is remarkably robust over a wide range of parameters. It occurs because food sources are only available for a limited period. Our study emphasizes the importance of time constraints and the analysis of dynamics, not just steady states, to understand social insect foraging. PMID:16087424

  19. Summertime blues: August foraging leaves honey bees empty-handed.

    PubMed

    Couvillon, Margaret J; Fensome, Katherine A; Quah, Shaun Kl; Schürch, Roger

    2014-01-01

    A successful honey bee forager tells her nestmates the location of good nectar and pollen with the waggle dance, a symbolic language that communicates a distance and direction. Because bees are adept at scouting out profitable forage and are very sensitive to energetic reward, we can use the distance that bees communicate via waggle dances as a proxy for forage availability, where the further the bees fly, the less forage can be found locally. Previously we demonstrated that bees fly furthest in the summer compared with spring or autumn to bring back forage that is not necessarily of better quality. Here we show that August is also the month when significantly more foragers return with empty crops (P = 7.63e-06). This provides additional support that summer may represent a seasonal foraging challenge for honey bees. PMID:25346794

  20. Spatiotemporal resource distribution and foraging strategies of ants (Hymenoptera: Formicidae)

    PubMed Central

    Lanan, Michele

    2014-01-01

    The distribution of food resources in space and time is likely to be an important factor governing the type of foraging strategy used by ants. However, no previous systematic attempt has been made to determine whether spatiotemporal resource distribution is in fact correlated with foraging strategy across the ants. In this analysis, I present data compiled from the literature on the foraging strategy and food resource use of 402 species of ants from across the phylogenetic tree. By categorizing the distribution of resources reported in these studies in terms of size relative to colony size, spatial distribution relative to colony foraging range, frequency of occurrence in time relative to worker life span, and depletability (i.e., whether the colony can cause a change in resource frequency), I demonstrate that different foraging strategies are indeed associated with specific spatiotemporal resource attributes. The general patterns I describe here can therefore be used as a framework to inform predictions in future studies of ant foraging behavior. No differences were found between resources collected via short-term recruitment strategies (group recruitment, short-term trails, and volatile recruitment), whereas different resource distributions were associated with solitary foraging, trunk trails, long-term trail networks, group raiding, and raiding. In many cases, ant species use a combination of different foraging strategies to collect diverse resources. It is useful to consider these foraging strategies not as separate options but as modular parts of the total foraging effort of a colony. PMID:25525497

  1. Utilisation of Intensive Foraging Zones by Female Australian Fur Seals

    PubMed Central

    Hoskins, Andrew J.; Costa, Daniel P.; Arnould, John P. Y.

    2015-01-01

    Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity ‘hot spots’ were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch. PMID:25692978

  2. Foraging theory for autonomous vehicle speed choice Theodore P. Pavlic , Kevin M. Passino 1

    E-print Network

    forager from optimal foraging theory (Stephens and Krebs, 1986). Optimal foraging theorists assume of proximate fitness functions to explain observed behaviors in nature. Lately, methods from optimal foraging that optimal behaviors are found on a continuum with foraging time minimization and net energetic intake

  3. Niche Selection for Foraging Tasks in Multi-Robot Teams Using Reinforcement Learning

    E-print Network

    distributions predicted by optimal foraging theory. These distributions are established without prior knowledge-Robot Systems, Reinforcement Learning, Foraging, Optimal Foraging 1 Introduction and Motivation Foraging tasks team to specialize. To address these questions we look towards the optimal foraging theory literature

  4. Discrimination learning in a foraging situation

    PubMed Central

    Mellgren, Roger L.; Brown, Steven W.

    1988-01-01

    Rats were allowed to forage in a simulated natural environment made up of eight food sources (patches) each containing a fixed number of pellets. Two of the eight contained an extra supply of peanuts. The peanut patches were signaled by an olfactory/visual cue located at the bottom of the ladder leading to the patch. In successive phases the number of sessions per day, height of the patches, and availability of peanuts were manipulated. Subjects showed evidence of discrimination learning under these conditions, although the degree of discriminatory behavior varied as a function of environmental manipulations. Assessment of behavior within foraging sessions showed that subjects systematically changed their patterns of utilization of patches across time. Sampling or exploration, as well as food reinforcement, seem implicated in these results. PMID:16812570

  5. On the intermittent behaviour of foraging animals

    NASA Astrophysics Data System (ADS)

    Reynolds, A. M.

    2006-08-01

    Many foragers adopt an intermittent searching behaviour in which active local search phases randomly alternate with relocation phases. The average duration of the searching phases has a power-law dependency upon the average duration of the relocation phases. Here it is shown that this observed power-law scaling can be understood within the context of an optimal scale-free (Lévy-flight) searching strategy.

  6. Understanding Forage Intake in Range Animals 

    E-print Network

    Lyons, Robert K.; Machen, Richard V.; Forbes, T. D. A.

    1999-02-08

    managed. Environmental Influences Climatic conditions in which range herbivores graze and browse can have a profound effect on forage intake (NRC 1987). Each herbivore species appears to have its own comfort zone with upper and lower temperature limits... their digestive tracts rapidly not only because they are quickly fermented and digested, but also because the browsers and intermediate feeders have an open rumen anatomy that allows materials to pass out more easily than the more compartment- alized rumen...

  7. Drought increases forage nitrate and cyanide.

    PubMed

    Pickrell, J A; Oehme, F W; Hickman, S R

    1991-06-01

    To investigate drought-associated increases in concentrations of nitrate and cyanide in animal forage, we compared forage nitrate and cyanide in 1986-87 (annual rainfall 33 in) to nitrate and cyanide in a drought (1988 and 1989; annual rainfall 20 and 27 in, respectively). Fifteen to 20% of the nitrate and cyanide samples from 1986-1987 had sufficiently high concentrations to be of concern (3000 ppm nitrate, 20 ppm cyanide as submitted). Only 4-6% of the 1986-1987 samples had concentrations sufficiently high to produce acute respiratory distress (13,000 ppm nitrate, 50 ppm cyanide as submitted). During 1988 sample numbers had more than doubled, suggesting increased concern for the possibility of nitrate or cyanide intoxication and yielding parallel increases in the number of samples with elevated nitrates or cyanides. By 1989, 25-33% of the samples had concentrations of health concern with respect to either nitrate or cyanide, while 14-19% had concentrations sufficiently high to produce acute respiratory signs. Shortages of forage caused by a 2-y drought were further exacerbated by nitrate and cyanide increases in that feed. Future efforts should concentrate on controlling groundwater nitrate and delivery of nitrate to the plant root-systems. PMID:1858304

  8. Foraging biology predicts food web complexity.

    PubMed

    Beckerman, Andrew P; Petchey, Owen L; Warren, Philip H

    2006-09-12

    Food webs, the networks of feeding links between species, are central to our understanding of ecosystem structure, stability, and function. One of the key aspects of food web structure is complexity, or connectance, the number of links expressed as a proportion of the total possible number of links. Connectance (complexity) is linked to the stability of webs and is a key parameter in recent models of other aspects of web structure. However, there is still no fundamental biological explanation for connectance in food webs. Here, we propose that constraints on diet breadth, driven by optimal foraging, provide such an explanation. We show that a simple diet breadth model predicts highly constrained values of connectance as an emergent consequence of individual foraging behavior. When combined with features of real food web data, such as taxonomic and trophic aggregation and cumulative sampling of diets, the model predicts well the levels of connectance and scaling of connectance with species richness, seen in real food webs. This result is a previously undescribed synthesis of foraging theory and food web theory, in which network properties emerge from the behavior of individuals and, as such, provides a mechanistic explanation of connectance currently lacking in food web models. PMID:16954193

  9. Common Attentional Constraints in Visual Foraging

    PubMed Central

    Kristjánsson, Árni; Jóhannesson, Ómar I.; Thornton, Ian M.

    2014-01-01

    Predators are known to select food of the same type in non-random sequences or “runs” that are longer than would be expected by chance. If prey are conspicuous, predators will switch between available sources, interleaving runs of different prey types. However, when prey are cryptic, predators tend to focus on one food type at a time, effectively ignoring equally available sources. This latter finding is regarded as a key indicator that animal foraging is strongly constrained by attention. It is unknown whether human foraging is equally constrained. Here, using a novel iPad task, we demonstrate for the first time that it is. Participants were required to locate and touch 40 targets from 2 different categories embedded within a dense field of distractors. When individual target items “popped-out” search was organized into multiple runs, with frequent switching between target categories. In contrast, as soon as focused attention was required to identify individual targets, participants typically exhausted one entire category before beginning to search for the other. This commonality in animal and human foraging is compelling given the additional cognitive tools available to humans, and suggests that attention constrains search behavior in a similar way across a broad range of species. PMID:24964082

  10. Short-term exploitative competition can explain human foraging patterns

    E-print Network

    Saavedra, Serguei; Switanek, Nicholas; Uzzi, Brian

    2012-01-01

    Theory purports that animal foraging choices evolve to maximize returns, such as net energy intake. Empirical research in both human and nonhuman animals reveals that many times foraging choices are context dependent and affected by the foraging choices of others. Yet, broad empirical facts on the link between optimal foraging patterns, competition and context-dependent information are only now emerging due to the complication of gathering field data or constructing experiments. Here, we analyze foraging choices by a cohort of professional day traders who face the trade-off of trading the same stock multiple times in a row---patch exploitation---or switching to a different stock---patch exploration---with potentially higher returns. Our findings indicate that traders' foraging patterns are characterized by short-term comparative returns that decrease in proportion to patch exploitation and exploration, a novel measure that captures the difference between a trader's resource intake and the competitors' expecte...

  11. To join or not to join: collective foraging strategies

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Kunal; Vicsek, Tamás

    2015-09-01

    We present a minimal model to address the issue of how the interaction between foragers influence their encounter rates with resources. We consider a two-dimensional lattice model to study the optimal strategy for a group of foragers (walkers) searching for targets distributed heterogeneously. A forager who has not detected any target has the choice of, either joining other foragers in the neighbourhood, who have detected targets, or continue searching independently. The optimal strategy appears to be a mixture of these choices. Remarkably, we observe that scale-free walks appear for strategies far from optimality. In general, we investigate the behaviour of the model with a parameter characterizing the propensity of the foragers to aggregate and the radius of interaction characterizing the neighbourhood of a forager.

  12. Suboptimal foraging behavior: A new perspective on gambling.

    PubMed

    Addicott, Merideth A; Pearson, John M; Kaiser, Nicole; Platt, Michael L; McClernon, F Joseph

    2015-10-01

    Why do people gamble? Conventional views hold that gambling may be motivated by irrational beliefs, risk-seeking, impulsive temperament, or dysfunction within the same reward circuitry affected by drugs of abuse. An alternate, unexplored perspective is that gambling is an extension of natural foraging behavior to a financial environment. However, when these foraging algorithms are applied to stochastic gambling outcomes, undesirable results may occur. To test this hypothesis, we recruited participants based on their frequency of gambling-yearly (or less), monthly, and weekly-and investigated how gambling frequency related to irrational beliefs, risk-taking/impulsivity, and foraging behavior. We found that increased gambling frequency corresponded to greater gambling-related beliefs, more exploratory choices on an explore/exploit foraging task, and fewer points earned on a Patchy Foraging Task. Gambling-related beliefs negatively related to performance on the Patchy Foraging Task, indicating that individuals with more gambling-related cognitions tended to leave a patch too quickly. This indicates that frequent gamblers have reduced foraging ability to maximize rewards; however, gambling frequency -and by extension, poor foraging ability- was not related to risk-taking or impulsive behavior. These results suggest that gambling reflects the application of a dysfunctional foraging process to financial outcomes. (PsycINFO Database Record PMID:26191945

  13. 78 FR 53370 - Common Crop Insurance Regulations; Forage Seed Crop Provisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-29

    ...Insurance Regulations; Forage Seed Crop Provisions AGENCY: Federal...regulations that provides forage seed insurance. The provisions will...action is to convert the Forage Seed pilot crop insurance program...Product Design Division, Risk Management Agency, United States...

  14. Macroalgal Mats in a Eutrophic Estuary Obscure Visual Foraging Cues and Increase Variability in Prey Availability

    E-print Network

    Blumstein, Daniel T.

    Macroalgal Mats in a Eutrophic Estuary Obscure Visual Foraging Cues and Increase Variability across shore- bird foraging guilds. Keywords Eutrophication . Forage . Generalist . Habitat . Macroalgal the protection and restoration of ecosystem function that can be disrupted by eutrophication. Anthropogenic

  15. Effect of Nitrogen Fertilization and Forage Maturity on the Nutritive Value of Bahiagrass 

    E-print Network

    Kenney, Nicole M

    2012-07-11

    Bahiagrass (paspalum notatum), a forage resource in the southern United States, often has lower forage quality than other forages, but may require fewer nutrient inputs. Our objectives were to determine the effects of N fertilization and maturity...

  16. Foraging distances and forager population sizes of the desert termite Gnathamitermes tubiformans (Buckley) (Isoptera: Termitidae) 

    E-print Network

    Narayanan, Anne Michelle

    2005-11-01

    ...........................................................................8 Plot Sites and Vouchers..............................................................................8 Baits and Termite Marking.........................................................................9 Foraging Distances Experimental Design... quadrant-based count of standing vegetation was taken in each 5 m x 5 m plot using a 1 m x 1 m frame..............................................................................9 2. Termite bait trap (10 cm diameter, 12.5 cm height...

  17. 2011 Forage Trials reporT The 2011 Forage Trials Report sum-

    E-print Network

    Guiltinan, Mark

    at Rock Springs and the Southeast Research and Extension Center at Landisville. 2011 Forage Growing Season consistent rains throughout the growing season. The generally poor haymaking conditions this year were- grass continue to be a problem. Growing-season precipitation amounts for the past four years at Rock

  18. Multimodal Floral Signals and Moth Foraging Decisions

    PubMed Central

    Riffell, Jeffrey A.; Alarcón, Ruben

    2013-01-01

    Background Combinations of floral traits – which operate as attractive signals to pollinators – act on multiple sensory modalities. For Manduca sexta hawkmoths, how learning modifies foraging decisions in response to those traits remains untested, and the contribution of visual and olfactory floral displays on behavior remains unclear. Methodology/Principal Findings Using M. sexta and the floral traits of two important nectar resources in southwestern USA, Datura wrightii and Agave palmeri, we examined the relative importance of olfactory and visual signals. Natural visual and olfactory cues from D. wrightii and A. palmeri flowers permits testing the cues at their native intensities and composition – a contrast to many studies that have used artificial stimuli (essential oils, single odorants) that are less ecologically relevant. Results from a series of two-choice assays where the olfactory and visual floral displays were manipulated showed that naïve hawkmoths preferred flowers displaying both olfactory and visual cues. Furthermore, experiments using A. palmeri flowers – a species that is not very attractive to hawkmoths – showed that the visual and olfactory displays did not have synergistic effects. The combination of olfactory and visual display of D. wrightii, however – a flower that is highly attractive to naïve hawkmoths – did influence the time moths spent feeding from the flowers. The importance of the olfactory and visual signals were further demonstrated in learning experiments in which experienced moths, when exposed to uncoupled floral displays, ultimately chose flowers based on the previously experienced olfactory, and not visual, signals. These moths, however, had significantly longer decision times than moths exposed to coupled floral displays. Conclusions/Significance These results highlight the importance of specific sensory modalities for foraging hawkmoths while also suggesting that they learn the floral displays as combinatorial signals and use the integrated floral traits from their memory traces to mediate future foraging decisions. PMID:23991154

  19. Complex scaling behavior in animal foraging patterns

    NASA Astrophysics Data System (ADS)

    Premachandra, Prabhavi Kaushalya

    This dissertation attempts to answer questions from two different areas of biology, ecology and neuroscience, using physics-based techniques. In Section 2, suitability of three competing random walk models is tested to describe the emergent movement patterns of two species of primates. The truncated power law (power law with exponential cut off) is the most suitable random walk model that characterizes the emergent movement patterns of these primates. In Section 3, an agent-based model is used to simulate search behavior in different environments (landscapes) to investigate the impact of the resource landscape on the optimal foraging movement patterns of deterministic foragers. It should be noted that this model goes beyond previous work in that it includes parameters such as spatial memory and satiation, which have received little consideration to date in the field of movement ecology. When the food availability is scarce in a tropical forest-like environment with feeding trees distributed in a clumped fashion and the size of those trees are distributed according to a lognormal distribution, the optimal foraging pattern of a generalist who can consume various and abundant food types indeed reaches the Levy range, and hence, show evidence for Levy-flight-like (power law distribution with exponent between 1 and 3) behavior. Section 4 of the dissertation presents an investigation of phase transition behavior in a network of locally coupled self-sustained oscillators as the system passes through various bursting states. The results suggest that a phase transition does not occur for this locally coupled neuronal network. The data analysis in the dissertation adopts a model selection approach and relies on methods based on information theory and maximum likelihood.

  20. Nutrient-Specific Foraging in Invertebrate Predators

    NASA Astrophysics Data System (ADS)

    Mayntz, David; Raubenheimer, David; Salomon, Mor; Toft, Søren; Simpson, Stephen J.

    2005-01-01

    Many herbivores and omnivores adjust their food selection behavior to regulate the intake of multiple nutrients. Carnivores, however, are generally assumed to optimize the rate of prey capture rather than select prey according to nutrient composition. We showed experimentally that invertebrate predators can forage selectively for protein and lipids to redress specific nutritional imbalances. This selection can take place at different stages of prey handling: The predator may select among foods of different nutritional composition, eat more of a prey if it is rich in nutrients that the predator is deficient in, or extract specific nutrients from a single prey item.

  1. Forage polyphenol oxidase and ruminant livestock nutrition

    PubMed Central

    Lee, Michael R. F.

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of the forage and therefore not related to PPO activity. PMID:25538724

  2. Forage polyphenol oxidase and ruminant livestock nutrition.

    PubMed

    Lee, Michael R F

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of the forage and therefore not related to PPO activity. PMID:25538724

  3. Alfalfa and forage kochia improve nutritive value of semiarid rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improving forage quality on semiarid grazing lands of the western United States is challenging. This study compared the late summer forage quality parameters crude protein (CP) and neutral detergent fiber (NDF) of 'Vavilov' Siberian wheatgrass (Agropyron fragile). 'Mustang' Altai wildrye (Leymus ang...

  4. Forage yield and quality differences among cool-season grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rotationally-stocked, perennial cool-season grasses are often utilized at a vegetative stage of maturity. We compared the yield and forage quality of leaves, stems, and total forage of meadow fescue, orchardgrass, quackgrass, reed canarygrass, smooth bromegrass, EF (endophyte-free) and EI (endophyte...

  5. An Optimal Foraging Approach to Information Seeking and Use.

    ERIC Educational Resources Information Center

    Sandstrom, Pamela Effrein

    1994-01-01

    Explores optimal foraging theory, derived from evolutionary ecology, for its potential to clarify and operationalize studies of scholarly communication. Metaphorical parallels between subsistence foragers and scholarly information seekers are drawn. Hypotheses to test the models are recommended. The place of ethnographic and bibliometric…

  6. Testing Dispersal Hypotheses in Foraging Green Sea Turtles (Chelonia

    E-print Network

    DeSalle, Rob

    Testing Dispersal Hypotheses in Foraging Green Sea Turtles (Chelonia mydas) of Brazil EUGENIA NARO@amnh.org. Abstract Testing theories of dispersal is challenging in highly migratory species. In sea turtles. Little is known, however, about these mechanisms in sea turtles foraging along the South American coast

  7. EPICURE: Spatial and Knowledge Limitations in Group Foraging

    E-print Network

    Goldstone, Robert

    foraging for aphids (Kareiva & Odell, 1987), and guppies choosing mates (Dugatkin, 1992). Mean- while information · undermatching 1 Introduction Animals often forage for resources and even mates in groups acquire social sampling information and learn new strategies in order to improve food intake and mate

  8. Polybia wasp biting interactions recruit foragers following experimental worker removals

    E-print Network

    O'Donnell, Sean

    'DONNELL Animal Behavior Program, University of Washington (Received 12 May 2005; initial acceptance 14 June 2005 experimental forager removals to test whether biting is a form of worker connectivity, inducing new recruits behavioural categories: nonforagers, individuals that stopped foraging after the manip- ulation, continuing

  9. Advances and Challenges in Breeding Forages with Improved Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly 50 years have passed since the initial efforts to select and breed forage grasses with increased digestibility at the Welsh Plant Breeding Station, Aberystwyth, Wales and the USDA-ARS, Tifton, Georgia. Early efforts to improve forage quality were viewed with extreme skepticism by many breede...

  10. Selection methods in forage breeding: a quantitative appraisal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage breeding can be extraordinarily complex because of the number of species, perenniality, mode of reproduction, mating system, and the genetic correlation for some traits evaluated in spaced plants vs. performance under cultivation. Aiming to compare eight forage breeding methods for direct sel...

  11. PATCH BURNING EFFECTS ON FORAGE UTILIZATION AND GRAZING DISTRIBUTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Post-fire forage growth is known to be a strong attractant for large herbivores. However, fire has generally been avoided as a grazing distribution tool for fear of localized over utilization of forage resources. Our objectives were to determine cattle grazing preference for burned sites relative ...

  12. MACROMINERAL CONCENTRATIONS OF GRAZED FORAGE FERTILIZED WITH BROILER LITTER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three farms in Northwest Arkansas and Northeast Oklahoma that utilized broiler litter for fertilizer were monitored for nutrient cycling from April 2000 to February 2001. Forage samples were taken monthly and analyzed for K, Ca, P, and Mg. Concentrations of these minerals in the forages were compa...

  13. Testing Optimal Foraging Theory Using Bird Predation on Goldenrod Galls

    ERIC Educational Resources Information Center

    Yahnke, Christopher J.

    2006-01-01

    All animals must make choices regarding what foods to eat, where to eat, and how much time to spend feeding. Optimal foraging theory explains these behaviors in terms of costs and benefits. This laboratory exercise focuses on optimal foraging theory by investigating the winter feeding behavior of birds on the goldenrod gall fly by comparing…

  14. DIGESTIBILITY AND FIBER OF A FORAGE BERMUDAGRASS CORE COLLECTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bermudagrass is the most important warm-season grass forage for the South. Cultivars with good quality traits such as high dry matter digestibility have translated into higher daily gains for beef and improved milk production in dairy cattle. A forage bermudagrass core collection consisting of 168...

  15. A Hybrid, Multi-Agent Model of Foraging Bottlenose Dolphins

    E-print Network

    Egerstedt, Magnus

    , and unmanned underwater vehicles. We draw inspiration from the foraging techniques of bottlenose dolphins of the entire foraging method - search, detect, and capture - where agents are modeled as first-order systems confine the movement of another group of robots (active rather than passive objects) and move them

  16. Spatial adaptations for plant foraging: women excel and calories count

    E-print Network

    Cosmides, Leda

    that the universal sexual division of foraging labour among described hunter­gatherers (Murdock 1967) characterized and other traditionally gatherable sessile food resources. In spite of extensive evidence for a male with the theory that a sexual division in ancestral foraging labour selected for gathering-specific spatial

  17. Group foraging by a stream minnow: shoals or aggregations?

    USGS Publications Warehouse

    Freeman, Mary C.; Grossman, G.D.

    1992-01-01

    The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

  18. Animal Foraging and the Evolution of Goal-Directed Cognition

    ERIC Educational Resources Information Center

    Hills, Thomas T.

    2006-01-01

    Foraging-and feeding-related behaviors across eumetazoans share similar molecular mechanisms, suggesting the early evolution of an optimal foraging behavior called area-restricted search (ARS), involving mechanisms of dopamine and glutamate in the modulation of behavioral focus. Similar mechanisms in the vertebrate basal ganglia control motor…

  19. FUZZY MODEL OF BIRD FLOCK FORAGING Miha Moskon1

    E-print Network

    Bajec, Iztok Lebar

    FUZZY MODEL OF BIRD FLOCK FORAGING BEHAVIOR Miha Moskon1 , Frank H. Heppner2 , Miha Mraz1 , Nikolaj for the simulation of bird foraging behavior. The core of the model is based on the fuzzy model for the computer simulation of bird flocking presented by Lebar Bajec et al. The later was extended in such way that allows

  20. Marker assisted selection in forage breeding: a broadened vision

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage breeding programs do not yet widely use molecular markers. Reasons include meager breeding program resources and mass selection’s ease and cost competitive nature (despite its extreme inefficiency). Most traditional forage breeding methods are based on 'Delta'G = kh'sigma-sub-A' (i.e., select...

  1. Two Foraging Algorithms for Robot Swarms Using Only Local Communication

    E-print Network

    Napp, Nils

    to build algorithms for robot swarms. Ant colony foraging is our primary example. Ants use pheromones1 Two Foraging Algorithms for Robot Swarms Using Only Local Communication Nicholas R. Hoff III, Amelia Sagoff, Robert J. Wood, Radhika Nagpal Abstract-- Large collections of robots have the potential

  2. LIVESTOCK FORAGE CONDITIONING AMONG 6 NORTHERN GREAT BASIN GRASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of Anderson and Scherzinger’s 1975 forage conditioning hypothesis have exhibited varied results. Our objectives were: 1) to evaluate late summer/early fall forage quality of crested wheatgrass (Agropyron desertorum (Fischer ex Link) Schultes), bluebunch wheatgrass (Agropyron spicatum [Pursh...

  3. QUALITY OF STOCKPILED EASTERN GAMAGRASS FORAGE AT TWO SOUTHEAST LOCATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate forage quantity and quality, especially during the cool-season, are limiting factors to cattle production in the southeastern United States. Eastern gamagrass (Tripsacum dactyloides L.) is being considered as a forage with potential to overcome some of these concerns. A two-year study to d...

  4. Introduction Forager honeybees (Apis mellifera) perform complex and

    E-print Network

    Menzel, Randolf - Institut für Biologie

    421 Introduction Forager honeybees (Apis mellifera) perform complex and highly controlled motor controlling dancing displays. Most importantly, although honeybees do not directly compare alternative sources of labour, in addition, is a common feature in honeybees. Upon returning to the nest, successful foragers

  5. Positional Communication and Private Information in Honeybee Foraging Models

    E-print Network

    Napp, Nils

    Positional Communication and Private Information in Honeybee Foraging Models Peter Bailis1.werfel@wyss.harvard.edu Abstract. Honeybees coordinate foraging efforts across vast areas through a complex system of advertising-quality food sources and oversubscribing them. 1 Introduction Honeybee colonies are well

  6. ANIMAL RESPONSES TO CIRCADIAN RHYTHMS IN FORAGE QUALITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Net photosynthesis and respiration in growing plants cause a circadian rhythm in forage quality. Soluble sugar concentrations increase in plants during the day causing a dilution in ADF and NDF. Herbivores show a strong preference for afternoon (PM) vs morning (AM) harvested forage. Cattle, sheep, g...

  7. Estimating the energetic cost of abiotic conditions using foraging behaviour

    E-print Network

    Dill, Lawrence M.

    ) in habitats that differed in either temperature or salinity. Results: The cost for saltwater-preferring fish in saltwater. The cost of foraging in freshwater was positively correlated with osmoregulatory enzyme activity among saltwater- preferring fish but, surprisingly, the cost of foraging in saltwater was not correlated

  8. Introduction King penguins perform extended foraging dive bouts, with

    E-print Network

    Fahlman, Andreas

    3344 Introduction King penguins perform extended foraging dive bouts, with long (5·min) and deep aerobically (Froget et al., 2004). In the king penguin, a surface interval exceeding 15·min has been is why do king penguins stop foraging, sometimes for hours, during a period when food may be readily

  9. Genetics of postweaning performance of beef cattle on forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increases in the costs of feed grains have revived interest in increasing the use of forages and grazing in order to either market as forage-finished beef or to produce heavy calves that will finish on less grain. However, little is known about the interactions of animal genetics and grazing enviro...

  10. Effect of wheat forage maturity and preservation method on forage chemical composition and performance of growing calves fed mixed diets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three 2.4-ha wheat (Triticum aestivum L) fields were used to test the effects of maturity at harvest (boot vs dough) and preservation method (hay vs silage) on forage yield, chemical composition, and animal performance when fed in mixed diets. Forages were incorporated into 4 diets in a 2 x 2 factor...

  11. EFFECTS OF FORAGE SPECIES ON FATTY ACID COMPOSITION OF BEEF LONGISSIMUS MUSCLE FROM FORAGE-FINISHED BEEF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forty-seven Angus-crossbred steers were used to evaluate the effects of forage species grazed in the last 41 d of the finishing period on rib composition, color, and palatability in forage-finished beef and compared to traditional high concentrate finished. Steers grazed naturalized pastures (bluegr...

  12. Trapline foraging by bumble bees: IV. Optimization of route geometry in the

    E-print Network

    Thomson, James D.

    Trapline foraging by bumble bees: IV. Optimization of route geometry in the absence of competition flower visitors such as bees do to optimize their foraging routes, that is, reduce return time or route-called ``trapline foraging''), which may also enhance their foraging efficiency. A moderate level of optimization

  13. Knowledge of Resources and Competitors in Human Foraging Robert L. Goldstone

    E-print Network

    Goldstone, Robert

    . Undermatching and Overmatching Although the assumption of optimal foraging in groups has enjoyed some striking of foragers to variations in the resource distribution, and b is a bias parameter. Optimal #12;Human ForagingKnowledge of Resources and Competitors in Human Foraging Robert L. Goldstone Benjamin C. Ashpole

  14. Optimization of Foraging Multi-Agent System Front: A Flux-Based Curve Evolution Method

    E-print Network

    Egerstedt, Magnus

    Optimization of Foraging Multi-Agent System Front: A Flux-Based Curve Evolution Method Musad Haque, Amir Rahmani, Magnus Egerstedt, and Anthony Yezzi Abstract-- Numerous social foragers form a foraging for a foraging multi-robot system. The presented flux-based algorithm has the desired property of generating more

  15. Effect of surfaces on the foraging efficiency of Solenopsis invicta (Hymenoptera: Formicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of different surfaces on the foraging efficiency of Solenopsis invicta workers were observed. The results indicated that the foragers of S. invicta were more efficient when they foraged on hard and smooth plastic surfaces than on soil surfaces. Similarly, foragers of S. invicta were less...

  16. Winter foraging behavior of elk in the shrub-steppe of Washington

    SciTech Connect

    McCorquodale, S.M. )

    1993-01-01

    Numerous models of ungulate foraging behavior have been published, but data on foraging behavior for wild North American ungulates relevant to model testing are scarce. I studied the detailed foraging behavior of elk from autumn through early spring in Washington's shrub-steppe using focal animal sampling and collected corollary data on elk diets, forage quality, and home ranges. I tested the hypotheses that foraging effort is proportional to energetic payoffs determined by the quality and abundance of various forages, and elk home-range size reflects relative foraging movements (i.e., macro and micro movements are related). Elk were mobile foragers during autumn and spring and were relatively sedentary during mid-winter. High mobility was associated with low diet diversity and generally with reduced forage harvesting rates. This mobile foraging occurred during periods of higher quality forage availability. Thus, mobile foraging appeared to reflect increased effort when energetic payoffs of selective foraging were enhanced. Degree of dietary specialization was limited by the relative abundance of preferred forages, being greater when grass quality was high, and less when forb quality was high. Indices of elk movement while foraging were also positively related to home-range size and distance between relocations of radio-collared elk. These data are generally consistent with ungulate foraging model predictions. 34 refs., 4 figs., 2 tabs.

  17. Silvopastures Some `whats' and `whys' John Fike for Progressive Forage Grower

    E-print Network

    Virginia Tech

    in these dynamics. Temperature Although trees may reduce available light to the forage canopy, there can be positive trade-offs. Forages under trees often green up sooner in spring because of the buffering effects trees have on the forage microclimate. Trees also can have energy-sparing effects on forages; cooling from

  18. Simulation of sandsage-bluestem forage growth under varying stocking rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of stocking rate on forage growth has attracted a great deal of research attention in forage science. Findings show that forage growth may be affected by stocking rate and there is the consensus that high stocking rates lead to soil compaction, which could also in turn affect forage growt...

  19. Differential Root Morphology Response to No versus High Phosphorus, in Three Hydroponically Grown Forage Chicory Cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage chicory is a productive forage resource for eastern North America; however, many soils in the region are acidic and deficient in P and might restrict the widespread use of forage chicory. There is no published information on response of forage chicory to P, or P acquisition strategies for mo...

  20. Differential root morphology response to no versus high phosphorus, in three hydroponically grown forage chicory cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage chicory is a productive forage resource for eastern North America; however, many soils in the region are acidic and deficient in P and might restrict the widespread use of forage chicory. There is no published information on response of forage chicory to P, or P acquisition strategies for mo...

  1. Optimal foraging by birds: feeder-based experiments for secondary and post-secondary students

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optimal foraging theory attempts to explain the foraging patterns observed in animals, including their choice of particular food items and foraging locations. Here, we describe three exercises designed to test hypotheses about food choice and foraging habitat preference using bird feeders. These e...

  2. Production and transcriptional regulation of proanthocyanidin biosynthesis in forage legumes.

    PubMed

    Zhou, Meiliang; Wei, Li; Sun, Zhanmin; Gao, Lihua; Meng, Yu; Tang, Yixiong; Wu, Yanmin

    2015-05-01

    Proanthocyanidins (PA), also known as condensed tannins, contribute to important forage legumes traits including disease resistance and forage quality. PA in forage plants has both positive and negative effects on feed digestibility and animal performance. The analytical methods and their applicability in measuring the contents of PA in forage plants are essential to studies on their nutritional effects. In spite of important breakthroughs in our understanding of the PA biosynthesis, important questions still remain to be answered such as the PA polymerization and transport. Recent advances in the understanding of transcription factor-mediated gene regulation mechanisms in anthocyanin and PA biosynthetic pathway in model plants suggest new approaches for the metabolic engineering of PA in forage plants. The present review will attempt to present the state-of-the-art of research in these areas and provide an update on the production and metabolic engineering of PA in forage plants. We hope that this will contribute to a better understanding of the ways in which PA production to manipulate the content of PA for beneficial effects in forage plants. PMID:25805345

  3. Personality, foraging and fitness consequences in a long lived seabird.

    PubMed

    Patrick, Samantha C; Weimerskirch, Henri

    2014-01-01

    While personality differences in animals are defined as consistent behavioural variation between individuals, the widely studied field of foraging specialisation in marine vertebrates has rarely been addressed within this framework. However there is much overlap between the two fields, both aiming to measure the causes and consequences of consistent individual behaviour. Here for the first time we use both a classic measure of personality, the response to a novel object, and an estimate of foraging strategy, derived from GPS data, to examine individual personality differences in black browed albatross and their consequences for fitness. First, we examine the repeatability of personality scores and link these to variation in foraging habitat. Bolder individuals forage nearer the colony, in shallower regions, whereas shyer birds travel further from the colony, and fed in deeper oceanic waters. Interestingly, neither personality score predicted a bird's overlap with fisheries. Second, we show that both personality scores are correlated with fitness consequences, dependent on sex and year quality. Our data suggest that shyer males and bolder females have higher fitness, but the strength of this relationship depends on year quality. Females who forage further from the colony have higher breeding success in poor quality years, whereas males foraging close to the colony always have higher fitness. Together these results highlight the potential importance of personality variation in seabirds and that the fitness consequences of boldness and foraging strategy may be highly sex dependent. PMID:24504180

  4. Chronic toxicity of un-ionized ammonia to early life-stages of endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) compared to the surrogate fathead minnow (Pimephales promelas)

    USGS Publications Warehouse

    Fairchild, J.F.; Allert, A.L.; Sappington, L.C.; Waddell, B.

    2005-01-01

    Ammonia-contaminated groundwater enters the Upper Colorado River from beneath the abandoned Moab Uranium Mill Tailings Pile near Moab, Utah. This reach of the Upper Colorado River was designated as critical habitat for four endangered fish species because it is one of the few existing areas with known spawning and rearing habitats. Un-ionized ammonia (NH3) concentrations frequently exceed 1.00 mg/L in backwaters adjacent to the tailings pile, which exceeds the Utah 30-d average chronic water quality criterion for un-ionized ammonia (0.07 mg/L NH3; temperature 20??C; pH 8.2) by a factor of more than 10. However, there is little published information regarding the sensitivity of endangered fishes to ammonia. We conducted 28-d static renewal studies with post-swim-up larvae to determine the relative sensitivity of Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), and the standard surrogate fathead minnow (Pimephales promelas) to NH3. Chronic values (ChVs) for mortality and growth were determined as the geometric mean of the no observed effect concentration and the lowest observed effect concentration based on analysis of variance. The ChVs for growth of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.40, and 0.67 mg/L NH3, respectively. The ChVs for mortality of fathead minnow, Colorado pikeminnow, and razorback sucker were 0.43, 0.70, and 0.67 mg/L NH3, respectively. Therefore, the ChVs for mortality and growth were similar for fathead minnow and razorback sucker; however, the ChV for growth was lower than the ChV for mortality for Colorado pikeminnow. Maximum likelihood regression was used to calculate 28-d lethal concentrations (LCx) for each species. The 28-d LC50, LC20, and LC1 values for fathead minnow were 0.69, 0.42, and 0.13 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for Colorado pikeminnow were 0.76, 0.61, and 0.38 mg/L NH3, respectively. The 28-d LC50, LC20, and LC1 values for razorback sucker were 0.54, 0.38, and 0.25 mg/L NH3, respectively. The fathead minnow, Colorado pikeminnow, and razorback sucker are relatively similar in sensitivity and rank at the 35th, 49th, and 31st percentiles, respectively, of the theoretical chronic fish sensitivity distributions for NH3. The existing water quality criteria for NH3, if met by remediation activities at the Moab site, would be protective of these endangered fishes even if fish sensitivity is based on the conservative LC1 value. ?? 2005 Springer Science+Business Media, Inc.

  5. Energetic cost of foraging in free-diving emperor penguins.

    PubMed

    Nagy, K A; Kooyman, G L; Ponganis, P J

    2001-01-01

    Hypothesizing that emperor penguins (Aptenodytes forsteri) would have higher daily energy expenditures when foraging for their food than when being hand-fed and that the increased expenditure could represent their foraging cost, we measured field metabolic rates (FMR; using doubly labeled water) over 4-d periods when 10 penguins either foraged under sea ice or were not allowed to dive but were fed fish by hand. Surprisingly, penguins did not have higher rates of energy expenditure when they dove and captured their own food than when they did not forage but were given food. Analysis of time-activity and energy budgets indicated that FMR was about 1.7 x BMR (basal metabolic rate) during the 12 h d(-1) that penguins were lying on sea ice. During the remaining 12 h d(-1), which we termed their "foraging period" of the day, the birds were alert and active (standing, preening, walking, and either free diving or being hand-fed), and their FMR was about 4.1 x BMR. This is the lowest cost of foraging estimated to date among the eight penguin species studied. The calculated aerobic diving limit (ADL(C)), determined with the foraging period metabolic rate of 4.1 x BMR and known O(2) stores, was only 2.6 min, which is far less than the 6-min ADL previously measured with postdive lactate analyses in emperors diving under similar conditions. This indicates that calculating ADL(C) from an at-sea or foraging-period metabolic rate in penguins is not appropriate. The relatively low foraging cost for emperor penguins contributes to their relatively low total daily FMR (2.9 x BMR). The allometric relationship for FMR in eight penguin species, including the smallest and largest living representatives, is kJ d(-1)=1,185 kg(0.705). PMID:11436138

  6. Individual Foraging Strategies Reveal Niche Overlap between Endangered Galapagos Pinnipeds

    PubMed Central

    Villegas-Amtmann, Stella; Jeglinski, Jana W. E.; Costa, Daniel P.; Robinson, Patrick W.; Trillmich, Fritz

    2013-01-01

    Most competition studies between species are conducted from a population-level approach. Few studies have examined inter-specific competition in conjunction with intra-specific competition, with an individual-based approach. To our knowledge, none has been conducted on marine top predators. Sympatric Galapagos fur seals (Arctocephalus galapagoensis) and sea lions (Zalophus wollebaeki) share similar geographic habitats and potentially compete. We studied their foraging niche overlap at Cabo Douglas, Fernandina Island from simultaneously collected dive and movement data to examine spatial and temporal inter- and intra-specific competition. Sea lions exhibited 3 foraging strategies (shallow, intermediate and deep) indicating intra-specific competition. Fur seals exhibited one foraging strategy, diving predominantly at night, between 0–80 m depth and mostly at 19–22 h. Most sea lion dives also occurred at night (63%), between 0–40 m, within fur seals' diving depth range. 34% of sea lions night dives occurred at 19–22 h, when fur seals dived the most, but most of them occurred at dawn and dusk, when fur seals exhibited the least amount of dives. Fur seals and sea lions foraging behavior overlapped at 19 and 21 h between 0–30 m depths. Sea lions from the deep diving strategy exhibited the greatest foraging overlap with fur seals, in time (19 h), depth during overlapping time (21–24 m), and foraging range (37.7%). Fur seals foraging range was larger. Cabo Douglas northwest coastal area, region of highest diving density, is a foraging “hot spot” for both species. Fur seals and sea lions foraging niche overlap occurred, but segregation also occurred; fur seals primarily dived at night, while sea lions exhibited night and day diving. Both species exploited depths and areas exclusive to their species. Niche breadth generally increases with environmental uncertainty and decreased productivity. Potential competition between these species could be greater during warmer periods when prey availability is reduced. PMID:23967096

  7. A neural coding scheme reproducing foraging trajectories

    PubMed Central

    Gutiérrez, Esther D.; Cabrera, Juan Luis

    2015-01-01

    The movement of many animals may follow Lévy patterns. The underlying generating neuronal dynamics of such a behavior is unknown. In this paper we show that a novel discovery of multifractality in winnerless competition (WLC) systems reveals a potential encoding mechanism that is translatable into two dimensional superdiffusive Lévy movements. The validity of our approach is tested on a conductance based neuronal model showing WLC and through the extraction of Lévy flights inducing fractals from recordings of rat hippocampus during open field foraging. Further insights are gained analyzing mice motor cortex neurons and non motor cell signals. The proposed mechanism provides a plausible explanation for the neuro-dynamical fundamentals of spatial searching patterns observed in animals (including humans) and illustrates an until now unknown way to encode information in neuronal temporal series. PMID:26648311

  8. Space use by foragers consuming renewable resources

    NASA Astrophysics Data System (ADS)

    Abramson, Guillermo; Kuperman, Marcelo N.; Morales, Juan M.; Miller, Joel C.

    2014-05-01

    We study a simple model of a forager as a walk that modifies a relaxing substrate. Within it simplicity, this provides an insight on a number of relevant and non-intuitive facts. Even without memory of the good places to feed and no explicit cost of moving, we observe the emergence of a finite home range. We characterize the walks and the use of resources in several statistical ways, involving the behavior of the average used fraction of the system, the length of the cycles followed by the walkers, and the frequency of visits to plants. Preliminary results on population effects are explored by means of a system of two non directly interacting animals. Properties of the overlap of home ranges show the existence of a set of parameters that provides the best utilization of the shared resource.

  9. A neural coding scheme reproducing foraging trajectories.

    PubMed

    Gutiérrez, Esther D; Cabrera, Juan Luis

    2015-01-01

    The movement of many animals may follow Lévy patterns. The underlying generating neuronal dynamics of such a behavior is unknown. In this paper we show that a novel discovery of multifractality in winnerless competition (WLC) systems reveals a potential encoding mechanism that is translatable into two dimensional superdiffusive Lévy movements. The validity of our approach is tested on a conductance based neuronal model showing WLC and through the extraction of Lévy flights inducing fractals from recordings of rat hippocampus during open field foraging. Further insights are gained analyzing mice motor cortex neurons and non motor cell signals. The proposed mechanism provides a plausible explanation for the neuro-dynamical fundamentals of spatial searching patterns observed in animals (including humans) and illustrates an until now unknown way to encode information in neuronal temporal series. PMID:26648311

  10. The Organization of Foraging in the Fire Ant, Solenopsis invicta

    PubMed Central

    Tschinkel, Walter R.

    2011-01-01

    Although natural selection in ants acts most strongly at the colony, or superorganismal level, foraging patterns have rarely been studied at that level, focusing instead on the behavior of individual foragers or groups of foragers. The experiments and observations in this paper reveal in broad strokes how colonies of the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), allocate their available labor to foraging, how they disperse that force within their territory, and how this force changes with colony size, season and worker age. Territory area is positively related to colony size and the number of foragers, more so during the spring than fall. Changes of colony size and territory area are driven by seasonal variation of sexual and worker production, which in turn drive seasonal variation of worker age-distribution. During spring sexual production, colonies shrink because worker production falls below replacement. This loss is proportional to colony size, causing forager density in the spring to be negatively related to colony and territory size. In the fall, colonies emphasize worker production, bringing colony size back up. However, because smaller colonies curtailed spring worker production less than larger ones, their fall forager populations are proportionally greater, causing them to gain territory at the expense of large colonies. Much variation of territory area remains unexplained and can probably be attributed to pressure from neighboring colonies. Boundaries between territories are characterized by “no ants' zones” mostly devoid of fire ants. The forager population can be divided into a younger group of recruitable workers that wait for scouts to activate them to help retrieve large food finds. About one-third of the recruits wait near openings in the foraging tunnels that underlie the entire territory, while two-thirds wait in the nest. Recruitment to food is initially very rapid and local from the foraging tunnels, while sustained recruitment gradually involves the recruits waiting in the nest. As recruits age, they become scouts searching for food on the surface, and die about two weeks later. Foraging tunnels decrease in cross-sectional area with distance from the nest, in keeping with the gradual bleeding off of workers to the surface with distance. Foragers lack route-faithfulness, and having been marked and released at one point within the territory, they can be recaptured at any other point a day later. The size of the territory actually occupied may be limited during dry weather, resulting in very large no-ants' zones. PMID:21529150

  11. Managing forage and grazing lands for multiple ecosystem services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage and grazing land systems are increasingly expected to provide services beyond food, feed, and fiber. The concept of multifunctionality in grassland agriculture recognizes ecosystem services beyond these traditional functions to include emerging services such as carbon sequestration, greenhous...

  12. Movements of foraging king penguins through marine mesoscale eddies

    PubMed Central

    Cotté, Cédric; Park, Young-Hyang; Guinet, Christophe; Bost, Charles-André

    2007-01-01

    Despite increasing evidence that marine predators associate with mesoscale eddies, how these marine features influence foraging movements is still unclear. This study investigates the relationship of at-sea movements of king penguins to mesoscale eddies using oceanographic remote sensing and movement data from 43 individual trips over 4 years. Simultaneous satellite measurements provided information on gradients of sea surface temperature and currents associated with eddies determined from altimetry. Penguins tended to swim rapidly with currents as they travelled towards foraging zones. Swimming speed indicative of foraging occurred within mesoscale fronts and strong currents associated with eddies at the Polar Front. These results demonstrate the importance of mesoscale eddies in directing foraging efforts to allow predators to rapidly get to rich areas where high concentrations of prey are likely to be encountered. When returning to the colony to relieve the incubating partner or to feed the chick, the birds followed a direct and rapid path, seemingly ignoring currents. PMID:17669726

  13. Foraging Behavior of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The foraging behavior of two serious structural pests, the Formosan subterranean termite, Coptotermes formosanus Shiraki and the eastern subterranean termite, Reticulitermes flavipes (Kollar) was examined. Comparative laboratory studies of the trail following, feeding, tunneling behavior, and intera...

  14. Specialist Osmia Bees Forage Indiscriminately Among Hybridizing Balsamorhiza Floral Hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Even generalist pollinators are typically taxonomic specialists during individual foraging bouts. Such floral constancy restricts pollen flow, and thereby gene flow, between otherwise inter-fertile flowering species, thus serving as an ethological mating barrier. Among incipient species, however, ...

  15. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Harvest. Severance of the forage plant from its roots. Acreage that is only grazed will...Normal stand —A population of live plants per square foot that meets the minimum required number of plants as shown in the Special...

  16. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Harvest. Severance of the forage plant from its roots. Acreage that is only grazed will...Normal stand . A population of live plants per square foot that meets the minimum required number of plants as shown in the Special...

  17. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Harvest. Severance of the forage plant from its roots. Acreage that is only grazed will...Normal stand . A population of live plants per square foot that meets the minimum required number of plants as shown in the Special...

  18. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Harvest. Severance of the forage plant from its roots. Acreage that is only grazed will...Normal stand —A population of live plants per square foot that meets the minimum required number of plants as shown in the Special...

  19. DYNAPHORE, INC., FORAGER SPONGE TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    The Forager Sponge is a volume reduction technology in which heavy metal contaminants from an aqueous medium are selectively concentrated into a smaller volume for facilitated disposal. he technology treats contaminated groundwater, surface voters and porous waters by absorbing d...

  20. SITE TECHNOLOGY CAPSULE: DYNAPHORE, INC., FORAGER SPONGE TECHNOLOGY

    EPA Science Inventory

    The Forager Sponge is a volume reduction technology in which heavy metal contaminants from an aqueous medium are selectively concentrated into a smaller volume for facilitated disposal. he technology treats contaminated groundwater, surface waters and porous waters by absorbing d...

  1. Simple cellular automata to mimic foraging ants submitted to abduction

    E-print Network

    Tejera, F

    2015-01-01

    Many species of ants forage by building up two files: an outbound one moving from the nest to the foraging area, and a nestbound one, returning from it to the nest. Those files are eventually submitted to different threats. If the danger is concentrated at one point of the file, one might expect that ants returning to the nest will pass danger information to their nestmates moving in the opposite direction towards the danger area. In this paper, we construct simple cellular automata models for foraging ants submitted to localized abduction, were danger information is transmitted using different protocols, including the possibility of no transmission. The parameters we have used in the simulations have been estimated from actual experiments under natural conditions. So, it would be easy to test our information-transmission hypothese in real experiments. Preliminary experimental results published elsewhere suggest that the behavior of foraging ants of the species Atta insularis is best described using the hypot...

  2. SITE TECHNOLOGY CAPSULE: DYNAPHORE, INC., FORAGER? SPONGE TECHNOLOGY

    EPA Science Inventory

    The Forager? Sponge is a volume reduction technology in which heavy metal contaminants from an aqueous medium are selectively concentrated into a smaller volume for facilitated disposal. The technology treats contaminated groundwater, surface waters, and process waters by absorbi...

  3. Learning, odour preference and flower foraging in moths 

    E-print Network

    Cunningham, John P; Moore, Chris J; Zalucki, Myron P; West, Stuart A

    2003-01-01

    Floral volatiles play a major role in plant–insect communication. We examined the influence of two volatiles, phenylacetaldehyde and a-pinene, on the innate and learnt foraging behaviour of the moth Helicoverpa armigera. ...

  4. ENVIRONMENTAL IMPACTS ON SESQUITERPENE LACTONE COMPOSITION OF FORAGE CHICORY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage chicory (Cichorium intybus L.) cultivars grown in different locations in the northeast have vastly different sesquiterpene lactone compositions. Investigations were conducted to identify specific environmental parameters that influence herbage sesquiterpene lactone concentration. Results i...

  5. Red Knots Forage for Horseshoe Crab Eggs at Delaware Bay

    USGS Multimedia Gallery

    Red knots forage for horseshoe crab eggs and other invertebrates on the beaches of Delaware Bay. The bird in the center has an orange leg flag indicating it was captured and flagged in the past in Argentina....

  6. Adélie Penguin Foraging Location Predicted by Tidal Regime Switching

    PubMed Central

    Oliver, Matthew J.; Irwin, Andrew; Moline, Mark A.; Fraser, William; Patterson, Donna; Schofield, Oscar; Kohut, Josh

    2013-01-01

    Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator. PMID:23383091

  7. Quantifying rhizosphere respiration for two cool-season perennial forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the regulation of ecosystem carbon dioxide flux from forage production systems requires knowledge of component fluxes, including photosynthetic uptake and respiratory loss. Experimental separation of soil respiration into its heterotrophic (free-living soil organisms) and rhizosphere c...

  8. Do naive juvenile seabirds forage differently from adults?

    PubMed Central

    Riotte-Lambert, Louise; Weimerskirch, Henri

    2013-01-01

    Foraging skills of young individuals are assumed to be inferior to those of adults. The reduced efficiency of naive individuals may be the primary cause of the high juvenile mortality and explain the deferment of maturity in long-lived species. However, the study of juvenile and immature foraging behaviour has been limited so far. We used satellite telemetry to compare the foraging movements of juveniles, immatures and breeding adult wandering albatrosses Diomedea exulans, a species where foraging success is positively influenced by the distance covered daily. We showed that juveniles are able to use favourable winds as soon as the first month of independence, but cover shorter distances daily and spend more time sitting on water than adults during the first two months after fledging. These reduced movement capacities do not seem to be the cause of higher juvenile mortality. Moreover, juveniles almost never restrict their movement to specific areas, as adults and immatures frequently do over shelf edges or oceanic zones, which suggest that the location of appropriate areas is learned through experience. Immatures and adults have equivalent movement capacities, but when they are central place foragers, i.e. when adults breed or immatures come to the colony to display and pair, immatures make shorter trips than adults. The long duration of immaturity in this species seems to be related to a long period of learning to integrate the foraging constraints associated with reproduction and central place foraging. Our results indicate that foraging behaviour of young albatrosses is partly innate and partly learned progressively over immaturity. The first months of learning appear critical in terms of survival, whereas the long period of immaturity is necessary for young birds to attain the skills necessary for efficient breeding without fitness costs. PMID:23926153

  9. The Forager Oral Tradition and the Evolution of Prolonged Juvenility

    PubMed Central

    Scalise Sugiyama, Michelle

    2011-01-01

    The foraging niche is characterized by the exploitation of nutrient-rich resources using complex extraction techniques that take a long time to acquire. This costly period of development is supported by intensive parental investment. Although human life history theory tends to characterize this investment in terms of food and care, ethnographic research on foraging skill transmission suggests that the flow of resources from old-to-young also includes knowledge. Given the adaptive value of information, parents may have been under selection pressure to invest knowledge – e.g., warnings, advice – in children: proactive provisioning of reliable information would have increased offspring survival rates and, hence, parental fitness. One way that foragers acquire subsistence knowledge is through symbolic communication, including narrative. Tellingly, oral traditions are characterized by an old-to-young transmission pattern, which suggests that, in forager groups, storytelling might be an important means by which adults transfer knowledge to juveniles. In particular, by providing juveniles with vicarious experience, storytelling may expand episodic memory, which is believed to be integral to the generation of possible future scenarios (i.e., planning). In support of this hypothesis, this essay reviews evidence that: mastery of foraging knowledge and skill sets takes a long time to acquire; foraging knowledge is transmitted from parent to child; the human mind contains adaptations specific to social learning; full assembly of learning mechanisms is not complete in early childhood; and forager oral traditions contain a wide range of information integral to occupation of the foraging niche. It concludes with suggestions for tests of the proposed hypothesis. PMID:21897825

  10. Do naive juvenile seabirds forage differently from adults?

    PubMed

    Riotte-Lambert, Louise; Weimerskirch, Henri

    2013-10-01

    Foraging skills of young individuals are assumed to be inferior to those of adults. The reduced efficiency of naive individuals may be the primary cause of the high juvenile mortality and explain the deferment of maturity in long-lived species. However, the study of juvenile and immature foraging behaviour has been limited so far. We used satellite telemetry to compare the foraging movements of juveniles, immatures and breeding adult wandering albatrosses Diomedea exulans, a species where foraging success is positively influenced by the distance covered daily. We showed that juveniles are able to use favourable winds as soon as the first month of independence, but cover shorter distances daily and spend more time sitting on water than adults during the first two months after fledging. These reduced movement capacities do not seem to be the cause of higher juvenile mortality. Moreover, juveniles almost never restrict their movement to specific areas, as adults and immatures frequently do over shelf edges or oceanic zones, which suggest that the location of appropriate areas is learned through experience. Immatures and adults have equivalent movement capacities, but when they are central place foragers, i.e. when adults breed or immatures come to the colony to display and pair, immatures make shorter trips than adults. The long duration of immaturity in this species seems to be related to a long period of learning to integrate the foraging constraints associated with reproduction and central place foraging. Our results indicate that foraging behaviour of young albatrosses is partly innate and partly learned progressively over immaturity. The first months of learning appear critical in terms of survival, whereas the long period of immaturity is necessary for young birds to attain the skills necessary for efficient breeding without fitness costs. PMID:23926153

  11. Information Foraging in Nuclear Power Plant Control Rooms

    SciTech Connect

    R.L. Boring

    2011-09-01

    nformation foraging theory articulates the role of the human as an 'informavore' that seeks information and follows optimal foraging strategies (i.e., the 'information scent') to find meaningful information. This paper briefly reviews the findings from information foraging theory outside the nuclear domain and then discusses the types of information foraging strategies operators employ for normal and off-normal operations in the control room. For example, operators may employ a predatory 'wolf' strategy of hunting for information in the face of a plant upset. However, during routine operations, the operators may employ a trapping 'spider' strategy of waiting for relevant indicators to appear. This delineation corresponds to information pull and push strategies, respectively. No studies have been conducted to determine explicitly the characteristics of a control room interface that is optimized for both push and pull information foraging strategies, nor has there been empirical work to validate operator performance when transitioning between push and pull strategies. This paper explores examples of control room operators as wolves vs. spiders and con- cludes by proposing a set of research questions to investigate information foraging in control room settings.

  12. Foraging decisions, patch use, and seasonality in egrets (Aves: ciconiiformes)

    USGS Publications Warehouse

    Erwin, R.M.

    1985-01-01

    Feeding snowy (Egretta thula) and great (Casmerodius albus) egrets were observed during 2 breeding seasons in coastal New Jersey and 2 brief winter periods in northeast Florida (USA). A number of tests based on assumptions of foraging models, predictions from foraging theory, and earlier empirical tests concerning time allocation and movement in foraging patches was made. Few of the expectations based on foraging theory and/or assumptions were supported by the empirical evidence. Snowy egrets fed with greater intensity and efficiency during the breeding season (when young were being fed) than during winter. They also showed some tendency to leave patches when their capture rate declined, and they spent more time foraging in patches when other birds were present nearby. Great egrets showed few of these tendencies, although they did leave patches when their intercapture intervals increased. Satiation differences had some influence on feeding rates in snowy egrets, but only at the end of feeding bouts. Some individuals of both species revisited areas in patches that had recently been exploited, and success rates were usually higher after the 2nd visit. Apparently, for predators of active prey, short-term changes in resource availability ('resource depression') may be more important than resource depletion, a common assumption in most optimal foraging theory models.

  13. Chaos-order transition in foraging behavior of ants.

    PubMed

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-06-10

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants' physical abilities, and ants' knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal. PMID:24912159

  14. Social Calls Predict Foraging Success in Big Brown Bats

    PubMed Central

    Wright, Genevieve Spanjer; Chiu, Chen; Xian, Wei; Wilkinson, Gerald S.; Moss, Cynthia F.

    2014-01-01

    Animals foraging in the dark are simultaneously engaged in prey pursuit, collision avoidance and interactions with conspecifics, making efficient, non-visual communication essential. A variety of birds and mammals emit food-associated calls that inform, attract, or repel conspecifics [e.g., 1]. Big brown bats (Eptesicus fuscus) are insectivorous aerial hawkers that may forage near conspecifics and are known to emit social calls [e.g., 2, 3, 4, 5]. Calls recorded in a foraging setting might attract [e.g., 6] or repel conspecifics [7] and could denote territoriality or food-claiming. Here, we provide evidence that a social call emitted only by male bats, exclusively in a foraging context [5], the “frequency-modulated bout” (FMB), is used to claim food and is individually distinct. Bats were studied individually and in pairs in a flight room equipped with synchronized high-speed stereo video and audio recording equipment, while sex and experience with a foraging task were experimentally manipulated. Male bats emitting the FMB showed greater success in capturing prey. Following FMB emission, inter-bat distance, diverging flight, and the other bat’s distance to the prey each increased. These findings highlight the importance and utility of vocal communication for a nocturnal animal mediating interactions with conspecifics in a fast-paced foraging setting. PMID:24684936

  15. Waggle Dance Distances as Integrative Indicators of Seasonal Foraging Challenges

    PubMed Central

    Couvillon, Margaret J.; Schürch, Roger; Ratnieks, Francis L. W.

    2014-01-01

    Even as demand for their services increases, honey bees (Apis mellifera) and other pollinating insects continue to decline in Europe and North America. Honey bees face many challenges, including an issue generally affecting wildlife: landscape changes have reduced flower-rich areas. One way to help is therefore to supplement with flowers, but when would this be most beneficial? We use the waggle dance, a unique behaviour in which a successful forager communicates to nestmates the location of visited flowers, to make a 2-year survey of food availability. We “eavesdropped” on 5097 dances to track seasonal changes in foraging, as indicated by the distance to which the bees as economic foragers will recruit, over a representative rural-urban landscape. In year 3, we determined nectar sugar concentration. We found that mean foraging distance/area significantly increase from springs (493 m, 0.8 km2) to summers (2156 m, 15.2 km2), even though nectar is not better quality, before decreasing in autumns (1275 m, 5.1 km2). As bees will not forage at long distances unnecessarily, this suggests summer is the most challenging season, with bees utilizing an area 22 and 6 times greater than spring or autumn. Our study demonstrates that dancing bees as indicators can provide information relevant to helping them, and, in particular, can show the months when additional forage would be most valuable. PMID:24695678

  16. Animation 1. Top view of data from a multibeam sonar observations of dolphin foraging. This animation is a composite of three observations overlapping in foraging

    E-print Network

    Benoit-Bird, Kelly J.

    1 Animation 1. Top view of data from a multibeam sonar observations of dolphin foraging of a complete foraging bout. Each frame is the composite of six successive sonar echoes, providing higher a multibeam sonar observation of a foraging dolphins. This animation is a composite of three observations

  17. Foraging proficiency during the nonbreeding season of a specialized forager: are juvenile American Oystercatchers "bumble-beaks" compared to adults?

    USGS Publications Warehouse

    Hand, Christine E.; Sanders, Felicia J.; Jodice, Patrick G.

    2010-01-01

    In many species, immature individuals are less proficient at foraging than are adults, and this difference may be especially critical during winter when survival can be at its minimum. We investigated the foraging proficiency of adult and immature American Oystercatchers (Haematopus palliatus) during the nonbreeding season. Oystercatchers forage on prey that must be handled with specialized skills, so age-related differences in foraging behavior may be expected. We found that adults spent more time searching than did immatures, a trend toward immatures taking longer to handle prey than did adults, and immatures more often handling prey unsuccessfully than did adults. Feeding rates and diet composition did not differ by age class. We posit that the immature birds traded off longer handling times with shorter searching times and that ultimately the abundant prey in the region may contribute to the ability of immature birds to feed at rates similar to those of adults.

  18. Performance and economic analyses of year-round forage systems for forage-fed beef production in the Gulf Coast.

    PubMed

    Scaglia, G; Rodriguez, J; Gillespie, J; Bhandari, B; Wang, J J; McMillin, K W

    2014-12-01

    On a global scale, most beef is produced from grazing pastures or rangelands. Certain limitations exist, however, such as not having adequate animal rates of gain for marbling and availability of adequate forage nutritional value and quantity for constant animal weight gains. In the last 20 yr, there has been an increased interest in forage-fed beef for multiple reasons (health related, environmental concerns, and welfare issues). Starting on June 5, 13, 14, and 8 in 4 consecutive yr, 54 steers (initial BW=259±5.6 kg; average of 9 mo of age) were randomly allotted to 3 yr-round forage systems. Each system occupied 6 ha/replicate and had the same stocking rate. System 1 had annual ryegrass (Lolium multiflorum) for winter grazing and bermudagrass (Cynodon dactylon) for summer grazing; while Systems 2 and 3 added rye and a clover mix to the ryegrass and diversified the use of pastures in the fall (dallisgrass [Paspalum dilatatum] and clovers [Trifolium spp.]). System 3 added the use of annual summer forages. During their respective growing season for each forage or forage mix, mass and height did not limit animal performance; however, there was a sampling date effect (P<0.05) for nutritive value variables since it decreased as forages became mature. The ADG observed (0.44 kg) for all systems (P=0.78) during summer was lower than expected and might have been limited by the observed temperature as well as forage nutritive value. Systems 1 and 2 had more grazing days (P=0.03) during summer (155 and 146 d, respectively) compared to System 3 (132 d) due to the greater pasture area of bermudagrass in those systems. Steers in System 3 were fed more hay for a longer period of time (P<0.05) than on the other 2 systems. System 1 and 2 produced more hay per hectare than System 3 (P<0.05). No differences (P>0.05) were detected between systems in ADG year round, during the winter season, or carcass characteristics. Return over total direct costs and total specified expenses were greater for Systems 1 and 2, while System 3 was the lowest. Hay making and bale sales played a major role in explaining the economic results of this study. Where possible, year-round forage systems are a viable alternative for forage-fed beef production; however, the low gains during summer and forage availability during the transition period when hay is necessary deserve further research to find alternatives to improve productivity during those times of the year. PMID:25367513

  19. Modality-specific attention in foraging bumblebees

    PubMed Central

    Nityananda, Vivek; Chittka, Lars

    2015-01-01

    Attentional demands can prevent humans and other animals from performing multiple tasks simultaneously. Some studies, however, show that tasks presented in different sensory modalities (e.g. visual and auditory) can be processed simultaneously. This suggests that, at least in these cases, attention might be modality-specific and divided differently between tasks when present in the same modality compared with different modalities. We investigated this possibility in bumblebees (Bombus terrestris) using a biologically relevant experimental set-up where they had to simultaneously choose more rewarding flowers and avoid simulated predatory attacks by robotic ‘spiders’. We found that when the tasks had to be performed using visual cues alone, bees failed to perform both tasks simultaneously. However, when highly rewarding flowers were indicated by olfactory cues and predators were indicated by visual cues, bees managed to perform both tasks successfully. Our results thus provide evidence for modality-specific attention in foraging bees and establish a novel framework for future studies of crossmodal attention in ecologically realistic settings. PMID:26587245

  20. Ocean acidification impairs crab foraging behaviour.

    PubMed

    Dodd, Luke F; Grabowski, Jonathan H; Piehler, Michael F; Westfield, Isaac; Ries, Justin B

    2015-07-01

    Anthropogenic elevation of atmospheric CO2 is driving global-scale ocean acidification, which consequently influences calcification rates of many marine invertebrates and potentially alters their susceptibility to predation. Ocean acidification may also impair an organism's ability to process environmental and biological cues. These counteracting impacts make it challenging to predict how acidification will alter species interactions and community structure. To examine effects of acidification on consumptive and behavioural interactions between mud crabs (Panopeus herbstii) and oysters (Crassostrea virginica), oysters were reared with and without caged crabs for 71 days at three pCO2 levels. During subsequent predation trials, acidification reduced prey consumption, handling time and duration of unsuccessful predation attempt. These negative effects of ocean acidification on crab foraging behaviour more than offset any benefit to crabs resulting from a reduction in the net rate of oyster calcification. These findings reveal that efforts to evaluate how acidification will alter marine food webs should include quantifying impacts on both calcification rates and animal behaviour. PMID:26108629

  1. A bioenergetics modeling evaluation of top-down control of ruffe in the St. Louis River, western Lake Superior

    USGS Publications Warehouse

    Mayo, Kathleen R.; Selgeby, James H.; McDonald, Michael E.

    1998-01-01

    Ruffe (Gymnocephalus cernuus), were accidentally introduced into the St. Louis River estuary, western Lake Superior, in the mid 1980s and it was feared that they might affect native fish through predation on eggs and competition for forage and habitat. In an effort to control the abundance of ruffe and limit dispersal, a top-down control strategy using predators was implemented in 1989. We used bioenergetics modeling to examine the efficacy of top-down control in the St. Louis River from 1991 to 1994. Five predators--northern pike (Esox lucius), walleye (Stizostedion vitreum vitreum), smallmouth bass (Micropterus dolomieui), brown bullhead (Ictalurus nebulosus), and yellow perch (Perca flavescens)--were modeled to determine their consumption of ruffe and four other native prey species-spottail shiner (Notropis hudsonius), emerald shiner (Notropis atherinoides), yellow perch (Perca flavescens), and black crappie (Pomoxis nigromaculatus). Although predators ate as much as 47% of the ruffe biomass in 1 year, they were not able to halt the increase in ruffe abundance. The St. Louis River is an open system that allows predators to move freely out of the system, and the biomass of managed predators did not increase. A selectivity index showed all five predators selected the native prey and avoided ruffe. The St. Louis River has several predator and prey species creating many complex predator-prey interactions; and top-down control of ruffe by the predators examined in this study did not occur.

  2. Sublethal imidacloprid effects on honey bee flower choices when foraging.

    PubMed

    Karahan, Ahmed; Çakmak, Ibrahim; Hranitz, John M; Karaca, Ismail; Wells, Harrington

    2015-11-01

    Neonicotinoids, systemic neuro-active pesticides similar to nicotine, are widely used in agriculture and are being investigated for a role in honey bee colony losses. We examined one neonicotinoid pesticide, imidacloprid, for its effects on the foraging behavior of free-flying honey bees (Apis mellifera anatoliaca) visiting artificial blue and white flowers. Imidacloprid doses, ranging from 1/5 to 1/50 of the reported LD50, were fed to bees orally. The study consisted of three experimental parts performed sequentially without interruption. In Part 1, both flower colors contained a 4 ?L 1 M sucrose solution reward. Part 2 offered bees 4 ?L of 1.5 M sucrose solution in blue flowers and a 4 ?L 0.5 M sucrose solution reward in white flowers. In Part 3 we reversed the sugar solution rewards, while keeping the flower color consistent. Each experiment began 30 min after administration of the pesticide. We recorded the percentage of experimental bees that returned to forage after treatment. We also recorded the visitation rate, number of flowers visited, and floral reward choices of the bees that foraged after treatment. The forager return rate declined linearly with increasing imidacloprid dose. The number of foraging trips by returning bees was also affected adversely. However, flower fidelity was not affected by imidacloprid dose. Foragers visited both blue and white flowers extensively in Part 1, and showed greater fidelity for the flower color offering the higher sugar solution reward in Parts 2 and 3. Although larger samples sizes are needed, our study suggests that imidacloprid may not affect the ability to select the higher nectar reward when rewards were reversed. We observed acute, mild effects on foraging by honey bees, so mild that storage of imidacloprid tainted-honey is very plausible and likely to be found in honey bee colonies. PMID:26415950

  3. Modelling foraging movements of diving predators: a theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency

    PubMed Central

    Barto?, Kamil A.; Scott, Beth E.; Travis, Justin M.J.

    2014-01-01

    Foraging in the marine environment presents particular challenges for air-breathing predators. Information about prey capture rates, the strategies that diving predators use to maximise prey encounter rates and foraging success are still largely unknown and difficult to observe. As well, with the growing awareness of potential climate change impacts and the increasing interest in the development of renewable sources it is unknown how the foraging activity of diving predators such as seabirds will respond to both the presence of underwater structures and the potential corresponding changes in prey distributions. Motivated by this issue we developed a theoretical model to gain general understanding of how the foraging efficiency of diving predators may vary according to landscape structure and foraging strategy. Our theoretical model highlights that animal movements, intervals between prey capture and foraging efficiency are likely to critically depend on the distribution of the prey resource and the size and distribution of introduced underwater structures. For multiple prey loaders, changes in prey distribution affected the searching time necessary to catch a set amount of prey which in turn affected the foraging efficiency. The spatial aggregation of prey around small devices (? 9 × 9 m) created a valuable habitat for a successful foraging activity resulting in shorter intervals between prey captures and higher foraging efficiency. The presence of large devices (? 24 × 24 m) however represented an obstacle for predator movement, thus increasing the intervals between prey captures. In contrast, for single prey loaders the introduction of spatial aggregation of the resources did not represent an advantage suggesting that their foraging efficiency is more strongly affected by other factors such as the timing to find the first prey item which was found to occur faster in the presence of large devices. The development of this theoretical model represents a useful starting point to understand the energetic reasons for a range of potential predator responses to spatial heterogeneity and environmental uncertainties in terms of search behaviour and predator–prey interactions. We highlight future directions that integrated empirical and modelling studies should take to improve our ability to predict how diving predators will be impacted by the deployment of manmade structures in the marine environment. PMID:25250211

  4. Pasture Production with Selected Forage Many species of grasses and legumes serve as forages. However, not all forage species are suited to New

    E-print Network

    New Hampshire, University of

    Pasture Production with Selected Forage Species Many species of grasses and legumes serve can be grouped into cool-season perennials, warm season grasses, and cool season annuals. None grasses and legumes. Kentucky bluegrass is a sod-forming grass, and its low growth habit enables

  5. Foraging area fidelity for Kemp's ridleys in the Gulf of Mexico

    PubMed Central

    Shaver, Donna J; Hart, Kristen M; Fujisaki, Ikuko; Rubio, Cynthia; Sartain, Autumn R; Peña, Jaime; Burchfield, Patrick M; Gamez, Daniel Gomez; Ortiz, Jaime

    2013-01-01

    For many marine species, locations of key foraging areas are not well defined. We used satellite telemetry and switching state-space modeling (SSM) to identify distinct foraging areas used by Kemp's ridley turtles (Lepidochelys kempii) tagged after nesting during 1998–2011 at Padre Island National Seashore, Texas, USA (PAIS; N = 22), and Rancho Nuevo, Tamaulipas, Mexico (RN; N = 9). Overall, turtles traveled a mean distance of 793.1 km (±347.8 SD) to foraging sites, where 24 of 31 turtles showed foraging area fidelity (FAF) over time (N = 22 in USA, N = 2 in Mexico). Multiple turtles foraged along their migratory route, prior to arrival at their “final” foraging sites. We identified new foraging “hotspots” where adult female Kemp's ridley turtles spent 44% of their time during tracking (i.e., 2641/6009 tracking days in foraging mode). Nearshore Gulf of Mexico waters served as foraging habitat for all turtles tracked in this study; final foraging sites were located in water <68 m deep and a mean distance of 33.2 km (±25.3 SD) from the nearest mainland coast. Distance to release site, distance to mainland shore, annual mean sea surface temperature, bathymetry, and net primary production were significant predictors of sites where turtles spent large numbers of days in foraging mode. Spatial similarity of particular foraging sites selected by different turtles over the 13-year tracking period indicates that these areas represent critical foraging habitat, particularly in waters off Louisiana. Furthermore, the wide distribution of foraging sites indicates that a foraging corridor exists for Kemp's ridleys in the Gulf. Our results highlight the need for further study of environmental and bathymetric components of foraging sites and prey resources contained therein, as well as international cooperation to protect essential at-sea foraging habitats for this imperiled species. PMID:23919146

  6. Evidence for foraging -site fidelity and individual foraging behavior of pelagic cormorants rearing chicks in the gulf of Alaska

    USGS Publications Warehouse

    Kotzerka, J.; Hatch, Shyla A.; Garthe, S.

    2011-01-01

    The Pelagic Cormorant (Phalacrocorax pelagicus) is the most widespread cormorant in the North Pacific, but little is known about its foraging and diving behavior. However, knowledge of seabirds' foraging behavior is important to understanding their function in the marine environment. In 2006, using GPS dataloggers, we studied the foraging behavior of 14 male Pelagic Cormorants rearing chicks on Middleton Island, Alaska. For foraging, the birds had high fidelity to a small area 8 km north of the colony. Within that area, the cormorants' diving activity was of two distinct kinds-near-surface dives (1-6 m) and benthic dives (28-33 m). Individuals were consistent in the depths of their dives, either mostly shallow or mostly deep. Few showed no depth preference. Dive duration, time at maximum depth, and pauses at the water surface between consecutive dives were shorter for shallow dives than for deep dives. The cormorants made dives of both types throughout the day, but the frequency of deep dives increased toward evening. Maximum foraging range was 9 km; maximum total distance traveled per trip was 43.4 km. Trip durations ranged from 0.3 to 7.7 hr. Maximum depth of a dive was 42.2 m, and duration of dives ranged from 4 to 120 sec. We found that Pelagic Cormorants at Middleton Island were faithful to one particular foraging area and individuals dived in distinct patterns. Distinct, specialized foraging behavior may be advantageous in reducing intra- and interspecific competition but may also render the species vulnerable to changing environmental conditions. Copyright ?? The Cooper Ornithological Society 2011.

  7. Contact rate modulates foraging efficiency in leaf cutting ants

    PubMed Central

    Bouchebti, S.; Ferrere, S.; Vittori, K.; Latil, G.; Dussutour, A.; Fourcassié, V.

    2015-01-01

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail. PMID:26686557

  8. Foraging Activities of Coptotermes formosanus in Subtropical Areas in China.

    PubMed

    Ruan, Guanhua; Song, Xiaogang; Hu, Yin; Han, Na; Zhang, Dayu

    2015-04-01

    The foraging activities, including foraging range and seasonal fluctuation of the Formosan subterranean termite, Coptotermes formosanus Shiraki, were investigated in subtropical areas in China. Six mature C. formosanus colonies were selected for this study. Foraging distance and area were conducted in Anqing1, Hengyang, and Wuxi1 colonies, while the seasonal fluctuation was conducted in Wuxi2, Wuwei, and Anqing2 colonies. Mark-release-recapture method analysis showed that the Formosan termites foraged at least 11.5, 28.7, and 56.8?m away from the main nest and covered 98.1, 543.7, and 671.9 m2 of foraging area at Anqing1, Hengyang, and Wuxi1 site, respectively. The seasonal fluctuation in termite colony activity showed an "M shape" pattern according to the wood damages caused by termites at monitoring stations. Peak colony activity at Wuxi2, Wuwei, and Anqing2 occurred in July and October, June and September, July and October, respectively. This study provides critical information for the integrated management of C. formosanus, including baiting application in the subtropical regions of China, where it constitutes the most destructive pest for household structures. PMID:26470181

  9. Contact rate modulates foraging efficiency in leaf cutting ants.

    PubMed

    Bouchebti, S; Ferrere, S; Vittori, K; Latil, G; Dussutour, A; Fourcassié, V

    2015-01-01

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail. PMID:26686557

  10. Foraging in corallivorous butterflyfish varies with wave exposure

    NASA Astrophysics Data System (ADS)

    Noble, Mae M.; Pratchett, Morgan S.; Coker, Darren J.; Cvitanovic, Christopher; Fulton, Christopher J.

    2014-06-01

    Understanding the foraging patterns of reef fishes is crucial for determining patterns of resource use and the sensitivity of species to environmental change. While changes in prey availability and interspecific competition have been linked to patterns of prey selection, body condition, and survival in coral reef fishes, rarely has the influence of abiotic environmental conditions on foraging been considered. We used underwater digital video to explore how prey availability and wave exposure influence the behavioural time budgets and prey selectivity of four species of obligate coral-feeding butterflyfishes. All four species displayed high selectivity towards live hard corals, both in terms of time invested and frequency of searching and feeding events. However, our novel analysis revealed that such selectivity was sensitive to wave exposure in some species, despite there being no significant differences in the availability of each prey category across exposures. In most cases, these obligate corallivores increased their selectivity towards their most favoured prey types at sites of high wave exposure. This suggests there are costs to foraging under different wave environments that can shape the foraging patterns of butterflyfishes in concert with other conditions such as prey availability, interspecific competition, and territoriality. Given that energy acquisition is crucial to the survival and fitness of fishes, we highlight how such environmental forcing of foraging behaviour may influence the ecological response of species to the ubiquitous and highly variable wave climates of shallow coral reefs.

  11. Landfills, nocturnal foraging, and risk to aircraft.

    PubMed

    Burger, J

    2001-10-12

    Open landfills serve as an attractant to birds, with increasing risk of bird-plane collisions. Managers are searching for methods to allow landfilling while reducing potential bird problems near airports. Some municipalities are considering nighttime landfilling as an avian deterrent, particularly where waste management facilities are located near airports. The objective of this report was to evaluate whether nighttime landfilling will result in increased risk to aircraft from birds at the Atlantic County Airport in coastal New Jersey. The risk to nearby aircraft from nighttime landfill is a function of (1) attractiveness of landfills, airports, or other habitats, (2) nocturnal behavior of gulls and other birds, (3) elevations and flight paths of birds, (4) changes in population levels of gulls and other potentially hazardous birds, and (5) harassment techniques that can deter birds from the landfills, adjacent habitat, and airports. The latter, however, can serve to move birds to locations or altitudes that pose an even greater risk to aircraft. The number of strikes is generally increasing. While most air strikes occur during the day at the Atlantic County Airport, over 12% occur at night and nearly 20% occur at dawn when any garbage remaining from nighttime landfilling would be an attractant. The peak of strikes occurs in the early fall, when young birds are learning to forage. Risk data suggests that gulls and a wide variety of other birds are active at night, and if any garbage is available they will be attracted, increasing the risk to aircraft landing at night. Some actual night dumping has been carried out since October 3 1997 without apparently attracting gulls, suggesting that careful operations with appropriate institutional controls can make nighttime dumping feasible. PMID:11594704

  12. Forage choice in pasturelands: Influence on cattle foraging behavior and performance.

    PubMed

    Villalba, J J; Cabassu, R; Gunter, S A

    2015-04-01

    We determined if combinations of adjacent pastures of 3 forage species led to complementary relationships that influenced animal behavior and performance over monocultures. Grazing bouts, behavioral levels of activity, blood urea N (BUN), chemical composition of feces, BW, and herbage biomass before and after grazing were monitored when beef calves strip-grazed 3 replications of 4 treatments from June 14 through August 23, 2013 (9 animals/treatment). Animals grazed monocultures of: 1) tall fescue (TF), 2) alfalfa (ALF), 3) sainfoin (SAN), or 4) a choice of strips of forages TF, ALF, and SAN (CHOICE). The lowest and greatest incidence of foraging bouts occurred for cattle in CHOICE and SAN, respectively (P < 0.01). Animals in CHOICE grazed SAN > ALF > TF (P < 0.01). Animals on TF and CHOICE took greater number of steps than animals grazing a monocultures of either legume (P = 0.01). Calves in TF had lower BUN (P < 0.01) and fecal CP concentration (P < 0.01) than calves grazing the remaining treatments, whereas animals in SAN showed the greatest concentrations of fecal CP (P < 0.01). Fecal NDF concentration was the greatest for animals grazing TF and the lowest for animals grazing SAN (P < 0.01), whereas fecal ADF concentration was greater for animals grazing TF and SAN than for animals grazing CHOICE and ALF (P = 0.02). Calcium, Mg, and Zn concentrations were the lowest in feces from calves grazing TF and the greatest for calves grazing a monoculture of either legume (P < 0.05). When averaging both periods, animals grazing SAN, ALF, or CHOICE gained more BW than animals grazing TF (P < 0.01). Thus, calves in CHOICE incorporated tall fescue into their diets, were more active, and displayed a lower number of grazing bouts than calves grazing monoculture of either legume. Herbage diversity may lead to levels of ADG comparable to legume monocultures with the potential benefit of maintaining plant species diversity in pasturelands. PMID:26020195

  13. Flower size preferences of the honeybee (Apis mellifera) foraging on Mimulus guttatus (Scrophulariaceae)

    E-print Network

    Upchurch, Gary - Department of Biology, Texas State University

    Flower size preferences of the honeybee (Apis mellifera) foraging on Mimulus guttatus) visiting naturally occurring flowers of Mimulus guttatus (Scrophulariaceae). The results indicate that A. mellifera preferentially selects larger M. guttatus flowers in their foraging bouts. Since differences

  14. Forage production in natural and afforested grasslands of the Pampas: ecological complementarity

    E-print Network

    Nacional de San Luis, Universidad

    Forage production in natural and afforested grasslands of the Pampas: ecological complementarity aboveground net primary productivity (ANPP) patterns in herbaceous understory to tree plantations and natural In managed rangelands periods of low primary productivity determine troughs of forage availability

  15. Methyl parathion modifies foraging behaviour in honeybees (Apis mellifera).

    PubMed

    Guez, David; Zhang, Shao-Wu; Srinivasan, Mandyam V

    2005-05-01

    We examined the effects of sublethal doses of an organophosphorus insecticide, Methyl Parathion (MeP), on the foraging behaviour of honeybees (Apis mellifera ligustica) in a flight cage. The results revealed that MeP modified the frequency of visits to a feeding station to which the bees had previously been trained. A dose of 50 ng per animal elicited an increase in the frequency of visits to the feeder, compared to control animals. A dose of 10 ng, on the other hand, led initially to a decrease in the visit frequency, followed by an increase to a level above that of the controls. A hypothesis is presented to account for the way in which MeP affects foraging behaviour. We propose that the behavioural assay presented here could be useful as a preliminary screening test to study sublethal effects of pesticides on foraging performance in honeybees. PMID:16385737

  16. Neuronal mechanism for acute mechanosensitivity in tactile-foraging waterfowl

    PubMed Central

    Schneider, Eve R.; Mastrotto, Marco; Laursen, Willem J.; Schulz, Vincent P.; Goodman, Jena B.; Funk, Owen H.; Gallagher, Patrick G.; Gracheva, Elena O.; Bagriantsev, Sviatoslav N.

    2014-01-01

    Relying almost exclusively on their acute sense of touch, tactile-foraging birds can feed in murky water, but the cellular mechanism is unknown. Mechanical stimuli activate specialized cutaneous end organs in the bill, innervated by trigeminal afferents. We report that trigeminal ganglia (TG) of domestic and wild tactile-foraging ducks exhibit numerical expansion of large-diameter mechanoreceptive neurons expressing the mechano-gated ion channel Piezo2. These features are not found in visually foraging birds. Moreover, in the duck, the expansion of mechanoreceptors occurs at the expense of thermosensors. Direct mechanical stimulation of duck TG neurons evokes high-amplitude depolarizing current with a low threshold of activation, high signal amplification gain, and slow kinetics of inactivation. Together, these factors contribute to efficient conversion of light mechanical stimuli into neuronal excitation. Our results reveal an evolutionary strategy to hone tactile perception in vertebrates at the level of primary afferents. PMID:25246547

  17. Evolution of Optimum Foraging Distributions in Two Dimensions

    NASA Astrophysics Data System (ADS)

    Dees, Nathan; Bahar, Sonya; Moss, Frank

    2008-03-01

    In the pursuit of optimally efficient foraging, preferred distributions of movement characteristics have been shown to exist for many types of animals and environments. Specifically, planktonic organisms such as Daphnia use exponential distributions of turning angles, ?, in a ``hop, pause, turn by angle ?, hop'' random walk-type sequence of movement when traversing experimentally prepared feeding solutions consisting of freeze dried Spirolina and water. We investigate the evolution of such random walks in a two-dimensional foraging model. In this model, agents traverse a feeding patch of finite size and for a finite amount of time using hop lengths and turning angles chosen randomly from inherited distributions. Distributions evolve as the choices made by the most efficient forager of one generation influence the distributions available to the succeeding generation. Preliminary results show that initially uniform turning angle distributions evolve to explicit exponential distributions after thousands of generations, consistent with the experimental observations described above.

  18. The Physiological Suppressing Factors of Dry Forage Intake and the Cause of Water Intake Following Dry Forage Feeding in Goats - A Review.

    PubMed

    Sunagawa, Katsunori; Nagamine, Itsuki

    2016-02-01

    The goats raised in the barn are usually fed on fresh grass. As dry forage can be stored for long periods in large amounts, dry forage feeding makes it possible to feed large numbers of goats in barns. This review explains the physiological factors involved in suppressing dry forage intake and the cause of drinking following dry forage feeding. Ruminants consume an enormous amount of dry forage in a short time. Eating rates of dry forage rapidly decreased in the first 40 min of feeding and subsequently declined gradually to low states in the remaining time of the feeding period. Saliva in large-type goats is secreted in large volume during the first hour after the commencement of dry forage feeding. It was elucidated that the marked suppression of dry forage intake during the first hour was caused by a feeding-induced hypovolemia and the loss of NaHCO3 due to excessive salivation during the initial stages of dry forage feeding. On the other hand, it was indicated that the marked decrease in feed intake observed in the second hour of the 2 h feeding period was related to ruminal distension caused by the feed consumed and the copious amount of saliva secreted during dry forage feeding. In addition, results indicate that the marked decreases in dry forage intake after 40 min of feeding are caused by increases in plasma osmolality and subsequent thirst sensations produced by dry forage feeding. After 40 min of the 2 h dry forage feeding period, the feed salt content is absorbed into the rumen and plasma osmolality increases. The combined effects of ruminal distension and increased plasma osmolality accounted for 77.6% of the suppression of dry forage intake 40 min after the start of dry forage feeding. The results indicate that ruminal distension and increased plasma osmolality are the main physiological factors in suppression of dry forage intake in large-type goats. There was very little drinking behavior observed during the first hour of the 2 h feeding period most water consumption occurring in the second hour. The cause of this thirst sensation during the second hour of dry forage feeding period was not hypovolemia brought about by excessive salivation, but rather increases in plasma osmolality due to the ruminal absorption of salt from the consumed feed. This suggests the water intake following dry forage feeding is determined by the level of salt content in the feed. PMID:26732440

  19. Does Foraging Behaviour Affect Female Mate Preferences and Pair Formation in Captive Zebra Finches?

    PubMed Central

    Boogert, Neeltje J.; Bui, Cavina; Howarth, Krista; Giraldeau, Luc-Alain; Lefebvre, Louis

    2010-01-01

    Background Successful foraging is essential for survival and reproductive success. In many bird species, foraging is a learned behaviour. To cope with environmental change and survive periods in which regular foods are scarce, the ability to solve novel foraging problems by learning new foraging techniques can be crucial. Although females have been shown to prefer more efficient foragers, the effect of males' foraging techniques on female mate choice has never been studied. We tested whether females would prefer males showing the same learned foraging technique as they had been exposed to as juveniles, or whether females would prefer males that showed a complementary foraging technique. Methodology/Principal Findings We first trained juvenile male and female zebra finches (Taeniopygia guttata) to obtain a significant proportion of their food by one of two foraging techniques. We then tested whether females showed a preference for males with the same or the alternative technique. We found that neither a male's foraging technique nor his foraging performance affected the time females spent in his proximity in the mate-choice apparatus. We then released flocks of these finches into an aviary to investigate whether assortative pairing would be facilitated by birds taught the same technique exploiting the same habitat. Zebra finches trained as juveniles in a specific foraging technique maintained their foraging specialisation in the aviary as adults. However, pair formation and nest location were random with regard to foraging technique. Conclusions/Significance Our findings show that zebra finches can be successfully trained to be foraging specialists. However, the robust negative results of the conditions tested here suggest that learned foraging specializations do not affect mate choice or pair formation in our experimental context. PMID:21179514

  20. Acoustics as a tool for the assessment of Great Lakes forage fishes

    USGS Publications Warehouse

    Argyle, Ray L.

    1992-01-01

    Sharp reductions in forage fish populations in Lake Michigan have raised concerns about the continued ability of the forage stocks to support large populations of lake trout and other salmonid predators. There was a need for a more comprehensive and accurate estimate of forage fish abundance and distribution to evaluate these concerns. In response, cooperative diel surveys of the Lake Michigan forage species were conducted in late summer 1987 and spring 1989 with acoustics, midwater and bottom trawls.

  1. Foraging rate versus sociality in the starling Sturnus vulgaris.

    PubMed Central

    Vásquez, R A; Kacelnik, A

    2000-01-01

    It is well established that social conditions often modify foraging behaviour, but the theoretical interpretation of the changes produced is not straightforward. Changes may be due to alterations of the foraging currency (the mathematical expression that behaviour maximizes) and/or of the available resources. An example of the latter is when both solitary and social foragers maximize rates of gain over time, but competition alters the behaviour required to achieve this, as assumed by ideal free distribution models. Here we examine this problem using captive starlings Sturnus vulgaris. Subjects had access to two depleting patches that replenished whenever the alternative patch was visited. The theoretical rate-maximizing policy was the same across all treatments, and consisted of alternating between patches following a pattern that could be predicted using the marginal value theorem (MVT). There were three treatments that differed in the contents of an aviary adjacent to one of the two patches (called the 'social' patch). In the control treatment, the aviary was empty, in the social condition it contained a group of starlings, and in a non-specific stimulus control it contained a group of zebra finches. In the control condition both patches were used equally and behaviour was well predicted by the MVT. In the social condition, starlings foraged more slowly in the social than in the solitary patch. Further, foraging in the solitary patch was faster and in the social patch slower in the social condition than in the control condition. Although these changes are incompatible with overall rate maximization (gain rate decreased by about 24% by self-imposed changes), if the self-generated gain functions were used the MVT was a good predictor of patch exploitation under all conditions. We discuss the complexities of nesting optimal foraging models in more comprehensive theoretical accounts of behaviour integrating functional and mechanistic perspectives. PMID:10687821

  2. Context dependence in foraging behaviour of Achillea millefolium.

    PubMed

    Karst, Justine D; Belter, Pamela R; Bennett, Jonathan A; Cahill, James F

    2012-12-01

    Context-dependent foraging behaviour is acknowledged and well documented for a diversity of animals and conditions. The contextual determinants of plant foraging behaviour, however, are poorly understood. Plant roots encounter patchy distributions of nutrients and soil fungi. Both of these features affect root form and function, but how they interact to affect foraging behaviour is unknown. We extend the use of the marginal value theorem to make predictions about the foraging behaviour of roots, and test our predictions by manipulating soil resource distribution and inoculation by soil fungi. We measured plant movement as both distance roots travelled and time taken to grow through nutrient patches of varied quality. To do this, we grew Achillea millefolium in the centers of modified pots with a high-nutrient patch and a low-nutrient patch on either side of the plant (heterogeneous) or patch-free conditions (homogeneous). Fungal inoculation, but not resource distribution, altered the time it took roots to reach nutrient patches. When in nutrient patches, root growth decreased relative to homogeneous soils. However, this change in foraging behaviour was not contingent upon patch quality or fungal inoculation. Root system breadth was larger in homogeneous than in heterogeneous soils, until measures were influenced by pot edges. Overall, we find that root foraging behaviour is modified by resource heterogeneity but not fungal inoculation. We find support for predictions of the marginal value theorem that organisms travel faster through low-quality than through high-quality environments, with the caveat that roots respond to nutrient patches per se rather than the quality of those patches. PMID:22622873

  3. COMMON FORAGE LEGUME INSECTS OF INDIANA 1. ALFALFA WEEVIL, Hypera postica (Gyllenhal). This weevil

    E-print Network

    Pittendrigh, Barry

    grown. Other species of cutworm may also damage forage legumes. 5. GRASSHOPPERS, Family Acrididae. Grasshoppers overwin ter as eggs in uncultivated soil, including forage legume fields. When these eggs hatch, the young grasshoppers usually remain in the field to feed, since forage legumes are among their favorite

  4. The Cost of Capturing Prey: Measuring Largemouth Bass Foraging Activity using Glycolytic Enzymes (Lactate Dehydrogenase)

    E-print Network

    The Cost of Capturing Prey: Measuring Largemouth Bass Foraging Activity using Glycolytic Enzymes THE COST OF CAPTURING PREY: MEASURING LARGEMOUTH BASS FORAGING ACTIVITY USING GLYCOLYTIC ENZYMES (LACTATE #12;11 The Cost of Capturing Prey: Measuring Largemouth Bass Foraging Activity using Glycolytic

  5. Spatial arrangement, population density and legume species effect of yield of forage sorghum-legume intercropping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorghum (Sorghum bicolor) is a stress tolerant forage crop grown extensively in the Southern High Plains. However, sorghum forage quality is lower than that of corn. Intercropping sorghum with legumes can improve quality and productivity of forage. However, tall statured sorghum limits the resources...

  6. Interspecies variation of forage nutritive value and nonstructural carbohydrates in perennial cool-season grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage nitrogen (N) and nonstructural carbohydrate (NSC) concentrations are important indicators of forage quality, and knowledge of N and NSC variation among grass germplasm is one element to consider in developing a successful forage and livestock management program. An experiment was conducted in...

  7. Explore vs. Exploit: Task Allocation for Multi-robot Foraging Christopher Baldassano and Naomi Ehrich Leonard

    E-print Network

    Leonard, Naomi

    settings, in the field of optimal foraging theory [6], [7], [8]. Models and optimal solu- tions have beenExplore vs. Exploit: Task Allocation for Multi-robot Foraging Christopher Baldassano and Naomi to allocate tasks in a multi- robot foraging problem. These heuristics can be used by a human supervisor

  8. Optimal Foraging on the Roof of the World: Himalayan Langurs and the Classical Prey Model

    E-print Network

    Norconk, Marilyn A.

    Optimal Foraging on the Roof of the World: Himalayan Langurs and the Classical Prey Model Ken ABSTRACT Optimal foraging theory has only been sporadically applied to nonhuman primates. The classical:000­000, 2009. VVC 2009 Wiley-Liss, Inc. Optimal foraging theory (OFT) operates on the assumption that behavior

  9. Efficient Multi-foraging in Swarm Robotics Alexandre Campo and Marco Dorigo

    E-print Network

    Libre de Bruxelles, Université

    birth to the field of optimal foraging. The hypothesis is that evolution has shaped individualEfficient Multi-foraging in Swarm Robotics Alexandre Campo and Marco Dorigo IRIDIA, CoDE, Universit´e Libre de Bruxelles, Brussels, Belgium {acampo, mdorigo}@ulb.ac.be Abstract. In the multi-foraging task

  10. Optimal foraging: Levy pattern or process? Plank, M. J. and James, A.

    E-print Network

    James, Alex

    Optimal foraging: L´evy pattern or process? Plank, M. J. and James, A. Department of Mathematics ballistic motion. Optimal strategies for destructive foraging have also been investigated by Bartumeus et al suggested to forage according to a L´evy walk, in which the distribu- tion of step lengths is heavy tailed

  11. Clustering PPI Data Based on Bacteria Foraging Optimization Algorithm Xiujuan Lei*1

    E-print Network

    Buffalo, State University of New York

    Clustering PPI Data Based on Bacteria Foraging Optimization Algorithm Xiujuan Lei*1 Shuang Wu2@buffalo.edu * Corresponding author Abstract--This paper proposed a novel method using Bacteria Foraging Optimization, but also automatically determined the cluster number. Keywords-bacteria foraging optimization algorithm

  12. Visual constraints in foraging bumblebees: Flower size and color affect search time

    E-print Network

    Chittka, Lars

    (received for review October 27, 2000) In optimal foraging theory, search time is a key variable defining addressed. Possibly for this reason, predictions of optimal foraging theory are often incon- sistentVisual constraints in foraging bumblebees: Flower size and color affect search time and flight

  13. Anim. Behao., 1989,37,444-454 Foraging in a patchy environment: prey-encounter rate

    E-print Network

    Chesson, Peter L.

    -time rule, where a forager stays in each patch for a constant optimal amount of time; (2) a constant numberAnim. Behao., 1989,37,444-454 Foraging in a patchy environment: prey-encounter rate and residence macrochirus, foraging among patches in the laboratory did not search systematically within a patch

  14. Behavioral Ecology Vol. 7 No. 2: 158-164 Trapline foraging by bumblebees: I.

    E-print Network

    Thomson, James D.

    as exemplars for study, and when optimal foraging theory stimulated a wave of new questions in the mid-1970sBehavioral Ecology Vol. 7 No. 2: 158-164 Trapline foraging by bumblebees: I. Persistence of flight By setting out arrays of potted plants of Penstemon strictus, I tested whether freely foraging bumblebee

  15. Ecological Modelling 175 (2004) 7785 Food hoarding: future value in optimal foraging decisions

    E-print Network

    Gerber, Leah R.

    2004-01-01

    Ecological Modelling 175 (2004) 77­85 Food hoarding: future value in optimal foraging decisions L form 26 August 2003; accepted 27 October 2003 Abstract Traditionally, optimal foraging theory has been of caching behavior in optimal foraging theory is the degree to which information about future value might

  16. Available online at www.sciencedirect.com A phylogenetic perspective on foraging mode evolution

    E-print Network

    Leal, Manuel S.

    a significant amount of research, including the development of optimal forag- ing theory (MacArthur & PiankaAvailable online at www.sciencedirect.com A phylogenetic perspective on foraging mode evolution) Although many descriptive studies of foraging mode have been performed, the factors that underlie

  17. Foraging Strategy of the Giant Rams-Horn Snail, Marisa cornuarietis: An Interpretive Model

    E-print Network

    Willig, Michael

    and physi- In general, optimal foraging behavior is hypothesized to ological differences among individualsForaging Strategy of the Giant Rams-Horn Snail, Marisa cornuarietis: An Interpretive Model Ö. K #12;OIKOS 72: 333-342. Copenhagen 1995 Foraging strategy of the giant rams-horn snail, Marisa

  18. Optimal Foraging in Semantic Memory Thomas T. Hills (thomas.hills@unibas.ch)

    E-print Network

    Jones, Michael

    Optimal Foraging in Semantic Memory Thomas T. Hills (thomas.hills@unibas.ch) Center for Cognitive the average rate for the entire task, as predicted by optimal foraging theory. Furthermore, participants an optimal foraging policy--called the marginal value theorem--when patches are defined strictly internally

  19. A Pheromone-Based Utility Model for Collaborative Foraging Liviu Panait

    E-print Network

    Luke, Sean

    the ability to create optimal foraging paths in the presence of obstacles, to cope with dynamic environmentsA Pheromone-Based Utility Model for Collaborative Foraging Liviu Panait Department of Computer for artificial agent foraging, trail-creation, and other tasks. Whereas practically all previous work

  20. Foraging speed in staging flocks of semipalmated sandpipers: evidence for scramble competition.

    PubMed

    Beauchamp, Guy

    2012-08-01

    Foraging speed is a key determinant of fitness affecting both foraging success and predator attack survival. In a scramble for food, for instance, evolutionary stable strategy models predict that speed should increase with competitor density and decrease when the risk of attack by predators increases. Foraging speed should also decrease in richer food patches where the level of competition is reduced. I tested these predictions in fall staging flocks of semipalmated sandpipers (Calidris pusilla) foraging for an evasive prey. Capture rate of these prey decreased with sandpiper density as the presence of competitors reduced the availability of resources for those behind. Foraging speed was evaluated indirectly by measuring the time needed to cross fixed boundaries on mudflats over 6 years. As predicted, foraging speed increased with sandpiper density and decreased with food density, but, unexpectedly, increased closer to obstructive cover where predation risk was deemed higher. When foraging closer to cover, from where predators launch surprise attacks, the increase in foraging speed may compensate for an increase in false alarms that interrupted foraging. While foraging in denser flocks decreases foraging success, joining such flocks may also increase safety against predators. In semipalmated sandpipers that occupy an intermediate position in the food chain, foraging behavior is influenced simultaneously by the evasive responses of their prey and by the risk of attack from their own predators. PMID:22302514

  1. FORAGING BEHAVIOR AND MONETARY IMPACT OF WADING BIRDS AT ARKANSAS BAITFISH FARMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We conducted foraging observations, food habits studies, and producer surveys to determine the foraging behavior and monetary impact of great blue herons Ardea herodias, great egrets A. alba, and little blue herons Egretta caerulea foraging at Arkansas baitfish farms. Although great egrets captured...

  2. PIGEON PEA: A POTENTIAL FORAGE AND GRAIN FOR THE SOUTHERN GREAT PLAINS IN U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A basic goal of livestock grazing programs is to provide high-quality forage year-around to reduce costs of storing and purchasing forage or concentrated feeds. Forage-based livestock production is a significant component of the agricultural economy throughout the Southern Great Plains of the U.S. ...

  3. Bumble bee pollen foraging regulation: role of pollen quality, storage levels, and odor

    E-print Network

    Nieh, James

    ERRATUM Bumble bee pollen foraging regulation: role of pollen quality, storage levels, and odor T was made to the article title. The correct title should read: Bumble bee pollen foraging regulation: role for Behavioral Ecology and Sociobiology Bumble bee pollen foraging regulation: role of pollen quality, storage

  4. POLLEN MAKES BEES HOT Forager bees like nothing more than a

    E-print Network

    Nieh, James

    Inside JEB iii POLLEN MAKES BEES HOT Forager bees like nothing more than a sweet supply of nectar. But bees do not live by nectar alone. One of their main sources of protein is pollen. Knowing that bees% pollen protein samples and offered them to a bee colony in an isolated foraging arena. Measuring foraging

  5. Resource diversity and landscape-level homogeneity drive native bee foraging

    E-print Network

    Resource diversity and landscape-level homogeneity drive native bee foraging Shalene Jhaa,b,1 of a critical native pollinator, Bombus vosnesenskii. Our findings demonstrate that native bee foraging is far strat- egy. Rather, bumble bees forage further in pursuit of species-rich floral patches

  6. RUMINANT PREFERENCE AND DAILY RESPONSE WHEN FED PM VS AM FORAGES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants accumulate photosynthate during the daylight hours to be subsequently used for their growth, reproduction and basic respiration. Sugar accumulation in forage plants could improve the nutritive value of the forage when grazed or harvested and stored as feed. This should also improved forage ...

  7. Breeding Better Forages to Help Feed Man and Preserve and Enhance the Environment

    ERIC Educational Resources Information Center

    Burton, Glenn W.

    1973-01-01

    Discusses the importance of forages in agriculture, and expresses the need for the same high level of technology that is used in the production of corn, wheat, and rice to be applied to forage production. Describes promising forage species, breeding objectives, and breeding procedures used in research. (JR)

  8. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with the... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The...

  9. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with the... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The...

  10. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with the... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The...

  11. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... vegetable oils are to be used in the oil mix. (f) The label of any dehydrated forage crops treated with the... and vitamin E in the forage crops. (c) It is added to the dehydrated forage crops in an oil mixture containing only suitable animal or suitable vegetable oil, prior to grinding and mixing. (d) The...

  12. Journal of Mammalogy, 82(2):430439, 2001 ASSESSING EFFECTS OF PREDATION RISK ON FORAGING

    E-print Network

    Brown, Joel S.

    optimal foraging theory to test effects of habitat and predation risk on foraging behavior of mule deer- cluded that deer are responding to predation risk by biasing their feeding efforts at the scale trade-offs. When foraging under predation risk, an animal should leave a depletable resource patch when

  13. Effects of forage quality and cell wall constituents of bermudagrass on biochemical conversion to ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 10 million acres of bermudagrass are grown for forage in Southern United States and is considered a potential feedstock for conversion of biomass to ethanol. Forage grasses have been improved through breeding to obtain high biomass yields and better forage quality (IVDMD). This improved biodeg...

  14. Case Study: Nutrient values for spring and summer annual forages in a single cut harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Annual forages were grown in the Central High Plains of the USA in both irrigated and dryland trials and the harvested forage was analyzed for forage composition and energy concentration. Three spring cereal crops (oats, barley, and triticale), three legumes (peas, soybeans, and vetch) and five sum...

  15. Research article Bumble bee olfactory information flow and contact-based foraging activation

    E-print Network

    Nieh, James

    Research article Bumble bee olfactory information flow and contact-based foraging activation M in foraging activation is poorly understood in bumble bees, as compared to honey bees and stingless bees. We therefore investigated olfactory information flow and foraging activation in the New World bumble bee

  16. MAPPING OF QUANTITATIVE TRAIT LOCI (QTL) FOR FORAGE QUALITY IN PERENNIAL RYEGRASS (LOLIUM PERENNE L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perennial ryegrass (Lolium perenne L.) has been widely used as a forage crop in temperate regions. Improvement of forage quality has important effect on ruminant animal nutrition and is an important forage breeding objective. A segregating population of 170 progenies derived from a cross between “Ma...

  17. Social Environment Influences Performance in a Cognitive Task in Natural Variants of the Foraging Gene

    E-print Network

    Sokolowski, Marla

    manipulations of PKG activity levels, the foraging (for) gene's gene product. Learning and memory is also Gene Nancy R. Kohn1,3. , Christopher J. Reaume2. , Celine Moreno1 , James G. Burns2 , Marla B Abstract In Drosophila melanogaster, natural genetic variation in the foraging gene affects the foraging

  18. Are genetic differences in foraging behaviour of laying hen chicks paralleled by hybrid-specic

    E-print Network

    Richner, Heinz

    Are genetic differences in foraging behaviour of laying hen chicks paralleled by hybrid behaviour found earlier, we hypothesised that genetically determined differences in foraging behaviour could the hypothesis put forward that genetic differences in foraging behaviour could be the basis for the genetic in

  19. Patches of Bare Ground as a Staple Commodity for Declining Ground-Foraging Insectivorous Farmland Birds

    E-print Network

    Richner, Heinz

    Patches of Bare Ground as a Staple Commodity for Declining Ground-Foraging Insectivorous Farmland is the status of insectivorous farmland birds that forage on the ground. We modelled the foraging habitat preferences of four declining insectivorous bird species (hoopoe, wryneck, woodlark, common redstart

  20. The effects of drought on Ngatatjara plant use: An evaluation of optimal foraging theory

    SciTech Connect

    Pate D.

    1986-03-01

    The different responses of plants to drought conditions are examined in the Western Desert of Australia to demonstrate the necessity of considering plant food availability prior to optimal foraging applications involving human hunter-gatherers. The correspondence of Ngatatjara dietary breadth changes to optimal foraging predictions is explained as an adaptive response to the unpredictable Western Desert reinfall. By minimizing the time allocated to food procurement, energy-efficient foraging reduces the risk involved in the exploitation of scattered, ephemeral water sources. Futher applications of optimal foraging models to hunter-gatherers is one line of promising investigation to address behavioral variability among human foragers.

  1. PIGEONPEA: NEW SOURCE OF FORAGE FOR THE SOUTHERN GREAT PLAINS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A universal goal of stocker calf production programs is to provide high quality grazing year-round to reduce the cost of harvested or purchased feed. The primary forage resource for livestock in the southern Great Plains is winter wheat from late fall through February or May, followed by warm-seaso...

  2. The hidden cost of information in collective foraging

    E-print Network

    Collins, Sean

    The hidden cost of information in collective foraging François-Xavier Dechaume-Moncharmont1 , Anna.dechaume@bristol.ac.uk, Telephone: +44 117 928 8443, Fax: +44 117 925 7374 Word count: 4109 words 1 #12;2 Abstract. Many animals that this will always increase 6 the colony's net energy gain. We test this assumption with a mathemati- 7 cal model

  3. Calculating foraging area using gloal navigation satellite system (GNSS) technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adjusting stocking rate to changing forage conditions is a critical part of pro-active range management. In general stocking rate approaches tend to assume more optimal landscape use patterns than will actually occur. Today we can monitor spatio-temporal landscape use on a 24/7 basis using animals...

  4. Managing Forage and Grazing Lands for Multiple Ecosystem Services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of the pasture ecology and management research project at University Park is to provide science-based information for establishing, maintaining, and managing diverse forage and grazing lands of the northeastern U.S. to support multiple ecosystem services. The concept of multifunctionality i...

  5. Genomic selection in forage breeding: designing an estimation population

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The benefits of genomic selection to livestock, crops and forest tree breeding can be extended to forage grasses and legumes. The main benefits expected are increased selection accuracy and reduced costs per unit of genotype evaluated and breeding cycle length. Aiming at designing a training populat...

  6. Behavioral Genomics of Honey Bee foraging and nest defense

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We superimposed confidence intervals (CIs) with genomic sequence for seven confirmed honey bee quantitative trait loci (QTLs) influencing foraging division of labor (pollen or nectar collecting) and nest defense (stinging and guarding). The high recombination rate of the bee allowed us to narrow th...

  7. A Simulation of Optimal Foraging: The Nuts and Bolts Approach.

    ERIC Educational Resources Information Center

    Thomson, James D.

    1980-01-01

    Presents a mechanical model for an ecology laboratory that introduces the concept of optimal foraging theory. Describes the physical model which includes a board studded with protruding machine bolts that simulate prey, and blindfolded students who simulate either generalist or specialist predator types. Discusses the theoretical model and data…

  8. OPTIMAL FORAGING BY LARGEMOUTH BASS IN STRUCTURED ENVIRONMENTS

    EPA Science Inventory

    The effects of different densities of vegetation on the foraging behavior of largemouth bass, Micropterus salmoides, were examined in the laboratory. Prey encounter rates and handling times and the swimming velocities of the bass while searching for and handling prey were signifi...

  9. RESEARCH ARTICLE Shorter-lived workers start foraging earlier

    E-print Network

    Tofilski , Adam

    RESEARCH ARTICLE Shorter-lived workers start foraging earlier A. Tofilski Received: 11 February. The optimal strategy of workers should be expected to depend not only on their age but also on their health the optimal time of switching between safe and risky tasks in a colony consisting of both healthy

  10. Optimal foraging, not biogenetic law, predicts spider orb web allometry

    NASA Astrophysics Data System (ADS)

    Gregori?, Matjaž; Kiesbüy, Heine C.; Quiñones Lebrón, Shakira G.; Rozman, Alenka; Agnarsson, Ingi; Kuntner, Matjaž

    2013-03-01

    The biogenetic law posits that the ontogeny of an organism recapitulates the pattern of evolutionary changes. Morphological evidence has offered some support for, but also considerable evidence against, the hypothesis. However, biogenetic law in behavior remains underexplored. As physical manifestation of behavior, spider webs offer an interesting model for the study of ontogenetic behavioral changes. In orb-weaving spiders, web symmetry often gets distorted through ontogeny, and these changes have been interpreted to reflect the biogenetic law. Here, we test the biogenetic law hypothesis against the alternative, the optimal foraging hypothesis, by studying the allometry in Leucauge venusta orb webs. These webs range in inclination from vertical through tilted to horizontal; biogenetic law predicts that allometry relates to ontogenetic stage, whereas optimal foraging predicts that allometry relates to gravity. Specifically, pronounced asymmetry should only be seen in vertical webs under optimal foraging theory. We show that, through ontogeny, vertical webs in L. venusta become more asymmetrical in contrast to tilted and horizontal webs. Biogenetic law thus cannot explain L. venusta web allometry, but our results instead support optimization of foraging area in response to spider size.

  11. Pollen collection and honey bee forager distribution in cantaloupe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Honey bee (Apis mellifera, L.) pollen collection and forager distribution were examined during the summer of 2002 in a cantaloupe (Cucumis melo, L., Cruiser cv.) field provided with plastic mulch and drip irrigation. The experimental site was located near the INIFAP Campo Experimental La Laguna, Ma...

  12. Genetic variability of a forage bermudagrass core collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bermudagrass (Cynodon sp.) is an important warm-season forage grass for the South and could also be used as a bio-energy feedstock. Cultivars have been developed with high yield and rumen digestibility, but further improvements are needed. Identification of genes that confer reduced recalcitrance...

  13. People's Study Time Allocation and its Relation to Animal Foraging

    PubMed Central

    Metcalfe, Janet; Jacobs, W. Jake

    2010-01-01

    In this article we suggest a relation between people's metacognitively guided study time allocation strategies and animal foraging. These two domains are similar insofar as people use specific metacognitive cues to assist their study time allocation just as other species use cues, such as scent marking. People decline to study items that they know they already know, just as other species use a win-shift strategy – avoiding already visited and depleted patches – in foraging. People selectively study the easiest as-yet-unlearned items first, before turning to more difficult items just as other species take the ‘just right’ size and challenge of prey--the so-called Goldilocks principle. People use a stop rule by which they give up on one item and turn to another when the returns diminish just as others species use a stop rule that guides shifting from one patch to another. The value that each item is assigned on the criterion test, if known during study, influenced which items people choose to study and how long they study them just as knowledge of the nutritional or energy value of the food influences choices and perseverance in foraging. Finally, study time allocation strategies can differ in their effectiveness depending upon the expertise of the student just as some species forage close to optimally while others do not. PMID:20026197

  14. Genomic selection in forage breeding: accuracy and methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main benefits expected from genomic selection in forage grasses and legumes are to increase selection accuracy, reduce evaluation costs per genotype, and reduce cycle time. Aiming at designing a training population and first generations of selection, deterministic equations were used to compare ...

  15. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the insured crop is damaged by an insurable cause of loss occurring within the insurance period to the... Damage or Loss) of the Basic Provisions (§ 457.8), the representative samples of the crop must be at... 7 Agriculture 6 2010-01-01 2010-01-01 false Forage seeding crop insurance provisions....

  16. Nutrient compensatory foraging in a free-living social insect

    NASA Astrophysics Data System (ADS)

    Christensen, Keri L.; Gallacher, Anthony P.; Martin, Lizzie; Tong, Desmond; Elgar, Mark A.

    2010-10-01

    The geometric framework model predicts that animal foraging decisions are influenced by their dietary history, with animals targeting a combination of essential nutrients through compensatory foraging. We provide experimental confirmation of nutrient-specific compensatory foraging in a natural, free-living population of social insects by supplementing their diet with sources of protein- or carbohydrate-rich food. Colonies of the ant Iridomyrmex suchieri were provided with feeders containing food rich in either carbohydrate or protein for 6 days, and were then provided with a feeder containing the same or different diet. The patterns of recruitment were consistent with the geometric framework: while feeders with a carbohydrate diet typically attracted more workers than did feeders with protein diet, the difference in recruitment between the two nutrients was smaller if the colonies had had prior access to carbohydrate than protein. Further, fewer ants visited feeders if the colony had had prior access to protein than to carbohydrates, suggesting that the larvae play a role in worker foraging behaviour.

  17. Multimodal signals enhance decision making in foraging bumble-bees

    E-print Network

    Papaj, Daniel

    Multimodal signals enhance decision making in foraging bumble-bees Ipek G. Kulahci*, Anna Dornhaus Street, Tucson, AZ 85721, USA Multimodal signals are common in nature and have recently attracted that multimodal signals improve decision making in receivers by influencing the speed and the accuracy

  18. Broiler litter effects on forage quality in tall fescue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land application of broiler chicken (Gallus gallus) litter to forage crops is one of the most obvious methods of recycling nutrients. However, manure management remains one of the greatest challenges for livestock producers, particularly where animals are produced on relatively small land areas. Tal...

  19. FORAGE ENERGY CROPS AS FEEDSTOCKS FOR PRODUCTION OF FUEL ETHANOL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alfalfa, reed canarygrass, and switchgrass are perennial herbaceous species that have potential as biomass energy crops in temperate regions. Each forage species was harvested at two or three maturity stages and analyzed for carbohydrates, lignin, protein, lipid, organic acids, and mineral composit...

  20. People's study time allocation and its relation to animal foraging.

    PubMed

    Metcalfe, Janet; Jacobs, W Jake

    2010-02-01

    In this article we suggest a relation between people's metacognitively guided study time allocation strategies and animal foraging. These two domains are similar insofar as people use specific metacognitive cues to assist their study time allocation just as other species use cues, such as scent marking. People decline to study items that they know they already know, just as other species use a win-shift strategy - avoiding already visited and depleted patches - in foraging. People selectively study the easiest as-yet-unlearned items first, before turning to more difficult items just as other species take the 'just right' size and challenge of prey-the so-called Goldilocks principle. People use a stop rule by which they give up on one item and turn to another when the returns diminish just as others species use a stop rule that guides shifting from one patch to another. The value that each item is assigned on the criterion test, if known during study, influences which items people choose to study and how long they study them just as knowledge of the nutritional or energy value of the food influences choices and perseverance in foraging. Finally, study time allocation strategies can differ in their effectiveness depending upon the expertise of the student just as some species forage close to optimally while others do not. PMID:20026197

  1. Wheat Forages Contain Variable Levels of Condensed Tannin Reactive Substances

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Even though winter wheat pasture in the southern Great Plains is considered excellent forage, devastating losses of stocker cattle can occur due to pasture bloat. Tannins are known to reduce the incidence and severity of bloat. We examined tannins in adapted wheat varieties that are commonly grazed ...

  2. FORAGE YIELD, NUTRITIVE VALUE, AND GRAZING TOLERANCE OF DALLISGRASS BIOTYPES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common dallisgrass(Paspalum dilatatum Poir.)is an important forage grass in many of the sub-tropical regions of the world including the southeastern USA. The term dallisgrass is synonymous with the common biotype; however, there are other biotypes of this species but little is known about their fora...

  3. GRAZING TOLERANCE AND FORAGE PRODUCTION OF SELECTED DALLISGRASS ACCESSIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common dallisgrass (Paspalum dilatatum Poir.), introduced into the USA from South America, is an important forage grass in many of the warmer regions of the world. The term dallisgrass is synonymous with the common biotype which is distributed throughout the southeastern USA and is widely used for ...

  4. RESEARCH ARTICLE The Role of Natural Enemy Foraging Guilds

    E-print Network

    Landis, Doug

    RESEARCH ARTICLE The Role of Natural Enemy Foraging Guilds in Controlling Cereal Aphids in Michigan aphids in Michigan winter wheat (Triticum aestivum L.) is largely unknown. The objectives cereal aphid population growth. We investigated these objectives during the spring and summer of 2012

  5. Potential energetic effects of mountain climbers on foraging grizzly bears

    USGS Publications Warehouse

    White, D., Jr.; Kendall, K.C.; Picton, H.D.

    1999-01-01

    Most studies of the effects of human disturbance on grizzly bears (Ursus arctos horribilis) have not quantified the energetic effects of such interactions. In this study, we characterized activity budgets of adult grizzly bears as they foraged on aggregations of adult army cutworm moths (Euxoa auxiliaris) in the alpine of Glacier National Park, Montana, during 1992, 1994, and 1995. We compared the activity budgets of climber-disturbed bears to those of undisturbed bears to estimate the energetic impact of climber disturbance. When bears detected climbers, they subsequently spent 53% less time foraging on moths, 52% more time moving within the foraging area, and 23% more time behaving aggressively, compared to when they were not disturbed. We estimated that grizzly bears could consume approximately 40,000 moths/day or 1,700 moths/hour. At 0.44 kcal/moth, disruption of moth feeding cost bears approximately 12 kcal/minute in addition to the energy expended in evasive maneuvers and defensive behaviors. To reduce both climber interruption of bear foraging and the potential for aggressive bear-human encounters, we recommend routing climbers around moth sites used by bears or limiting access to these sites during bear-use periods.

  6. Response of Forage Chicory Seedlings to Available Soil Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus fertility may be responsible for observed differences in chemical composition of forage chicory (Cichorium intybus L.) on West Virginia and Pennsylvania soils, but P effects on chicory growth on these soils are unclear. We evaluated the effect of available soil P (ASP) on ‘Puna’, ‘Lacert...

  7. Packing bunkers and piles to maximize forage preservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage is a valuable commodity stored on dairy farms. Bunker and pile silos have increased in use due to increasing herd size. Losses in feed value in bunker and pile silos are frequently higher than they should be because producers are not packing them sufficiently to exclude oxygen during the stor...

  8. Finger millet: An alternative forage crop for Southern High Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Southern High Plains, dairies are expanding to take advantage of favorable climatic conditions. Currently corn (Zea mays L.) and forage sorghum (Sorghum bicolor (L.) Moench) are the two major crops grown in the region to meet the current silage demand. Corn and sorghum have relatively large w...

  9. Competition in foraging flocks of migrating semipalmated sandpipers.

    PubMed

    Beauchamp, Guy

    2007-11-01

    I examined the effect of competitor density on foraging success in staging semipalmated sandpipers (Calidris pusilla) foraging on a burrowing amphipod (Corophium volutator) in each of two study years. Little is known about the effect of competitor density when predation attempts disturb prey, causing a temporary decrease in food availability. Controlling for Corophium density and other potentially confounding factors such as temperature, pecking rate and capture rate increased linearly with sandpiper density. Success rate, the ratio of captures to pecks, was not influenced by sandpiper density. The effect of sandpiper density was similar in each of the two study years and was documented early and late in the low tide period. The increase in foraging rate is argued to be a response to increased competition for rapidly depleting prey at the temporal scale of exploitation by a flock. Potential fitness costs associated with higher foraging costs may include decreased ability to distinguish between the profitability of different prey and reduced vigilance against predators. PMID:17676344

  10. Evolving Foraging Behaviors Liviu Panait and Sean Luke

    E-print Network

    Luke, Sean

    , such a foraging for food far away from the nest or clustering objects into piles, can be solved through relatively problems. Our experimental substrate was a toroidal grid environment with a single nest and point food was significantly less than that afforded in the hand-coded designs we discussed in another paper submitted

  11. ORGANOCHLORINE CONTAMINANTS OF WINTERING DUCKS FORAGING ON DETROIT RIVER SEDIMENTS

    EPA Science Inventory

    Organochlorine analysis was performed on carcasses of 13 diving ducks from a 1981 wintering population that foraged on contaminated sediments in the lower Detroit River. Mean total PCB concentrations were 10 mg/kg for seven lesser scaups (Aythya affinis), 11 mg/kg for three great...

  12. Germplasm evaluation of Rhizoma peanut for growth and forage potential.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizoma peanut (Arachis glabrata Benth.) is a warm-season perennial forage legume, adapted to southern USA. It has similar dry matter (DM) and nutritive value to alfalfa (Medicago sativa L.). Recent studies indicated that rhizoma peanut can be grown further north (zone '8b) than previously suggest...

  13. NOTE / NOTE Foraging behaviour by gray wolves on salmon

    E-print Network

    Reimchen, Thomas E.

    NOTE / NOTE Foraging behaviour by gray wolves on salmon streams in coastal British Columbia C they co-evolve. Gray wolves (Canis lupus), primarily predators of ungulates, are sympatric with salmon observations of direct and indirect evidence of salmon predation by wolves in several watersheds of coastal

  14. Effects of humic acid on forage digestibility in ruminants 

    E-print Network

    Faulkenbery, James Marcus

    1995-01-01

    Three experiments were conducted to determine the effects of purified humic acid (HA) on rate and extent of microbial digestion of various forages in ruminants. In Exp. 1 the in vitro dry matter disappearance (DMD) of Coastal Bermuda grass hay (CBH...

  15. Improving yield and protein content of forages under flooded condition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flooding can have catastrophic impacts on the productivity of arable farmland, grassland pastures, as most crops including forages are intolerant to excess water. The objectives of this study were to determine the effect of flooding duration and nitrogen (N) fertilization on dry matter yield (DMY) a...

  16. Adaptive foraging and flexible food web topology Vlastimil Krivan

    E-print Network

    Krivan, Vlastimil

    modelling shows that single systems of predators, adaptive herbivores and resources can display food chain, adaptive omnivory causes the exploitative competition, linear food chain and multi-trophic level omnivory be confounded by topological shifts in the system itself. Keywords: adaptive foraging, food chain, food web

  17. Estimating Forage Quality of Grazing Ruminants (Part 2)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meeting the nutritional needs of a mother cow through the different physiological stages of reproduction, lactation and recovery from parturition is very important to sustained productivity. Having a calf and nursing it to weaning every year is quite a task. Consuming sufficient high quality forag...

  18. Fish Foraging on an Artificial Reef in Puget Sound, Washington

    E-print Network

    Fish Foraging on an Artificial Reef in Puget Sound, Washington GREGORY J. HUECKEL and R. LEE 1977 and December 1978. The Study Area The artificial reef is located off the west shoreline of Edmonds with the artificial reef than did smallfish ofthe same species. Abundance of preferred food items of medium and large

  19. ORIGINAL PAPER Vortex formation and foraging in polyphenic spadefoot

    E-print Network

    Couzin, Iain D.

    ORIGINAL PAPER Vortex formation and foraging in polyphenic spadefoot toad tadpoles Sepideh Bazazi tadpoles: Spea bombifrons and Spea multiplicata. Tadpoles of these species develop into either. multiplicata are more likely to develop into omnivores and feed on suspended organic matter in the water body

  20. Fact Sheet: Accurately measuring forage yield in pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers have a few options for measuring pasture yield. These include pasture rulers, plate meters, and electronic gauges. Pasture rulers simply measure canopy height and assume that forage yield is directly related to height. Plate meters improve accuracy by measuring compressed height. Electronic ...

  1. Yield and persistence response of forage chicory to phosphorus fertility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage chicory (Cichorium intybus) is a productive plant that appears particularly well suited to improving summer yield of pastures in the USA. Poor palatability of some chicory cultivars in locations with low soil phosphorus fertility has been linked to high levels of sesquiterpene lactone, a bit...

  2. Effect of Precipitation During Key Months on Forage Growth Potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ranchers and range managers find themselves at the mercy of Mother Nature when making stocking decisions early in the spring. Most forage growth potential is determined by precipitation during key months in the spring (Heitschmidt et al., 1999) – often multiple spring months are important with resp...

  3. Effect of forage species on ruminal fermentation in continuous culture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intake and digestion of pasture herbage can be influenced by canopy structure. A dual-flow continuous culture fermenter system was used to investigate the effect of forage species on digestion and ruminal fermentation. Four grass species [reed canarygrass (RCG), Phalaris arundinacea L; quackgrass (Q...

  4. Dietary Forage Impacts on Dairy Slurry N Availability to Corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More precise feeding of protein and mineral supplement reduces nutrient excretion in dairy manure and losses to the environment. No information is available on the impacts of feeding different forages to dairy cattle on manure N chemistry and subsequent N cycling in soils. Slurry (feces plus urine) ...

  5. Sap Analysis for Diagnosis of Nitrate Accumulation in Cereal Forages

    E-print Network

    Lawrence, Rick L.

    Sap Analysis for Diagnosis of Nitrate Accumulation in Cereal Forages Mal Westcott1 , Dennis Cash2 be expected after harvest. Our objective was to determine if nitrate concentrations in sap expressed from in the dry hay. We also sought to determine if this sap nitrate analysis could be reliably performed

  6. Imidacloprid Alters Foraging and Decreases Bee Avoidance of Predators

    E-print Network

    Nieh, James

    Imidacloprid Alters Foraging and Decreases Bee Avoidance of Predators Ken Tan1,2 *, Weiwen Chen2 Bee Research Institute, Yunnan Agricultural University, Heilongtan, Kunming, Yunnan Province, China, 3 of neonicotinoid pesticides, which can impair honey bee cognition. We provide the first demonstration

  7. Utilization of Pasture and Forages by Ruminants: A Historical Perspective

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pastures, forages and grasslands dominate the landscape across the United States and support a large ruminant population that supplies the nation with value-added animal products. An historical perspective is presented of the innovations as they occurred in the Journal of Animal Science over the pas...

  8. Use of Urban Marine Habitats by Foraging Wading Birds

    EPA Science Inventory

    Wading birds that utilize coastal habitats may be at risk from increasing urbanization near their foraging and stopover sites. However, the relative importance of human disturbance in the context of other landscape and biological factors that may be influencing their distributio...

  9. Sampling requirements for forage quality characterization of rectangular hay bales

    SciTech Connect

    Sheaffer, C.C.; Martin, N.P.; Jewett, J.G.; Halgerson, J.; Moon, R.D.; Cuomo, G.R.

    2000-02-01

    Commercial lots of alfalfa (Medicago sativa L.) hay are often bought and sold on the basis of forage quality. Proper sampling is essential to obtain accurate forage quality results for pricing of alfalfa hay, but information about sampling is limited to small, 20- to 40-kg rectangular bales. Their objectives were to determine the within-bale variation in 400-kg rectangular bales and to determine the number and distribution of core samples required to represent the crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and dry matter (DM) concentration in commercial lots of alfalfa hay. Four bales were selected from each of three hay lots and core sampled nine times per side for a total of 54 cores per bale. There was no consistent pattern of forage quality variation within bales. Averaged across lots, any portion of a bale was highly correlated with bale grand means for CP, ADF, NDF, and DM. Three lots of hay were probed six times per bale, one core per bale side from 55, 14, and 14 bales per lot. For determination of CP, ADF, NDF, and DM concentration, total core numbers required to achieve an acceptable standard error (SE) were minimized by sampling once per bale. Bootstrap analysis of data from the most variable hay lot suggested that forage quality of any lot of 400-kg alfalfa hay bales should be adequately represented by 12 bales sampled once per bale.

  10. Forage Kochia (Kochia Prostrata) for Fall and Winter Grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage kochia (Kochia prostrata (L.) Scrad), also known as prostrate kochia, or prostrate summer cypress is a long-lived, perennial, semi-evergreen, half-shrub well adapted to the temperate, semiarid and arid regions of central Asia and the western U.S. In these areas, it has proven to be a valuabl...

  11. Cervid forage utilization in noncommercially thinned ponderosa pine forests

    USGS Publications Warehouse

    Gibbs, M.C.; Jenks, J.A.; Deperno, C.S.; Sowell, B.F.; Jenkins, Kurt J.

    2004-01-01

    To evaluate effects of noncommercial thinning, utilization of forages consumed by elk (Cervus elaphus L.), mule deer (Odocoileus hemionus Raf.), and white-tailed deer (Odocoileus virginianus Raf.) was measured in ponderosa pine (Pinus ponderosa P. & C. Lawson) stands in Custer State Park, S. D. Treatments consisted of unthinned (control; 22 to 32 m2/ha basal area), moderately thinned (12 to 22 m2/ha basal area), and heavily thinned (3 to 13 m2/ha basal area) stands of ponderosa pine. During June, July, and August, 1991 and 1992, about 7,000 individual plants were marked along permanent transects and percent-weight-removed by grazing was ocularly estimated. Sample plots were established along transects and plants within plots were clipped to estimate standing biomass. Pellet groups were counted throughout the study area to determine summer habitat use of elk and deer. Diet composition was evaluated using microhistological analysis of fecal samples. Average percent-weight-removed from all marked plants and percent-plants-grazed were used to evaluate forage utilization. Standing biomass of graminoids, shrubs, and forbs increased (P 0.05) across treatments. Forb use averaged less than 5% within sampling periods when measured as percent-weight-removed and percent-of-plants grazed and did not differ among treatments. Results of pellet group surveys indicated that cervids were primarily using meadow habitats. When averaged over the 2 years, forbs were the major forage class in deer diets, whereas graminoids were the major forage class in diets of elk.

  12. DYNAPHORE, INC. FORAGER? SPONGE TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    The Forager? Sponge is an open-celled cellulose sponge incorporating an amine-containing chelating polymer that selectively absorbs dissolved heavy metals from aqueous waste streams. The Developer states that the technology can be utilized to remove and concentrate heavy metals f...

  13. Rational Analyses of Information Foraging on the Web

    ERIC Educational Resources Information Center

    Pirolli, Peter

    2005-01-01

    This article describes rational analyses and cognitive models of Web users developed within information foraging theory. This is done by following the rational analysis methodology of (a) characterizing the problems posed by the environment, (b) developing rational analyses of behavioral solutions to those problems, and (c) developing cognitive…

  14. Benefits of Perennial Forages for Soils, Crops, and Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alfalfa is the most widely grown perennial forage species in the US, with the greatest acreage in the upper Midwest and Western states. But alfalfa acreage has been declining steadily for the past 50 years, while the acreage of soybeans and, more recently, corn has been increasing. There are costs a...

  15. PERENNIAL GRASS BREEDING PROGRAM FOR FORAGE AND BIOFUELS - TIFTON, GA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage improvement of bermudagrass and bahiagrass continues within the Crop Genetics and Breeding Research Unit of USDA/ARS. Recently, a new effort has begun within the unit toward developing perennial grass crops as feedstocks for bio-energy in the Southeast. An emphasis beginning three years ago...

  16. Quest for Nutritional and Medicinal Forages for Meat Goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Appalachian meat goat producers are encountering animal nutritional and health problems for which research-based solutions are limited. Goats prefer to eat weeds and browse, selecting the highest quality herbage available. Foraging on traditional pastures not only limits the variety of plant speci...

  17. ORIGINAL ARTICLE Collective decisions in ants when foraging

    E-print Network

    Nicolis, Stamatios C.

    ORIGINAL ARTICLE Collective decisions in ants when foraging under crowded conditions Audrey-recruiting ant Lasius niger. In our experiment, ants had to go from their nest to a food source by crossing underlying the choice of route in ants. A mathematical model was developed to evaluate the impor- tance

  18. INTRODUCTION Individual foraging ants show remarkable navigational abilities.

    E-print Network

    Cheng, Ken

    44 INTRODUCTION Individual foraging ants show remarkable navigational abilities. Our current of the strategies underpinning the use of visual information can be observed in the field by capturing homing ants just before they reach their nest (i.e. zero-vector ants) and displacing them to different locations

  19. DUSKY DOLPHIN (LAGENORHYNCHUS OBSCURUS) FORAGING IN TWO DIFFERENT

    E-print Network

    Benoit-Bird, Kelly J.

    DUSKY DOLPHIN (LAGENORHYNCHUS OBSCURUS) FORAGING IN TWO DIFFERENT HABITATS: ACTIVE ACOUSTIC DETECTION OF DOLPHINS AND THEIR PREY KELLY J. BENOIT-BIRD Hawaii Institute of Marine Biology and Department to determine the distribution of dusky dolphins and potential prey in two different New Zealand locations

  20. The Effects of Ant Mutualism on the Foraging and Diet

    E-print Network

    Pierce, Naomi E.

    12 The Effects of Ant Mutualism on the Foraging and Diet of Lycaenid Caterpillars Matthew Baylis; Atsatt 198 Ib; Cottrell 1984; Pierce 1987). Mutualisms in which the fitness of each partner is increased-ant mutualisms and the responses of Iycaenids to those challenges. We will begin with a brief overview of some

  1. 7 CFR 457.151 - Forage seeding crop insurance provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... designated by the calendar year in which the planting is made for spring planted acreage and the next... Special Provisions provide a sales closing date for both fall seeded and spring seeded practices for the... coverage after the fall sales closing date for the fall seeded practice. Spring planted—A forage...

  2. Extending the Particle Swarm Algorithm to Model Animal Foraging Behaviour

    E-print Network

    Poli, Riccardo

    Extending the Particle Swarm Algorithm to Model Animal Foraging Behaviour Cecilia Di Chio1 behaviour represents a first step in simulating more complex group behaviour in animals. 2 Approach The simulation of animal grouping behaviour is extremely complex. Therefore, in order to make progress, we focus

  3. Foraging success of biological Lévy flights recorded in situ.

    PubMed

    Humphries, Nicolas E; Weimerskirch, Henri; Queiroz, Nuno; Southall, Emily J; Sims, David W

    2012-05-01

    It is an open question how animals find food in dynamic natural environments where they possess little or no knowledge of where resources are located. Foraging theory predicts that in environments with sparsely distributed target resources, where forager knowledge about resources' locations is incomplete, Lévy flight movements optimize the success of random searches. However, the putative success of Lévy foraging has been demonstrated only in model simulations. Here, we use high-temporal-resolution Global Positioning System (GPS) tracking of wandering (Diomedea exulans) and black-browed albatrosses (Thalassarche melanophrys) with simultaneous recording of prey captures, to show that both species exhibit Lévy and Brownian movement patterns. We find that total prey masses captured by wandering albatrosses during Lévy movements exceed daily energy requirements by nearly fourfold, and approached yields by Brownian movements in other habitats. These results, together with our reanalysis of previously published albatross data, overturn the notion that albatrosses do not exhibit Lévy patterns during foraging, and demonstrate that Lévy flights of predators in dynamic natural environments present a beneficial alternative strategy to simple, spatially intensive behaviors. Our findings add support to the possibility that biological Lévy flight may have naturally evolved as a search strategy in response to sparse resources and scant information. PMID:22529349

  4. The influence of Hawaiian seamounts on the forage base

    E-print Network

    Hawai'i at Manoa, University of

    The influence of Hawaiian seamounts on the forage base for oceanic predators Jeffrey Drazen1, Lisa Fishery Science Center, NMFS, NOAA Need photo of trawl #12;Background · Over 30,000 seamounts and banks on benthic fish aggregations (i.e. orange roughy, alfonsino's, rockfishes) · Some seamounts function as tuna

  5. Empty-headed dynamical model of infant visual foraging.

    PubMed

    Robertson, Steven S

    2014-07-01

    Visual foraging is one important way that very young infants explore and learn about their environment. We recently showed that a simple stochastic dynamical model acts quantitatively like free-looking 1-month-old infants, even though it does not include any components that directly represent the perceptual-cognitive processes that operate on the input from visual foraging. This suggested that early in development, generic low-level processes like noise and hysteresis in the mechanisms controlling gaze may drive visual foraging behavior and therefore regulate the input to higher-level perceptual-cognitive processes that later come to have more influence on free looking. Here we evaluate the model's ability to behave like 3-month-olds studied under the same experimental conditions as 1-month-olds. The results show that the empty-headed model can also behave like 3-month-old infants, although not as well as 1-month-olds. Its partial success at 3 months suggests that generic low-level processes controlling gaze remain important in visual foraging. Its pattern of failure suggests that by 3 months time-dependent processes like attention have become especially important. PMID:24009070

  6. Generalizing foraging theory for analysis The International Journal of

    E-print Network

    random environments. As nature selects for foraging behaviors that maximize lifetime calorie gain a random value that is analo- gous to calorie content. In addition, when an agent chooses to prosecute lifetime calorie content or minimize the probability of starvation, engineering design favors decision

  7. FORAGE YIELD AND PERSISTENCE OF CHICORY AND ENGLISH PLANTAIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graziers in the northeast often face forage shortages in midsummer. Chicory (Cichorium intybus L.) and English plantain (Plantago lanceolata L.) have been introduced in the USA as perennial herbs for pastures and have been touted as drought tolerant. We conducted two field-plot experiments at Rock S...

  8. GROWTH OF THREE FORAGE SPECIES IN SALINE CONDITIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potential forage crops were evaluated under simulated saline conditions found in southeast Colorado. Due to elevated salinity levels in both the soils and in the irrigation waters of this region identifying salt tolerant crops for sustained productivity is important. The objective of the greenhous...

  9. At-Sea Associations in Foraging Little Penguins

    PubMed Central

    Berlincourt, Maud; Arnould, John P. Y.

    2014-01-01

    Prey distribution, patch size, and the presence of conspecifics are important factors influencing a predator’s feeding tactics, including the decision to feed individually or socially. Little is known about group behaviour in seabirds as they spend most of their lives in the marine environment where it is difficult to observe their foraging activities. In this study, we report on at-sea foraging associations of little penguins (Eudyptula minor) during the breeding season. Individuals could be categorised as (1) not associating; (2) associating when departing from and/or returning to the colony; or (3) at sea when travelling, diving or performing synchronised dives. Out of 84 separate foraging tracks, 58 (69.0%) involved associations with conspecifics. Furthermore, in a total of 39 (46.4%), individuals were found to dive during association and in 32 (38.1%), individuals were found to exhibit synchronous diving. These behaviours suggest little penguins forage in groups, could synchronise their underwater movements and potentially cooperate to concentrate their small schooling prey. PMID:25119718

  10. Fall Growth Potential of Cereal Grain Forages in Northern Arkansas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Arkansas, producers utilizing cereal grains as fall forage for weaned calves usually do not harvest a grain crop the following summer. This contrasts sharply from practices observed commonly in neighboring Oklahoma, and allows for much wider latitude with respect to management strategies, especia...

  11. Fall Growth Potential of Cereal-Grain Forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Arkansas, producers utilizing cereal grains as fall forage for weaned calves usually do not produce a grain crop the following summer. Our objectives were to evaluate eight diverse varieties of wheat (Triticum aestivum L.), oat (Avena sativa L.), rye (Secale cereale L.), and triticale (X Triticos...

  12. Allocating Great Lakes forage bases in response to multiple demand

    USGS Publications Warehouse

    Brown, Edward H., Jr.; Busiahn, Thomas R.; Jones, Michael L.; Argyle, Ray L.

    1999-01-01

    Forage base allocation, which has become an important issue because of major changes in the fish communities and fisheries of the Great Lakes since the 1950s is examined and documented in this chapter. Management initiatives that were used to address the issue, and supporting research and development that provided new or improved methods of field sampling and analysis are also highlighted.

  13. Foraging Ecology Predicts Learning Performance in Insectivorous Bats

    E-print Network

    Page, Rachel

    Foraging Ecology Predicts Learning Performance in Insectivorous Bats Theresa M. A. Clarin1 insectivorous European bat species of the genus Myotis that belong to three different functional groups based Ecology Predicts Learning Performance in Insectivorous Bats. PLoS ONE 8(6): e64823. doi:10.1371/journal

  14. Adelie Penguin Foraging Location Predicted by Tidal Regime Switching

    E-print Network

    Ade´lie Penguin Foraging Location Predicted by Tidal Regime Switching Matthew J. Oliver1 *, Andrew and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, United States of America Abstract Penguin of their habitat. We investigated the effect of local tidal currents on a population of Ade´lie penguins on Humble

  15. Legume-Cereal Intercropping Improves Forage Yield, Quality and Degradability

    PubMed Central

    Xie, Yuhuai; Li, Jing.; Yang, Zaibin; Zhang, Guiguo

    2015-01-01

    Intercropping legume with cereal is an extensively applied planting pattern in crop cultivation. However, forage potential and the degradability of harvested mixtures from intercropping system remain unclear. To investigate the feasibility of applying an intercropping system as a forage supply source to ruminants, two consecutive experiments (experiments 1 and 2) involving a field cultivation trial and a subsequent in vivo degradable experiment were conducted to determine the forage production performance and the ruminally degradable characteristics of a harvested mixture from an alfalfa/corn-rye intercropping system. In experiment 1, the intercropping system was established by alternating alfalfa and corn or rye with a row ratio of 5:2. Dry matter (DM) and nutrient yields were determined. In experiment 2, forages harvested from the different treatments were used as feedstuff to identify nutrient degradation kinetics and distribution of components between the rapidly degradable (a), potentially degradable (b) and the degradation rate constant (c) of ‘b’ fraction by in sacco method in Small-Tail Han wether Sheep. The intercropping system of alfalfa and corn-rye provided higher forage production performance with net increases of 9.52% and 34.81% in DM yield, 42.13% and 16.74% in crude protein (CP) yield, 25.94% and 69.99% in degradable DM yield, and 16.96% and 5.50% in degradable CP yield than rotation and alfalfa sole cropping systems, respectively. In addition, the harvest mixture from intercropping system also had greater ‘a’ fraction, ‘b’ fraction, ‘c’ values, and effective degradability (E value) of DM and CP than corn or rye hay harvested from rotation system. After 48-h exposure to rumen microbes, intercropping harvest materials were degraded to a higher extent than separately degraded crop stems from the sole system as indicated by visual microscopic examination with more tissues disappeared. Thus, the intercropping of alfalfa and corn-rye exhibited a greater forage production potential, and could be applied as forage supply source for ruminants. The improved effective degradability of harvest mixture material could be attributed to greater degradable components involving the rapidly degradable fractions (a), potentially degradable (b) fractions, and degradable rate constant (c), than that of corn and rye hay. PMID:26672990

  16. Legume-Cereal Intercropping Improves Forage Yield, Quality and Degradability.

    PubMed

    Zhang, Jie; Yin, Binjie; Xie, Yuhuai; Li, Jing; Yang, Zaibin; Zhang, Guiguo

    2015-01-01

    Intercropping legume with cereal is an extensively applied planting pattern in crop cultivation. However, forage potential and the degradability of harvested mixtures from intercropping system remain unclear. To investigate the feasibility of applying an intercropping system as a forage supply source to ruminants, two consecutive experiments (experiments 1 and 2) involving a field cultivation trial and a subsequent in vivo degradable experiment were conducted to determine the forage production performance and the ruminally degradable characteristics of a harvested mixture from an alfalfa/corn-rye intercropping system. In experiment 1, the intercropping system was established by alternating alfalfa and corn or rye with a row ratio of 5:2. Dry matter (DM) and nutrient yields were determined. In experiment 2, forages harvested from the different treatments were used as feedstuff to identify nutrient degradation kinetics and distribution of components between the rapidly degradable (a), potentially degradable (b) and the degradation rate constant (c) of 'b' fraction by in sacco method in Small-Tail Han wether Sheep. The intercropping system of alfalfa and corn-rye provided higher forage production performance with net increases of 9.52% and 34.81% in DM yield, 42.13% and 16.74% in crude protein (CP) yield, 25.94% and 69.99% in degradable DM yield, and 16.96% and 5.50% in degradable CP yield than rotation and alfalfa sole cropping systems, respectively. In addition, the harvest mixture from intercropping system also had greater 'a' fraction, 'b' fraction, 'c' values, and effective degradability (E value) of DM and CP than corn or rye hay harvested from rotation system. After 48-h exposure to rumen microbes, intercropping harvest materials were degraded to a higher extent than separately degraded crop stems from the sole system as indicated by visual microscopic examination with more tissues disappeared. Thus, the intercropping of alfalfa and corn-rye exhibited a greater forage production potential, and could be applied as forage supply source for ruminants. The improved effective degradability of harvest mixture material could be attributed to greater degradable components involving the rapidly degradable fractions (a), potentially degradable (b) fractions, and degradable rate constant PMID:26672990

  17. Predation Risk Perception, Food Density and Conspecific Cues Shape Foraging Decisions in a Tropical Lizard

    PubMed Central

    Kolbe, Jason J.

    2015-01-01

    When foraging, animals can maximize their fitness if they are able to tailor their foraging decisions to current environmental conditions. When making foraging decisions, individuals need to assess the benefits of foraging while accounting for the potential risks of being captured by a predator. However, whether and how different factors interact to shape these decisions is not yet well understood, especially in individual foragers. Here we present a standardized set of manipulative field experiments in the form of foraging assays in the tropical lizard Anolis cristatellus in Puerto Rico. We presented male lizards with foraging opportunities to test how the presence of conspecifics, predation-risk perception, the abundance of food, and interactions among these factors determines the outcome of foraging decisions. In Experiment 1, anoles foraged faster when food was scarce and other conspecifics were present near the feeding tray, while they took longer to feed when food was abundant and when no conspecifics were present. These results suggest that foraging decisions in anoles are the result of a complex process in which individuals assess predation risk by using information from conspecific individuals while taking into account food abundance. In Experiment 2, a simulated increase in predation risk (i.e., distance to the feeding tray) confirmed the relevance of risk perception by showing that the use of available perches is strongly correlated with the latency to feed. We found Puerto Rican crested anoles integrate instantaneous ecological information about food abundance, conspecific activity and predation risk, and adjust their foraging behavior accordingly. PMID:26384236

  18. Sub-ice foraging behavior of emperor penguins.

    PubMed

    Ponganis, P J; Van Dam, R P; Marshall, G; Knower, T; Levenson, D H

    2000-11-01

    Emperor penguins (Aptenodytes forsteri) were equipped with a remote underwater video camera, the Crittercam, to evaluate sub-ice foraging behavior while the birds dived from an isolated dive hole. Three birds dived and foraged successfully for 1 h periods after being trained to wear and to dive with a harness for camera attachment. Video and depth profile recordings revealed that emperor penguins travel at shallow depths (<50 m), ascend to the undersurface of the ice to feed on fish, and descend back to depth to return to the exit hole. Although the mean durations of dives of individual birds with the Crittercam were 21-35 % shorter than the diving durations of these same birds without the camera, the dive profiles in both situations were similar, thus demonstrating a similar foraging strategy in birds diving without the camera. Despite shorter diving durations with the camera, the penguins were still successful at prey capture in 80 % of 91 dives greater than 1 min in duration. Prey included the sub-ice fish Pagothenia borchgrevinki. Hunting ascents (from depth to within 5 m of the surface) occurred in 85 % of dives, ranged from zero to three per dive, and were associated with successful prey capture in 77 % of 128 ascents. Occasionally, several fish were captured during a single ascent. These observations and this application of video technology create a model for further physiological and behavioral studies of foraging, and also emphasize the potential importance of shallow dives as sources of food intake for emperor penguins during foraging trips to sea. PMID:11023847

  19. The dilemma of foraging herbivores: dealing with food and fear.

    PubMed

    McArthur, Clare; Banks, Peter B; Boonstra, Rudy; Forbey, Jennifer Sorensen

    2014-11-01

    For foraging herbivores, both food quality and predation risk vary across the landscape. Animals should avoid low-quality food patches in favour of high-quality ones, and seek safe patches while avoiding risky ones. Herbivores often face the foraging dilemma, however, of choosing between high-quality food in risky places or low-quality food in safe places. Here, we explore how and why the interaction between food quality and predation risk affects foraging decisions of mammalian herbivores, focusing on browsers confronting plant toxins in a landscape of fear. We draw together themes of plant-herbivore and predator-prey interactions, and the roles of animal ecophysiology, behaviour and personality. The response of herbivores to the dual costs of food and fear depends on the interplay of physiology and behaviour. We discuss detoxification physiology in dealing with plant toxins, and stress physiology associated with perceived predation risk. We argue that behaviour is the interface enabling herbivores to stay or quit food patches in response to their physiological tolerance to these risks. We hypothesise that generalist and specialist herbivores perceive the relative costs of plant defence and predation risk differently and intra-specifically, individuals with different personalities and physiologies should do so too, creating individualised landscapes of food and fear. We explore the ecological significance and emergent impacts of these individual-based foraging outcomes on populations and communities, and offer predictions that can be clearly tested. In doing so, we provide an integrated platform advancing herbivore foraging theory with food quality and predation risk at its core. PMID:25270335

  20. Feasibility study of wood stork foraging habitat mapping using landsat multispectral data

    SciTech Connect

    Jensen, J.R.; Hodgson, M.E.; Coulter, M.; Mackey, H.E. Jr.

    1986-01-01

    The wood stork is a large wading bird which forages in shallow wetlands up to 70 kilometers from the colony. Landsat data were evaluated to determine if remote sensing data were suitable for locating and estimating the extent of potential foraging habitat for this species over such a large range. Thematic Mapper data of north-central Georgia and the Savannah River floodplain in South Carolina were obtained May 5, 1984. Spectral signatures from known foraging sites near a colony in Georgia were identified. Computer clustering techniques were used to identify and map shallow water and marsh wetland foraging habitats. Foraging acreages were computed, and maps of the locations of candidate foraging sites were produced for a 1520-square-kilometer area. Remote sensing appears to provide a feasible method of evaluating the regional wetland foraging habitat available to this wide-ranging species.

  1. Forage yield of grass-alfalfa and grass-forage kochia mixtues on semi-arid rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased productivity of semiarid western U.S.A. grazing lands is possible with the appropriate plant material combinations. The objective of this study was to compare late summer forage yield of 'Vavilov' Siberian wheatgrass (Agropyron fragile) and 'Mustang' altai wildrye (Leymus angustus) in bin...

  2. Foraging honeybees can learn many things (Menzel and Giurfa, 2001) and thus have many memories. In foraging, they

    E-print Network

    Cheng, Ken

    1019 Foraging honeybees can learn many things (Menzel and Giurfa, 2001) and thus have many memories (honeybees: Collett and Kelber, 1988; Collett et al., 1997) and indoors (honeybees: Collett and Baron, 1995 interference is found (Fauria et al., 2002). In recent work, we created situations in which honeybees exhibited

  3. Foraging fidelity as a recipe for a long life: foraging strategy and longevity in male Southern Elephant Seals.

    PubMed

    Authier, Matthieu; Bentaleb, Ilham; Ponchon, Aurore; Martin, Céline; Guinet, Christophe

    2012-01-01

    Identifying individual factors affecting life-span has long been of interest for biologists and demographers: how do some individuals manage to dodge the forces of mortality when the vast majority does not? Answering this question is not straightforward, partly because of the arduous task of accurately estimating longevity in wild animals, and of the statistical difficulties in correlating time-varying ecological covariables with a single number (time-to-event). Here we investigated the relationship between foraging strategy and life-span in an elusive and large marine predator: the Southern Elephant Seal (Mirounga leonina). Using teeth recovered from dead males on îles Kerguelen, Southern Ocean, we first aged specimens. Then we used stable isotopic measurements of carbon (?13C) in dentin to study the effect of foraging location on individual life-span. Using a joint change-point/survival modelling approach which enabled us to describe the ontogenetic trajectory of foraging, we unveiled how a stable foraging strategy developed early in life positively covaried with longevity in male Southern Elephant Seals. Coupled with an appropriate statistical analysis, stable isotopes have the potential to tackle ecological questions of long standing interest but whose answer has been hampered by logistic constraints. PMID:22505993

  4. Native bark-foraging birds preferentially forage in infected ash (Fraxinus spp.) and prove effective predators of the invasive

    E-print Network

    Farnsworth, George - Department of Biology, Xavier University

    bark-foraging bird predation on EAB larvae in a deciduous forest of central Ohio. Results of our regulate EAB populations and their spread in a mixed deciduous forest. We suggest that maintaining snags and, thus, their biological control of pest insects in temperate deciduous forests. Ó 2013 Elsevier B

  5. The Role of Non-Foraging Nests in Polydomous Wood Ant Colonies

    PubMed Central

    Ellis, Samuel; Robinson, Elva J. H.

    2015-01-01

    A colony of red wood ants can inhabit more than one spatially separated nest, in a strategy called polydomy. Some nests within these polydomous colonies have no foraging trails to aphid colonies in the canopy. In this study we identify and investigate the possible roles of non-foraging nests in polydomous colonies of the wood ant Formica lugubris. To investigate the role of non-foraging nests we: (i) monitored colonies for three years; (ii) observed the resources being transported between non-foraging nests and the rest of the colony; (iii) measured the amount of extra-nest activity around non-foraging and foraging nests. We used these datasets to investigate the extent to which non-foraging nests within polydomous colonies are acting as: part of the colony expansion process; hunting and scavenging specialists; brood-development specialists; seasonal foragers; or a selfish strategy exploiting the foraging effort of the rest of the colony. We found that, rather than having a specialised role, non-foraging nests are part of the process of colony expansion. Polydomous colonies expand by founding new nests in the area surrounding the existing nests. Nests founded near food begin foraging and become part of the colony; other nests are not founded near food sources and do not initially forage. Some of these non-foraging nests eventually begin foraging; others do not and are abandoned. This is a method of colony growth not available to colonies inhabiting a single nest, and may be an important advantage of the polydomous nesting strategy, allowing the colony to expand into profitable areas. PMID:26465750

  6. Sex-Related Differences in the Trade-Off between Foraging and Vigilance in a Granivorous Forager

    PubMed Central

    Powolny, Thibaut; Bretagnolle, Vincent; Aguilar, Astrid; Eraud, Cyril

    2014-01-01

    The relationship between intake rate and food density can provide the foundation for models that predict the spatiotemporal distribution of organisms across a range of resource densities. The functional response, describing the relationship between resource density and intake rate is often interpreted mechanistically as the relationships between times spend searching and handling. While several functional response models incorporate anti-predator vigilance (defined here as an interruption of feeding or some other activity to visually scan the environment, directed mainly towards detecting potential predators), the impacts of environmental factors influencing directly anti-predator vigilance remains unclear. We examined the combined effects of different scenarios of predation risk and food density on time allocation between foraging and anti-predator vigilance in a granivorous species. We experimentally exposed Skylarks to various cover heights and seed densities, and measured individual time budget and pecking and intake rates. Our results indicated that time devoted to different activities varied as a function of both seed density and cover height. Foraging time increased with seed density for all cover heights. Conversely, an increased cover height resulted in a decreased foraging time. Contrary to males, the decreased proportion of time spent foraging did not translate into a foraging disadvantage for females. When vegetation height was higher, females maintained similar pecking and intake rates compared to intermediate levels, while males consistently decreased their energy gain. This difference in anti-predator responses suggests a sexually mediated strategy in the food-safety trade-off: when resource density is high a females would adopt a camouflage strategy while an escape strategy would be adopted by males. In other words, males would leave risky-areas, whereas females would stay when resource density is high. Our results suggest that increased predation risk might generate sexually mediated behavioural responses that functional response models should perhaps better consider in the future. PMID:24984028

  7. Fearful foragers: honey bees tune colony and individual foraging to multi-predator presence and food quality.

    PubMed

    Tan, Ken; Hu, Zongwen; Chen, Weiwen; Wang, Zhengwei; Wang, Yuchong; Nieh, James C

    2013-01-01

    Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller) and V. tropica (bigger) preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive) as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w), colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55-79% and residence times by 17-33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose), colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger), colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees. PMID:24098734

  8. Fearful Foragers: Honey Bees Tune Colony and Individual Foraging to Multi-Predator Presence and Food Quality

    PubMed Central

    Tan, Ken; Hu, Zongwen; Chen, Weiwen; Wang, Zhengwei; Wang, Yuchong; Nieh, James C.

    2013-01-01

    Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller) and V. tropica (bigger) preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive) as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w), colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55–79% and residence times by 17–33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose), colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger), colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees. PMID:24098734

  9. Short-term evaluation of visible implant alpha tags in juveniles of three fish species under laboratory conditions.

    PubMed

    Turek, K C; Pegg, M A; Pope, K L

    2014-04-01

    Visible implant alpha (VI alpha) tag-induced changes in mortality and condition, as well as tag retention and readability, were examined during a 4-week period for juveniles of three fish species: tiger muskellunge Esox masquinongy × Esox lucius (91?±?7?mm total length, L(T), mean?±?s.d.), Snake River cutthroat trout Oncorhynchus clarki behnkei (84?±?8?mm) and rainbow trout Oncorhynchus mykiss (85?±?5?mm). Mortality and condition did not differ between tagged fish and control fish for any species and overall tag retention rates were high (92% for E. masquinongy × E. lucius, 91% for O. c. behnkei and 100% for O. mykiss). Short-term readability of VI alpha tags was low in juvenile E. masquinongy × E. lucius and juvenile O. c. behnkei. Therefore, it is not recommend to use VI alpha tags in juvenile E. masquinongy × E. lucius or juvenile O. c. behnkei for periods >2?weeks, but VI alpha tags seem to be suitable for juvenile O. mykiss for a period of at least 4?weeks. PMID:24689672

  10. Exploring behavior of an unusual megaherbivore: A spatially explicit foraging model of the hippopotamus

    USGS Publications Warehouse

    Lewison, R.L.; Carter, J.

    2004-01-01

    Herbivore foraging theories have been developed for and tested on herbivores across a range of sizes. Due to logistical constraints, however, little research has focused on foraging behavior of megaherbivores. Here we present a research approach that explores megaherbivore foraging behavior, and assesses the applicability of foraging theories developed on smaller herbivores to megafauna. With simulation models as reference points for the analysis of empirical data, we investigate foraging strategies of the common hippopotamus (Hippopotamus amphibius). Using a spatially explicit individual based foraging model, we apply traditional herbivore foraging strategies to a model hippopotamus, compare model output, and then relate these results to field data from wild hippopotami. Hippopotami appear to employ foraging strategies that respond to vegetation characteristics, such as vegetation quality, as well as spatial reference information, namely distance to a water source. Model predictions, field observations, and comparisons of the two support that hippopotami generally conform to the central place foraging construct. These analyses point to the applicability of general herbivore foraging concepts to megaherbivores, but also point to important differences between hippopotami and other herbivores. Our synergistic approach of models as reference points for empirical data highlights a useful method of behavioral analysis for hard-to-study megafauna. ?? 2003 Elsevier B.V. All rights reserved.

  11. Honey loading for pollen collection: regulation of crop content in honeybee pollen foragers on leaving hive.

    PubMed

    Harano, Ken-ichi; Mitsuhata-Asai, Akiko; Sasaki, Masami

    2014-07-01

    Before foraging honeybees leave the hive, each bee loads its crop with some amount of honey "fuel" depending on the distance to the food source and foraging experience. For pollen collection, there is evidence that foragers carry additional honey as "glue" to build pollen loads. This study examines whether pollen foragers of the European honeybee Apis mellifera regulate the size of the crop load according to food-source distances upon leaving the hive and how foraging experience affects load regulation. The crop contents of bees foraging on crape myrtle Lagerstroemia indica, which has no nectary, were larger than those foraging on nectar from other sources, confirming a previous finding that pollen foragers carry glue in addition to fuel honey from the hive. Crop contents of both waggle dancers and dance followers showed a significant positive correlation with waggle-run durations. These results suggest that bees carry a distance-dependent amount of fuel honey in addition to a fixed amount of glue honey. Crop contents on leaving the hive were statistically larger in dancers than followers. Based on these results, we suggest that pollen foragers use information obtained through foraging experience to adjust crop contents on leaving the hive. PMID:24925356

  12. Honey loading for pollen collection: regulation of crop content in honeybee pollen foragers on leaving hive

    NASA Astrophysics Data System (ADS)

    Harano, Ken-ichi; Mitsuhata-Asai, Akiko; Sasaki, Masami

    2014-07-01

    Before foraging honeybees leave the hive, each bee loads its crop with some amount of honey "fuel" depending on the distance to the food source and foraging experience. For pollen collection, there is evidence that foragers carry additional honey as "glue" to build pollen loads. This study examines whether pollen foragers of the European honeybee Apis mellifera regulate the size of the crop load according to food-source distances upon leaving the hive and how foraging experience affects load regulation. The crop contents of bees foraging on crape myrtle Lagerstroemia indica, which has no nectary, were larger than those foraging on nectar from other sources, confirming a previous finding that pollen foragers carry glue in addition to fuel honey from the hive. Crop contents of both waggle dancers and dance followers showed a significant positive correlation with waggle-run durations. These results suggest that bees carry a distance-dependent amount of fuel honey in addition to a fixed amount of glue honey. Crop contents on leaving the hive were statistically larger in dancers than followers. Based on these results, we suggest that pollen foragers use information obtained through foraging experience to adjust crop contents on leaving the hive.

  13. Intersexual and temporal variation in foraging ecology of prothonotary warblers during the breeding season

    USGS Publications Warehouse

    Petit, L.J.; Petit, D.R.; Petit, K.E.; Fleming, W.J.

    1990-01-01

    We studied foraging ecology of Prothonotary Warblers (Protonotaria citrea) over four breeding seasons to determine if this species exhibited sex-specific or temporal variation in foraging behavior. Significant differences between sexes during the prenestling period were found for foraging height and substrate height (foraging method, plant species/substrate, perch diameter, horizontal location from trunk, and prey location were not significantly different). During the nestling period, this divergence between sexes was evident for foraging height, substrate height, substrate / tree species, and prey location. Additionally, male warblers significantly altered their behavior for all seven foraging variables between the two periods, whereas females exhibited changes similar to those of males for five of the foraging variables. This parallel shift suggests a strong behavioral response by both sexes to proximate factors (such as vegetation structure, and prey abundance and distribution) that varied throughout the breeding season. Sex-specific foraging behavior during the prenestling period was best explained by differences in reproductive responsibilities rather than by the theory of intersexual competition for limited resources. During the nestling period, neither hypothesis by itself explained foraging divergences adequately. However, when integrated with the temporal responses of the warblers to changes in prey availability, reproductive responsibilities seemed to be of primary importance in explaining intersexual niche partitioning during the nestling period. We emphasize the importance of considering both intersexual and intraseasonal variation when quantifying a species' foraging ecology.

  14. Effects of selection for honey bee worker reproduction on foraging traits.

    PubMed

    Oldroyd, Benjamin P; Beekman, Madeleine

    2008-03-01

    The "reproductive ground plan" hypothesis (RGPH) proposes that reproductive division of labour in social insects had its antecedents in the ancient gene regulatory networks that evolved to regulate the foraging and reproductive phases of their solitary ancestors. Thus, queens express traits that are characteristic of the reproductive phase of solitary insects, whereas workers express traits characteristic of the foraging phase. The RGPH has also been extended to help understand the regulation of age polyethism within the worker caste and more recently to explain differences in the foraging specialisations of individual honey bee workers. Foragers that specialise in collecting proteinaceous pollen are hypothesised to have higher reproductive potential than individuals that preferentially forage for nectar because genes that were ancestrally associated with the reproductive phase are active. We investigated the links between honey bee worker foraging behaviour and reproductive traits by comparing the foraging preferences of a line of workers that has been selected for high rates of worker reproduction with the preferences of wild-type bees. We show that while selection for reproductive behaviour in workers has not altered foraging preferences, the age at onset of foraging of our selected line has been increased. Our findings therefore support the hypothesis that age polyethism is related to the reproductive ground plan, but they cast doubt on recent suggestions that foraging preferences and reproductive traits are pleiotropically linked. PMID:18318602

  15. GPS tracking devices reveal foraging strategies of black-legged kittiwakes

    USGS Publications Warehouse

    Kotzerka, Jana; Garthe, Stefan; Hatch, Scott A.

    2010-01-01

    The Black-legged Kittiwake Rissa tridactyla is the most abundant gull species in the world, but some populations have declined in recent years, apparently due to food shortage. Kittiwakes are surface feeders and thus can compensate for low food availability only by increasing their foraging range and/or devoting more time to foraging. The species is widely studied in many respects, but long-distance foraging and the limitations of conventional radio telemetry have kept its foraging behavior largely out of view. The development of Global Positioning System (GPS) loggers is advancing rapidly. With devices as small as 8 g now available, it is possible to use this technology for tracking relatively small species of oceanic birds like kittiwakes. Here we present the first results of GPS telemetry applied to Black-legged Kittiwakes in 2007 in the North Pacific. All but one individual foraged in the neritic zone north of the island. Three birds performed foraging trips only close to the colony (within 13 km), while six birds had foraging ranges averaging about 40 km. The maximum foraging range was 59 km, and the maximum distance traveled was 165 km. Maximum trip duration was 17 h (mean 8 h). An apparently bimodal distribution of foraging ranges affords new insight on the variable foraging behaviour of Black-legged Kittiwakes. Our successful deployment of GPS loggers on kittiwakes holds much promise for telemetry studies on many other bird species of similar size and provides an incentive for applying this new approach in future studies.

  16. Small is profitable: No support for the optimal foraging theory in sea stars Asterias rubens foraging on the blue edible mussel Mytilus edulis

    NASA Astrophysics Data System (ADS)

    Hummel, Christiaan; Honkoop, Pieter; van der Meer, Jaap

    2011-07-01

    Doubt has been shed recently on the most popular optimal foraging theory stating that predators should maximize prey profitability, i.e., select that prey item that contains the highest energy content per handling time. We hypothesized that sea stars do not forage on blue mussels according to the classical optimal foraging theory but are actively avoiding damage that may be caused by e.g. capture of foraging on too-strong mussel shells, hence the sea stars will have a stronger preference for mussels that are smaller than the most profitable ones. Here we present experimental evidence of the sea star Asterias rubens as a predator that indeed chooses much smaller blue mussels Mytilus edulis to forage on than the most profitable ones. Hence this study does not support the optimal foraging theory. There may be other constraints involved in foraging than just optimizing energy intake, for example predators may also be concerned with preventing potential loss or damage of their foraging instruments.

  17. Root Foraging Increases Performance of the Clonal Plant Potentilla reptans in Heterogeneous Nutrient Environments

    PubMed Central

    Wang, Zhengwen; van Kleunen, Mark; During, Heinjo J.; Werger, Marinus J. A.

    2013-01-01

    Background Plastic root-foraging responses have been widely recognized as an important strategy for plants to explore heterogeneously distributed resources. However, the benefits and costs of root foraging have received little attention. Methodology/Principal Findings In a greenhouse experiment, we grew pairs of connected ramets of 22 genotypes of the stoloniferous plant Potentilla reptans in paired pots, between which the contrast in nutrient availability was set as null, medium and high, but with the total nutrient amount kept the same. We calculated root-foraging intensity of each individual ramet pair as the difference in root mass between paired ramets divided by the total root mass. For each genotype, we then calculated root-foraging ability as the slope of the regression of root-foraging intensity against patch contrast. For all genotypes, root-foraging intensity increased with patch contrast and the total biomass and number of offspring ramets were lowest at high patch contrast. Among genotypes, root-foraging intensity was positively related to production of offspring ramets and biomass in the high patch-contrast treatment, which indicates an evolutionary benefit of root foraging in heterogeneous environments. However, we found no significant evidence that the ability of plastic foraging imposes costs under homogeneous conditions (i.e. when foraging is not needed). Conclusions/Significance Our results show that plants of P. reptans adjust their root-foraging intensity according to patch contrast. Moreover, the results show that the root foraging has an evolutionary advantage in heterogeneous environments, while costs of having the ability of plastic root foraging were absent or very small. PMID:23472211

  18. PCNN document segmentation method based on bacterial foraging optimization algorithm

    NASA Astrophysics Data System (ADS)

    Liao, Yanping; Zhang, Peng; Guo, Qiang; Wan, Jian

    2014-04-01

    Pulse Coupled Neural Network(PCNN) is widely used in the field of image processing, but it is a difficult task to define the relative parameters properly in the research of the applications of PCNN. So far the determination of parameters of its model needs a lot of experiments. To deal with the above problem, a document segmentation based on the improved PCNN is proposed. It uses the maximum entropy function as the fitness function of bacterial foraging optimization algorithm, adopts bacterial foraging optimization algorithm to search the optimal parameters, and eliminates the trouble of manually set the experiment parameters. Experimental results show that the proposed algorithm can effectively complete document segmentation. And result of the segmentation is better than the contrast algorithms.

  19. Dynamic averaging and foraging decisions in horses (Equus callabus).

    PubMed

    Devenport, Jill A; Patterson, Megan R; Devenport, Lynn D

    2005-08-01

    The variability of most environments taxes foraging decisions by increasing the uncertainty of the information available. One solution to the problem is to use dynamic averaging, as do some granivores and carnivores. Arguably, the same strategy could be useful for grazing herbivores, even though their food renews and is more homogeneously distributed. Horses (Equus callabus) were given choices between variable patches after short or long delays. When patch information was current, horses returned to the patch that was recently best, whereas those without current information matched choices to the long-term average values of the patches. These results demonstrate that a grazing species uses dynamic averaging and indicate that, like granivores and carnivores, they can use temporal weighting to optimize foraging decisions. PMID:16131264

  20. Forage as a Primary Source of Mycotoxins in Animal Diets

    PubMed Central

    Skládanka, Ji?í; Ned?lník, Jan; Adam, Vojt?ch; Doležal, Petr; Moravcová, Hana; Dohnal, Vlastimil

    2011-01-01

    The issue of moulds and, thus, contamination with mycotoxins is very topical, particularly in connexion with forages from grass stands used at the end of the growing season. Deoxynivalenol (DON), zearalenone (ZEA), fumonisins (FUM) and aflatoxins (AFL) are among the most common mycotoxins. The aim of the paper was to determine concentrations of mycotoxins in selected grasses (Lolium perenne, Festulolium pabulare, Festulolium braunii) and their mixtures with Festuca rubra an/or Poa pratensis during the growing season as a marker of grass safety, which was assessed according to content of the aforementioned mycotoxins. During the growing season grass forage was contaminated with mycotoxins, most of all by DON and ZEA. The contents of AFL and FUM were zero or below the limit of quantification. Moreover, the level of the occurrence of mould was quantified as ergosterol content, which was higher at the specific date of cut. All results were statistically processed and significant changes were discussed. PMID:21318013

  1. Protecting rain forests and forager's rights using LANDSAT imagery

    NASA Technical Reports Server (NTRS)

    Wilkie, David S.

    1991-01-01

    Creating rain forest reserves is vital given the global decline in biodiversity. Yet, the plants and animals that will be protected from untrammeled commercial exploitation within such reserves constitute essential resources for indigenous foragers and farmers. Balancing the needs of local subsistence level populations with the goals of national and international conservation agencies requires a thorough understanding of the mutual impacts that arise from the interaction of park and people. In the Ituri forest of Zaire, LANDSAT TM image analysis and GPS ground truth data were used to locate human settlements so that boundaries of the proposed Okapi Reserve could be chosen to minimize its impact on the subsistence practices of the local foragers and farmers. Using satellite imagery in conjunction with cultural information should help to ensure traditional resource exploitation rights of indigenous peoples whilst simultaneously protecting the largest contiguous area of undisturbed forest.

  2. Physical barrier to reduce WP mortalities of foraging waterfowl

    SciTech Connect

    Pochop, P.A.; Cummings, J.L.; Yoder, C.A.; Gossweiler, W.A.

    2000-02-01

    White phosphorus (WP) has been identified as the cause of mortality to certain species of water-fowl at Eagle River Flats, a tidal marsh in Alaska, used as an ordinance impact area by the US Army. A blend of calcium bentonite/organo clays, gravel, and binding polymers was tested for effectiveness as a barrier to reduce duck foraging and mortality. Following the application of the barrier to one of two contaminated ponds, the authors observed greater duck foraging and higher mortality in the untreated pond and no mortality in the treated pond after a year of tidal inundations and ice effects. Emergent vegetation recovered within a year of treatment. WP levels in the barrier were less than the method limit of detection, indicating no migration of WP into the materials. Barrier thickness remained relatively stable over a period of 4 years, and vegetation was found to be important in stabilizing the barrier material.

  3. Emerging technologies advancing forage and turf grass genomics.

    PubMed

    Kopecký, David; Studer, Bruno

    2014-01-01

    Grassland is of major importance for agricultural production and provides valuable ecosystem services. Its impact is likely to rise in changing socio-economic and climatic environments. High yielding forage grass species are major components of sustainable grassland production. Understanding the genome structure and function of grassland species provides opportunities to accelerate crop improvement and thus to mitigate the future challenges of increased feed and food demand, scarcity of natural resources such as water and nutrients, and high product qualities. In this review, we will discuss a selection of technological developments that served as main drivers to generate new insights into the structure and function of nuclear genomes. Many of these technologies were originally developed in human or animal science and are now increasingly applied in plant genomics. Our main goal is to highlight the benefits of using these technologies for forage and turf grass genome research, to discuss their potentials and limitations as well as their relevance for future applications. PMID:24309540

  4. Activity Time Budget during Foraging Trips of Emperor Penguins

    PubMed Central

    Watanabe, Shinichi; Sato, Katsufumi; Ponganis, Paul J.

    2012-01-01

    We developed an automated method using depth and one axis of body acceleration data recorded by animal-borne data loggers to identify activities of penguins over long-term deployments. Using this technique, we evaluated the activity time budget of emperor penguins (n?=?10) both in water and on sea ice during foraging trips in chick-rearing season. During the foraging trips, emperor penguins alternated dive bouts (4.8±4.5 h) and rest periods on sea ice (2.5±2.3 h). After recorder deployment and release near the colony, the birds spent 17.9±8.4% of their time traveling until they reached the ice edge. Once at the ice edge, they stayed there more than 4 hours before the first dive. After the first dive, the mean proportions of time spent on the ice and in water were 30.8±7.4% and 69.2±7.4%, respectively. When in the water, they spent 67.9±3.1% of time making dives deeper than 5 m. Dive activity had no typical diurnal pattern for individual birds. While in the water between dives, the birds had short resting periods (1.2±1.7 min) and periods of swimming at depths shallower than 5 m (0.25±0.38 min). When the birds were on the ice, they primarily used time for resting (90.3±4.1% of time) and spent only 9.7±4.1% of time traveling. Thus, it appears that, during foraging trips at sea, emperor penguins traveled during dives >5 m depth, and that sea ice was primarily used for resting. Sea ice probably provides refuge from natural predators such as leopard seals. We also suggest that 24 hours of sunlight and the cycling of dive bouts with short rest periods on sea ice allow emperor penguins to dive continuously throughout the day during foraging trips to sea. PMID:23185608

  5. [Selection of foraging tactics in leaf Warblers (phylloscopus)].

    PubMed

    Batova, O N

    2011-01-01

    Aviary observations revealed particularities of foraging behavior in seven species of leaf warblers of the genus Phylloscopus, which sympatrically inhabit the middle-taiga Yenisei. The differences consist in the ratio of the tactics of each type, including the flight, frequency of using them, and selectivity with respect to maneuvers. The obtained results are discussed from the point of view of particularities of the external morphology of the species. PMID:21789995

  6. Optimal web investment in sub-optimal foraging conditions

    NASA Astrophysics Data System (ADS)

    Harmer, Aaron M. T.; Kokko, Hanna; Herberstein, Marie E.; Madin, Joshua S.

    2012-01-01

    Orb web spiders sit at the centre of their approximately circular webs when waiting for prey and so face many of the same challenges as central-place foragers. Prey value decreases with distance from the hub as a function of prey escape time. The further from the hub that prey are intercepted, the longer it takes a spider to reach them and the greater chance they have of escaping. Several species of orb web spiders build vertically elongated ladder-like orb webs against tree trunks, rather than circular orb webs in the open. As ladder web spiders invest disproportionately more web area further from the hub, it is expected they will experience reduced prey gain per unit area of web investment compared to spiders that build circular webs. We developed a model to investigate how building webs in the space-limited microhabitat on tree trunks influences the optimal size, shape and net prey gain of arboricolous ladder webs. The model suggests that as horizontal space becomes more limited, optimal web shape becomes more elongated, and optimal web area decreases. This change in web geometry results in decreased net prey gain compared to webs built without space constraints. However, when space is limited, spiders can achieve higher net prey gain compared to building typical circular webs in the same limited space. Our model shows how spiders optimise web investment in sub-optimal conditions and can be used to understand foraging investment trade-offs in other central-place foragers faced with constrained foraging arenas.

  7. Woolly Locoweed and Forage Response to Herbicides in West Texas. 

    E-print Network

    Freeman, M.R.; Ueckert, D.N.; Nelson, J.T.

    1982-01-01

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mentioned in Text back cover KEYWORDS: Poisonous plantslrange managementlwoolly locoweed/Earle loco/purple loco/Texas loco/ 2,4-D/dicamba/3,6-dichloropicolinic a id~picloram/tebuthiuron/trichlopyr/pelleted herbicides. Woolly Locoweed and Forage Response... of foliar sprays containing picloram, whereas control usually was not manifested for almost a year following application of picloram pellets. Woolly locoweed was effectively controlled in the fall with foliar sprays of picloram + triclopyr ester (1:l...

  8. Soil, Water and Forage Testing Laboratory Potassium recommendations applicable for

    E-print Network

    80 75 70 65 60 50 40 GRAIN SORGHUM (1000 LBS/A) 20 15 15 15 10 10 10 10 10 5 5 GRAIN SORGHUM (10000 LBS/A) 150 140 130 120 110 105 100 95 90 80 70 GRAIN SORGHUM (1500 LBS/A) 20 15 15 15 10 10 10 10 10 5 5GRAIN SORGHUM (1500 LBS/A) 20 15 15 15 10 10 10 10 10 5 5 #12;Soil, Water and Forage Testing

  9. Methane Production of Different Forages in In vitro Ruminal Fermentation.

    PubMed

    Meale, S J; Chaves, A V; Baah, J; McAllister, T A

    2012-01-01

    An in vitro rumen batch culture study was completed to compare effects of common grasses, leguminous shrubs and non-leguminous shrubs used for livestock grazing in Australia and Ghana on CH4 production and fermentation characteristics. Grass species included Andropodon gayanus, Brachiaria ruziziensis and Pennisetum purpureum. Leguminous shrub species included Cajanus cajan, Cratylia argentea, Gliricidia sepium, Leucaena leucocephala and Stylosanthes guianensis and non-leguminous shrub species included Annona senegalensis, Moringa oleifera, Securinega virosa and Vitellaria paradoxa. Leaves were harvested, dried at 55°C and ground through a 1 mm screen. Serum bottles containing 500 mg of forage, modified McDougall's buffer and rumen fluid were incubated under anaerobic conditions at 39°C for 24 h. Samples of each forage type were removed after 0, 2, 6, 12 and 24 h of incubation for determination of cumulative gas production. Methane production, ammonia concentration and proportions of VFA were measured at 24 h. Concentration of aNDF (g/kg DM) ranged from 671 to 713 (grasses), 377 to 590 (leguminous shrubs) and 288 to 517 (non-leguminous shrubs). After 24 h of in vitro incubation, cumulative gas, CH4 production, ammonia concentration, proportion of propionate in VFA and IVDMD differed (p<0.05) within each forage type. B. ruziziensis and G. sepium produced the highest cumulative gas, IVDMD, total VFA, proportion of propionate in VFA and the lowest A:P ratios within their forage types. Consequently, these two species produced moderate CH4 emissions without compromising digestion. Grazing of these two species may be a strategy to reduce CH4 emissions however further assessment in in vivo trials and at different stages of maturity is recommended. PMID:25049482

  10. Methane Production of Different Forages in In vitro Ruminal Fermentation

    PubMed Central

    Meale, S. J.; Chaves, A. V.; Baah, J.; McAllister, T. A.

    2012-01-01

    An in vitro rumen batch culture study was completed to compare effects of common grasses, leguminous shrubs and non-leguminous shrubs used for livestock grazing in Australia and Ghana on CH4 production and fermentation characteristics. Grass species included Andropodon gayanus, Brachiaria ruziziensis and Pennisetum purpureum. Leguminous shrub species included Cajanus cajan, Cratylia argentea, Gliricidia sepium, Leucaena leucocephala and Stylosanthes guianensis and non-leguminous shrub species included Annona senegalensis, Moringa oleifera, Securinega virosa and Vitellaria paradoxa. Leaves were harvested, dried at 55°C and ground through a 1 mm screen. Serum bottles containing 500 mg of forage, modified McDougall’s buffer and rumen fluid were incubated under anaerobic conditions at 39°C for 24 h. Samples of each forage type were removed after 0, 2, 6, 12 and 24 h of incubation for determination of cumulative gas production. Methane production, ammonia concentration and proportions of VFA were measured at 24 h. Concentration of aNDF (g/kg DM) ranged from 671 to 713 (grasses), 377 to 590 (leguminous shrubs) and 288 to 517 (non-leguminous shrubs). After 24 h of in vitro incubation, cumulative gas, CH4 production, ammonia concentration, proportion of propionate in VFA and IVDMD differed (p<0.05) within each forage type. B. ruziziensis and G. sepium produced the highest cumulative gas, IVDMD, total VFA, proportion of propionate in VFA and the lowest A:P ratios within their forage types. Consequently, these two species produced moderate CH4 emissions without compromising digestion. Grazing of these two species may be a strategy to reduce CH4 emissions however further assessment in in vivo trials and at different stages of maturity is recommended. PMID:25049482

  11. Fine-Scale Variability in Harbor Seal Foraging Behavior

    PubMed Central

    Wilson, Kenady; Lance, Monique; Jeffries, Steven; Acevedo-Gutiérrez, Alejandro

    2014-01-01

    Understanding the variability of foraging behavior within a population of predators is important for determining their role in the ecosystem and how they may respond to future ecosystem changes. However, such variability has seldom been studied in harbor seals on a fine spatial scale (<30 km). We used a combination of standard and Bayesian generalized linear mixed models to explore how environmental variables influenced the dive behavior of harbor seals. Time-depth recorders were deployed on harbor seals from two haul-out sites in the Salish Sea in 2007 (n?=?18) and 2008 (n?=?11). Three behavioral bout types were classified from six dive types within each bout; however, one of these bout types was related to haul-out activity and was excluded from analyses. Deep foraging bouts (Type I) were the predominant type used throughout the study; however, variation in the use of bout types was observed relative to haul-out site, season, sex, and light (day/night). The proportional use of Type I and Type II (shallow foraging/traveling) bouts differed dramatically between haul-out sites, seasons, sexes, and whether it was day or night; individual variability between seals also contributed to the observed differences. We hypothesize that this variation in dive behavior was related to habitat or prey specialization by seals from different haul-out sites, or individual variability between seals in the study area. The results highlight the potential influence of habitat and specialization on the foraging behavior of harbor seals, and may help explain the variability in diet that is observed between different haul-out site groups in this population. PMID:24717815

  12. Sexy birds are superior at solving a foraging problem.

    PubMed

    Mateos-Gonzalez, Fernando; Quesada, Javier; Senar, Juan Carlos

    2011-10-23

    Yellow, red or orange carotenoid-based colorations in male birds are often a signal to prospecting females about body condition, health status and ability to find food. However, this general 'ability to find food' has never been defined. Here we show that more brightly ornamented individuals may also be more efficient when foraging in novel situations. The results highlight the fact that evolution may have provided females tools to evaluate cognitive abilities of the males. PMID:21450725

  13. Mapping the navigational knowledge of individually foraging ants, Myrmecia croslandi

    PubMed Central

    Narendra, Ajay; Gourmaud, Sarah; Zeil, Jochen

    2013-01-01

    Ants are efficient navigators, guided by path integration and visual landmarks. Path integration is the primary strategy in landmark-poor habitats, but landmarks are readily used when available. The landmark panorama provides reliable information about heading direction, routes and specific location. Visual memories for guidance are often acquired along routes or near to significant places. Over what area can such locally acquired memories provide information for reaching a place? This question is unusually approachable in the solitary foraging Australian jack jumper ant, since individual foragers typically travel to one or two nest-specific foraging trees. We find that within 10 m from the nest, ants both with and without home vector information available from path integration return directly to the nest from all compass directions, after briefly scanning the panorama. By reconstructing panoramic views within the successful homing range, we show that in the open woodland habitat of these ants, snapshot memories acquired close to the nest provide sufficient navigational information to determine nest-directed heading direction over a surprisingly large area, including areas that animals may have not visited previously. PMID:23804615

  14. COMMUNICATION: Stochastic resonance and the evolution of Daphnia foraging strategy

    NASA Astrophysics Data System (ADS)

    Dees, Nathan D.; Bahar, Sonya; Moss, Frank

    2008-12-01

    Search strategies are currently of great interest, with reports on foraging ranging from albatrosses and spider monkeys to microzooplankton. Here, we investigate the role of noise in optimizing search strategies. We focus on the zooplankton Daphnia, which move in successive sequences consisting of a hop, a pause and a turn through an angle. Recent experiments have shown that their turning angle distributions (TADs) and underlying noise intensities are similar across species and age groups, suggesting an evolutionary origin of this internal noise. We explore this hypothesis further with a digital simulation (EVO) based solely on the three central Darwinian themes: inheritability, variability and survivability. Separate simulations utilizing stochastic resonance (SR) indicate that foraging success, and hence fitness, is maximized at an optimum TAD noise intensity, which is represented by the distribution's characteristic width, ?. In both the EVO and SR simulations, foraging success is the criterion, and the results are the predicted characteristic widths of the TADs that maximize success. Our results are twofold: (1) the evolving characteristic widths achieve stasis after many generations; (2) as a hop length parameter is changed, variations in the evolved widths generated by EVO parallel those predicted by SR. These findings provide support for the hypotheses that (1) ? is an evolved quantity and that (2) SR plays a role in evolution.

  15. Evidence for acoustic communication among bottom foraging humpback whales

    PubMed Central

    Parks, Susan E.; Cusano, Dana A.; Stimpert, Alison K.; Weinrich, Mason T.; Friedlaender, Ari S.; Wiley, David N.

    2014-01-01

    Humpback whales (Megaptera novaeangliae), a mysticete with a cosmopolitan distribution, demonstrate marked behavioural plasticity. Recent studies show evidence of social learning in the transmission of specific population level traits ranging from complex singing to stereotyped prey capturing behaviour. Humpback whales have been observed to employ group foraging techniques, however details on how individuals coordinate behaviour in these groups is challenging to obtain. This study investigates the role of a novel broadband patterned pulsed sound produced by humpback whales engaged in bottom-feeding behaviours, referred to here as a ‘paired burst' sound. Data collected from 56 archival acoustic tag deployments were investigated to determine the functional significance of these signals. Paired burst sound production was associated exclusively with bottom feeding under low-light conditions, predominantly with evidence of associated conspecifics nearby suggesting that the sound likely serves either as a communicative signal to conspecifics, a signal to affect prey behaviour, or possibly both. This study provides additional evidence for individual variation and phenotypic plasticity of foraging behaviours in humpback whales and provides important evidence for the use of acoustic signals among foraging individuals in this species. PMID:25512188

  16. Bee Swarm Optimization for Medical Web Information Foraging.

    PubMed

    Drias, Yassine; Kechid, Samir; Pasi, Gabriella

    2016-02-01

    The present work is related to Web intelligence and more precisely to medical information foraging. We present here a novel approach based on agents technology for information foraging. An architecture is proposed, in which we distinguish two important phases. The first one is a learning process for localizing the most relevant pages that might interest the user. This is performed on a fixed instance of the Web. The second takes into account the openness and the dynamicity of the Web. It consists on an incremental learning starting from the result of the first phase and reshaping the outcomes taking into account the changes that undergoes the Web. The whole system offers a tool to help the user undertaking information foraging. We implemented the system using a group of cooperative reactive agents and more precisely a colony of artificial bees. In order to validate our proposal, experiments were conducted on MedlinePlus, a benchmark dedicated for research in the domain of Health. The results are promising either for those related to Web regularities and for the response time, which is very short and hence complies the real time constraint. PMID:26590978

  17. Seasonality, extractive foraging and the evolution of primate sensorimotor intelligence.

    PubMed

    Melin, Amanda D; Young, Hilary C; Mosdossy, Krisztina N; Fedigan, Linda M

    2014-06-01

    The parallel evolution of increased sensorimotor intelligence in humans and capuchins has been linked to the cognitive and manual demands of seasonal extractive faunivory. This hypothesis is attractive on theoretical grounds, but it has eluded widespread acceptance due to lack of empirical data. For instance, the effects of seasonality on the extractive foraging behaviors of capuchins are largely unknown. Here we report foraging observations on four groups of wild capuchins (Cebus capucinus) inhabiting a seasonally dry tropical forest. We also measured intra-annual variation in temperature, rainfall, and food abundance. We found that the exploitation of embedded or mechanically protected invertebrates was concentrated during periods of fruit scarcity. Such a pattern suggests that embedded insects are best characterized as a fallback food for capuchins. We discuss the implications of seasonal extractive faunivory for the evolution of sensorimotor intelligence (SMI) in capuchins and hominins and suggest that the suite of features associated with SMI, including increased manual dexterity, tool use, and innovative problem solving are cognitive adaptations among frugivores that fall back seasonally on extractable foods. The selective pressures acting on SMI are predicted to be strongest among primates living in the most seasonal environments. This model is proffered to explain the differences in tool use between capuchin lineages, and SMI as an adaptation to extractive foraging is suggested to play an important role in hominin evolution. PMID:24636732

  18. Olfactory eavesdropping by a competitively foraging stingless bee, Trigona spinipes.

    PubMed

    Nieh, James C; Barreto, Lillian S; Contrera, Felipe A L; Imperatriz-Fonseca, Vera L

    2004-08-01

    Signals that are perceived over long distances or leave extended spatial traces are subject to eavesdropping. Eavesdropping has therefore acted as a selective pressure in the evolution of diverse animal communication systems, perhaps even in the evolution of functionally referential communication. Early work suggested that some species of stingless bees (Hymenoptera, Apidae, Meliponini) may use interceptive olfactory eavesdropping to discover food sources being exploited by competitors, but it is not clear if any stingless bee can be attracted to the odour marks deposited by an interspecific competitor. We show that foragers of the aggressive meliponine bee, Trigona spinipes, can detect and orient towards odour marks deposited by a competitor, Melipona rufiventris, and then rapidly take over the food source, driving away or killing their competitors. When searching for food sources at new locations that they are not already exploiting, T. spinipes foragers strongly prefer M. rufiventris odour marks to odour marks deposited by their own nest-mates, whereas they prefer nest-mate odour marks over M. rufiventris odour marks at a location already occupied by T. spinipes nest-mates. Melipona rufiventris foragers flee from T. spinipes odour marks. This olfactory eavesdropping may have played a role in the evolution of potentially cryptic communication mechanisms such as shortened odour trails, point-source only odour marking and functionally referential communication concealed at the nest. PMID:15306311

  19. Experimental Evidence that Social Relationships Determine Individual Foraging Behavior.

    PubMed

    Firth, Josh A; Voelkl, Bernhard; Farine, Damien R; Sheldon, Ben C

    2015-12-01

    Social relationships are fundamental to animals living in complex societies [1-3]. The extent to which individuals base their decisions around their key social relationships, and the consequences this has on their behavior and broader population level processes, remains unknown. Using a novel experiment that controlled where individual wild birds (great tits, Parus major) could access food, we restricted mated pairs from being allowed to forage at the same locations. This introduced a conflict for pair members between maintaining social relationships and accessing resources. We show that individuals reduce their own access to food in order to sustain their relationships and that individual foraging activity was strongly influenced by their key social counterparts. By affecting where individuals go, social relationships determined which conspecifics they encountered and consequently shaped their other social associations. Hence, while resource distribution can determine individuals' spatial and social environment [4-8], we illustrate how key social relationships themselves can govern broader social structure. Finally, social relationships also influenced the development of social foraging strategies. In response to forgoing access to resources, maintaining pair bonds led individuals to develop a flexible "scrounging" strategy, particularly by scrounging from their pair mate. This suggests that behavioral plasticity can develop to ameliorate conflicts between social relationships and other demands. Together, these results illustrate the importance of considering social relationships for explaining behavioral variation due to their significant impact on individual behavior and demonstrate the consequences of key relationships for wider processes. PMID:26585280

  20. Foraging and farming as niche construction: stable and unstable adaptations

    PubMed Central

    Rowley-Conwy, Peter; Layton, Robert

    2011-01-01

    All forager (or hunter–gatherer) societies construct niches, many of them actively by the concentration of wild plants into useful stands, small-scale cultivation, burning of natural vegetation to encourage useful species, and various forms of hunting, collectively termed ‘low-level food production’. Many such niches are stable and can continue indefinitely, because forager populations are usually stable. Some are unstable, but these usually transform into other foraging niches, not geographically expansive farming niches. The Epipalaeolithic (final hunter–gatherer) niche in the Near East was complex but stable, with a relatively high population density, until destabilized by an abrupt climatic change. The niche was unintentionally transformed into an agricultural one, due to chance genetic and behavioural attributes of some wild plant and animal species. The agricultural niche could be exported with modifications over much of the Old World. This was driven by massive population increase and had huge impacts on local people, animals and plants wherever the farming niche was carried. Farming niches in some areas may temporarily come close to stability, but the history of the last 11 000 years does not suggest that agriculture is an effective strategy for achieving demographic and political stability in the world's farming populations. PMID:21320899

  1. Wild chacma baboons (Papio ursinus) remember single foraging episodes.

    PubMed

    Noser, Rahel; Byrne, Richard W

    2015-07-01

    Understanding animal episodic-like memory is important for tracing the evolution of the human mind. However, our knowledge about the existence and nature of episodic-like memory in non-human primates is minimal. We observed the behaviour of a wild male chacma baboon faced with a trade-off between protecting his stationary group from aggressive extra-group males and foraging among five out-of-sight platforms. These contained high-priority food at a time of natural food shortage. In 10 morning and eight evening trials, the male spontaneously visited the platforms in five and four different sequences, respectively. In addition, he interrupted foraging sequences at virtually any point on eight occasions, returning to the group for up to 2 h. He then visited some or all of the remaining platforms and prevented revisits to already depleted ones, apparently based on his memory for the previous foraging episode about food value, location, and time. Efficient use of memory allowed him to keep minimal time absent from his group while keeping food intake high. These findings support the idea that episodic-like memory offers an all-purpose solution to a wide variety of problems that require flexible, quick, yet precise decisions in situations arising from competition for food and mates in wild primates. PMID:25833223

  2. Piping Plover brood foraging ecology on New York barrier islands

    USGS Publications Warehouse

    Elias, S.P.; Fraser, J.D.; Buckley, P.A.

    2000-01-01

    Effective management of piping plover (Charadrius melodus) populations requires knowledge of the habitats that foster successful reproduction. We studied piping plover chick foraging ecology and survival on the central barrier islands of Long Island, New York, 1992 and 1993. Within the 90-km study area, all 1-km beach segments with ephemeral pools or bay tidal flats were used for nesting and brood rearing, whereas <50% of beach segments without these habitats were used. On beach segments with ephemeral pools, broods preferred ephemeral pools to ocean intertidal zone, wrack, backshore, open vegetation, and interdune habitat. Indices of terrestrial arthropod abundance and foraging rates were greater in ephemeral pools than in other habitats. In 1992, chick survival was higher on beach segments with ephemeral pools than on segments without ephemeral pools. On beach segments with bay tidal flats, broods preferred bay tidal flats and wrack to ocean intertidal zone, backshore, and open vegetation habitats. Foraging rates in bay tidal flats were similar to those in ephemeral pools and greater than in open vegetation, wrack, and backshore habitats. On beach segments without ephemeral pools and bay tidal flats, broods preferred wrack to all other habitats, and open vegetation was second most preferred. To assist in the recovery of the piping plover, land-use planners should avoid beach management practices (e.g., beach filling, dune building, renourishment) that typically inhibit natural renewal of ephemeral pools, bay tidal flats, and open vegetation habitats.

  3. Olfactory eavesdropping by a competitively foraging stingless bee, Trigona spinipes.

    PubMed Central

    Nieh, James C.; Barreto, Lillian S.; Contrera, Felipe A. L.; Imperatriz-Fonseca, Vera L.

    2004-01-01

    Signals that are perceived over long distances or leave extended spatial traces are subject to eavesdropping. Eavesdropping has therefore acted as a selective pressure in the evolution of diverse animal communication systems, perhaps even in the evolution of functionally referential communication. Early work suggested that some species of stingless bees (Hymenoptera, Apidae, Meliponini) may use interceptive olfactory eavesdropping to discover food sources being exploited by competitors, but it is not clear if any stingless bee can be attracted to the odour marks deposited by an interspecific competitor. We show that foragers of the aggressive meliponine bee, Trigona spinipes, can detect and orient towards odour marks deposited by a competitor, Melipona rufiventris, and then rapidly take over the food source, driving away or killing their competitors. When searching for food sources at new locations that they are not already exploiting, T. spinipes foragers strongly prefer M. rufiventris odour marks to odour marks deposited by their own nest-mates, whereas they prefer nest-mate odour marks over M. rufiventris odour marks at a location already occupied by T. spinipes nest-mates. Melipona rufiventris foragers flee from T. spinipes odour marks. This olfactory eavesdropping may have played a role in the evolution of potentially cryptic communication mechanisms such as shortened odour trails, point-source only odour marking and functionally referential communication concealed at the nest. PMID:15306311

  4. Imidacloprid Alters Foraging and Decreases Bee Avoidance of Predators

    PubMed Central

    Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C.

    2014-01-01

    Concern is growing over the effects of neonicotinoid pesticides, which can impair honey bee cognition. We provide the first demonstration that sublethal concentrations of imidacloprid can harm honey bee decision-making about danger by significantly increasing the probability of a bee visiting a dangerous food source. Apis cerana is a native bee that is an important pollinator of agricultural crops and native plants in Asia. When foraging on nectar containing 40 µg/L (34 ppb) imidacloprid, honey bees (Apis cerana) showed no aversion to a feeder with a hornet predator, and 1.8 fold more bees chose the dangerous feeder as compared to control bees. Control bees exhibited significant predator avoidance. We also give the first evidence that foraging by A. cerana workers can be inhibited by sublethal concentrations of the pesticide, imidacloprid, which is widely used in Asia. Compared to bees collecting uncontaminated nectar, 23% fewer foragers returned to collect the nectar with 40 µg/L imidacloprid. Bees that did return respectively collected 46% and 63% less nectar containing 20 µg/L and 40 µg/L imidacloprid. These results suggest that the effects of neonicotinoids on honey bee decision-making and other advanced cognitive functions should be explored. Moreover, research should extend beyond the classic model, the European honey bee (A. mellifera), to other important bee species. PMID:25025334

  5. Swimming speed and foraging strategies of northern elephant seals

    NASA Astrophysics Data System (ADS)

    Hassrick, Jason L.; Crocker, Daniel E.; Zeno, Ramona L.; Blackwell, Susanna B.; Costa, Daniel P.; Le Boeuf, Burney J.

    2007-02-01

    We investigated swimming speed, a key variable in both the management of oxygen stores and foraging strategies, and its relationship to diving behaviour in northern elephant seals , Mirounga angustirostris. Swimming speed significantly reduced the dive duration and time at depth for presumed foraging dives, but increased with dive depth. This suggests that the extended duration of deep dives is made possible by physiological adjustments and not by changes in swimming speed or effort. Swimming speeds were similar across sex and age classes despite different predicted minimum cost of transport speeds. All seals exhibited characteristic dive shapes and swimming speed patterns that support their putative functions, but two-dimensional dive shapes and swimming angles varied between sexes and age classes. Mean dive angles on descent were markedly shallow, suggesting use of negative buoyancy to cover horizontal distance while diving. Buoyancy also appeared to affect two-dimensional dive shapes and ability to use extended gliding behaviours between surface and deep foraging zones. Significant differences in diving behaviour between sexes and between young and adult females were evident for various phases of the dive cycle, potentially resulting from physical constraints or differences in dive functionality.

  6. Food foraging of honey bees in a microwave field (2. 45 GHz CW)

    SciTech Connect

    Gary, N.E.; Westerdahl, B.B.

    1982-02-15

    Honey bees were trained to fly 400 m from their colony to an indoor laboratory foraging arena exposed to 2.45 GHz continuous wave microwaves at 5 power densities (0, 5, 10, 20, and 40 mW/cm/sup 2/). Foraging behavior did not differ from controls foraging within an unexposed sham arena in (1) number of round trips completed during a 3-h exposure session, (2) round trip time between the colony and the foraging arena, and (3) the length of time required to navigate the illuminated foraging arena. This study indicates that honey bees would not be adversely affected by foraging within a similar microwave field that would exist in future receiving antennae for the proposed solar power satellite energy transmission system in which power levels are expected to range from 23 mW/cm/sup 2/ at the antenna center to 1 mW/cm/sup 2/ at the edge.

  7. Nocturnal activity and foraging of prairie raccoons (Procyon lotor) in North Dakota

    USGS Publications Warehouse

    Greenwood, R.J.

    1982-01-01

    Nocturnal activity and foraging of 39 radio-equipped raccoons (Procyon lotor) in eastern North Dakota were studied from April-July in 1974-1976. Sixteen of the raccoons were collected after foraging bouts for stomach content analysis. Raccoon activity consisted of running (13%), walking (49%) and local movement in confined areas (38%). Local movement was foraging on large or locally abundant food items. Adult males traveled farther in a night, ran twice as often, and moved locally only half as often as adult females and yearlings. Differences in activity patterns between adult females and yearlings were not detected. There was no difference among age-sex groups in use of foraging habitats. All raccoons foraged extensively in farmyards and wetlands. Stomach content analysis substantiated foraging determinations obtained by radiotelemetry. Principal foods were grain, aquatic animals, rodents, birds and bird eggs.

  8. Loggerhead Turtles (Caretta caretta) Use Vision to Forage on Gelatinous Prey in Mid-Water

    PubMed Central

    Narazaki, Tomoko; Sato, Katsufumi; Abernathy, Kyler J.; Marshall, Greg J.; Miyazaki, Nobuyuki

    2013-01-01

    Identifying characteristics of foraging activity is fundamental to understanding an animals’ lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-borne imaging system and three-dimensional data logger simultaneously to observe the foraging behaviour of large juvenile and adult sized loggerhead turtles (Caretta caretta) in their natural environment. Video recordings showed that the turtles foraged on gelatinous prey while swimming in mid-water (i.e., defined as epipelagic water column deeper than 1 m in this study). By linking video and 3D data, we found that mid-water foraging events share the common feature of a marked deceleration phase associated with the capture and handling of the sluggish prey. Analysis of high-resolution 3D movements during mid-water foraging events, including presumptive events extracted from 3D data using deceleration in swim speed as a proxy for foraging (detection rate?=?0.67), showed that turtles swam straight toward prey in 171 events (i.e., turning point absent) but made a single turn toward the prey an average of 5.7±6.0 m before reaching the prey in 229 events (i.e., turning point present). Foraging events with a turning point tended to occur during the daytime, suggesting that turtles primarily used visual cues to locate prey. In addition, an incident of a turtle encountering a plastic bag while swimming in mid-water was recorded. The fact that the turtle’s movements while approaching the plastic bag were analogous to those of a true foraging event, having a turning point and deceleration phase, also support the use of vision in mid-water foraging. Our study shows that integrated video and high-resolution 3D data analysis provides unique opportunities to understand foraging behaviours in the context of the sensory ecology involved in prey location. PMID:23776603

  9. Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water.

    PubMed

    Narazaki, Tomoko; Sato, Katsufumi; Abernathy, Kyler J; Marshall, Greg J; Miyazaki, Nobuyuki

    2013-01-01

    Identifying characteristics of foraging activity is fundamental to understanding an animals' lifestyle and foraging ecology. Despite its importance, monitoring the foraging activities of marine animals is difficult because direct observation is rarely possible. In this study, we use an animal-borne imaging system and three-dimensional data logger simultaneously to observe the foraging behaviour of large juvenile and adult sized loggerhead turtles (Caretta caretta) in their natural environment. Video recordings showed that the turtles foraged on gelatinous prey while swimming in mid-water (i.e., defined as epipelagic water column deeper than 1 m in this study). By linking video and 3D data, we found that mid-water foraging events share the common feature of a marked deceleration phase associated with the capture and handling of the sluggish prey. Analysis of high-resolution 3D movements during mid-water foraging events, including presumptive events extracted from 3D data using deceleration in swim speed as a proxy for foraging (detection rate?=?0.67), showed that turtles swam straight toward prey in 171 events (i.e., turning point absent) but made a single turn toward the prey an average of 5.7±6.0 m before reaching the prey in 229 events (i.e., turning point present). Foraging events with a turning point tended to occur during the daytime, suggesting that turtles primarily used visual cues to locate prey. In addition, an incident of a turtle encountering a plastic bag while swimming in mid-water was recorded. The fact that the turtle's movements while approaching the plastic bag were analogous to those of a true foraging event, having a turning point and deceleration phase, also support the use of vision in mid-water foraging. Our study shows that integrated video and high-resolution 3D data analysis provides unique opportunities to understand foraging behaviours in the context of the sensory ecology involved in prey location. PMID:23776603

  10. [Application and prospect of near infrared reflectance spectroscopy in forage analysis].

    PubMed

    Ren, Xiu-Zhen; Guo, Hong-Ru; Jia, Yu-Shan; Ge, Gen-Tu; Wang, Kun

    2009-03-01

    Forage was the material basis of animal husbandry production, and its quality is directly related to the quality of animal products. It was very important to control the forage quality and detect the composition of forage raw materials in forage production. Predication of forage quality was often completed by the traditional and classical methods in the past, which were complex, time consuming and expensive, and could not acquire the nutritional value of forage timely. Near infrared reflectance spectroscopy was a highly efficient and rapid modern analysis technique developed in 1970's. It comprehensively applied the latest research results of computer technique, spectroscopy and chemometrics, and has been widely used in various fields owing to its unique advantages such as being timely, less expensive, non-destructive, and so on. Near infrared reflectance spectroscopy has gained more and more importance though its application to forage analysis was very late. Presently, not only conventional composition (such as moisture, dry matter, crude protein, crude fiber, crude fat, crude ash neutral detergent fiber, acid detergent fiber, etc.), but also non-conventional composition (including minerals, trace elements, enzyme and anti-nutritional factors etc. ) and anti-nutritional factors in forage were determined by means of near infrared reflectance spectroscopy. Testing and analyzing the conventional composition in forage was the traditional applied field of near infrared reflectance spectroscopy, a lot of studies of which were done and it has already been one of the standard methods of testing the conventional composition. Forage bioavaibility was also evaluated by near infrared reflectance spectroscopy, so as to assess the utilization rate and nutritional value of forage. Moreover, near infrared spectroscopy could be used successfully to predict the botanical composition in grassland and leaf/stem ratios. Near infrared spectroscopy technique and its application and prospect in forage analysis were reviewed in the present paper. PMID:19455789

  11. Spatial working memory for clustered and linear configurations of sites in a virtual reality foraging task.

    PubMed

    De Lillo, Carlo; James, Frances C

    2012-08-01

    Two experiments using an immersive virtual reality foraging environment determined the spatial strategies spontaneously deployed by people in a foraging task and the effects on immediate serial recall of trajectories though the foraging space, which could conform or violate specific organisational constraints. People benefitted from the use of organised search patterns when attempting to monitor their travel though either a clustered "patchy" space or a matrix of locations. The results are discussed within a comparative framework. PMID:22802028

  12. Liberating Lévy walk research from the shackles of optimal foraging.

    PubMed

    Reynolds, Andy

    2015-09-01

    There is now compelling evidence that many organisms have movement patterns that can be described as Lévy walks, or Lévy flights. Lévy movement patterns have been identified in cells, microorganisms, molluscs, insects, reptiles, fish, birds and even human hunter-gatherers. Most research into Lévy walks as models of organism movement patterns has been shaped by the 'Lévy flight foraging hypothesis'. This states that, since Lévy walks can optimize search efficiencies, natural selection should lead to adaptations that select ?for Lévy walk foraging. However, a growing body of research on generative mechanisms suggests that Lévy walks can arise freely as by-products of otherwise innocuous behaviours; consequently their advantageous properties are purely coincidental. This suggests that the Lévy flight foraging hypothesis should be amended, or even replaced, by a simpler and more general hypothesis. This new hypothesis would state that 'Lévy walks emerge spontaneously and naturally from innate behaviours and innocuous responses to the environment but, if advantageous, then there could be selection against losing them'. The new hypothesis has the virtue of making fewer assumptions and being broader than the original hypothesis; it also encompasses the many examples of suboptimal Lévy patterns that challenge the prevailing paradigm. This does not detract from the Lévy flight foraging hypothesis, in fact, it adds to the theory by providing a stronger and more compelling case for the occurrence of Lévy walks. It dispenses with concerns about the theoretical arguments in support of the Lévy flight foraging hypothesis and so may lead to a wider acceptance of Lévy walks as models of movement pattern data. Furthermore, organisms can approximate Lévy walks by adapting intrinsic behaviour in simple ways; this occurs when Lévy movement patterns are advantageous, but come with an associated cost. These new developments represent a major change in perspective and provide the broadest picture yet of Lévy movement patterns. However, the process of understanding and identifying Lévy movement patterns still has a long way to go, and further reinterpretations and shifts in understanding will occur. In conclusion, Lévy walk research remains exciting precisely because so much remains to be understood, and because, even relatively small studies, are interesting discoveries in their own right. PMID:25835600

  13. Characterizing Variation of Isotopic Markers in Northern Alaskan Caribou Forages

    NASA Astrophysics Data System (ADS)

    VanSomeren, L.; Barboza, P. S.; Gustine, D. D.; Parrett, L. S.; Stricker, C. A.

    2013-12-01

    Isotopic markers in feces and tissues are a potential tool for monitoring the importance of feeding areas for migratory herbivores such as caribou (Rangifer tarandus). Many of these techniques are currently limited by gaps in our knowledge of how these isotopic signatures vary over the landscape. We collected seven species of preferred caribou forages along a latitudinal gradient in the summer ranges of the Central Arctic (9 sites) and Teshekpuk Lake (4 sites) caribou herds during 2011 and 2012. We analyzed forages at peak protein content and at the end of the season to characterize temporal, species-specific, and spatial variation in isotopic markers. The availability of C and N was measured by digestion in vitro. Isotopic signatures of digested samples were used to calculate fractionation that would bias the isotopic signature of feces. The range of values for isotopes (all values ‰) of nitrogen (?15N -9.5 - +4.3), and sulfur (?34S -3.6 - +15.5) were greater than those for carbon (?13C -30.5 - -24.9). Small declines in forage ?13C with latitude (Carex aquatilis, Eriophorum vaginatum, Salix pulchra, and S. richardsonii [all P < 0.01]), season (all species except C. bigelowii [all P ? 0.01]), and season x year (S. richardsonii; P = 0.01) were probably associated with changes in water availability. Fractionation of ?13C in early season forages was 0.1 × 1.0 and positively related to C availability (58% × 15%; P < 0.01) with the greatest fractionation for the highly digestible forb Pedicularis langsdorfii (1.43 × 0.44; P < 0.01). Sedges (Carex and Eriophorum) were significantly higher in ?15N than Salix spp. and other dicots (2.0 × 1.1 vs. -2.9 × 2.2; P < 0.01). For Salix spp., ?15N was consistent over the season and between years. Fractionation of ?15N in early season forages was 0.2 × 1.8 and not related to N availability (60% × 17%). For S. pulchra, ?34S may indicate usage of coastal habitats over foothills because ?34S was higher on the coastal plain than in the foothills (11.1 × 3.3 and 3.1 × 2.6; P < 0.01). Isotopic ratios in N and S show the greatest promise for tracking diet and location of migratory caribou whereas the narrow range in ?13C is affected by species, season and location.

  14. Liberating Lévy walk research from the shackles of optimal foraging

    NASA Astrophysics Data System (ADS)

    Reynolds, Andy

    2015-09-01

    There is now compelling evidence that many organisms have movement patterns that can be described as Lévy walks, or Lévy flights. Lévy movement patterns have been identified in cells, microorganisms, molluscs, insects, reptiles, fish, birds and even human hunter-gatherers. Most research into Lévy walks as models of organism movement patterns has been shaped by the 'Lévy flight foraging hypothesis'. This states that, since Lévy walks can optimize search efficiencies, natural selection should lead to adaptations that select for Lévy walk foraging. However, a growing body of research on generative mechanisms suggests that Lévy walks can arise freely as by-products of otherwise innocuous behaviours; consequently their advantageous properties are purely coincidental. This suggests that the Lévy flight foraging hypothesis should be amended, or even replaced, by a simpler and more general hypothesis. This new hypothesis would state that 'Lévy walks emerge spontaneously and naturally from innate behaviours and innocuous responses to the environment but, if advantageous, then there could be selection against losing them'. The new hypothesis has the virtue of making fewer assumptions and being broader than the original hypothesis; it also encompasses the many examples of suboptimal Lévy patterns that challenge the prevailing paradigm. This does not detract from the Lévy flight foraging hypothesis, in fact, it adds to the theory by providing a stronger and more compelling case for the occurrence of Lévy walks. It dispenses with concerns about the theoretical arguments in support of the Lévy flight foraging hypothesis and so may lead to a wider acceptance of Lévy walks as models of movement pattern data. Furthermore, organisms can approximate Lévy walks by adapting intrinsic behaviour in simple ways; this occurs when Lévy movement patterns are advantageous, but come with an associated cost. These new developments represent a major change in perspective and provide the broadest picture yet of Lévy movement patterns. However, the process of understanding and identifying Lévy movement patterns still has a long way to go, and further reinterpretations and shifts in understanding will occur. In conclusion, Lévy walk research remains exciting precisely because so much remains to be understood, and because, even relatively small studies, are interesting discoveries in their own right.

  15. Mercury bioaccumulation and risk to three waterbird foraging guilds is influenced by foraging ecology and breeding stage.

    PubMed

    Eagles-Smith, Collin A; Ackerman, Joshua T; De La Cruz, Susan E W; Takekawa, John Y

    2009-07-01

    We evaluated mercury (Hg) in five waterbird species representing three foraging guilds in San Francisco Bay, CA. Fish-eating birds (Forster's and Caspian terns) had the highest Hg concentrations in their tissues, but concentrations in an invertebrate-foraging shorebird (black-necked stilt) were also elevated. Foraging habitat was important for Hg exposure as illustrated by within-guild differences, where species more associated with marshes and salt ponds had higher concentrations than those more associated with open-bay and tidal mudflats. Importantly, Hg concentrations increased with time spent in the estuary. Surf scoter concentrations tripled over six months, whereas Forster's terns showed an up to 5-fold increase between estuary arrival and breeding. Breeding waterbirds were at elevated risk of Hg-induced reproductive impairment, particularly Forster's terns, in which 48% of breeding birds were at high risk due to their Hg levels. Our results highlight the importance of habitat and exposure timing, in addition to trophic position, on waterbird Hg bioaccumulation and risk. PMID:19398255

  16. Nectar robbing, forager efficiency and seed set: Bumblebees foraging on the self incompatible plant Linaria vulgaris (Scrophulariaceae)

    NASA Astrophysics Data System (ADS)

    Stout, Jane C.; Allen, John A.; Goulson, Dave

    2000-07-01

    In southern England, Linaria vulgaris (common yellow toadflax) suffers from high rates of nectar robbery by bumblebees. In a wild population of L. vulgaris we found that 96 % of open flowers were robbed. Five species of bumblebee were observed foraging on these flowers, although short-tongued species ( Bombus lapidarius, B. lucorum and B. terrestris) robbed nectar whilst longer-tongued ones behaved as legitimate pollinators ( B. hortorum and B. pascuorum). Nectar rewards were highly variable; on average there was less nectar in robbed than in unrobbed flowers, but this difference was not statistically significant. The proportion of flowers containing no nectar was significantly higher for robbed flowers compared with unrobbed flowers. Secondary robbers and legitimate pollinators had similar handling times on flowers and, assuming they select flowers at random to forage on, received approximately the same nectar profit per minute, largely because most flowers had been robbed. There was no significant difference in the number of seeds in pods of robbed flowers and in pods of flowers that were artificially protected against robbing. However, more of the robbed flowers set at least some seed than the unrobbed flowers, possibly as a consequence of the experimental manipulation. We suggest that nectar robbing has little effect on plant fecundity because legitimate foragers are present in the population, and that seed predation and seed abortion after fertilization may be more important factors in limiting seed production in this species.

  17. Mercury bioaccumulation and risk to three waterbird foraging guilds is influenced by foraging ecology and breeding stage

    USGS Publications Warehouse

    Eagles-Smith, C. A.; Ackerman, J.T.; de la Cruz, S.E.W.; Takekawa, J.Y.

    2009-01-01

    We evaluated mercury (Hg) in five waterbird species representing three foraging guilds in San Francisco Bay, CA. Fish-eating birds (Forster's and Caspian terns) had the highest Hg concentrations in thier tissues, but concentrations in an invertebrate-foraging shorebird (black-necked stilt) were also elevated. Foraging habitat was important for Hg exposure as illustrated by within-guild differences, where species more associated with marshes and salt ponds had higher concentrations than those more associated with open-bay and tidal mudflats. Importantly, Hg concentrations increased with time spent in the estuary. Surf scoter concentrations tripled over six months, whereas Forster's terns showed an up to 5-fold increase between estuary arrival and breeding. Breeding waterbirds were at elevated risk of Hg-induced reproductive impairment, particularly Forster's terns, in which 48% of breeding birds were at high risk due to their Hg??levels. Our results highlight the importance of habitat and exposure timing, in addition to trophic position, on waterbird Hg bioaccumulation and risk.

  18. Simulating secondary succession of elk forage values in a managed forest landscape, western Washington

    USGS Publications Warehouse

    Jenkins, Kurt J.; Starkey, Edward E.

    1996-01-01

    Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.

  19. Diet Overlap and Foraging Activity between Feral Pigs and Native Peccaries in the Pantanal.

    PubMed

    Galetti, Mauro; Camargo, Hiléia; Siqueira, Tadeu; Keuroghlian, Alexine; Donatti, Camila I; Jorge, Maria Luisa S P; Pedrosa, Felipe; Kanda, Claudia Z; Ribeiro, Milton C

    2015-01-01

    Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu) with the invasive feral pig (Sus scrofa) in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods. PMID:26536608

  20. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals.

    PubMed

    Peterson, Sarah H; Ackerman, Joshua T; Costa, Daniel P

    2015-07-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200-1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and ?(13)C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation. PMID:26085591

  1. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

    USGS Publications Warehouse

    Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

    2015-01-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and ?13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

  2. Diet Overlap and Foraging Activity between Feral Pigs and Native Peccaries in the Pantanal

    PubMed Central

    Galetti, Mauro; Camargo, Hiléia; Siqueira, Tadeu; Keuroghlian, Alexine; Donatti, Camila I.; Jorge, Maria Luisa S. P.; Pedrosa, Felipe; Kanda, Claudia Z.; Ribeiro, Milton C.

    2015-01-01

    Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu) with the invasive feral pig (Sus scrofa) in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods. PMID:26536608

  3. How long will honey bees (Apis mellifera L.) be stimulated by scent to revisit past-profitable forage sites?

    PubMed

    Beekman, Madeleine

    2005-12-01

    Honey bees utilise floral food sources that vary temporally in their relative and absolute quality. Via a sophisticated colony organisation, a honey bee colony allocates its foragers such that the colony focuses on the most profitable forage sites while keeping track of changes within its foraging environment. One important mechanism of the allocation of foragers is the ability of experienced foragers to revisit past-profitable forage sites after a period of temporary dearth caused by, for example, inclement weather. The scent of past-profitable forage within the colony brought back by other foragers is sufficient to reactivate these experienced foragers. Here I determine for how long bees react to the scent of a past-profitable forage site. I show that the ability of foragers to revisit the location of a past-profitable food source diminishes rapidly over a period of 10 days, until no forager reacts to the cue (scent). I discuss the implications of these findings with respect to the colony's ability to react rapidly to changing foraging conditions. PMID:16049699

  4. Differential regulation of the foraging gene associated with task behaviors in harvester ants

    PubMed Central

    2011-01-01

    Background The division of labor in social insect colonies involves transitions by workers from one task to another and is critical to the organization and ecological success of colonies. The differential regulation of genetic pathways is likely to be a key mechanism involved in plasticity of social insect task behavior. One of the few pathways implicated in social organization involves the cGMP-activated protein kinase gene, foraging, a gene associated with foraging behavior in social insect species. The association of the foraging gene with behavior is conserved across diverse species, but the observed expression patterns and proposed functions of this gene vary across taxa. We compared the protein sequence of foraging across social insects and explored whether the differential regulation of this gene is associated with task behaviors in the harvester ant, Pogonomyrmex occidentalis. Results Phylogenetic analysis of the coding region of the foraging gene reveals considerable conservation in protein sequence across insects, particularly among hymenopteran species. The absence of amino acid variation in key active and binding sites suggests that differences in behaviors associated with this gene among species may be the result of changes in gene expression rather than gene divergence. Using real time qPCR analyses with a harvester ant ortholog to foraging (Pofor), we found that the brains of harvester ant foragers have a daily fluctuation in expression of foraging with mRNA levels peaking at midday. In contrast, young workers inside the nest have low levels of Pofor mRNA with no evidence of daily fluctuations in expression. As a result, the association of foraging expression with task behavior within a species changes depending on the time of day the individuals are sampled. Conclusions The amino acid protein sequence of foraging is highly conserved across social insects. Differences in foraging behaviors associated with this gene among social insect species are likely due to differences in gene regulation rather than evolutionary changes in the encoded protein. The task-specific expression patterns of foraging are consistent with the task-specific circadian rhythms observed in harvester ants. Whether the molecular clock plays a role in regulating foraging gene expression (or vice versa) remains to be determined. Our results represent the first time series analysis of foraging gene expression and underscore the importance of assaying time-related expression differences in behavioral studies. Understanding how this gene is regulated within species is critical to explaining the mechanism by which foraging influences behavior. PMID:21831307

  5. Foraging behaviour at multiple temporal scales in a wild alpine equid.

    PubMed

    St-Louis, Antoine; Côté, Steeve D

    2012-05-01

    Forage abundance, forage quality, and social factors are key elements of the foraging ecology of wild herbivores. For non-ruminant equids, forage-limited environments are likely to impose severe constraints on their foraging behaviour. We used a multi-scale approach to study foraging behaviour in kiang (Equus kiang), a wild equid inhabiting the high-altitude rangelands of the Tibetan Plateau. Using behavioural observations and vegetation sampling, we first assessed how patterns of plant abundance and quality affected (i) the instantaneous forage intake rate (fine scale) and (ii) the proportion of time spent foraging (coarse scale) across seasons. We also tested whether foraging behaviour differed among group types, between sex in adults, and between females of different reproductive status. At a fine scale, intake rate increased linearly with bite size and increased following a type II curvilinear function with biomass on feeding sites. Forage intake rate also increased linearly with plant quality. Male and female kiangs had similar intake rates. Likewise, gravid and lactating females had similar intake rates as barren and non-lactating females. At a coarse scale, kiangs spent longer time feeding in mesic than in xeric habitats, and spent more time feeding in early summer and fall than in late summer. Groups of adults with foals spent less time feeding than male groups and groups of adults without foals. Our findings suggest that kiangs use flexible foraging behaviours in relation to seasonal variations of vegetation quality and abundance, a likely outcome of the extreme seasonal conditions encountered on the Tibetan Plateau. PMID:22033764

  6. Systematic review of the influence of foraging habitat on red-cockaded woodpecker reproductive success.

    SciTech Connect

    Garabedian, James E.

    2014-04-01

    Relationships between foraging habitat and reproductive success provide compelling evidence of the contribution of specific vegetative features to foraging habitat quality, a potentially limiting factor for many animal populations. For example, foraging habitat quality likely will gain importance in the recovery of the threatened red-cockaded woodpecker Picoides borealis (RCW) in the USA as immediate nesting constraints are mitigated. Several researchers have characterized resource selection by foraging RCWs, but emerging research linking reproductive success (e.g. clutch size, nestling and fledgling production, and group size) and foraging habitat features has yet to be synthesized. Therefore, we reviewed peer-refereed scientific literature and technical resources (e.g. books, symposia proceedings, and technical reports) that examined RCW foraging ecology, foraging habitat, or demography to evaluate evidence for effects of the key foraging habitat features described in the species’ recovery plan on group reproductive success. Fitness-based habitat models suggest foraging habitat with low to intermediate pine Pinus spp. densities, presence of large and old pines, minimal midstory development, and herbaceous groundcover support more productive RCW groups. However, the relationships between some foraging habitat features and RCW reproductive success are not well supported by empirical data. In addition, few regression models account for > 30% of variation in reproductive success, and unstandardized multiple and simple linear regression coefficient estimates typically range from -0.100 to 0.100, suggesting ancillary variables and perhaps indirect mechanisms influence reproductive success. These findings suggest additional research is needed to address uncertainty in relationships between foraging habitat features and RCW reproductive success and in the mechanisms underlying those relationships.

  7. Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation.

    PubMed

    Geib, Jennifer C; Strange, James P; Galenj, Candace

    2015-04-01

    Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species (Bombus balteatus, B. flavifrons, B. bifarius, and B. sylvicola), and two host plants that differ in their degrees of pollinator specialization (Trifolium dasyphyllum and T. parryi). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km2. The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi, was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum, was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured here (nest abundance, forager abundance, and foraging distance) could increase the usefulness of foraging worker inventories in nionitoring, managing, and conserving pollinator populations. PMID:26214921

  8. When Michaelis and Menten met Holling: towards a mechanistic theory of plant nutrient foraging behaviour.

    PubMed

    McNickle, Gordon G; Brown, Joel S

    2014-01-01

    Plants are adept at assessing and responding to nutrients in soil, and generally proliferate roots into nutrient-rich patches. An analogy between this growth response and animal foraging movement is often drawn, but because of differences between plants and animals it has not always been clear how to directly apply existing foraging theory to plants. Here we suggest one way to unite pre-existing ideas in plant nutrient uptake with foraging theory. First, we show that the Michaelis-Menten equation used by botanists and the Holling disc equation used by zoologists are actually just rearrangements of the same functional response. This mathematical unity permits the translation of existing knowledge about the nutrient uptake physiology of plants into the language of foraging behaviour, and as a result gives botanists direct access to foraging theory. Second, we developed a model of root foraging precision based on the Holling disc equation and the marginal value theorem, and parameterize it from the literature. The model predicts (i) generally plants should invest in higher quality patches compared to lower quality patches, and as patch background-contrast increases; (ii) low encounter rates between roots and nutrients result in high root foraging precision; and (iii) low handling times for nutrients should result in high root foraging precision. The available data qualitatively support these predictions. Third, to parameterize the model above we undertook a review of the literature. From that review we obtained parameter estimates for nitrate and/or ammonium uptake for 45 plant species from 38 studies. We observe that the parameters ranged over six orders of magnitude, there was no trade-off in foraging ability for nitrate versus ammonium: plants that were efficient foragers for one form of nitrogen were efficient foragers for the other, and there was also no phylogenetic signal in the parameter estimates. PMID:25341427

  9. The Importance of Predation Risk and Missed Opportunity Costs for Context-Dependent Foraging Patterns

    PubMed Central

    Eccard, Jana A.; Liesenjohann, Thilo

    2014-01-01

    Correct assessment of risks and costs of foraging is vital for the fitness of foragers. Foragers should avoid predation risk and balance missed opportunities. In risk-heterogeneous landscapes animals prefer safer locations over riskier, constituting a landscape of fear. Risk-uniform landscapes do not offer this choice, all locations are equally risky. Here we investigate the effects of predation risk in patches, travelling risk between patches, and missed social opportunities on foraging decisions in risk-uniform and risk-heterogeous landscapes. We investigated patch leaving decisions of 20 common voles (M. arvalis) in three experimental landscapes: safe risk-uniform, risky risk-uniform and risk-heterogeneous. We varied both the predation risk level and the predation risk distribution between two patches experimentally and in steps, assuming that our manipulation consequently yield different distributions and levels of risk while foraging, risk while travelling, and costs of missed, social opportunities (MSOCs). We measured mean GUDs (giving-up density of food left in the patch) for both patches as a measure of foraging gain, and delta GUD, the differences among patches, as a measure of the spatial distribution of foraging effort over a period of six hours. Distribution of foraging effort was most even in the safe risk-uniform landscapes and least even in the risk-heterogeneous landscape, with risky risk-uniform landscapes in between. Foraging gain was higher in the safe than in the two riskier landscapes (both uniform and heterogeneous). Results supported predictions for the effects of risk in foraging patches and while travelling between patches, however predictions for the effects of missed social opportunities were not met in this short term experiment. Thus, both travelling and foraging risk contribute to distinct patterns observable high risk, risk-uniform landscapes. PMID:24809666

  10. The importance of predation risk and missed opportunity costs for context-dependent foraging patterns.

    PubMed

    Eccard, Jana A; Liesenjohann, Thilo

    2014-01-01

    Correct assessment of risks and costs of foraging is vital for the fitness of foragers. Foragers should avoid predation risk and balance missed opportunities. In risk-heterogeneous landscapes animals prefer safer locations over riskier, constituting a landscape of fear. Risk-uniform landscapes do not offer this choice, all locations are equally risky. Here we investigate the effects of predation risk in patches, travelling risk between patches, and missed social opportunities on foraging decisions in risk-uniform and risk-heterogeous landscapes. We investigated patch leaving decisions of 20 common voles (M. arvalis) in three experimental landscapes: safe risk-uniform, risky risk-uniform and risk-heterogeneous. We varied both the predation risk level and the predation risk distribution between two patches experimentally and in steps, assuming that our manipulation consequently yield different distributions and levels of risk while foraging, risk while travelling, and costs of missed, social opportunities (MSOCs). We measured mean GUDs (giving-up density of food left in the patch) for both patches as a measure of foraging gain, and delta GUD, the differences among patches, as a measure of the spatial distribution of foraging effort over a period of six hours. Distribution of foraging effort was most even in the safe risk-uniform landscapes and least even in the risk-heterogeneous landscape, with risky risk-uniform landscapes in between. Foraging gain was higher in the safe than in the two riskier landscapes (both uniform and heterogeneous). Results supported predictions for the effects of risk in foraging patches and while travelling between patches, however predictions for the effects of missed social opportunities were not met in this short term experiment. Thus, both travelling and foraging risk contribute to distinct patterns observable high risk, risk-uniform landscapes. PMID:24809666

  11. The Bacterial Communities Associated with Honey Bee (Apis mellifera) Foragers

    PubMed Central

    Corby-Harris, Vanessa; Maes, Patrick; Anderson, Kirk E.

    2014-01-01

    The honey bee is a key pollinator species in decline worldwide. As part of a commercial operation, bee colonies are exposed to a variety of agricultural ecosystems throughout the year and a multitude of environmental variables that may affect the microbial balance of individuals and the hive. While many recent studies support the idea of a core microbiota in guts of younger in-hive bees, it is unknown whether this core is present in forager bees or the pollen they carry back to the hive. Additionally, several studies hypothesize that the foregut (crop), a key interface between the pollination environment and hive food stores, contains a set of 13 lactic acid bacteria (LAB) that inoculate collected pollen and act in synergy to preserve pollen stores. Here, we used a combination of 454 based 16S rRNA gene sequencing of the microbial communities of forager guts, crops, and corbicular pollen and crop plate counts to show that (1) despite a very different diet, forager guts contain a core microbiota similar to that found in younger bees, (2) corbicular pollen contains a diverse community dominated by hive-specific, environmental or phyllosphere bacteria that are not prevalent in the gut or crop, and (3) the 13 LAB found in culture-based studies are not specific to the crop but are a small subset of midgut or hindgut specific bacteria identified in many recent 454 amplicon-based studies. The crop is dominated by Lactobacillus kunkeei, and Alpha 2.2 (Acetobacteraceae), highly osmotolerant and acid resistant bacteria found in stored pollen and honey. Crop taxa at low abundance include core hindgut bacteria in transit to their primary niche, and potential pathogens or food spoilage organisms seemingly vectored from the pollination environment. We conclude that the crop microbial environment is influenced by worker task, and may function in both decontamination and inoculation. PMID:24740297

  12. Transport Infrastructure Shapes Foraging Habitat in a Raptor Community

    PubMed Central

    Planillo, Aimara; Kramer-Schadt, Stephanie; Malo, Juan E.

    2015-01-01

    Transport infrastructure elements are widespread and increasing in size and length in many countries, with the subsequent alteration of landscapes and wildlife communities. Nonetheless, their effects on habitat selection by raptors are still poorly understood. In this paper, we analyzed raptors’ foraging habitat selection in response to conventional roads and high capacity motorways at the landscape scale, and compared their effects with those of other variables, such as habitat structure, food availability, and presence of potential interspecific competitors. We also analyzed whether the raptors’ response towards infrastructure depends on the spatial scale of observation, comparing the attraction or avoidance behavior of the species at the landscape scale with the response of individuals observed in the proximity of the infrastructure. Based on ecological hypotheses for foraging habitat selection, we built generalized linear mixed models, selected the best models according to Akaike Information Criterion and assessed variable importance by Akaike weights. At the community level, the traffic volume was the most relevant variable in the landscape for foraging habitat selection. Abundance, richness, and diversity values reached their maximum at medium traffic volumes and decreased at highest traffic volumes. Individual species showed different degrees of tolerance toward traffic, from higher abundance in areas with high traffic values to avoidance of it. Medium-sized opportunistic raptors increased their abundance near the traffic infrastructures, large scavenger raptors avoided areas with higher traffic values, and other species showed no direct response to traffic but to the presence of prey. Finally, our cross-scale analysis revealed that the effect of transport infrastructures on the behavior of some species might be detectable only at a broad scale. Also, food availability may attract raptor species to risky areas such as motorways. PMID:25786218

  13. Harvest management of switchgrass for biomass feedstock and forage production

    SciTech Connect

    Sanderson, M.A.; Read, J.C.; Reed, R.L.

    1999-02-01

    Switchgrass (Panicum virgatum L.), a warm-season perennial grass native to North America, has potential as a biomass energy crop. Their objective was to develop harvest management recommendations for biomass feedstock and forage production. Alamo switchgrass was established in 1992 at Stephenville and Dallas, TX. Four harvest frequencies (one to four cuts per year) and three final autumn harvests (Sept., Oct., or Nov.) were imposed from 1993 to 1996. Tiller densities were counted each spring. Neutral detergent fiber (NDF) and crude protein (CP) concentrations were measured in 1993 and 1994. Concentrations of NDF were lowest and of CP were highest in May-harvested biomass. Forage quality of regrowth decreased with age, reaching NDF concentrations of 790 g kg{sup {minus}1} and CP of < 20 g kg{sup {minus}1}. Total seasonal yields decreased as harvest frequency increased; however, a severe drought reversed this trend at Dallas in 1996. The highest yields occurred with a single harvest in mid-September. Delaying the final harvest until November reduced yields. Harvest date and frequency did not affect tiller density, although tiller density decreased from 900 to 650 and 630 to 310 m{sup {minus}2} at Dallas and Stephenville, respectively, during 1994 to 1997. Thus, a single mid-September harvest should maximize biomass yields in the south-central USA. A two-cut (spring-autumn) system may allow a farmer to use initial growth as forage and the regrowth for biomass, but total yields would be reduced. More frequent harvests would reduce yields further.

  14. Ants Can Learn to Forage on One-Way Trails

    PubMed Central

    Ribeiro, Pedro Leite; Helene, André Frazão; Xavier, Gilberto; Navas, Carlos; Ribeiro, Fernando Leite

    2009-01-01

    The trails formed by many ant species between nest and food source are two-way roads on which outgoing and returning workers meet and touch each other all along. The way to get back home, after grasping a food load, is to take the same route on which they have arrived from the nest. In many species such trails are chemically marked by pheromones providing orientation cues for the ants to find their way. Other species rely on their vision and use landmarks as cues. We have developed a method to stop foraging ants from shuttling on two-way trails. The only way to forage is to take two separate roads, as they cannot go back on their steps after arriving at the food or at the nest. The condition qualifies as a problem because all their orientation cues – chemical, visual or any other - are disrupted, as all of them cannot but lead the ants back to the route on which they arrived. We have found that workers of the leaf-cutting ant Atta sexdens rubropilosa can solve the problem. They could not only find the alternative way, but also used the unidirectional traffic system to forage effectively. We suggest that their ability is an evolutionary consequence of the need to deal with environmental irregularities that cannot be negotiated by means of excessively stereotyped behavior, and that it is but an example of a widespread phenomenon. We also suggest that our method can be adapted to other species, invertebrate and vertebrate, in the study of orientation, memory, perception, learning and communication. PMID:19337369

  15. Transport infrastructure shapes foraging habitat in a raptor community.

    PubMed

    Planillo, Aimara; Kramer-Schadt, Stephanie; Malo, Juan E

    2015-01-01

    Transport infrastructure elements are widespread and increasing in size and length in many countries, with the subsequent alteration of landscapes and wildlife communities. Nonetheless, their effects on habitat selection by raptors are still poorly understood. In this paper, we analyzed raptors' foraging habitat selection in response to conventional roads and high capacity motorways at the landscape scale, and compared their effects with those of other variables, such as habitat structure, food availability, and presence of potential interspecific competitors. We also analyzed whether the raptors' response towards infrastructure depends on the spatial scale of observation, comparing the attraction or avoidance behavior of the species at the landscape scale with the response of individuals observed in the proximity of the infrastructure. Based on ecological hypotheses for foraging habitat selection, we built generalized linear mixed models, selected the best models according to Akaike Information Criterion and assessed variable importance by Akaike weights. At the community level, the traffic volume was the most relevant variable in the landscape for foraging habitat selection. Abundance, richness, and diversity values reached their maximum at medium traffic volumes and decreased at highest traffic volumes. Individual species showed different degrees of tolerance toward traffic, from higher abundance in areas with high traffic values to avoidance of it. Medium-sized opportunistic raptors increased their abundance near the traffic infrastructures, large scavenger raptors avoided areas with higher traffic values, and other species showed no direct response to traffic but to the presence of prey. Finally, our cross-scale analysis revealed that the effect of transport infrastructures on the behavior of some species might be detectable only at a broad scale. Also, food availability may attract raptor species to risky areas such as motorways. PMID:25786218

  16. Behavioral genomics of honeybee foraging and nest defense

    NASA Astrophysics Data System (ADS)

    Hunt, Greg J.; Amdam, Gro V.; Schlipalius, David; Emore, Christine; Sardesai, Nagesh; Williams, Christie E.; Rueppell, Olav; Guzmán-Novoa, Ernesto; Arechavaleta-Velasco, Miguel; Chandra, Sathees; Fondrk, M. Kim; Beye, Martin; Page, Robert E.

    2007-04-01

    The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search to regions containing only 17-61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes. An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization. The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling ( Am5HT 7 serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior to the identification of underlying genes.

  17. Assigning a Value to Dried Distillers' Grains as a Protein Supplement in Cattle Consuming Low-Quality Forage 

    E-print Network

    Rambo, Zachary Joseph

    2011-08-08

    neutral detergent fiber intake (DNDFI) increased as a result of supplementation (P = 0.06). Forage organic matter intake did not increase as a result of protein supplementation (P = 0.20). However, forage organic matter intake (FOMI) responded...

  18. Evaluation of physiological and pheromonal factors regulating honey bee, apis mellifera l. (hymenoptera: apidae) foraging and colony growth 

    E-print Network

    Sagili, Ramesh Reddy

    2009-05-15

    -pollen foragers and pollen load weights collected between the treatments. These results supported the pollen foraging effort predictions generated from the direct independent effects hypothesis. In the third study we tested whether brood pheromone (BP) regulated...

  19. Echolocation-based foraging by harbor porpoises and sperm whales, including effects of noise and acoustic propagation

    E-print Network

    DeRuiter, Stacy L

    2008-01-01

    In this thesis, I provide quantitative descriptions of toothed whale echolocation and foraging behavior, including assessment of the effects of noise on foraging behavior and the potential influence of ocean acoustic ...

  20. Activity time budget during foraging trips of emperor penguins.

    PubMed

    Watanabe, Shinichi; Sato, Katsufumi; Ponganis, Paul J

    2012-01-01

    We developed an automated method using depth and one axis of body acceleration data recorded by animal-borne data loggers to identify activities of penguins over long-term deployments. Using this technique, we evaluated the activity time budget of emperor penguins (n = 10) both in water and on sea ice during foraging trips in chick-rearing season. During the foraging trips, emperor penguins alternated dive bouts (4.8 ± 4.5 h) and rest periods on sea ice (2.5 ± 2.3 h). After recorder deployment and release near the colony, the birds spent 17.9 ± 8.4% of their time traveling until they reached the ice edge. Once at the ice edge, they stayed there more than 4 hours before the first dive. After the first dive, the mean proportions of time spent on the ice and in water were 30.8 ± 7.4% and 69.2 ± 7.4%, respectively. When in the water, they spent 67.9 ± 3.1% of time making dives deeper than 5 m. Dive activity had no typical diurnal pattern for individual birds. While in the water between dives, the birds had short resting periods (1.2 ± 1.7 min) and periods of swimming at depths shallower than 5 m (0.25 ± 0.38 min). When the birds were on the ice, they primarily used time for resting (90.3 ± 4.1% of time) and spent only 9.7 ± 4.1% of time traveling. Thus, it appears that, during foraging trips at sea, emperor penguins traveled during dives >5 m depth, and that sea ice was primarily used for resting. Sea ice probably provides refuge from natural predators such as leopard seals. We also suggest that 24 hours of sunlight and the cycling of dive bouts with short rest periods on sea ice allow emperor penguins to dive continuously throughout the day during foraging trips to sea. PMID:23185608

  1. Photo Guide to Forage Supplies on Texas Rangelands 

    E-print Network

    Hanselka, C. Wayne; McGinty, Allan

    2006-06-21

    , The Texas A&M University System. L-5476 06/06 Accurately determining stocking rate is important to successful range manage- ment. Because forage supplies on range- lands vary drastically across seasons and years, livestock numbers should be appropriate..., Extension Range Specialist Emeritus, and Calvin Richardson, currently with the Texas Parks and Wildlife Department. 69 lb/ac hairy tridens, red grama 212 lb/ac buffalograss 826 lb/ac little bluestem, seep muhly, dropseed, sideoats grama 1247 lb/ac Tx...

  2. Woolly Locoweed and Forage Response to Herbicides in West Texas. 

    E-print Network

    Freeman, M. R.; Ueckert, D. N.; Nelson, J. T.

    1982-01-01

    /range management/woolly locoweed/Earle loco/purple loco/Texas loco/ 2, 4-D/ dicam ba/3, 6-dichloropicolinic acid/picloram/tebuthiuron/trichlopyr/pelleted herbicides. Woolly Locoweed and Forage Response to Herbicides in West Texas M. R. Freeman, D. N. Ueckert... was not manifested for almost a year following application of picloram pellets. Woolly locoweed was effectively controlled in the fall with foliar sprays of picloram + triclopyr ester (1: 1) at 0. 6 kg/ha; picloram at 1.1 kg/ha; 3, 6-dichloropicolinic acid...

  3. Foraging behavior of the dead leaf butterfly, Kallima inachus.

    PubMed

    Tang, Yuchong; Zhou, Chengli; Chen, Xiaoming; Zheng, Hua

    2013-01-01

    The behavioral responses of foraging adults of Kallima inachus (Boisduval) (Lepidoptera: Nymphalidae) to four colors and to six different fermented fruit juices were observed in order to determine the cues used by foraging adults. According to the results, adults did not show a behavioral response to red, yellow, purple, or white artificial flowers without food odors, but flowers with the fermented pear juice strongly attracted them, and they showed a behavioral response to fermented juices of the six fruits (pear, apple, banana, watermelon, orange, and persimmon) with no statistically significant preference. The fruit volatiles were collected using dynamic headspace adsorption, and the volatile components were analyzed by auto thermal-desorption gas chromatography-mass spectrometry to assess which volatiles existed in the fruits. Only alcohols, esters, and ketones were common in the volatiles of all six fermenting fruits. The five volatile components found in the six fruits, as well as two others found to be in other fermented foods by previous studies, were selected to test the behavioral and electroantennogram (EAG) responses of naive adults to estimate behavioral preference and antennal perception. In field behavioral tests, alcohols were the most attractive, followed by esters, while ?-pinene, butanone, and acetic acid were much less attractive. Relative to other volatile combinations and ethanol alone, the mixture of ethyl acetate and ethanol attracted the most feeding adults. The number of adults attracted was significantly positively correlated with the concentration of both ethanol and ethyl acetate. The EAG responses of naive adults showed that the EAG responses to 3-methyl-1-butanol, isoamyl acetate, ethyl acetate, ?-pinene, butanone, and acetic acid were all higher than those to ethanol (100%) at doses of either 5 µl/mL or 50 µl/mL. Sexual differences only existed in 3-methyl-1-butanol and acetic acid at particular concentrations. Sexual differences in response to chemical mixtures were not significant at 50 µl/mL. In addition, the EAG responses in the within-sex trials were not correlated to the dosage (0.01, 0.1, 1, 5, 10, and µl/mL) of either ethanol or ethyl acetate. The results showed that olfactory cues played a crucial role in the foraging of adult K. inachus, and that foraging adults can use a variety of chemical signals derived from food; however, the feeding preference to volatiles was not necessary correlated with the EAG responses. PMID:23909654

  4. Production and Feeding of Forage Sorghum in Texas. 

    E-print Network

    Quinby, J. R.; Marion, P. T.

    1960-01-01

    widely grown in Texas, but early maturing varieties can be grown in the northern Panhandle. The most widely grown varieties in Texas are Atlas, Sumac, Sourless (African Millet), Tracy and Honey. Dual-purpose forage sorghums, such as Hegari, Early... (Boddie), Corn earworrn Elasmopalpus lignosellus (Zell.) , Lesser corn.stalk l 11 hi fl I k; ! B- 911 'el XU a XY 7 nb md me ietr Ulu I Sl 1 led u b atr "1 I ~fl (!iit:l~a ~orghielln (Riley) , Sorghum webworm Dx...

  5. Suggestions for Weed Control in Pastures and Forages 

    E-print Network

    Baumann, Paul A.; Bade, David H.

    2004-04-06

    anent grass pastur es and established grass cr ops (continued) Pr oduct A pplication rate (H erbicide common name) per acr e W eeds contr olled Company (br oadcast) T ime to apply R e mar k s S mutgrass and other w eeds in V elpar L ? 2.75 to 4.5 pts... ermanent grass pastur es and established grass cr op ............................5 barley , r y egrass and mixtur es ther eof ) ........ ..............................12 5S orghum-sudan hybrids (forage types...

  6. Production and Management of Small Grains for Forage

    E-print Network

    Holt, E. C.; Norris, M. J.; Lancaster, J. A.

    1969-01-01

    . Research has shown that nitratt tends to be higher in basal parts of the plant, 1% favored by overcast weather and darkness 2nd is favored to some extent by use of high rates r~l Factors influencing choice of variety il- elude disease reaction, cold... of dis- tae also is related to humidity and general mois- ture conditions. Several outbreaks of disease :rould alter the yield-rainfall relationships. I Response to Cutting Height Forage production and total above-ground i.umulative growth of a...

  7. Collective Energy Foraging of Robot Swarms and Robot Organisms

    E-print Network

    Kernbach, Serge

    2011-01-01

    Cooperation and competition among stand-alone swarm agents increase collective fitness of the whole system. A principally new kind of collective systems is demonstrated by some bacteria and fungi, when they build symbiotic organisms. Symbiotic life forms emerge new functional and self-developmental capabilities, which allow better survival of swarm agents in different environments. In this paper we consider energy foraging scenario for two robotic species, swarm robots and symbiotic robot organism. It is indicated that aggregation of microrobots into a robot organism can provide better functional fitness for the whole group. A prototype of microrobots capable of autonomous aggregation and disaggregation are shown.

  8. SHORT-DURATION PIGEONPEA - A POTENTIAL GRAIN AND FORAGE FOR THE SOUTHERN PLAINS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage based livestock production systems occur extensively throughout the southern Great Plains (SPG). However, a period of limited forage availability occurs from late July to early November in the region. In semi-arid regions of Asia, pigeon-pea (Cajanus cajan L. Millsp) is grown for grain and ...

  9. The foraging benefits of being fat in a highly migratory marine mammal

    PubMed Central

    Adachi, Taiki; Maresh, Jennifer L.; Robinson, Patrick W.; Peterson, Sarah H.; Costa, Daniel P.; Naito, Yasuhiko; Watanabe, Yuuki Y.; Takahashi, Akinori

    2014-01-01

    Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animal-borne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat. PMID:25377461

  10. EFFECTS OF NUTRIENT INPUTS AND FORAGE (CATTLE GRAZING) ON SOIL MICROBIAL COMMUNITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of nutrient inputs and forage utilization on soil carbon stocks and the soil microbial community is important in developing sustainable production systems. In this study, we sampled plots with varying forage utilization that were fertilized with either inorganic N-P-K or high broiler li...

  11. Diffuse Reflectance Fourier Transform Mid-Infrared Spectral Properties of Forages with Varied Fatty Acid Content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ruminant diet can affect the fatty acid (FA) content of meat and dairy products, which indicates that managing forage consumption is important in determining the quality of the animal products. Mid-infrared spectroscopy is sensitive to changes in forage FA and has been used successfully to quantify ...

  12. Diffuse Reflectance Fourier Transform Mid-infrared Spectral Properties of Forages with Varied Fatty Acid Content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ruminant diet can affect the fatty acid (FA) content of meat and dairy products, which indicates that managing forage consumption is important in determining the quality of the animal products. Mid-infrared spectroscopy is sensitive to changes in forage FA and has been used successfully to quantify ...

  13. Biomass production and quality of indian-origin forage Guar in Southern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guar [Cyamopsis tetragonoloba (L.) Taub.] is a warm-season annual pulse grown in semi-arid regions of the world as a multi-purpose vegetable, forage, cover or fodder crop. Guar could provide late summer forage in the southern Great Plains (SGP), but has largely been used as a grain crop, and no func...

  14. Management and Conservation Article Prescribed Fire Effects on Wintering, Bark-Foraging Birds

    E-print Network

    Beier, Paul

    Management and Conservation Article Prescribed Fire Effects on Wintering, Bark-Foraging Birds of prescribed fire on 3 wintering, bark-foraging birds, hairy woodpeckers (Picoides villosus), pygmy nuthatches, and bark beetle activity among burned treatment and unburned control units. Hairy woodpecker density was 5

  15. OIKOS 88: 291300. Copenhagen 2000 Foraging and community consequences of seed size for coexisting

    E-print Network

    Brown, Joel S.

    OIKOS 88: 291­300. Copenhagen 2000 Foraging and community consequences of seed size for coexisting, J. S. 2000. Foraging and community consequences of seed size for coexisting Negev Desert granivores. ­ Oikos 88: 291­300. We examined the effects of seed size on patch use and diet selection for three co

  16. Original Research Article High Prevalence of Cannabis Use Among Aka Foragers of the Congo Basin

    E-print Network

    Original Research Article High Prevalence of Cannabis Use Among Aka Foragers of the Congo Basin Pasteur, Bangui, Central African Republic Objectives: Little is known about cannabis use in hunter-gatherers. Therefore, we investigated cannabis use in the Aka, a population of foragers of the Congo Basin. Because

  17. Behavioural responses of Eastern grey squirrels, Sciurus carolinensis, to cues of risk while foraging.

    PubMed

    Jayne, Kimberley; Lea, Stephen E G; Leaver, Lisa A

    2015-07-01

    Previous studies have shown that Eastern grey squirrels modify their behaviour while foraging to offset risks of social and predatory costs, but none have simultaneously compared whether such modifications are performed at a cost to foraging. The present study directly compares how grey squirrels respond to cues of these risks while foraging. We simulated social risk and predatory risk using acoustic playbacks of stimuli that grey squirrels might be exposed to at a foraging patch: calls of conspecifics, heterospecifics (competitor and non-competitor) and predators. We found that grey squirrels responded to predator, heterospecific competitor and conspecific playbacks by altering their foraging and vigilance behaviours. Foraging was most disrupted by increased vigilance when we played calls of predators. Squirrels' response to calls of heterospecific competitors did not differ from their response to conspecific calls, and they resumed foraging more quickly after both compared to predator calls: whereas they showed little response to calls of non-competitor heterospecifics and a white noise control. We conclude that squirrels respond differentially to calls made by conspecifics, heterospecific competitors and predators, with the most pronounced response being to calls of predators. We suggest that squirrels may view conspecific and corvid vocalisations as cues of potential conflict while foraging, necessitating increased vigilance. PMID:25957953

  18. YIELD AND PERSISTENCE OF FORAGE AND ROOT-TYPE CHICORY CULTIVARS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A challenge in managing chicory (Cichorium intybus L.) as a forage is dealing with bolting of flower stalks in spring. Root-type cultivars of chicory with reduced bolting potential are available. An experiment was conducted at Rock Springs, PA to compare forage cultivars and European root-type culti...

  19. Variations in harbour seal Phoca vitulina diet and dive-depths in relation to foraging habitat

    E-print Network

    Aberdeen, University of

    Variations in harbour seal Phoca vitulina diet and dive-depths in relation to foraging habitat D. J-tagged seals to identify the summer foraging areas used by 31 harbour seals from two different haul-out sites in the Moray Firth, N.E. Scotland. We then determine whether seals tend to occur over particular sediment types

  20. APPLICATIONS OF A FORAGE PRODUCTION MODEL IN SEMI-ARID NORTHERN MIXED-GRASS PRAIRIE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Predictions of forage production derived from site-specific environmental information (e.g. soil type, weather, plant community composition, etc.) could help land managers decide on appropriate stocking rates of livestock. This study assessed the applicability of the GPFARM forage growth model (Anda...