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1

Mercury elimination by a top predator, Esox lucius.  

PubMed

Top-level piscivores are highly sought after for consumption in freshwater fisheries, yet these species contain the highest levels of the neurotoxin monomethylmercury (MMHg) and therefore present the greatest concern for MMHg exposure to humans. The slow elimination of MMHg is one factor that contributes to high levels of this contaminant in fish; however, little quantitative information exists on elimination rates by top predators in nature. We determined rates of MMHg elimination in northern pike (Esox lucius) by transferring fish that had naturally accumulated isotope-enriched MMHg (spike MMHg) through a whole-lake Hg loading study to a different lake. Over a period of ~7 y, pike were periodically recaptured and a small amount of muscle tissue was extracted using a nonlethal biopsy. Spike total mercury (THg) persisted in muscle tissue throughout the entire study despite discontinuing exposure upon transfer to the new lake. Spike THg burdens increased for the first ~460 d, followed by a decline to 65% of original burden levels over the next 200 d, and subsequently reached a plateau near original burden levels for the remainder of the study. We estimated the half-life of muscle THg to be 3.3 y (1193 d), roughly 1.2- to 2.7-fold slower than predicted by current elimination models. We advocate for further long-term field studies that examine kinetics of MMHg in fish to better inform predictive models estimating the recovery of MMHg-contaminated fisheries. PMID:23566175

Van Walleghem, Jillian L A; Blanchfield, Paul J; Hrenchuk, Lee E; Hintelmann, Holger

2013-05-01

2

Ovarian alterations in wild northern pike Esox lucius females.  

PubMed

The aim of the present study was to analyse the occurrence of macroscopically visible ovary alterations in 2 populations of northern pike Esox lucius L. originating from lakes in the Mazurian Lake District (NE Poland). The alterations were characterised by ovary tissue that was morphologically malformed, in part or in whole, and contained immature oocytes, i.e. trophoplastic or previtellogenic oocytes instead of vitellogenic oocytes. These alterations were found only in the ovaries, and no morphological alterations of the testes were noted. Macroscopic and histological analyses were carried out in order to classify the observed alterations in the ovaries. Three types of alterations were identified in which morphological malformations as well as histological investigation of the ovaries were considered. An analysis of the size and age of the fish in relation to the occurrence of alterations as well as of the macroscopic and histological nature of the alteration types was made. The data obtained revealed no lake or age dependency of the observed alterations. Based on the results obtained, we suggest that the presence of endocrine disruptors in the environment or/and genetic factors could be responsible for these kinds of gonad anomalies. However, our results did not allow us to determine the aetiology of the alterations. PMID:24062552

Zarski, Daniel; Rechulicz, Jacek; Krejszeff, S?awomir; Czarkowski, Tomasz K; Sta?czak, Katarzyna; Pali?ska, Katarzyna; Gryzi?ska, Magdalena; Targo?ska, Katarzyna; Koz?owski, Krzysztof; Mamcarz, Andrzej; Hliwa, Piotr

2013-09-24

3

Taxonomic characteristics and physiological properties of microorganisms from the gut of pike ( Esox lucius )  

Microsoft Academic Search

The taxonomic composition and distribution of microorganisms differing in the degree of association with the intestinal mucosa\\u000a of the pike (Esox lucius) has been studied. Microorgansism of the families Enterobacteriaceae, Aeromonadaceae, and Vibrionaceae dominate in the gut\\u000a microflora. Numerically prevailing bacterial species are characterized by high proteolytic and amylolytic enzyme activities\\u000a as well as by high persistence accounted for by

G. I. Izvekova; N. V. Nemtseva; A. O. Plotnikov

2008-01-01

4

The growth of pike ( Esox lucius Linnaeus, 1798) in Lake Trasimeno (Umbria, Italy)  

Microsoft Academic Search

The growth of the pike (Esox lucius L.) population of Lake Trasimeno was studied. A total of 166 specimens was captured in two monthly sampling series, from May 1993 to 1994 and from February to April 1998. There were 45 females and 79 males; nine age classes were present. Regression analysis between total length (TL) and weight (W) was W=0.0001×TL3.0366;

Massimo Lorenzoni; Massimiliano Corboli; A. J Martin Dörr; Mario Mearelli; Giancarlo Giovinazzo

2002-01-01

5

Biomarkers of Contaminant Exposure in Northern Pike ( Esox lucius ) from the Yukon River Basin, Alaska  

Microsoft Academic Search

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\\u000a organochlorine pesticide (total p,p’-DDT, total chlordane, dieldrin, and toxaphene), total polychlorinated biphenyls (PCBs), and elemental contaminant (arsenic,\\u000a cadmium, copper, lead, total mercury, selenium, and zinc) concentrations. A suite

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

2007-01-01

6

Assessment of oxidative stress and histopathology in juvenile northern pike ( Esox lucius) inhabiting lakes downstream of a uranium mill  

Microsoft Academic Search

Lakes receiving effluent from the Key Lake uranium mill in northern Saskatchewan contain elevated trace metals, some of which are associated with increased reactive oxygen species (ROS) in cells and tissues causing oxidative stress. The potential for oxidative stress was assessed in juvenile (age 1+) northern pike (Esox lucius) collected from two exposure (high and low) and one reference lake

Jocelyn M. Kelly; David M. Janz

2009-01-01

7

DIETS OF MICROPTERUS SALMOIDES LAC. AND ESOX LUCIUS L. IN LAKE TRASIMENO (UMBRIA, ITALY) AND THEIR DIET OVERLAP  

Microsoft Academic Search

The aim of this study was to gather information about the feeding habits of Micropterus salmoides Lac., an exotic species recently introduced into Lake Trasimeno and Esox lucius L., in order to determine the degree of overlap between the two diets. The stomachs of 179 largemouth basses and 125 pikes were examined. The index of diet overlap (?) was determined

M. LORENZONI; M. CORBOLI; A. J. M. DÖRR; G. GIOVINAZZO; S. SELVI; M. MEARELLI

2002-01-01

8

Helminth position within the intestine of naturally infected pike (Esox lucius) relative to host stomach contents.  

PubMed

The positions of 3 cestode species, Triaenophorus crassus Forel, Triaenophorus nodulosus (Pallas), and Proteocephalus pinguis LaRue, and a nematode, Raphidascaris acus (Bloch), within the intestine of naturally infected pike (Esox lucius L.) were evaluated with respect to the presence or absence and state of digestion of host stomach contents. The positions of scolices and strobilae of the cestodes did not vary with respect to host stomach contents. By contrast, R. acus was anterior (near the stomach) when the stomach contained partially digested items, posterior when the stomach was empty, and in an intermediate position when the stomach contained only intact items. These results are interpreted as migration of R. acus, but not T. crassus, T. nodulosus, or P. pinguis, in response to feeding activity of the host. Adult and larval R. acus migrated, but the extent of migration was reduced in hosts harboring T. crassus, more so for larval than adult R. acus. PMID:2614600

Shostak, A W; Dick, T A

1989-12-01

9

Mercury Elimination Rates for Adult Northern Pike Esox lucius: Evidence for a Sex Effect.  

PubMed

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. PMID:24667854

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

2014-08-01

10

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

USGS Publications Warehouse

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.

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

1999-01-01

11

Mechanical suppression of northern pike (Esox lucius) populations in small Arizona reservoirs  

USGS Publications Warehouse

Introduced populations of northern pike Esox lucius have provided angling opportunities in the western United States (McMahon and Bennett 1996). However, the northern pike is a voracious piscivore and its large size, high fecundity, and broad physiological tolerance make it capable of drastically altering ecosystems it invades (Marchetti et al. 2004). Indeed, predation by northern pike has been shown to significantly alter fish community structure and put native fishes at a higher extinction risk (He and Kitchell 1990, Findlay et al. 2000). Predation by northern pike is viewed as a significant threat to native stocks of salmonids in Washington, British Columbia, and California (McMahon and Bennett 1996, California Department of Fish and Game [CDFG] 2003).

Kuzmenko, Yuliya; Spesiviy, Timofy; Bonar, Scott A.

2010-01-01

12

Assessment of natal origin of pike ( Esox lucius ) in the Baltic Sea using Sr:Ca in otoliths  

Microsoft Academic Search

Spawning habitat of pike (Esox lucius) in the Baltic Sea include brackish water bays, brooks and rivers. Elevated salinity concentrations are one of several stressors\\u000a that might increase the use and importance of freshwater habitats for spawning. In the Baltic Sea, one of the largest brackish\\u000a seas in the world, freshwater species like pike, perch (Perca fluviatilis), whitefish (Coregonus sp),

Olof Engstedt; Patrik Stenroth; Per Larsson; Lars Ljunggren; Mikael Elfman

2010-01-01

13

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

USGS Publications Warehouse

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.

Owens, Randall W.; Pronin, Nikolai M.

2000-01-01

14

Susceptibility of pike Esox lucius to a panel of Ranavirus isolates.  

PubMed

In order to study the pathogenicity of ranaviruses to a wild European freshwater fish species, pike Esox lucius fry were challenged with the following Ranavirus isolates: epizootic haematopoietic necrosis virus (EHNV), European sheatfish virus (ESV), European catfish virus (ECV), pike-perch iridovirus (PPIV), New Zealand eel virus (NZeelV) and frog virus 3 (FV3). The fry were infected using bath challenge at 12 and 22 degrees C. Significant mortalities were observed at 12 degrees C for EHNV, ESV, PPIV and NZeelV. Background mortality was too high in the experiments performed at 22 degrees C for any conclusions about viral pathogenicity at this temperature to be drawn. Viruses could be re-isolated from samples from all challenged groups, and their presence in infected tissue was demonstrated using immunohistochemistry. The findings suggest that pike fry are susceptible to EHNV, ESV, PPIV and NZeelV and can be a vector for ECV and FV3. Statistical analysis of the factors associated with positive virus re-isolation showed that the number of fish in the sample influenced the outcome of virus re-isolation. Moreover, the likelihood of positive virus re-isolation significantly differed among the 6 viral isolates. The temperature from where the sample was taken and the number of days after infection were not associated with the probability of a positive virus re-isolation. PMID:19402450

Jensen, Britt Bang; Ersbřll, Annette Kjaer; Ariel, Ellen

2009-02-25

15

Accumulation of some heavy metals in Raphidascaris acus (Bloch, 1779) and its host (Esox lucius L., 1758).  

PubMed

Concentrations of some heavy metals (Fe, Zn, Cu, Mn and Cr) in liver of pike (Esox lucius L., 1758) and its endoparasite [Raphidascaris acus (Bloch, 1779)] inhabiting I?ikli Lake (Turkey) were analyzed using atomic absorption spectrophotometry. Only Fe and Zn were detected in R. acus and liver of fish, while levels of Cu, Mn and Cr were below detection limit (<0.028). The Fe and Zn level in R. acus were 68.4 and 86.9 times higher than in the liver. Nematodes could provide reliable information about the heavy metal pollution of the lakes. PMID:18224628

Tekin-Ozan, Selda; Kir, Ismail

2007-01-01

16

Mercury toxicity in livers of northern pike (Esox lucius) from Isle Royale, USA.  

PubMed

Many laboratory studies have documented that mercury can be toxic to fish, but it is largely unknown if mercury is toxic to fish in their natural environments. The objective of our study was to investigate the toxic effects of mercury on northern pike (Esox lucius) at Isle Royale, Michigan. In 124 northern pike from eight inland lakes, concentrations of total mercury in skin-on fillets ranged from 0.069 to 0.622 microg/g wet mass (wet wt). Concentrations of total mercury in livers increased exponentially compared with concentrations in fillets, to a maximum of 3.1 microg/g wet wt. Methylmercury constituted a majority of the mercury in livers with total mercury concentrations <0.5 microg/g wet wt, but declined to 28-51% of the mercury in livers with total mercury concentrations >0.5 microg/g wet wt. Liver color (absorbance at 400 nm) varied among northern pike and was positively related to liver total mercury concentration. The pigment causing variation in liver color was identified as lipofuscin, which results from lipid peroxidation of membranous organelles. An analysis of covariance revealed lipofuscin accumulation was primarily associated with mercury exposure, and this association obscured any normal accumulation from aging. We also documented decreased lipid reserves in livers and poor condition factors of northern pike with high liver total mercury concentrations. Our results suggest (i) northern pike at Isle Royale are experiencing toxicity at concentrations of total mercury common for northern pike and other piscivorous fish elsewhere in North America and (ii) liver color may be useful for indicating mercury exposure and effects in northern pike at Isle Royale and possibly other aquatic ecosystems and other fish species. PMID:18262851

Drevnick, Paul E; Roberts, Aaron P; Otter, Ryan R; Hammerschmidt, Chad R; Klaper, Rebecca; Oris, James T

2008-04-01

17

Biomarkers of contaminant exposure in Northern Pike (Esox lucius) from the Yukon River Basin, Alaska.  

PubMed

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). Vitellogenin concentrations in female (0.09 to 5.32 mg/mL) and male (<0.0005 to 0.097 mg/mL) pike were not correlated with any contaminant, but vitellogenin concentrations >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/mm(2)), size (812 to 1481 microm(2)), 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 (< or =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. PMID:17396212

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

2007-05-01

18

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

USGS Publications Warehouse

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.

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

2007-01-01

19

[Taxonomic characteristics and physiological properties of microorganisms from the gut of pike (Esox lucius)].  

PubMed

The taxonomic composition and distribution of microorganisms differing in the degree of association with the intestinal mucosa of the pike (Lucius lucius) has been studied. Microorgansism of the families Enterobacteriaceae, Aeromonadaceae, and Vibrionaceae dominate in the gut microflora. Numerically prevailing bacterial species are characterized by high proteolytic and amylolytic enzyme activities as well as by high persistence accounted for by antilysozyme and antihistone activities. The results of this study show that Hafnia alvei, Yersinia ruckeri, Vibrio vulnificus, V. furnissii, Aeromonas salmonicida, and Shewanella putrefaciens may be regarded as normal components of the pike gut microflora. PMID:19198074

Izveskova, G I; Nemtseva, N V; Plotnikov, A O

2008-01-01

20

[Seasonal distributions and effects of parasites in pike (esox lucius l., 1758) inhabiting the i?ikli dam lake (Denizli).].  

PubMed

The aim of this study carried out from December 2000-November 2001 was to determine the endoparasites of pike (Esox lucius L., 1758) inhabiting the I?ikli Dam Lake. A total of 160 samples were caught and investigated parasitologically. Bathybothrium rectangulum (Cestoda), Raphidascaris acus, Camallanus truncatus (Nematoda) and Neoechinorhynchus rutili (Acanthocephala) were detected as a result of this study. R. acus was the most prevalent species. The highest seasonal infection in the pike samples was determined to be 84.2% in the spring. The rates of infection are 40.4% in male pikes and 65.1% in females. According to age groups, the highest infection ratio has been determined to be 85.7% in pikes that were one year old. Investigations on samples caught during the same month and of the same age and gender showed that infected pikes were 2.5% shorter and 7.6% lighter than non-infected pikes. Among the parasites determined in this study, Bathybothrium rectangulum was detected for the first time in Turkish pike. PMID:17124691

Kir, Ismail; Ozan, Selda Tek?n

2005-01-01

21

Spatial analysis of Cd and Pb in the Pike (Esox lucius) from Western Anzali wetlands of Iran.  

PubMed

Geostatistical studies are used to estimate pollution burden in aquatic ecosystems and to plan large-scale control programs to protect these environments. Geostatistical studies allow us to predicted pollutant concentrations for areas that have not been sampled. This is done by taking into account the spatial correlations between estimated and sampled points and by minimizing the variance of estimation error. The use of geostatistical techniques in biomonitoring of fish species can illuminate extent and source of pollution, thereby providing an effective tool for developing intervention strategies to protect such environments. This study investigates the spatial distribution patterns of cadmium and lead in the Pike (Esox lucius). Fish were captured in the western parts of the Anzali wetlands located on the Caspian Sea in Iran. The muscle tissue of Anzali Pike had 5 ± 0.25 and 168 ± 18.4 (ng/g dw) cadmium and lead, respectively. Positive relationships were detected between Pike's length and weight (r = 0.85, p < 0.05), length and age (r = 0.35, p < 0.05), and muscle cadmium and lead (r = 0.45, p < 0.05). By contrast, there was a negative relationship between lead levels and weight in Pike (r = -0.36, p < 0.05). For both metals, the resulting metal concentration maps indicated higher pollutant concentrations in the southeast parts of the study area. Considerable boat traffic activity and agricultural activity contribute to the pollution in these areas, undermining the integrity of local habitat for fish survival and reproduction. PMID:23292487

Zamani-Ahmadmahmoodi, R; Esmaili-Sari, A; Mohammadi, J; Riyahi Bakhtiari, A; Savabieasfahani, M

2013-04-01

22

Investigation of first year biotic and abiotic influences on the recruitment of pike Esox lucius over 48 years in Windermere, UK.  

PubMed

Estimated pike Esox lucius recruitment varied by a factor of 16 for females from 1944 to 1991 and by a factor of 27 for males from 1943 to 1990 in Windermere, a temperate, mesotrophic U.K. lake. No significant stock-recruitment relationships were found, but analysis with general additive models (GAMs) revealed that early autumnal water temperature, strength and direction of the North Atlantic Oscillation displacement (corresponding to different climatic conditions in winter) and zooplankton abundance but above all, late summer water temperature were important explanatory variables over the entire time series. Female recruitment was also influenced by young-of-the-year winter temperature. There was no evidence that perch Perca fluviatilis year-class strength, lake level or the summer position of the Gulf Stream influenced recruitment. The fitted models explained up to c. 65% of the overall observed variation between years. PMID:20735553

Paxton, C G M; Winfield, I J; Fletcher, J M; George, D G; Hewitt, D P

2009-07-01

23

DNA adduct formation and persistence in liver and extrahepatic tissues of northern pike (Esox lucius) following oral exposure to benzo[a]pyrene, benzo[k]fluoranthene and 7H-dibenzo[c,g]carbazole.  

PubMed

The formation and persistence of DNA adducts in liver, intestinal mucosa, gills and brain of juvenile northern pike (Esox lucius) following oral exposure to benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF) and 7H-dibenzo[c,g]carbazol (DBC) were analysed by 32P-postlabelling. The dosage was 25 micromol/kg body weight of each substance, administered on 5 occasions with an interval of 12-14 days. Sampling was carried out 9 days after the second treatment, and 9, 16, 33 and 78 days after the fifth treatment. Pikes were also fed with the substances singly for comparison of adduct patterns. A complex pattern of adducts was detected in all examined tissues from fish treated with the mixture. Total adduct levels were highest in intestine (347+/-17.4 nmol adducts/mol nucleotides, mean+/-SE), followed by liver (110+/-9.3), gills (69+/-6) and brain (14+/-4.2). In pike treated with BaP alone, one major adduct was detected in all examined tissues. This BaP-adduct made up approximately 50% of the total amount of adducts in the brain. Corresponding values in liver, intestine and gills were 23, 31 and 34%, respectively. One relatively weak BkF-adduct and at least 10 different DBC-adducts were detected in all analysed tissues. Total adduct level in the intestine declined to 29.4% of the maximum value 78 days after the last exposure, while there was no significant decline in adduct levels in liver, gills or brain. The results suggest that intestine is more susceptible to adduct formation than liver after oral exposure, and that adduct levels in the intestine represent ongoing or relatively recent exposure. DNA adducts in the other investigated tissues were much more persistent and may therefore accumulate during long-term exposure. PMID:10393267

Ericson, G; Noaksson, E; Balk, L

1999-06-30

24

DNA adduct formation in northern pike (Esox lucius) exposed to a mixture of benzo[a]pyrene, benzo[k]fluoranthene and 7H-dibenzo[c, g]carbazole: time-course and dose-response studies.  

PubMed

The time-course and dose dependent formation of DNA adducts in juvenile northern pike (Esox lucius) following a single exposure to a mixture of benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF) and 7H-dibenzo[c,g]carbazole (DBC) were investigated by use of the (32)P-postlabelling assay. A complex adduct pattern was detected in liver and intestine of exposed fish. For the time-course studies fish were exposed either by oral administration or by intraperitoneal (i.p.) injection. Following a single i.p. injection of the mixture (40micromole/kg body weight of each substance) significantly elevated DNA adduct levels were detected in the liver after 1 day. Adduct levels were higher in liver than in intestine, in which significant elevation were detected from day 3 to 12. Following exposure via food (80micromole/kg body weight of each substance), adduct levels were detected in both liver and intestine 1 day after exposure, and continued to increase until day 3 in liver and day 6 in intestine. Calculation of a binding index, which compensates for differences in dosage, resulted in much higher adduct formation (five times in liver and 22 times in intestine) following oral exposure. Pikes receiving single oral doses of 12.5, 50, 100 or 200micromole/kg body weight of each substance exhibited significantly higher adduct levels in both liver and intestine compared to controls. Hepatic adduct levels were also higher in fish given 100 and 200micromole/kg compared to 12.5micromole/kg. Results from this study show that DNA adducts are rapidly formed in juvenile northern pike following both i.p. injection and feeding of a mixture of BaP, BkF and DBC. A maximum level was reached within a few days, which then persisted at approximately the same level for at least 9-12 days. The results also shows that higher levels of adducts were obtained following oral administration compared to i.p. injection, particularly in the intestine. PMID:11035155

Ericson, G; Balk, L

2000-11-01

25

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

USGS Publications Warehouse

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.

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

2008-01-01

26

Effects of Environmental Mercury on Gonadal Function in Lake Champlain Northern Pike ( Esox lucius )  

Microsoft Academic Search

Levels of mercury in the environment have increased steadily over the past two centuries, primarily because of human activity. Common point sources of this heavy metal include industrial waste discharge from chloralkali and paper pulp plants. More diffuse emissions, which become widely distributed by global wind currents, result from the combustion of fossil fuels and incineration of municipal wastes. Stricter

A. S. Friedmann; M. C. Watzin; J. C. Leiter; T. Brinck-Johnsen

1996-01-01

27

Effects of environmental mercury on gonadal function in Lake Champlain northern pike (Esox lucius)  

SciTech Connect

Levels of mercury in the environment have increased steadily over the past two centuries, primarily because of human activity. Common point sources of this heavy metal include industrial waste discharge from chloralkali and paper pulp plants. More diffuse emissions, which become widely distributed by global wind currents, result from the combustion of fossil fuels and incineration of municipal wastes. Stricter laws in the United States have decreased the amount of pollution from point sources. In contrast, mercury from diffuse atmospheric origins has been increasing, causing a rise in rainwater concentrations and aquatic environments frequently distant from the source of pollution. Once in aquatic systems, mercury is readily converted to the more toxic methylated form and is the only heavy metal that indisputably biomagnifies through the food web. Acid rain compounds the environmental impact of anthropogenic mercury because aquatic organisms concentrate more mercury when living in waters with lower alkalinity. The persistence of this heavy metal in teleosts is illustrated by the finding that mercury, unlike cadmium, arsenic, and lead, did not decrease in North American freshwater fish between 1976 and 1984.

Friedmann, A.S.; Leiter, J.C. [Dartmouth Medical School, Lebanon, NH (United States)] [Dartmouth Medical School, Lebanon, NH (United States); Watzin, M.C. [Univ. of Vermont, Burlington, VT (United States)] [and others] [Univ. of Vermont, Burlington, VT (United States); and others

1996-03-01

28

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

SciTech Connect

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.

Meldrum, A. [Oak Ridge National Lab., TN (United States); Halden, N.M. [Univ. of Manitoba, Winnipeg (Canada). Dept. of Geological Sciences

1997-12-31

29

Food of Young Pike, Esox Lucius L., and Associated Fishes in Peterson's Ditches, Houghton Lake, Michigan  

Microsoft Academic Search

Stomach contents of 551 young pike (11–152 millimeters in length), 345 small yellow perch, and 431 other fish representing 18 species were examined. All specimens were collected from an area widely used by spawning pike from Houghton Lake, Michigan. Organisms utilized for food by young pike included Entomostraca, insects (chiefly Chironomidae), tadpoles, minnows, darters, and other pike. As pike increased

Burton P. Hunt; William F. Carbine

1951-01-01

30

Length-weight relationship of northern pike, Esox lucius, from East Harbor, Ohio  

USGS Publications Warehouse

The northern pike is one of Ohio's largest game fish but is well known to comparatively few anglers. Large numbers of the big fish spawn in the Ohio marshes adjacent to Lake Erie. Movements related to spawning reach a peak in late March or early April. Later the spawning population disperses and is seldom represented in catches by experimental gear or by anglers. The short period of availability was used to obtain life history information in March of 1951 through 1953. No comprehensive length-weight data for this species have previously been published from this area. East Harbor is a sandspit pond separated from Lake Erie by a large sand bar. Waters and fish populations of the harbor and lake can mix freely through a permanent connecting channel. The larger part of the 850 surface acres of the harbor is normally less than 8 feet deep. The male northern pike averaged 20.5 inches in length and ranged from 13.5 to 28.5 inches. The conspicuously larger females averaged 26.0 inches and ranged from 15.5 to 37.5 inches.

Brown, Edward H. Jr.; Clark, Clarence F.

1965-01-01

31

Seasonal dynamics of fatty acid composition in female northern pike ( Esox lucius L.)  

Microsoft Academic Search

Seasonal changes in the fatty acid composition of neutral and polar lipids were measured in the ovary, liver, white muscle, and adipopancreatic tissue of northern pike. The role of environmental and physiological factors underlying these changes was evaluated. From late summer (August–September) to winter (January–March), the weight percentage of n-3 polyunsaturated fatty acids (especially 22:6n3) declined significantly in the neutral

K. Schwalme; W. C. Mackay; M. T. Clandinin

1993-01-01

32

Pike (Esox lucius L.) stocking as a biomanipulation tool 2. Effects on lower trophic levels in Lake Lyng, Denmark  

Microsoft Academic Search

In order to study how pike stocking affects trophic structurepikefingerlings (0–3600 ha-1) were stocked during six yearsineutrophic Lake Lyng (lake area 10 ha), Denmark. Subsequently,marked changes were recorded in the abundance ofzooplanktivorousfish, catch per unit effort of roach, which was the dominantfishspecies, thus varied from 17 to 272. Simultaneously, markedchangeswere recorded in the abundance and relative composition ofzooplankton. Daphnia abundance

Martin Sřndergaard; Erik Jeppesen; Sřren Berg

1997-01-01

33

Partial characterization of serotonin N - acetyltransferases from northern pike ( Esox lucius , L. pineal organ and retina: effects of temperature  

Microsoft Academic Search

In vertebrates, the nocturnal rise in pineal organ and retinal melatonin synthesis results from the increase in the activity\\u000a of the serotonin N-acetyltransferase (NAT), a cAMP-dependent enzyme. In the fish pineal organ in culture, light and temperature act in a similar\\u000a manner on cAMP content and NAT activity. It is not known whether the effects of temperature are mediated through

Jack Falcón; Valérie Bolliet; Jean Pierre Collin

1996-01-01

34

Pilot Evaluation of Enhanced E-SOx Process.  

National Technical Information Service (NTIS)

The paper discusses pilot-plant tests with a 28 cu m/min (1000 cfm) electrostatic precipitator (ESP) to evaluate techniques that have a potential for enhancing the SO2 removal of the E-SOx process for retrofit application. The techniques investigated incl...

J. C. S. Chang L. S. Hovis

1990-01-01

35

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....

36

PILOT EVALUATION OF ENHANCED E-SOX PROCESS  

EPA Science Inventory

The paper discusses pilot-plant tests with a 28 cu m/min (1000 cfm)electrostatic precipitator (ESP) to evaluate techniques that havea potential for enhancing the S02 removal of the E-SOx process forretrofit application. he techniques investigated includedmass-transfer additives, ...

37

Evaluation of Sex Reversal Treatment and Improvement of Gynogenetic Technique in Muskellunge (ESOX MASQUINONGY).  

National Technical Information Service (NTIS)

The sport fishery for muskellunge Esox masquinongy relies on annual artificial propagation and stocking of fingerlings because of failure of natural reproduction in reservoirs. Muskellunge exhibits dimorphic growth, such that females grow much faster than...

K. Dabrowski F. Lin M. A. Garcia-Abiado J. Rinchard

2001-01-01

38

Reproduction and Early Life History of the Redfin Pickerel, (Esox americanus americanus).  

National Technical Information Service (NTIS)

The reproductive strategy of the redf in pickerel (Esox americanus americanus) in a blackwater system in Sumter County, South Carolina was studied using daily aging techniques derived from otolith analysis. The presence of biannual spawning, a significant...

M. S. Ballek

1994-01-01

39

The effect of egg size and nutrient content on larval performance: implications to protracted spawning in northern pike ( Esox lucius Linnaeus)  

Microsoft Academic Search

Variation in developmental rate from fertilization to swim-up, and body size at swim-up, may affect the growth and survival\\u000a of young-of-the-year fish. Fish egg size (diameter) is often positively correlated to adult female size, but whether increased\\u000a egg size equates to higher egg nutrient content and subsequently improved embryo\\/larval performance, remains unclear. Artificially\\u000a fertilized northern pike eggs from individual females

Brent A. Murry; John M. Farrell; Kimberly L. Schulz; Mark A. Teece

2008-01-01

40

Biomagnification of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) studied in pike ( Esox lucius), perch ( Perca fluviatilis) and roach ( Rutilus rutilus) from the Baltic Sea  

Microsoft Academic Search

Pike, perch and roach from rural waters of the Baltic Sea were investigated for possible biomagnification of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). For this we used data on ?15N, weight and sex of the fish. We were able to separate body size effects from trophic position effects on biomagnification. Both these parameters lead to biomagnification of PCBs

Sven Burreau; Yngve Zebühr; Dag Broman; Rasha Ishaq

2004-01-01

41

Spatial relations of mercury contents in Pike (Esox lucius) and sediments concentration of the Anzali wetland, along the southern shores of the Caspian Sea, Iran.  

PubMed

In recent decades, the Anzali wetland has been threatened and destroyed by environmental pollution from several sources. The purpose of this study was to determine the possible relationships between mercury concentrations in Pike and their respective sediments within the assumed multiple activity center scales of Pike (100, 250 and 500m in radius). To gain a better understanding spatial distribution pattern of Hg in sediments and to pursue the main purpose of this study, kriging (geostatistic spatial interpolation method) was applied. Poor relationships were found between mercury concentrations of Pike and sediments within the assumed multiple activity center scales of Pike. The mercury sediment influence diminished with the increasing radii of assumed activity centers. The results of the present study indicate that fish and sediment mercury concentrations in western parts of the Anzali wetland were low in comparison with the concentrations reported in the literature from other regions. PMID:24933165

Zamani-Ahmadmahmoodi, Rasool; Bakhtiari, Alireza Riyahi; Rodríguez Martín, José Antonio

2014-07-15

42

Early Life History of the Northern Pike, Esox lucius L., with Special Reference to the Factors Influencing the Numerical Strength of Year Classes  

Microsoft Academic Search

The early life history of northern pike was studied to determine the relationship of adult pike abundance to the strength of resulting year classes and the existence and chronology of critical survival periods, along with the nature and origin of the mortality mechanisms involved. Adult abundance and the strength of the resulting year classes were not directly related. Two critical

Donald R. Franklin; Lloyd L. Smith Jr

1963-01-01

43

Stocking impact and temporal stability of genetic composition in a brackish northern pike population (Esox lucius L.), assessed using microsatellite DNA analysis of historical and contemporary samples  

Microsoft Academic Search

During the last decade, brackish northern pike populations in Denmark have been subject to stocking programmes, using nonindigenous pike from freshwater lakes, in order to compensate for drastic population declines. The present study was designed to investigate the genetic impact of stocking freshwater pike into a brackish pike population in Stege Nor, Denmark. We analysed polymorphism at eight microsatellite loci

P F Larsen; M M Hansen; E E Nielsen; L F Jensen; V Loeschcke

2005-01-01

44

Reproductive status and lipid content as factors in PCB, DDT and HCH contamination of a population of pike (Esox lucius L. )  

SciTech Connect

Levels of persistent pollutants, including PCBs, [Sigma]DDT, and [gamma]-hexachlorocyclohexane, were examined in a pike population inhabiting a eutrophic lake in southern Scandinavia. For females, levels of persistent pollutants decreased linearly with age, weight, or length. This decline was ascribed to the seasonal elimination of the lipophilic pollutants in roe, which contained up to 10 times higher fat levels compared to muscle and over 10 times the amounts of pollutants. Male pike contained higher levels of pollutants than females, probably due to the lower elimination via gonadal products, as germinal tissue constitutes only 2% of the male total body weight and has a lower fat content than ovaries. Female germinal tissue can account for as much as 15% of the body weight. No major fat deposits other than those in germinal tissue were found in pike, which also had a low muscle fat content, suggesting that the importance of roe elimination in removing pollutants may be greater in pike than in salmonids. Uptake of persistent pollutants can vary greatly within a species, owing to differences in sex, age, and so forth, as well as between species, owing to differences in fat deposition strategies.

Larsson, P.; Okla, L.; Collvin, L. (Dept. of Ecology, Lund (Sweden))

1993-05-01

45

Selenium Concentrations in the Colorado Pikeminnow ( Ptychocheilus lucius ): Relationship with Flows in the Upper Colorado River  

Microsoft Academic Search

.   A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western\\u000a Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado\\u000a River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus).

B. C. Osmundson; T. W. May; D. B. Osmundson

2000-01-01

46

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

Microsoft Academic Search

Synopsis  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 m?2). Both predators spent most of their time in the vegetation. Largemouth bass searched for bluegills and ambushed minnows,\\u000a whereas

Jacqueline F. Savino; Roy A. Stein

1989-01-01

47

Foraging Experiences with Children  

ERIC Educational Resources Information Center

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)

Russell, Helen Ross

1976-01-01

48

Foraging search: Prototypical intelligence  

NASA Astrophysics Data System (ADS)

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. .

Mobus, George

2000-05-01

49

Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): relationship with flows in the upper Colorado River.  

PubMed

A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 microg/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 microg/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995. PMID:10787099

Osmundson, B C; May, T W; Osmundson, D B

2000-05-01

50

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

PubMed Central

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.

Vinson, Mark R.; Angradi, Ted R.

2014-01-01

51

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

PubMed

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

Vinson, Mark R; Angradi, Ted R

2014-01-01

52

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

USGS Publications Warehouse

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.

Vinson, Mark R.; Angradi, Ted R.

2014-01-01

53

Forage Kochia: Friend or Foe  

Microsoft Academic Search

Perennial forage kochia (Kochia prostrata) is a half- shrub valuable for reclamation, fire breaks, and livestock and wildlife forage on semiarid and saline rangelands. Interest is mount- ing about this species, but some are concerned that it will become an invader of perennial communities. Only one cultivar (Immigrant) has been released in the United States. Eighty-one forage kochia plantings (mainly

Blair L. Waldron; R. Deane Harrison; N. Jerry Chatterton; Burke W. Davenport

54

Does Foraging Activity Affect Foraging Success in the Western Harvester Ant (Hymenoptera: Formicidae)  

Microsoft Academic Search

Foraging behavior has been extensively studied in harvester ants (Hymenoptera: Formicidae); however, there is little information about the determinants of foraging success. We developed a path analysis model to quantify the functional relationships among the components of foraging at the colony level (onset, duration, number of foragers) and foraging success. Variation in the onset of foraging among colonies directly inßuences

Blaine J. Cole; Rebecca Edwards; Carter Tate Holbrook; Lindsey Holm; Joslin Heyward; Diane C. Wiernasz

2008-01-01

55

Learning foraging thresholds for lizards  

SciTech Connect

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.

Goldberg, L.A. [Univ. of Warwick, Coventry (United Kingdom). Dept. of Computer Science; Hart, W.E. [Sandia National Labs., Albuquerque, NM (United States); Wilson, D.B. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1996-01-12

56

Life History of the Colorado Squawfish, Ptychocheilus lucius, and the Colorado Chub, Gila robusta, in the Green River in Dinosaur National Monument, 1964–1966  

Microsoft Academic Search

Investigations of the ecology and life history of the Colorado squawfish, Ptychocheilus lucius, and the Colorado chub, Gila robusta, in the Green River in Dinosaur National Monument, Colorado-Utah, were conducted from May 1964, to October 1966. A total of 1,469 squawfish and 2,393 chubs was collected with gill nets, seines, fry gear, and an electric shocker. The operation of Flaming

C. David Vanicek; Robert H. Kramer

1969-01-01

57

Detection of viral hemorrhagic septicemia virus-IVb antibodies in sera of muskellunge Esox masquinongy using competitive ELISA.  

PubMed

A competitive enzyme-linked immunosorbent assay (cELISA) was developed for the detection of antibodies to viral hemorrhagic septicemia virus genotype IVb (VHSV-IVb) in fish sera. Assay conditions were standardized using known negative and positive muskellunge Esox masquinongy. A positive-negative threshold of 14.6% inhibition was established based on analysis of sera of 60 muskellunge with no previous exposure to VHSV-IVb. The cELISA was then used to investigate immune responses of wild muskellunge sampled from 5 water bodies in Michigan and Wisconsin, USA, between 2005 and 2012. Antibodies were detected in fish from Lake St. Clair, Michigan, and Lower Fox River/Green Bay, Wisconsin. Both water systems were considered enzootic for VHSV-IVb. Additionally, antibodies were detected in muskellunge from Thornapple Lake, a Michigan inland lake previously considered negative for VHSV-IVb based on virus isolation methods. Muskellunge populations from Lake Hudson, Michigan, and Butternut Lake, Wisconsin, lacked evidence of an immune response to VHSV-IVb. When results of the cELISA were compared to the 50% plaque neutralization test for several groups of fish, there was 78.4% agreement between the tests for antibody presence. The cELISA is a rapid and efficient test for the detection of binding antibodies to VHSV-IVb and will be a useful non-lethal tool for monitoring the spread of this serious pathogen. PMID:24695232

Millard, Elena V; Brenden, Travis O; Lapatra, Scott E; Marcquenski, Susan; Faisal, Mohamed

2014-04-01

58

Foraging Behaviour in Drosophila Larvae: Mushroom Body Ablation  

Microsoft Academic Search

Drosophila larvae and adults exhibit a naturally occurring genetically based behavioural polymorphism in locomotor activity while foraging. Larvae of the rover morph exhibit longer foraging trails than sitters and forage between food patches, while sitters have shorter foraging trails and forage within patches. This behaviour is influenced by levels of cGMP-dependent protein kinase (PKG) encoded by the foraging (for) gene.

Kathleen A. Osborne; J. Steven de Belle; Marla B. Sokolowski

2001-01-01

59

FORAGING ECOLOGY OF NORTHERN ELEPHANT SEALS  

Microsoft Academic Search

Sexual segregation in foraging is predicted from the great size disparity of male and female northern elephant seals, Mirounga angustirostris.Our aim was to test this prediction by measuring diving and foraging behavior, foraging locations, and distribution of the sexes during biannual migrations in the northeastern Pacific Ocean. Daily movements of 27 adult males and 20 adult females, during 56 migrations

B. J. LE BOEUF; D. E. C ROCKER; D. P. C OSTA; S. B. B LACKWELL; P. M. W EBB; D. S. HOUSER

2000-01-01

60

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...

61

Squirrel Foraging Preferences: Gone Nuts?  

ERIC Educational Resources Information Center

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…

Darling, Randi A.

2007-01-01

62

Learning foraging thresholds for lizards.  

National Technical Information Service (NTIS)

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...

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

1996-01-01

63

Nitrate accumulation in forage brassicas  

Microsoft Academic Search

Previous research has shown that the application of fertilizer nitrogen (N) can lead to an accumulation of nitrate nitrogen (NO3-N) in forage brassicas, particularly when N application rates exceed that required to obtain maximum crop yield. However, there are no data examining the effect of timing of fertilizer application on NO3-N accumulation. An experiment was established in 2009 with four

AL Fletcher; E Chakwizira

2012-01-01

64

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

USGS Publications Warehouse

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.

Savino, Jacqueline F.; Stein, Roy A.

1989-01-01

65

Hazardous duty pay and the foraging cost of predation  

Microsoft Academic Search

We review the concepts and research associated with measuring fear and its consequences for foraging. When foraging, animals should and do demand hazardous duty pay. They assess a foraging cost of predation to compensate for the risk of predation or the risk of catastrophic injury. Similarly, in weighing foraging options, animals tradeoff food and safety. The foraging cost of predation

Joel S. Brown; Burt P. Kotler

2004-01-01

66

Focusing the metaphor: plant root foraging behaviour.  

PubMed

Many authors assert that plants exhibit complex behaviours which are analogous to animal behaviour. However, plant ecologists rarely root these studies in a conceptual foundation as fertile as that used by animal behaviourists. Here we adapt the optimality principles that facilitated numerous advances in the study of animal foraging behaviour to create one possible framework for plant foraging behaviour. Following the traditions of animal foraging ecology, we discuss issues of search and handling in relation to plant root foraging. We also develop a basic plant-centered model that incorporates modular growth and foraging currencies relevant to plant growth. We conclude by demonstrating how this new foundation could be adapted to address five fundamental questions in plant foraging ecology. PMID:19409652

McNickle, Gordon G; St Clair, Colleen Cassady; Cahill, James F

2009-08-01

67

Reduction of foraging work and cooperative breeding.  

PubMed

Using simple stochastic models, we discuss how cooperative breeders, especially wasps and bees, can improve their productivity by reducing foraging work. In a harsh environment, where foraging is the main cause of mortality, such breeders achieve greater productivity by reducing their foraging effort below full capacity, and they may thrive by adopting cooperative breeding. This could prevent the population extinction of cooperative breeders under conditions where a population of lone breeders cannot be maintained. PMID:24619571

Toyoizumi, Hiroshi; Field, Jeremy

2014-06-01

68

Genetic determination of nectar foraging, pollen foraging, and nest-site scouting in honey bee colonies  

Microsoft Academic Search

Allozyme analyses of honey bee workers revealed significant differences in the intracolonial subfamily composition of groups of nectar foragers, pollen foragers, and nest-site scouts. These differences demonstrate that colony genetic structure influences the division of labor among older foraging-age bees just as it does for younger workers. The maintenance of genetic variability for the behavior of individual workers and its

Gene E. Robinson; Robert E. Page

1989-01-01

69

INTAKE AND DIGESTIBILITY RESPONSE TO FORAGE KOCHIA (KOCHIA PROSTRATA) IN A LOW QUALITY FORAGE DIET  

Microsoft Academic Search

Forage kochia (Kochia prostrata), a half-shrub native to arid regions of central Eurasia, has potential to be a source of forage for the beef industry in the western U.S., but little is known about its nutritional value. Our objective was to evaluate intake and digestibility using different dietary ratios of forage kochia and tall wheatgrass (Elytrigia elongata). Four ruminally fistulated

K. C. Olson; C. A. Stonecipher; J. C. Malechek; D. D. Carter

70

Social foraging by honeybees: how colonies allocate foragers among patches of flowers  

Microsoft Academic Search

To understand how a colony of honeybees keeps its forager force focussed on rich sources of food, and analysis was made of how the individual foragers within a colony decide to abandon or continue working (and perhaps even recruit to) patches of flowers. A nectar forager grades her behavior toward a patch in response to both the nectar intake rate

Thomas D. Seeley

1986-01-01

71

Boa constrictor (Boa constrictor): foraging behavior  

USGS Publications Warehouse

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.

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

2011-01-01

72

Observation strategies for morphological characterisation of forages  

Microsoft Academic Search

Several different methods using different numbers of plants and observations have been used for characterisation of germplasm. In this study, two different observation strategies for characterisation were tested in order to determine the minimum number of observations and plants per accession whilst still obtaining accurate results using eight forage legume species, eight forage grass species multiplied from seeds and eight

Mark van de Wouw; Jean Hanson; Sagary Nokoe

1999-01-01

73

In sacco macromineral release from selected forages  

Microsoft Academic Search

An in sacco technique was used to measure the release of Mg, Ca, Na, K from six forages - lucerne hay from the 1 st and 2 nd cut (LH1 and LH2), orchard grass hybrid Rela (GR) and hybrid Niva (GN), grass silage (GS), red clover silage treated with Feedtech (CSFT) and\\/or with Kofasil (CSKO). The forages differed in the

Z. ?ereš?áková; P. F?ak; M. Polá?iková; M. Chrenková

74

Sulfur Dioxide Preservation of Forage Crops1  

Microsoft Academic Search

One of the most difficult problems in grassland farming is that of storing the crop for later feeding. Most forage crops are produced and should be harvested for their maximum feeding value at a time of year when it is very difficult to field-dry and nlake thenl into hay. In efforts to find a better method of pre- serving forage

S. R. Skaggs; C. B. Knodt

1952-01-01

75

Human foraging behavior in a virtual environment  

Microsoft Academic Search

A problem faced by all mobile organisms is how to search their environment for resources. Animals forage their environment for food, Web-users surf the Internet for desired data, and businesses mine the land for valuable minerals. When an organism forages in an environment that consists, in part, of other organisms that are also for- aging, unique complexities arise. The resources

ROBERT L. GOLDSTONE; BENJAMIN C. ASHPOLE

2004-01-01

76

Impact of Defoliation on Corn Forage Yield  

Microsoft Academic Search

yield. Forage yield reductions from 75% defoliation at the 7- and 11-leaf stages averaged 6 and 23%, respec- Farmers, agronomists, and crop insurance adjusters question tively. The standard industry hail damage corn leaf loss whether leaf defoliation damage caused by hail or other factors affects corn (Zea mays L.) forage yield the same as grain yield. Our objective chart (National

J. G. Lauer; G. W. Roth; M. G. Bertram

2004-01-01

77

Bacteria foraging in turbulent waters  

NASA Astrophysics Data System (ADS)

Marine bacteria are the Ocean's recyclers, contributing to as much as 50% of the productivity of the marine food web. Bacteria forage on patches of dissolved nutrients using chemotaxis, the ability to swim up chemical gradients. As turbulence is ubiquitous in the Ocean, it is important to understand how turbulent flow conditions affect bacterial foraging. We used three-dimensional, isotropic direct numerical simulations coupled with a bacterial transport equation to address this problem. After the flow is continuously forced until it reaches a steady state, microscale nutrient patches are injected into the turbulent flow, and stirring produces thin nutrient filaments. Two populations of bacteria compete against each other: one population is motile and chemotactic (`active'), the other is non-motile (`passive'). The distribution of both populations is initially uniform. Chemotaxis allows active bacteria to cluster near the center of the nutrient filaments, increasing their nutrient uptake relative to passive bacteria. Increasing the turbulence intensity increases the short-term chemotactic advantage by quickly producing large gradients in the nutrient concentration, but also leads to rapid mixing of the nutrient field, which makes the chemotactic advantage short-lived. The results suggest that the evolutionary advantage of chemotaxis, based on the increase in nutrient uptake relative to the energetic cost of swimming, strongly depends on the turbulence level.

Taylor, John; Tang, Wenbo; Stocker, Roman

2009-11-01

78

Information Foraging in Nuclear Power Plant Control Rooms  

Microsoft Academic Search

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

R. L. Boring

2011-01-01

79

Ungulate foraging strategies: energy maximizing or time minimizing?  

Microsoft Academic Search

Summary 1. Many classical models of ungulate foraging are premised on energy maximization, yet limited empirical evidence and untested currency assumptions make the choice of currency a non-trivial issue. The primary constraints on forage intake of ungulates are forage quality and availability. Using a model that incorporates these two constraints, we predicted the optimal biomass of forage patches for ungulate

Carita M. Bergman; John M. Fryxell; C. Cormack Gates; Daniel Fortin

2001-01-01

80

The short-term regulation of foraging in harvester ants  

Microsoft Academic Search

In the seed-eating ant Pogonomyrmex barbatus, the return of successful foragers stimulates inactive foragers to leave the nest. The rate at which successful foragers return to the nest depends on food availability; the more food available, the more quickly foragers will find it and bring it back. Field experiments examined how quickly a colony can adjust to a decline in

Deborah M. Gordon; Susan Holmes; S. Nacu

2007-01-01

81

Gregarious foraging in barn swallows after the breeding season  

Microsoft Academic Search

Aerial vertebrate foragers, e.g. insectivorous bats, martins and swallows, often show gregarious behavior such as colonial breeding, communal roosting and aggregating behavior during foraging. Studies of gregariousness in aerial foragers have mostly focused on colonial breeding or communal roosting, and only a few intensive studies have dealt with gregariousness during foraging. Here, we report on large and stable aggregations of

Go Fujita; Hiroyoshi Higuchi

2005-01-01

82

Perennial Forages as Second Generation Bioenergy Crops  

PubMed Central

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.

Sanderson, Matt A.; Adler, Paul R.

2008-01-01

83

Worker honey bee pheromone regulation of foraging ontogeny  

NASA Astrophysics Data System (ADS)

The evolution of sociality has configured communication chemicals, called primer pheromones, which play key roles in regulating the organization of social life. Primer pheromones exert relatively slow effects that fundamentally alter developmental, physiological, and neural systems. Here, I demonstrate how substances extracted from the surface of foraging and young pre-foraging worker bees regulated age at onset of foraging, a developmental process. Hexane-extractable compounds washed from foraging workers increased foraging age compared with controls, whereas extracts of young pre-foraging workers decreased foraging age. This represents the first known direct demonstration of primer pheromone activity derived from adult worker bees.

Pankiw, Tanya

84

Metabolic rate during foraging in the honeybee.  

PubMed

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

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

1992-01-01

85

Aggressive and foraging behavioral interactions among ruffe  

USGS Publications Warehouse

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.

Savino, Jacqueline F.; Kostich, Melissa J.

2000-01-01

86

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

USGS Publications Warehouse

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.

Savino, Jacqueline F.; Stein, Roy A.

1989-01-01

87

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

USGS Publications Warehouse

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.

Wolfert, David R.; Miller, Terence J.

1978-01-01

88

Effects of artificial illumination on the nocturnal foraging of waders  

NASA Astrophysics Data System (ADS)

Large areas of natural and semi-natural habitats are exposed to artificial illumination from adjacent urban areas and roads. Estuarine and coastal wetlands are particularly exposed to such illumination because shorelines often are heavily utilized by man. However, the impact of artificial illumination on the waders that forage in these highly productive habitats is virtually unknown. We evaluated the effects of artificial illumination on the nocturnal habitat selection and foraging behaviour of six wader species with different feeding strategies: three visual foragers, two species that alternate visual and tactile strategies (mixed foragers), and one tactile forager. We quantified the number of birds and their foraging behaviour at sites affected and not affected by streetlights, and also before and after illuminating experimental sites. Areas illuminated by streetlights were used more during the night by visual foragers, and to a lesser extent by mixed foragers, than non-illuminated areas. Visual foragers increased their foraging effort in illuminated areas, and mixed foragers changed to more efficient visual foraging strategies. These behavioural shifts improved prey intake rate by an average of 83% in visual and mixed foragers. We have showed that artificial illumination has a positive effect on the nocturnal foraging of waders, but on the other hand may draw them to degraded areas close to urban centres, and potentially raises their exposure to predators. Our findings suggest that artificial illumination is worth investigation as a tool in the management of intertidal habitats for waders.

Santos, Carlos D.; Miranda, Ana C.; Granadeiro, José P.; Lourenço, Pedro M.; Saraiva, Sara; Palmeirim, Jorge M.

2010-03-01

89

Cognitive Plasticity in Foraging Vespula germanica Wasps  

PubMed Central

Vespula germanica (F.) (Hymenoptera: Vespidae) is a highly invasive social wasp that exhibits a rich behavioral repertoire in which learning and memory play a fundamental role in foraging. The learning abilities of these wasps were analyzed while relocating a food source and whether V. germanica foragers are capable of discriminating between different orientation patterns and generalizing their choice to a new pattern. Foraging wasps were trained to associate two different stripe orientation patterns with their respective food locations. Their response to a novel configuration that maintained the orientation of one of the learned patterns but differed in other aspects (e.g. width of stripes) was then evaluated. The results support the hypothesis that V. germanica wasps are able to associate a particular oriented pattern with the location of a feeder and to generalize their choice to a new pattern, which differed in quality, but presented the same orientation.

D'Adamo, Paola; Lozada, Mariana

2011-01-01

90

BROMELIAD FORAGING SPECIALIZATION AND DIET SELECTION OF PSEUDOCOLAPTES LAWRENCII (FURNARIIDAE)  

Microsoft Academic Search

Over 50 species of Neotropical birds have been recorded foraging for animal prey in bromeliads. Of these bird species, Pseudocolaptes lawrencii is one of the most specialized. At a montane rainforest site in Costa Rica, 74% of its documented foraging efforts were in epiphytic bromeliads. P. lawrencii selected large bromeliads and foraged for arthropods within leaf litter and organic debris

T. SCOTT SILLETT; ANNE JAMES; KRISTINE B. SILLETT

91

Economic emission load dispatch through fuzzy based bacterial foraging algorithm  

Microsoft Academic Search

This paper presents a newly developed optimization approach involving a modified bacterial foraging algorithm (MBFA) applied for the solution of the economic and emission load dispatch (EELD) problem. The approach utilizes the natural selection of global optimum bacterium having successful foraging strategies in the fitness function. The bacterial foraging algorithm (BFA) appears to be a robust and reliable optimization algorithm

P. K. Hota; A. K. Barisal; R. Chakrabarti

2010-01-01

92

Is There an Endogenous Tidal Foraging Rhythm in Marine Iguanas?  

Microsoft Academic Search

As strictly herbivorous reptiles, Galápagos marine iguanas graze on algae in the intertidal areas during low tide. Daily foraging rhythms were observed on two islands during 3 years to determine the proximate factors underlying behavioral synchrony with the tides. Marine iguanas walked to their intertidal foraging grounds from far-off resting areas in anticipation of the time of low tide. Foraging

Martin Wikelski; Michaela Hau

1995-01-01

93

Foraging strategies of the marine iguana, Amblyrhynchus cristatus  

Microsoft Academic Search

Two foraging strategies were found in marine iguanas (Amblyrhynchus cristatus); (1) subtidal feeding: the animals swam out to sea and dived for algae in the subtidal zone; (2) intertidal feeding: the animals foraged around low tide in the intertidal zone on more or less exposed algae. Most marine iguanas were very consistent in their foraging strategy and so could be

Krisztina G. K. Trillmich; Fritz Trillmich

1986-01-01

94

Perennial Grass Breeding Program for Forage and Biofuels - Tifton, GA  

Microsoft Academic Search

The perennial grass breeding program at Tifton, Georgia has a long history. Drs. Glenn Burton and Wayne Hanna, with collaborators, developed a significant number of forage and turf cultivars over the past 60-plus years. Work is continuing in areas of forage and turf improvements for the South. Forage improvement of bermudagrass and bahiagrass continues within the Crop Genetics and Breeding

Bill Anderson

95

FORAGING RATES OF DIFFERENT APIS SPECIES VISITING PARENTAL LINES OF  

Microsoft Academic Search

Most of the insect pollinators of Brassica crops belong to Apis species. Foraging rate is one of the important factors to compare pollination efficiency of different bee species. In general, more the foraging frequency, more the chances of pollination. The number of flowers visited per minute by any bee species depends upon the number of factors including instinctive foraging behaviour,

Jasvir Singh; O. P. Agrawal; R. C. Mishra

96

Is there an endogenous tidal foraging rhythm in marine iguanas?  

PubMed

As strictly herbivorous reptiles, Galápagos marine iguanas graze on algae in the intertidal areas during low tide. Daily foraging rhythms were observed on two islands during 3 years to determine the proximate factors underlying behavioral synchrony with the tides. Marine iguanas walked to their intertidal foraging grounds from far-off resting areas in anticipation of the time of low tide. Foraging activity was restricted to daytime, resulting in a complex bitidal rhythm including conspicuous switches from afternoon foraging to foraging during the subsequent morning when low tide occurred after dusk. The animals anticipated the daily low tide by a maximum of 4 h. The degree of anticipation depended on environmental parameters such as wave action and food supply. "Early foragers" survived in greater numbers than did animals arriving later at foraging sites, a result indicating selection pressure on the timing of anticipation. The timing of foraging trips was better predicted by the daily changes in tabulated low tide than it was by the daily changes in actual exposure of the intertidal foraging flats, suggesting an endogenous nature of the foraging rhythms. Endogenous rhythmicity would also explain why iguanas that had spontaneously fasted for several days nevertheless went foraging at the "right" time of day. A potential lunar component of the foraging rhythmicity of marine iguanas showed up in their assemblage on intertidal rocks during neap tide nights. This may indicate that iguanas possessed information on the semi-monthly rhythms in tide heights. Enclosure experiments showed that bitidal foraging rhythms of iguanas may free run in the absence of direct cues from the intertidal areas and operate independent of the light:dark cycle and social stimuli. Therefore, the existence of a circatidal oscillator in marine iguanas is proposed. The bitidal foraging pattern may result from an interaction of a circadian system with a circatidal system. Food intake or related stimuli may be used as tidal zeitgebers in synchronizing the foraging rhythms of these reptiles under natural conditions. PMID:8639942

Wikelski, M; Hau, M

1995-12-01

97

Regulation of ants' foraging to resource productivity.  

PubMed

We investigate the behavioural rule used by ant societies to adjust their foraging response to the honeydew productivity of aphids. When a scout finds a single food source, the decision to lay a recruitment trail is an all-or-none response based on the opportunity for this scout to ingest a desired volume acting as a threshold. Here, we demonstrate, through experimental and theoretical approaches, the generic value of this recruitment rule that remains valid when ants have to forage on multiple small sugar feeders to reach their desired volume. Moreover, our experiments show that when ants decide to recruit nest-mates they lay trail marks of equal intensity, whatever the number of food sources visited. A model based on the 'desired volume' rule of recruitment as well as on experimentally validated parameter values was built to investigate how ant societies adjust their foraging response to the honeydew productivity profile of aphids. Simulations predict that, with such recruiting rules, the percentage of recruiting ants is directly related to the total production of honeydew. Moreover, an optimal number of foragers exists that maximizes the strength of recruitment, this number being linearly related to the total production of honeydew by the aphid colony. The 'desired volume' recruitment rule that should be generic for all ant species is enough to explain how ants optimize trail recruitment and select aphid colonies or other liquid food resources according to their productivity profile. PMID:12908982

Mailleux, Anne-Catherine; Deneubourg, Jean-Louis; Detrain, Claire

2003-08-01

98

Memory dynamics and foraging strategies of honeybees  

Microsoft Academic Search

Summary The foraging behavior of a single bee in a patch of four electronic flower dummies (feeders) was studied with the aim of analyzing the informational components in the choice process. In different experimental combinations of reward rates, color marks, odors and distances of the feeders, the behavior of the test bee was monitored by a computer in real time

Uwe Greggers; Randolf Menzel

1993-01-01

99

The Dynamics of Infant Visual Foraging  

ERIC Educational Resources Information Center

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…

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

2004-01-01

100

Foraging behaviour in fishes: perspectives on variance  

Microsoft Academic Search

Synopsis The positive relationship between size of prey and frequency of ingestion by predators has been a focal point of investigations in foraging ecology. Field studies compare the frequency distribution of prey sizes in the predator's gut with that in the environment. Laboratory and field (enclosure) studies are based upon comparison of the frequency distributions of prey sizes in controlled

Brian M. Marcotte; Howard I. Browman

1986-01-01

101

Foraging strategy of cattle in patchy grassland  

Microsoft Academic Search

We tested several strategies of foraging that grazing herbivores may adopt in a patchy habitat in relation to energy intake. The patch selection of cattle was investigated in an Agrostis\\/Festuca grassland and in a Lolium grassland in 13 observation periods over 2 years. Both grasslands were stocked with five yearling steers. Bite counts were made on patches of different vegetation

Michiel F. Wallis Vries; Cees Daleboudt

1994-01-01

102

The hidden cost of information in collective foraging  

PubMed Central

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.

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

2005-01-01

103

SEASONAL VARIATION IN THE FORAGING BEHAVIOR OF SOME MIGRATORY WESTERN WOOD WARBLERS  

Microsoft Academic Search

I observed the foraging behavior of four warbler species (Dendroica petechia, Oporornis tolmiei, Geothlypis trichas, and Wilsonia pusilla) in the summer in Wyoming and in the winter in Nayarit, Mxico. Of six variables (absolute foraging height, relative foraging height, vegetation density, horizontal foraging position, feeding method, and foraging substrate) believed to be potentially important in distinguishing the warbler species ecologically,

RICHARD L. HUTTO

104

Uncovering the complexity of ant foraging trails  

PubMed Central

The common garden ant Lasius niger use both trail pheromones and memory of past visits to navigate to and from food sources. In a recent paper we demonstrated a synergistic effect between route memory and trail pheromones: the presence of trail pheromones results in experienced ants walking straighter and faster. We also found that experienced ants leaving a pheromone trail deposit less pheromone. Here we focus on another finding of the experiment: the presence of cuticular hydrocarbons (CHCs), which are used as home range markers by ants, also affects pheromone deposition behavior. When walking on a trail on which CHCs are present but trail pheromones are not, experienced foragers deposit less pheromone on the outward journey than on the return journey. The regulatory mechanisms ants use during foraging and recruitment behavior is subtle and complex, affected by multiple interacting factors such as route memory, travel direction and the presence trail pheromone and home-range markings.

Gruter, Christoph; Jones, Sam M.; Ratnieks, Francis L.W.

2012-01-01

105

Common Attentional Constraints in Visual Foraging  

PubMed Central

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.

Kristjansson, Arni; Johannesson, Omar I.; Thornton, Ian M.

2014-01-01

106

Foraging biology predicts food web complexity  

PubMed Central

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.

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

2006-01-01

107

Soldiers Initiate Foraging Activities in the Subterranean Termite, Heterotermes tenuis  

PubMed Central

Caste polyethism has been recorded in some termite species, however the foraging behavior of subterranean termites remains poorly known. Heterotermes tenuis Hagen (Isoptera: Rhinotermitidae) is a subterranean termite that is native to Brazil and is an agricultural and urban pest. The aim of this study was to investigate which caste acts as scouts when searching for food sources and determinate the percentages of each caste present in the foraging territories of field colonies of H. tenuis. Our results showed no significant differences among the caste proportions present in the foraging territories of the three colonies studied in the field. Laboratory experiments showed that minor soldiers were the most frequent initiators of foraging activities. This result suggests that the exploratory phase of the foraging behavior may be regulated by the number of soldiers present in the foraging territories of each colony.

Casarin, Fabiana Elaine; Costa-Leonardo, Ana Maria

2008-01-01

108

Positional Communication and Private Information in Honeybee Foraging Models  

Microsoft Academic Search

\\u000a Honeybees coordinate foraging efforts across vast areas through a complex system of advertising and recruitment. One mechanism\\u000a for coordination is the waggle dance, a movement pattern which carries positional information about food sources. However,\\u000a recent evidence suggests that recruited foragers may not use the dance’s positional information to the degree that has traditionally\\u000a been believed. We model bee colony foraging

Peter Bailis; Radhika Nagpal; Justin Werfel

2010-01-01

109

Forage kochia ( Kochia prostrata) for fall and winter grazing  

Microsoft Academic Search

Forage kochia (Kochia prostrata (L.) Schrad.), 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 valuable forage plant for sheep, goats, camels, cattle, and horses. Forage kochia is a

B. L. Waldron; J.-S. Eun; D. R. ZoBell; K. C. Olson

2010-01-01

110

Brood pheromone stimulates pollen foraging in honey bees ( Apis mellifera )  

Microsoft Academic Search

Foraging and the mechanisms that regulate the quantity of food collected are important evolutionary and ecological attributes\\u000a for all organisms. The decision to collect pollen by honey bee foragers depends on the number of larvae (brood), amount of\\u000a stored pollen in the colony, as well as forager genotype and available resources in the environment. Here we describe how\\u000a brood pheromone

Tanya Pankiw; Robert E. Page Jr; M. Kim Fondrk

1998-01-01

111

Are seabirds foraging for unpredictable resources?  

NASA Astrophysics Data System (ADS)

It is generally assumed that the extreme life history traits of pelagic seabirds, such as low fecundity or slow growth of chicks, result from the difficulties obtaining energy at sea from unpredictable and patchily distributed resources. However, little information on seabird prey distribution and availability exists to sustain this widely accepted hypothesis. Using tracking studies of 68 sub-populations of flying seabirds, I examine whether it is possible to gain information on the predictability of their marine resources. Because prey are clustered from fine to large scale in nested unities, from swarms to patches and concentrations of patches, it is important to take into account spatial scale. In temperate and polar regions, at large and meso-scales, seabirds appear to have a good knowledge of the location and concentrations of patches and generally use a commuting type of trip to reach foraging zones. Predictability appears to be high at large and meso-scales, with individuals from each sub-population heading in a particular direction from the colony to reach favoured habitats of known enhanced productivity such as shelf edges, frontal zones, upwellings. Within these mesoscale features, the animals use an area-restricted search behaviour to search for patches and swarms at finer scales. Using information on foraging site fidelity of individual birds, I show that differences in predictability at coarse scales are related to the distance and time spent foraging, and in particular to the specific types of foraging habitat. Some habitats appear to be more predictable than others: birds return consistently to the same coarse-scale sectors on shelf edges, whereas predictability is low in oceanic waters, even in frontal zones. Preliminary results on tropical species suggest that the environment here is less predictable in tropic than in temperate or polar zones. This review highlights that patchiness and predictability of marine resources are complex notions: predictability is dependent on the spatial and temporal scale considered, and especially on the marine habitat of foraging interest. I discuss the potential consequences of these results for the breeding success and life history of seabirds.

Weimerskirch, Henri

2007-02-01

112

78 FR 23738 - Monsanto Company and Forage Genetics International (FGI); Availability of Petition for...  

Federal Register 2010, 2011, 2012, 2013

...APHIS-2013-0013] Monsanto Company and Forage Genetics International (FGI); Availability...from the Monsanto Company and Forage Genetics International (FGI) seeking a determination...from the Monsanto Company and Forage Genetics International (FGI) seeking a...

2013-04-22

113

The impact of weather on kingbird foraging behavior  

SciTech Connect

Foraging data on Eastern Kingbirds (Tyrannus tyrannus) were collected during the early breeding season in eastern Kansas to test the hypothesis that foraging rate and other aspects of foraging behavior vary with weather. Foraging characteristics of five additional kingbird species were also examined to assess Fitzpatrick's 1980 generalization that kingbirds (Tyrannus spp.) are aerial hawking specialists. In Eastern Kingbirds, total foraging rate was independent of air temperature, cloud cover, wind speed, and time of day, but the rate of aerial hawking varied directly with air temperature and inversely with cloud cover (both P < 0.05). Effects of the two variables were additive. The percentage of foraging movements that were aerial hawks also increased with temperature and declined with cloud cover, and hover-gleaning and perch-to-ground sallying were observed mainly during cloudy weather. Sally (i.e., foraging flight) distance correlated directly with perch height and air temperature, and large insects were captured almost exclusively in long upward or horizontal flights. I interpret these data to indicate that foraging behavior and the capture of large, flying insects depends on weather because of how it affects the activity of insect prey. Foraging data on kingbirds support Fitzpatrick's generalization, but the relative use of aerial hawking varies considerably among species. Resident Tropical Kingbirds (T. melancholicus) are the most specialized foragers, whereas the migrant and widely distributed Eastern Kingbird appears to be the most generalized. Certain habitats also appear to favor the use of particular foraging methods (e.g., outward striking in grasslands, and perch-to-ground sallying in drier, open habitats).

Murphy, M.T. (Museum of Natural History, The University of Kansas, Lawrence, KS 66045)

1987-01-01

114

Eye size, foraging methods and the timing of foraging in shorebirds  

Microsoft Academic Search

Summary 1. Birds with large eyes can achieve a greater pupil diameter and\\/or focal length, and hence, all other things being equal, greater visual sensitivity and resolution than birds with small eyes. Thus eye size is predicted to reflect adaptations to ecology. 2. We tested three predictions about the relationships between eye size, foraging method (from wholly visual to tactile

R. J. THOMAS; T. SZEKELY; R. F. POWELL; I. C. CUTHILL

2006-01-01

115

A search theory model of patch-to-patch forager movement with application to pollinator-mediated gene flow  

Microsoft Academic Search

We present a spatially implicit analytical model of forager movement, designed to address a simple scenario common in nature. We assume minimal depression of patch resources, and discrete foraging bouts, during which foragers fill to capacity. The model is particularly suitable for foragers that search systematically, foragers that deplete resources in a patch only incrementally, and for sit-and-wait foragers, where

Martin Hoyle; James E. Cresswell

2007-01-01

116

Complex scaling behavior in animal foraging patterns  

NASA Astrophysics Data System (ADS)

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.

Premachandra, Prabhavi Kaushalya

117

Multimodal Floral Signals and Moth Foraging Decisions  

PubMed Central

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 naďve 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 naďve 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.

Riffell, Jeffrey A.; Alarcon, Ruben

2013-01-01

118

Comparative Sucrose Responsiveness in Apis mellifera and A. cerana Foragers  

PubMed Central

In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources.

Yang, Wenchao; Kuang, Haiou; Wang, Shanshan; Wang, Jie; Liu, Wei; Wu, Zhenhong; Tian, Yuanyuan; Huang, Zachary Y.; Miao, Xiaoqing

2013-01-01

119

Use of Tilapia as Supplemental Forage for Channel Catfish Broodstock  

Microsoft Academic Search

The purpose of this study was to determine the effects of supplemental feeding with forage fish on the spawning success and egg quality of channel catfish Ictalurus punctatus. Channel catfish broodstock were maintained for 2 years on a diet of either commercial catfish feed with 32% protein or commercial catfish feed and live blue tilapia. Fish fed forage fish had

Les Torrans; Fran Lowell

2001-01-01

120

Bacteria Foraging Algorithm based Economic Load Dispatch with Wind Energy  

Microsoft Academic Search

This paper presents new optimization approach involving a modified Bacteria Foraging Algorithm (BFA) applied to economic load dispatch involving wind energy conversion systems (WECS). The approach utilizes the natural selection of global optimum bacterium having successful foraging strategies in the cost function including the factors of overestimation and underestimation of available wind energy. According to the stochastic nature of wind

M. Tripathy; A. K. Barisal

2009-01-01

121

Promoting Interactive Learning: A Classroom Exercise to Explore Foraging Strategies  

ERIC Educational Resources Information Center

We describe a classroom exercise to allow students to explore foraging strategies in higher vertebrates. The exercise includes an initial interactive session in which students act as predators and are guided through foraging simulations, and a subsequent student-led session where classmates are employed as experimental subjects. Students rated the…

Beaumont, Ellen S.; Rowe, Graham; Mikhaylov, Natalie S.

2012-01-01

122

The hunting handicap: costly signaling in human foraging strategies  

Microsoft Academic Search

Humans sometimes forage or distribute the products of foraging in ways that do not maximize individual energetic return rates. As an alternative to hypotheses that rely on reciprocal altruism to counter the costs of inefficiency, we suggest that the cost itself could be recouped through signal benefit. Costly signaling theory predicts that signals can provide fitness benefits when costs are

Rebecca Bliege Bird; Eric Alden Smith; Douglas W. Bird

2001-01-01

123

Testing Optimal Foraging Theory Using Bird Predation on Goldenrod Galls  

ERIC Educational Resources Information Center

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…

Yahnke, Christopher J.

2006-01-01

124

Comparative sucrose responsiveness in Apis mellifera and A. cerana foragers.  

PubMed

In the European honey bee, Apis mellifera, pollen foragers have a higher sucrose responsiveness than nectar foragers when tested using a proboscis extension response (PER) assay. In addition, Africanized honey bees have a higher sucrose responsiveness than European honey bees. Based on the biology of the Eastern honey bee, A. cerana, we hypothesized that A. cerana should also have a higher responsiveness to sucrose than A. mellifera. To test this hypothesis, we compared the sucrose thresholds of pollen foragers and nectar foragers in both A. cerana and A. mellifera in Fujian Province, China. Pollen foragers were more responsive to sucrose than nectar foragers in both species, consistent with previous studies. However, contrary to our hypothesis, A. mellifera was more responsive than A. cerana. We also demonstrated that this higher sucrose responsiveness in A. mellifera was not due to differences in the colony environment by co-fostering two species of bees in the same mixed-species colonies. Because A. mellifera foragers were more responsive to sucrose, we predicted that their nectar foragers should bring in less concentrated nectar compared to that of A. cerana. However, we found no differences between the two species. We conclude that A. cerana shows a different pattern in sucrose responsiveness from that of Africanized bees. There may be other mechanisms that enable A. cerana to perform well in areas with sparse nectar resources. PMID:24194958

Yang, Wenchao; Kuang, Haiou; Wang, Shanshan; Wang, Jie; Liu, Wei; Wu, Zhenhong; Tian, Yuanyuan; Huang, Zachary Y; Miao, Xiaoqing

2013-01-01

125

Animal Foraging and the Evolution of Goal-Directed Cognition  

ERIC Educational Resources Information Center

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…

Hills, Thomas T.

2006-01-01

126

Stockpiled Forage Kochia to Maintain Beef Cows During Winter  

Microsoft Academic Search

Extending grazing into the winter, as opposed to feeding of harvested forages, can increase the sustainability of ranching in the western US. This study was conducted to determine the economic value of grazing stockpiled forage kochia (Kochia prostrata (L.) Scrad.) and crested wheatgrass (Agropyron desertorum (Fisch. Ex Link) Schultes) during the fall and winter. Changes in cow body weight, body

Blair L. Waldron; Dale R. ZoBell; Kenneth C. Olson; Kevin B. Jensen; Donald L. Snyder

2006-01-01

127

Selective Defecation and Selective Foraging: Antiparasite Behavior in Wild Ungulates?  

Microsoft Academic Search

Selective defecation and selective foraging are two potential antiparasite behaviors used by grazing ungulates to reduce infection by fecal-oral transmitted parasites. While there is some evidence that domestic species use these strategies, less is known about the occurrence and efficacy of these behaviors in wild ungulates. In this study, I examined whether wild antelope use selective defecation and selective foraging

Vanessa O. Ezenwa

2004-01-01

128

Honeybees foraging response in genetically diversified opium poppy.  

PubMed

Studies were carried out on honeybees foraging on plant flowers. Results showed significantly higher foraging response of honeybees (Apis mellifera) in genetically divergent narcotic plant opium poppy (Papaver somniferum). Of the 18 mutants and two locally adapted cultivars of diverse genotypes screened, eight revealed significantly greater foraging response manifesting honeybee's preference towards specific plant morphotypes. The number of flower bloom did not correspond to number of foraging bees in both mutant and cultivar plant types of opium poppy. The genotype specific foraging response of honeybees could be attributed to physico-chemical properties of opium poppy flowers. This could have implications for the development of opium alkaloid fortified honeys for novel pharmaceuticals and isolation of natural spray compounds to attract honeybee pollinators for promoting crossing and sustainable hybridity in crops. PMID:16150594

Srivastava, H K; Singh, Dwijendra

2006-09-01

129

Foraging swarms as nash equilibria of dynamic games.  

PubMed

The question of whether foraging swarms can form as a result of a noncooperative game played by individuals is shown here to have an affirmative answer. A dynamic game played by N agents in 1-D motion is introduced and models, for instance, a foraging ant colony. Each agent controls its velocity to minimize its total work done in a finite time interval. The game is shown to have a unique Nash equilibrium under two different foraging location specifications, and both equilibria display many features of a foraging swarm behavior observed in biological swarms. Explicit expressions are derived for pairwise distances between individuals of the swarm, swarm size, and swarm center location during foraging. PMID:24122615

Ozguler, Arif Bulent; Yildiz, Aykut

2014-06-01

130

Linking foraging decisions to residential yard bird composition.  

PubMed

Urban bird communities have higher densities but lower diversity compared with wildlands. However, recent studies show that residential urban yards with native plantings have higher native bird diversity compared with yards with exotic vegetation. Here we tested whether landscape designs also affect bird foraging behavior. We estimated foraging decisions by measuring the giving-up densities (GUD; amount of food resources remaining when the final forager quits foraging on an artificial food patch, i.e seed trays) in residential yards in Phoenix, AZ, USA. We assessed how two yard designs (mesic: lush, exotic vegetation; xeric: drought-tolerant and native vegetation) differed in foraging costs. Further, we developed a statistical model to calculate GUDs for every species visiting the seed tray. Birds foraging in mesic yards depleted seed trays to a lower level (i.e. had lower GUDs) compared to birds foraging in xeric yards. After accounting for bird densities, the lower GUDs in mesic yards appeared largely driven by invasive and synanthropic species. Furthermore, behavioral responses of individual species were affected by yard design. Species visiting trays in both yard designs had lower GUDs in mesic yards. Differences in resource abundance (i.e., alternative resources more abundant and of higher quality in xeric yards) contributed to our results, while predation costs associated with foraging did not. By enhancing the GUD, a common method for assessing the costs associated with foraging, our statistical model provided insights into how individual species and bird densities influenced the GUD. These differences we found in foraging behavior were indicative of differences in habitat quality, and thus our study lends additional support for native landscapes to help reverse the loss of urban bird diversity. PMID:22927974

Lerman, Susannah B; Warren, Paige S; Gan, Hilary; Shochat, Eyal

2012-01-01

131

Biomimicry of Social Foraging Bacteria for Distributed Optimization: Models, Principles, and Emergent Behaviors  

Microsoft Academic Search

In this paper, we explain the social foraging behavior of E. coli and M. xanthus bacteria and develop simulation models based on the principles of foraging theory that view foraging as optimization. This provides us with novel models of their foraging behavior and with new methods for distributed nongradient optimization. Moreover, we show that the models of both species of

Y. Liu; K. M. Passino

2002-01-01

132

Biomimicry of Social Foraging Bacteria for Distributed Optimization: Models, Principles, and Emergent Behaviors1  

Microsoft Academic Search

In this paper, we explain the social foraging behavior of E. coli and M. xanthus bacteria and develop simulation models based on the principles of foraging theory that view foraging as optimization. This provides us with novel models of their foraging behavior and with new methods for distributed nongradient optimization. Moreover, we show that the models of both species of

Y. LIU; K. M. PASSINO

2002-01-01

133

Floral odor learning within the hive affects honeybees' foraging decisions  

NASA Astrophysics Data System (ADS)

Honeybees learn odor cues quickly and efficiently when visiting rewarding flowers. Memorization of these cues facilitates the localization and recognition of food sources during foraging flights. Bees can also use information gained inside the hive during social interactions with successful foragers. An important information cue that can be learned during these interactions is food odor. However, little is known about how floral odors learned in the hive affect later decisions of foragers in the field. We studied the effect of food scent on foraging preferences when this learning is acquired directly inside the hive. By using in-hive feeders that were removed 24 h before the test, we showed that foragers use the odor information acquired during a 3-day stimulation period with a scented solution during a food-choice situation outside the nest. This bias in food preference is maintained even 24 h after the replacement of all the hive combs. Thus, without being previously collected outside by foragers, food odors learned within the hive can be used during short-range foraging flights. Moreover, correct landings at a dual-choice device after replacing the storing combs suggests that long-term memories formed within the colony can be retrieved while bees search for food in the field.

Arenas, Andrés; Fernández, Vanesa M.; Farina, Walter M.

2007-03-01

134

Foraging behavior delays mechanically-stimulated escape responses in fish.  

PubMed

Foraging and the evasion of predators are fundamental for the survival of organisms, but they impose contrasting demands that can influence performance in each behavior. Previous studies suggested that foraging organisms may experience decreased vigilance to attacks by predators; however, little is known about the effect of foraging on escape performance with respect to the kinematics and the timing of the response. This study tested the hypothesis that engaging in foraging activities affected escape performance by comparing fast-start escape responses of silver-spotted sculpins Blepsias cirrhosus under three conditions: (1) control (no foraging involved), (2) while targeting prey, and (3) immediately after capture of prey. Escape response variables (non-locomotor and locomotor) were analyzed from high-speed videos. Responsiveness was lower immediately after capturing a prey item compared with the other two treatments, and latency of performance was higher in the control treatment than in the other two. Locomotor variables such as maximum speed, maximum acceleration, and turning rates did not show statistical differences among the three groups. Our results demonstrate that foraging can negatively affect two fundamental components of the escape response: (1) responsiveness and (2) latency of escape, suggesting that engaging in foraging may decrease an individual's ability to successfully evade predators. PMID:23624863

Bohórquez-Herrera, Jimena; Kawano, Sandy M; Domenici, Paolo

2013-11-01

135

Individual Foraging Strategies Reveal Niche Overlap between Endangered Galapagos Pinnipeds  

PubMed Central

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.

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

2013-01-01

136

Transformation of forage legumes using Agrobacterium tumefaciens.  

PubMed

Galls were induced in six species of forage legumes following inoculation with wild-type strains of A. tumefaciens. The plant species was more influential than the bacterial strain in determining the type of tumour produced. Inoculation of Medicago sativa resulted in small, disorganised tumours. The three Trifolium species, T. repens, T. hybridum and T. pratense, formed galls which tended to produce roots and both Onobrychis viciifolia and Lotus corniculatus produced teratomatous galls. The shoots elongated in the latter species only. In L. corniculatus, tissues that were infected by five bacterial strains were capable of shoot regeneration when cultured on a hormone-free medium. The transformed nature of these shoots was confirmed by their failure to root, the production of callus from leaves cultured on hormone-free medium and the presence of opines. PMID:24247771

Webb, K J

1986-04-01

137

Space use by foragers consuming renewable resources  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

138

The organization of foraging in the fire ant, Solenopsis invicta.  

PubMed

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

Tschinkel, Walter R

2011-01-01

139

The Organization of Foraging in the Fire Ant, Solenopsis invicta  

PubMed Central

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.

Tschinkel, Walter R.

2011-01-01

140

Genotype and colony environment affect honeybee ( Apis mellifera L.) development and foraging behavior  

Microsoft Academic Search

We examined the interaction of genotype and environment on foraging-behavior development and forage choice in honeybees. High- and low-pollen-hoarding strains and unselected wild-type bees were co-fostered in pairs of colonies manipulated to differentially stimulate high and low pollen foraging. The high-pollen-foraging stimulus consisted of high amounts of larvae, a known stimulus for pollen foraging, plus low amounts of pollen, known

Tanya Pankiw; Robert E. Page Jr

2001-01-01

141

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...

142

SITE TECHNOLOGY CAPSULE: DYNAPHORE, INC., FORAGERż SPONGE TECHNOLOGY  

EPA Science Inventory

The Foragerż 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...

143

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...

144

Adélie penguin foraging location predicted by tidal regime switching.  

PubMed

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

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

2013-01-01

145

LOCOMOTOR CAPACITY AND FORAGING BEHAWOUR OF KALAHARI LACERTIQ LIZARDS  

Microsoft Academic Search

Closely related lacertid lizards (Eremias, Nucras) in the Kalahari desert differ in patterns of foraging behaviour. Some species are relatively sedentary ('sit-and-wait'), whereas others are more active ('widely-foraging') predators. We determined whether whole-animal locomotor capacities (cruising endurance on a treadmill, initial speed and maximum burst speed in a racetrack, and sprint endurance in a torus-shaped track) correlated with interspecific differences

RAYMOND B. HUEY; ALBERT F. BENNETT; HENRY JOHN-ALDER; KENNETH A. NAGY

1984-01-01

146

Hunter–Gatherers Optimize Their Foraging Patterns Using Lévy Flights  

Microsoft Academic Search

\\u000a We present evidence that human hunter-gatherers employ foraging movement patterns that are described by the statistics of\\u000a Lévy flights rather than by conventional Gaussian statistics. Human movement across the landscape is not usually considered\\u000a an anthropological problem as such. For example, Green (1987, p. 273) observed that the way foragers move between resource\\u000a patches has been the subject of little

Clifford T. Brown; Larry S. Liebovitch; Rachel Glendon

147

SPATIAL DISTRIBUTION AND TEMPERATURE SELECTION OF FISH NEAR THE THERMAL OUTFALL OF A POWER PLANT DURING FALL, WINTER, AND SPRING  

EPA Science Inventory

The movement patterns of 4 fish species: yellow perch (Perca flavescens), northern pike (Esox lucius), largemouth bass (Micropterus salmoides) and walleye (Stizostedion vitreum) were monitored by radio telemetry near the thermal discharge of a power plant (delta T 15C nominal). F...

148

Ranking Predatory Threats by Nonnative Fishes in the Yampa River, Colorado, via Bioenergetics Modeling  

Microsoft Academic Search

Because of its relatively natural hydrograph, the Yampa River, Colorado, is considered the crown jewel of native fish habitat in the upper basin of the Colorado River and has supported a relatively intact native fish assemblage. Nonnative fishes are thought to pose the greatest threat to native fishes in this system. Removal programs for nonnative northern pike Esox lucius and

Brett M. Johnson; Patrick J. Martinez; John A. Hawkins; Kevin R. Bestgen

2008-01-01

149

Learned Recognition of Predation Risk by Enallagma Damselfly Larvae (Odonata, Zygoptera) on the Basis of Chemical Cues  

Microsoft Academic Search

We studied two populations of damselfly larvae (Enallagma boreale): one population cooccurred with a predatory fish (northern pike, Esox lucius); the other did not. Damselflies that cooccurred with pike adopted antipredator behavior (reduced activity) in response to chemical stimuli from injured conspecifics, and to chemical stimuli from pike, relative to a distilled water control. Damselflies from an area where pike

Brian D. Wisenden; Douglas P. Chivers; R. Jan. F. Smith

1997-01-01

150

Genetic Divergence among Northern Pike from Spawning Locations in the Upper St. Lawrence River  

Microsoft Academic Search

To assess the ecological consequences associated with the degradation of riparian wetlands that historically provided spawning and rearing habitat for northern pike Esox lucius, annual spawning migrations and genetic structure were used to examine this species' dependence on four specific spawning areas in the Thousand Islands region of the Saint Lawrence River. Tagging and recapture over three consecutive spawning seasons

Aaron Bosworth; John M. Farrell

2006-01-01

151

Mercury and selenium concentrations in fish, sediments, and water of two Northwestern Quebec lakes  

Microsoft Academic Search

Research report:In an effort to learn more about mercury in the aquatic ecosystem and about possible ways to moderate the toxicity of mercury accumulated by aquatic organisms, sediment and water samples from Lake Dufault and Lake Duparquet in the Rouyn-Naranda region of Quebec were analyzed. Both mercury and selenium concentrations in muscle tissue of northern pike (Esox lucius) were determined.

M. R. Speyer

1980-01-01

152

Evaluation of Nonlethal Methods for the Analysis of Mercury in Fish Tissue  

Microsoft Academic Search

Thousands of fish are sacrificed each year to determine potential human exposure to mercury (Hg) from fish consumption. In this paper, we use lake whitefish Coregonus clupeaformis and northern pike Esox lucius to demonstrate that accurate and reliable measures of fish muscle Hg concentrations can be determined from small samples (<100 mg) harvested with biopsy tools. Reliability of results primarily

R. F. Baker; P. J. Blanchfield; M. J. Paterson; R. J. Flett; L. Wesson

2004-01-01

153

Qualitative indices of edible and inedible products obtained from fish in the lower Yenisei River basin  

Microsoft Academic Search

The results of biochemical investigations of samples of products obtained from burbot (Lota lota L.), perch (Perca fluviatilis L.), and pike (Esox lucius L.) inhabiting the lower reaches of the Yenisei River basin are given. Biologically active substances—macro- and microelements,\\u000a fatty acids, amino acids, and vitamins—are analyzed.

A. A. Gnedov; A. A. Kaizer

2010-01-01

154

Oviduct Insertion of Radio Transmitters as a Means of Locating Northern Pike Spawning Habitat  

Microsoft Academic Search

I inserted radio transmitters into the oviducts of northern pike Esox lucius in an attempt to find their spawning grounds. Oviduct insertion of miniature radio transmitters was quick and easy. I hoped that transmitters would be expelled with the eggs to aid in identifying critical habitat used for egg deposition. Ten transmitters were implanted in the egg masses of female

Rodney B. Pierce

2004-01-01

155

Relationship between Mercury Concentration and Growth Rates for Walleyes, Northern Pike, and Lake Trout from Quebec Lakes  

Microsoft Academic Search

The relationship between mercury (Hg) concentrations in fish muscle and fish growth rates was assessed for 54 walleye Sander vitreus, 52 northern pike Esox lucius, and 35 lake trout Salvelinus namaycush populations throughout the Province of Quebec, Canada. We used the von Bertalanffy growth model to estimate the ages of fish specimens for a given length, and Hg concentrations in

Mélyssa Lavigne; Marc Lucotte; Serge Paquet

2010-01-01

156

Northern Pike Year-Class Strength and Spring Water Levels  

Microsoft Academic Search

Relationships between spring water levels and strength of year classes of northern pike (Esox lucius) produced in Ball Club Lake of north-central Minnesota are considered for the 7 years between 1945 and 1952. The years are ranked according to water conditions, including height during spawning and fluctuation during egg incubation, and according to the strength of year classes produced as

Fritz H. Johnson

1957-01-01

157

Lymphosarcoma in Hatchery-Reared Yearling Tiger Muskellunge  

Microsoft Academic Search

Yearling tiger muskellunge (northern pike Esox lucius × muskellunge E. masquinongy) being cultured within the Colorado Division of Wildlife's fish hatchery system were found to have external lesions that were grossly and microscopically consistent with descriptions of esocid lymphosarcoma. This neoplasia has been described as a tumor of adult northern pike and muskellunge; a retroviral etiology has been proposed for

Paul R. Bowser; James W. Casey; Gregory A. Wooster; Rodman G. Getchell; Chun-Yao Chen; Linda Chittum

2002-01-01

158

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...

159

Evaluation of Muskellunge and Tiger Muskellunge Stocking Program.  

National Technical Information Service (NTIS)

In the project, five jobs related to muskellunge and tiger muskellunge stocking evaluations were conducted over a seven year period. Those jobs were: (1) size specific survival of muskellunge (Esox masquinongy) and tiger muskellunge (E.m. x E. lucius); (2...

D. H. Wahl L. M. Einfalt T. A. Szendrey D. F. Clapp

1997-01-01

160

Chaos-order transition in foraging behavior of ants.  

PubMed

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

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

2014-06-10

161

Waggle Dance Distances as Integrative Indicators of Seasonal Foraging Challenges  

PubMed Central

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.

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

2014-01-01

162

Sex-specific foraging behaviour in a monomorphic seabird.  

PubMed Central

Sexual differences in the foraging behaviour of parents have been observed in a number of sexually sizedimorphic birds, particularly seabirds, and the usual inference has been that these sex-specific differences are mediated primarily by differences in body size. To test this explanation, we compared the foraging behaviour of parents in a monomorphic seabird species, the northern gannet Morus bassanus. Using specially designed instruments and radio telemetry we found that individuals of both sexes were consistent in the directions and durations of their foraging trips. However, there were significant differences in the foraging behaviour of males and females. Female gannets were not only more selective than males in the areas where they foraged, but they also made longer, deeper dives and spent more time on the sea surface than males. As the sexes are morphologically similar in this species, then these differences are unlikely to have been mediated by body size. Our work highlights the need to investigate sexual differences in the foraging behaviour of seabirds and other species more closely, in order to test alternative theories that do not rely on differences in body size.

Lewis, S; Benvenuti, S; Dall'Antonia, L; Griffiths, R; Money, L; Sherratt, T N; Wanless, S; Hamer, K C

2002-01-01

163

Waggle dance distances as integrative indicators of seasonal foraging challenges.  

PubMed

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

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

2014-01-01

164

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

USGS Publications Warehouse

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.

Erwin, R.M.

1985-01-01

165

Social calls predict foraging success in big brown bats.  

PubMed

Animals foraging in the dark are engaged simultaneously in prey pursuit, collision avoidance, and interactions with conspecifics, making efficient nonvisual communication essential. A variety of birds and mammals emit food-associated calls that inform, attract, or repel conspecifics (e.g.,). Big brown bats (Eptesicus fuscus) are insectivorous aerial hawkers that may forage near conspecifics and are known to emit social calls (e.g.,). Calls recorded in a foraging setting might attract (e.g.,) or repel conspecifics and could denote territoriality or food claiming. Here, we provide evidence that the "frequency-modulated bout" (FMB), a social call emitted only by male bats (exclusively in a foraging context), 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, interbat 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

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

2014-04-14

166

Major Quantitative Trait Loci Affecting Honey Bee Foraging Behavior  

PubMed Central

We identified two genomic regions that affect the amount of pollen stored in honey bee colonies and influence whether foragers will collect pollen or nectar. We selected for the amount of pollen stored in combs of honey bee colonies, a colony-level trait, and then used random amplified polymorphic DNA (RAPD) markers and interval mapping procedures with data from backcross colonies to identify two quantitative trait loci (pln1 and pln2, LOD 3.1 and 2.3, respectively). Quantitative trait loci effects were confirmed in a separate cross by demonstrating the cosegregation of marker alleles with the foraging behavior of individual workers. Both pln1 and pln2 had an effect on the amount of pollen carried by foragers returning to the colony, as inferred by the association between linked RAPD marker alleles, D8-.3f and 301-.55, and the individual pollen load weights of returning foragers. The alleles of the two marker loci were nonrandomly distributed with respect to foraging task. The two loci appeared to have different effects on foraging behavior. Individuals with alternative alleles for the marker linked to pln2 (but not pln1) differed with respect to the nectar sugar concentration of their nectar loads.

Hunt, G. J.; Page-Jr., R. E.; Fondrk, M. K.; Dullum, C. J.

1995-01-01

167

Harvester Ant Colony Variation in Foraging Activity and Response to Humidity  

PubMed Central

Collective behavior is produced by interactions among individuals. Differences among groups in individual response to interactions can lead to ecologically important variation among groups in collective behavior. Here we examine variation among colonies in the foraging behavior of the harvester ant, Pogonomyrmex barbatus. Previous work shows how colonies regulate foraging in response to food availability and desiccation costs: the rate at which outgoing foragers leave the nest depends on the rate at which foragers return with food. To examine how colonies vary in response to humidity and in foraging rate, we performed field experiments that manipulated forager return rate in 94 trials with 17 colonies over 3 years. We found that the effect of returning foragers on the rate of outgoing foragers increases with humidity. There are consistent differences among colonies in foraging activity that persist from year to year.

Gordon, Deborah M.; Dektar, Katherine N.; Pinter-Wollman, Noa

2013-01-01

168

Color and polarization vision in foraging Papilio.  

PubMed

This paper gives an overview of behavioral studies on the color and polarization vision of the Japanese yellow swallowtail butterfly, Papilio xuthus. We focus on indoor experiments on foraging individuals. Butterflies trained to visit a disk of certain color correctly select that color among various other colors and/or shades of gray. Correct selection persists under colored illumination, but is systematically shifted by background colors, indicating color constancy and simultaneous color contrast. While their eyes contain six classes of spectral receptors, their wavelength discrimination performance indicates that their color vision is tetrachromatic. P. xuthus innately prefers brighter targets, but can be trained to select dimmer ones under certain conditions. Butterflies trained to a dark red stimulus select an orange disk presented on a bright gray background over one on dark gray. The former probably appears darker to them, indicating brightness contrast. P. xuthus has a strong innate preference for vertically polarized light, but the selection of polarized light changes depending on the intensity of simultaneously presented unpolarized light. Discrimination of polarization also depends on background intensity. Similarities between brightness and polarization vision suggest that P. xuthus perceive polarization angle as brightness, such that vertical polarization appears brighter than horizontal polarization. PMID:24722674

Kinoshita, Michiyo; Arikawa, Kentaro

2014-06-01

169

Mixed encounters, limited perception and optimal foraging.  

PubMed

This article demonstrates how perceptual constraints of predators and the possibility that predators encounter prey both sequentially (one prey type at a time) and simultaneously (two or more prey types at a time) may influence the predator attack decisions, diet composition and functional response of a behavioural predator-prey system. Individuals of a predator species are assumed to forage optimally on two prey types and to have exact knowledge of prey population numbers (or densities) only in a neighbourhood of their actual spatial location. The system characteristics are inspected by means of a discrete-time, discrete-space, individual-based model of the one-predator-two-prey interaction. Model predictions are compared with ones that have been obtained by assuming only sequential encounters of predators with prey and/or omniscient predators aware of prey population densities in the whole environment. It is shown that the zero-one prey choice rule, optimal for sequential encounters and omniscient predators, shifts to abruptly changing partial preferences for both prey types in the case of omniscient predators faced with both types of prey encounters. The latter, in turn, become gradually changing partial preferences when predator omniscience is considered only local. PMID:11016087

Berec, L

2000-09-01

170

Comparative digestibility by cattle versus sheep: effect of forage quality.  

PubMed

The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned to 1 of 3 forage sources within ruminant specie, and the study was conducted over 3 periods. For forage source, both animal and period served as the blocking factor with all forage sources represented once within each animal and all forage sources represented at least once within each period. The treatment structure was arranged in a 2 × 3 factorial with ruminant species (2) and forage source (3) as the factors. Forage sources were 1) alfalfa hay (Medicago sativa; 17.5% CP and 34.1% NDF, DM basis), 2) warm-season grass hay mix (Bothriochloa ischaemum and Cynodon dactylon; 7.3% CP and 74.7% NDF, DM basis), and 3) lovegrass hay (Eragrostis curvula; 2.5% CP and 81.9% NDF, DM basis). As a percent of BW, steers and wethers consumed similar (P ? 0.06) amounts of forage, and intake was more influenced by forage quality (P < 0.001) than ruminant species (P = 0.35). When expressed per unit of metabolic BW, cattle consumed more (P < 0.001) DM, NDF, and N than sheep. Apparent total tract digestibility was similar among steers and wethers when alfalfa or grass hay was fed, but decreased to a greater extent in wethers when low-quality lovegrass hay was fed (ruminant species × diet interaction, P ? 0.01). Rate (%/h) of ruminal NDF disappearance was greater (P = 0.02) for alfalfa and grass hay than lovegrass, but was not influenced (P = 0.12) by ruminant species. In addition, ruminal DM fill was influenced more (P < 0.01) by forage than by ruminant species (P = 0.07). Steers and wethers had greater (P < 0.01) DM fill from grass hay and lovegrass hay than alfalfa before and 5 h after feeding. Ruminal VFA were generally not influenced (P ? 0.06) by ruminant specie. Results suggest that apparent total tract digestibilities are more similar among ruminant species when moderate- to high-quality forages are evaluated. However, sheep are not an adequate model for cattle when low-quality forages are compared because cattle digest low-quality forages to a greater extent than sheep. Expressing digestibility as digestible intake per unit of BW allows for a wider range of forage qualities to be compared when substituting sheep for cattle. PMID:24663196

Soto-Navarro, S A; Lopez, R; Sankey, C; Capitan, B M; Holland, B P; Balstad, L A; Krehbiel, C R

2014-04-01

171

Subjective costs drive overly patient foraging strategies in rats on an intertemporal foraging task  

PubMed Central

Laboratory studies of decision making often take the form of two-alternative, forced-choice paradigms. In natural settings, however, many decision problems arise as stay/go choices. We designed a foraging task to test intertemporal decision making in rats via stay/go decisions. Subjects did not follow the rate-maximizing strategy of choosing only food items associated with short delays. Instead, rats were often willing to wait for surprisingly long periods, and consequently earned a lower rate of food intake than they might have by ignoring long-delay options. We tested whether foraging theory or delay discounting models predicted the behavior we observed but found that these models could not account for the strategies subjects selected. Subjects’ behavior was well accounted for by a model that incorporated a cost for rejecting potential food items. Interestingly, subjects’ cost sensitivity was proportional to environmental richness. These findings are at odds with traditional normative accounts of decision making but are consistent with retrospective considerations having a deleterious influence on decisions (as in the “sunk-cost” effect). More broadly, these findings highlight the utility of complementing existing assays of decision making with tasks that mimic more natural decision topologies.

Wikenheiser, Andrew M.; Stephens, David W.; Redish, A. David

2013-01-01

172

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

USGS Publications Warehouse

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.

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

2013-01-01

173

Effects of adult mortality risks on parasitoid foraging tactics  

PubMed

When searching on Scots pines, females of the aphid parasitoid Pauesia silvestris responded to differences in mortality risks, host distribution and host quality by changing foraging tactics. They foraged more successfully (i.e. they laid more eggs per unit time) on the pine aphid Cinara pini than on Cinara pineaTherefore, the former species was considered to be of higher quality. However, P. silvestris suffered from a high mortality (19.5%) from ant aggression when foraging for C. piniwhile mortality was zero on pines with C. pineaAll females that were killed were foraging on the bark, while females searching on needles were safe from ant attacks. When searching for C. pineaP. silvestris spent significantly more time on needles if the aphid colonies were ant-attended. On pines with C. piniin contrast, females spent more time on bark in ant-attended colonies. The high adult mortality risk on bark was counterbalanced by a significantly higher foraging success in ant-attended colonies. PMID:9268467

VÖLKL; Kroupa

1997-08-01

174

Predator interference alters foraging behavior of a generalist predatory arthropod.  

PubMed

Interactions between predators foraging in the same patch may strongly influence patch use and functional response. In particular, there is continued interest in how the magnitude of mutual interference shapes predator-prey interactions. Studies commonly focus on either patch use or the functional response without attempting to link these important components of the foraging puzzle. Predictions from both theoretical frameworks suggest that predators should modify foraging efforts in response to changes in feeding rate, but this prediction has received little empirical attention. We study the linkage between patch departure rates and food consumption by the hunting spider, Pardosa milvina, using field enclosures in which prey and predator densities were manipulated. Additionally, the most appropriate functional response model was identified by fitting alternative functional response models to laboratory foraging data. Our results show that although prey availability was the most important determinant of patch departure rates, a greater proportion of predators left enclosures containing elevated predator abundance. Functional response parameter estimation revealed significant levels of interference among predators leading to lower feeding rates even when the area allocated for each predator was kept constant. These results suggest that feeding rates determine patch movement dynamics, where interference induces predators to search for foraging sites that balance the frequency of agonistic interactions with prey encounter rates. PMID:24648022

Schmidt, Jason M; Crist, Thomas O; Wrinn, Kerri; Rypstra, Ann L

2014-06-01

175

Foraging in corallivorous butterflyfish varies with wave exposure  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

176

Corticosterone predicts foraging behavior and parental care in macaroni penguins.  

PubMed

Corticosterone has received considerable attention as the principal hormonal mediator of allostasis or physiological stress in wild animals. More recently, it has also been implicated in the regulation of parental care in breeding birds, particularly with respect to individual variation in foraging behavior and provisioning effort. There is also evidence that prolactin can work either inversely or additively with corticosterone to achieve this. Here we test the hypothesis that endogenous corticosterone plays a key physiological role in the control of foraging behavior and parental care, using a combination of exogenous corticosterone treatment, time-depth telemetry, and physiological sampling of female macaroni penguins (Eudyptes chrysolophus) during the brood-guard period of chick rearing, while simultaneously monitoring patterns of prolactin secretion. Plasma corticosterone levels were significantly higher in females given exogenous implants relative to those receiving sham implants. Increased corticosterone levels were associated with significantly higher levels of foraging and diving activity and greater mass gain in implanted females. Elevated plasma corticosterone was also associated with an apparent fitness benefit in the form of increased chick mass. Plasma prolactin levels did not correlate with corticosterone levels at any time, nor was prolactin correlated with any measure of foraging behavior or parental care. Our results provide support for the corticosterone-adaptation hypothesis, which predicts that higher corticosterone levels support increased foraging activity and parental effort. PMID:22673661

Crossin, Glenn T; Trathan, Phil N; Phillips, Richard A; Gorman, Kristen B; Dawson, Alistair; Sakamoto, Kentaro Q; Williams, Tony D

2012-07-01

177

Perchlorate accumulation in forage and edible vegetation.  

PubMed

The accumulation of perchlorate in vegetation is becoming a concern, with increasing numbers of sites reporting the presence of perchlorate in groundwater and surface water. This study investigated potential perchlorate uptake and distribution by a variety of forage and edible crops in both the laboratory and the field. Perchlorate concentrations in soybean leaves grown in the greenhouse were significantly higher than perchlorate concentrations in soybean seeds and pods. Perchlorate concentrations in alfalfa grown in sand were significantly lower than those in alfalfa grown in soil. The concentration of perchlorate in tomato was lower in the fruit than the leaves. Commercially grown wheat and alfalfa samples all contained perchlorate, 0.72-8.6 mg/kg of fresh weight (FW) in the wheat stems, 0.71-4.4 mg/kg of FW in the wheat heads, and 2.9 mg/kg of FW in alfalfa. All field garden samples tested (including cucumber, cantaloupe, and tomato) that were irrigated with perchlorate-tainted water contained perchlorate at various concentrations ranging from 0.040 to 1.65 mg/kg of FW. Bioconcentration factors (BCF), ratios of plant fresh weight concentrations to estimated or measured groundwater concentrations [(microg/kg of FW)/microg/L], were all in the same order of magnitude ranging from 215 +/- 126 for wheat stems to 233 +/- 264 for wheat heads and to 380 +/- 89 for alfalfa. BCF for garden fruit samples were much lower (0.5-20). Results from this study highlight the potential for perchlorate exposure by routes other than drinking water. PMID:15656674

Jackson, W Andrew; Joseph, Preethi; Laxman, Patil; Tan, Kui; Smith, Philip N; Yu, Lu; Anderson, Todd A

2005-01-26

178

Foraging reactivation in the honeybee Apis mellifera L.: factors affecting the return to known nectar sources  

NASA Astrophysics Data System (ADS)

This paper addresses, what determines that experienced forager honeybees return to places where they have previously exploited nectar. Although there was already some evidence that dance and trophallaxis can cause bees to return to feed, the fraction of unemployed foragers that follow dance or receive food from employed foragers before revisiting the feeder was unknown. We found that 27% of the experienced foragers had no contact with the returning foragers inside the hive. The most common interactions were dance following (64%) and trophallaxis (21%). The great variability found in the amount of interactions suggests that individual bees require different stimulation before changing to the foraging mode. This broad disparity negatively correlated with the number of days after marking at the feeder, a variable that is closely related to the foraging experience, suggesting that a temporal variable might affect the decision-making in reactivated foragers.

Gil, Mariana; Farina, Walter Marcelo

2002-05-01

179

The M?ller-Lyer Illusion in Ant Foraging  

PubMed Central

The Müller-Lyer illusion is a classical geometric illusion in which the apparent (perceived) length of a line depends on whether the line terminates in an arrow tail or arrowhead. This effect may be caused by economic compensation for the gap between the physical stimulus and visual fields. Here, we show that the Müller-Lyer illusion can also be produced by the foraging patterns of garden ants (Lasius niger) and that the pattern obtained can be explained by a simple, asynchronously updated foraging ant model. Our results suggest that the geometric illusion may be a byproduct of the foraging process, in which local interactions underlying efficient exploitation can also give rise to global exploration, and that visual information processing in human could implement similar modulation between local efficient processing and widespread computation.

Sakiyama, Tomoko; Gunji, Yukio-Pegio

2013-01-01

180

Trait-mediated trophic interactions: is foraging theory keeping up?  

PubMed

Many ecologists believe that there is a lack of foraging theory that works in community contexts, for populations of unique individuals each making trade-offs between food and risk that are subject to feedbacks from behavior of others. Such theory is necessary to reproduce the trait-mediated trophic interactions now recognized as widespread and strong. Game theory can address feedbacks but does not provide foraging theory for unique individuals in variable environments. 'State- and prediction-based theory' (SPT) is a new approach that combines existing trade-off methods with routine updating: individuals regularly predict future food availability and risk from current conditions to optimize a fitness measure. SPT can reproduce a variety of realistic foraging behaviors and trait-mediated trophic interactions with feedbacks, even when the environment is unpredictable. PMID:22995894

Railsback, Steven F; Harvey, Bret C

2013-02-01

181

Foraging by a wood-decomposing fungus is ecologically adaptive.  

PubMed

We show that fungi that forage for wood do not conform to the paradigm of symmetric radial growth and grow asymmetrically by default. Asymmetry is further accentuated by contact with a resource that also partially polarizes growth in the direction of the resource. Despite marked changes at the perimeter, overall growth allocation on an area basis is, however, unchanged implying sophisticated regulation at the colony level. Using mathematical models, we show that this behaviour is best explained as a local response of the immediate segment contacting the resource. The model reveals that foraging behaviour is adaptive but only for resources that are clustered in space and is selectively neutral for randomly scattered resources. This clustered spatial distribution matches that found in the natural environment. Modelling also shows that the foraging strategy used by these fungi involves substantial risks as well as benefits. PMID:23947589

Darrah, P R; Fricker, M D

2014-01-01

182

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

USGS Publications Warehouse

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.

Argyle, Ray L.

1992-01-01

183

Common marmosets ( Callithrix jacchus ) do not utilize social information in three simultaneous social foraging tasks  

Microsoft Academic Search

Social foraging is suggested to increase foraging efficiency, as individuals might benefit from public information acquired\\u000a by monitoring the foraging activities of other group members. We conducted a series experiments with captive common marmosets\\u000a (Callithrix jacchus) to investigate to what extent marmosets utilize social information about food location when foraging simultaneously with\\u000a conspecifics. Subjects were confronted with dominant and subordinate

Bernhard Voelkl; Ludwig Huber

2007-01-01

184

Context dependence in foraging behaviour of Achillea millefolium.  

PubMed

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

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

2012-12-01

185

Phase transitions and bistability in honeybee foraging dynamics.  

PubMed

Many physical and biological systems display phase transitions, where a slight change in a parameter greatly changes the behavior of the system; and bistability, where for a certain range of this parameter either of two phases can be obtained, depending on initial conditions. We suggest the presence of these phenomena in a model of foraging honeybees. The eventual number of foragers depends in a complex way on the bee concentration and on the scouting rate. The results hold relevance for other multi-agent systems with potential jumps in system behavior or efficiency, depending on agent concentration. PMID:18171134

Loengarov, Andreas; Tereshko, Valery

2008-01-01

186

Auto-Clustering Using Particle Swarm Optimization and Bacterial Foraging  

NASA Astrophysics Data System (ADS)

This paper presents a hybrid approach for clustering based on particle swarm optimization (PSO) and bacteria foraging algorithms (BFA). The new method AutoCPB (Auto-Clustering based on particle bacterial foraging) makes use of autonomous agents whose primary objective is to cluster chunks of data by using simplistic collaboration. Inspired by the advances in clustering using particle swarm optimization, we suggest further improvements. Moreover, we gathered standard benchmark datasets and compared our new approach against the standard K-means algorithm, obtaining promising results. Our hybrid mechanism outperforms earlier PSO-based approaches by using simplistic communication between agents.

Olesen, Jakob R.; Cordero H., Jorge; Zeng, Yifeng

187

FORAGING STRATEGY OF WANDERING ALBATROSSES THROUGH THE BREEDING SEASON: A STUDY USING SATELLITE TELEMETRY  

Microsoft Academic Search

Satellite telemetry of Wandering Albatrosses (Diomedea exulans) breeding on the Crozet Islands, southwestern Indian Ocean, revealed two distinct foraging strategies during successive stages of the breeding season: systematic foraging over extensive distances; and use of specific areas close to the colony. During early incubation, Wandering Albatrosses foraged over pelagic waters at an average range of 1,284 kin. The length of

HENRI WEIMERSKIRCH; MARC SALAMOLARD; FRANCOIS SARRAZIN; PIERRE JOUVENTIN

1993-01-01

188

The influence of reproductive status on foraging by hoary marmots ( Marmota caligata )  

Microsoft Academic Search

Predictions were made and tested, comparing the foraging behavior of reproductive (rf) and nonreproductive (nrf) female hoary marmots, with the following findings: In June, no differences occur between rf's and nrf's, regarding daytime foraging. However, rf's forage more in the evening and during inclement weather, suggesting that greater nutritional needs and higher reproductive value select for the assumption of more

David P. Barash

1980-01-01

189

Temporal pattern of foraging and microhabitat use by Galápagos marine iguanas, Amblyrhynchus cristatus  

Microsoft Academic Search

We observed a colony of marine iguanas (Amblyrhynchus cristatus) on Isla Fernandina, Galápagos, Ecuador, while measuring local micrometeorological and tidal conditions. We found size-related differences in foraging mode, with smaller iguanas feeding intertidally during daytime low tides and larger iguanas feeding subtidally. Despite having greater opportunity, subtidal foragers did not time their foraging bouts or exploit their environment in ways

William A. Buttemer; William R. Dawson

1993-01-01

190

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

PubMed

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

Beauchamp, Guy

2012-08-01

191

Latitudinal Range Influences the Seasonal Variation in the Foraging Behavior of Marine Top Predators  

Microsoft Academic Search

Non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. Populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. We studied two species of resident central place foragers from temperate and equatorial

Stella Villegas-Amtmann; Samantha E. Simmons; Carey E. Kuhn; Luis A. Huckstadt; Daniel P. Costa

2011-01-01

192

Innovation in forage development: empirical evidence from Alaba Special District, southern Ethiopia  

Microsoft Academic Search

Forage development is one of the strategies to address feed scarcity and low livestock productivity in Ethiopia. In line with government strategy, multiple actors took part in a forage development programme for six years (2004–09) in Alaba Special District, in southern Ethiopia. This paper analyses the six-year forage development programme, comparing its two phases, from an innovation systems perspective to

Abebe Shiferaw; Ranjitha Puskur; Azage Tegegne; Dirk Hoekstra

2011-01-01

193

EMERGING ISSUES FOR ALFALFA AND OTHER FORAGES IN THE GREAT BASIN  

Microsoft Academic Search

Factors affecting forage production, quality, marketing, and utilization include urbanization; availability of crop production resources; approaches to environmental stewardship; and other social and economic forces. Two factors of particular interest are 1) availability of pesticides for use in alfalfa and other forage crops; and 2) new laboratory procedures for predicting forage nutritional value, and changing targets for optimum protein levels

Thomas C. Griggs; Willie Riggs

194

Specialization and development of beach hunting, a rare foraging behavior, by wild bottlenose dolphins ( Tursiops sp.)  

Microsoft Academic Search

Foraging behaviors of bottlenose dolphins vary within and among populations, but few studies attempt to ad- dress the causes of individual variation in foraging behavior. We examined how ecological, social, and developmental factors relate to the use of a rare foraging tactic by wild bottlenose dolphins (Tursiops sp. Gervais, 1855) in Shark Bay, Western Australia. Beach hunting involves partial and

B. L. Sargeant; J. Mann; P. Berggren; M. Krützen

2005-01-01

195

FORBEEF: A Forage-Livestock System Computer Model Used as a Teaching Aid for Decision Making.  

ERIC Educational Resources Information Center

Describes the development of a computer simulation model of forage-beef production systems, which is intended to incorporate soil, forage, and animal decisions into an enterprise scenario. Produces a summary of forage production and livestock needs. Cites positive assessment of the program's value by participants in inservice training workshops.…

Stringer, W. C.; And Others

1987-01-01

196

[Study on foraging behaviors of honeybee Apis mellifera based on RFID technology].  

PubMed

Honeybee foragers can flexibly adjust their out-hive activities to ensure growth and reproduction of the colony. In order to explore the characteristics of honey bees foraging behaviors, in this study, their flight activities were monitored 24 hours per day for a duration of 38 days, using an radio frequency identification (RFID) system designed and manufactured by the Honeybee Research Institute of Jiangxi Agricultural University in cooperation with the Guangzhou Invengo Information Technology Co., Ltd. Our results indicated that 63.4% and 64.5% of foragers were found rotating more than one day off during the foraging period in two colonies, and 22.5% and 26.4% of the total foraging days were used for rest respectively. Further, although the total foraging time between rotating day-off foragers and continuously working foragers was equal, the former had a significant longer lifespan than the latter. Additionally, the lifespan of the early developed foragers was significantly lower than that of the normally developed foragers. This study enriched the content of foraging behaviors of honey bees, and it could be used as the basis for the further explorations on evolutionary mechanism of foraging behaviors of eusocial insects. PMID:24984504

Tian, Liu-Qing; He, Xu-Jiang; Wu, Xiao-Bo; Gan, Hai-Yan; Han, Xu; Liu, Hao; Zeng, Zhi-Jiang

2014-03-01

197

Rodent foraging is affected by indirect, but not by direct, cues of predation risk  

Microsoft Academic Search

We used foraging trays to determine whether oldfield mice, Peromyscus polionotus, altered foraging in response to direct cues of predation risk (urine of native and nonnative predators) and indirect cues of predation risk (foraging microhabitat, precipitation, and moon illumination). The proportion of seeds remaining in each tray (a measure of the giving-up density [GUD]) was used to measure risk perceived

John L. Orrock; Brent J. Danielson; R. Jory Brinkerhoffb; R. Brinkerhoff; Jory

2004-01-01

198

Evaluation of predation risk in the collectively foraging termite Macrotermes bellicosus  

Microsoft Academic Search

Summary. Few studies have investigated foraging decisions in collectively foraging social insects with no studies in termites. In termites predation is assumed to be a key mortality factor. Therefore, we experimentally investigated the role of predation pressure in foraging decisions of the fungus cultivating, mound building termite Macrotermes bellicosus in two habitats of the Comoé National Park (Ivory Coast). We

J. Korb; K. E. Linsenmair

2002-01-01

199

Wing wear affects wing use and choice of floral density in foraging bumble bees  

Microsoft Academic Search

Damage to structures that enable mobility can potentially influence foraging behavior. Bumble bees vary in extent of individual wing wear, a trait predicted to affect mechanical performance during foraging. This study asks 1) do bumble bees distribute themselves across different floral densities in accordance with their concurrent wing wear? and 2) does wing use in foraging bumble bees depend on

Danusha J. Foster; Ralph V. Cartar

2011-01-01

200

A phylogenetic perspective on foraging mode evolution and habitat use in West Indian Anolis lizards  

Microsoft Academic Search

Although many descriptive studies of foraging mode have been performed, the factors that underlie the evolution of foraging mode remain poorly understood. To test the hypothesis that foraging mode evolu- tion is affected by habitat use, we analysed two data sets including 31 species of West Indian Anolis lizards. In this genus, the same suite of habitat specialists (or ecomorphs)

Michele A. Johnson; Manuel Leal; Lourdes Rodríguez Schettino; Ada Chamizo Lara; Liam J. Revell; Jonathan B. Losos

2008-01-01

201

Scale-free foraging by primates emerges from their interaction with a complex environment  

Microsoft Academic Search

Scale-free foraging patterns are widespread among animals. These may be the outcome of an optimal searching strategy to find scarce randomly distributed resources, but a less explored alternative is that this behaviour may result from the interaction of foraging animals with a particular distribution of resources. We introduce a simple foraging model where individuals follow mental maps and choose their

Denis Boyer; Gabriel Ramos-Fernández; Octavio Miramontes; José L. Mateos; Germinal Cocho; Hernán Larralde; Humberto Ramos; Fernando Rojas

2006-01-01

202

Foraging in the seed-harvester ant genus Pogonomyrmex : are energy costs important?  

Microsoft Academic Search

Energy intake and expenditure on natural foraging trips were estimated for the seed-harvester ants, Pogonomyrmex maricopa and P. rugosus. During seed collection, P. maricopa foraged individually, whereas P. rugosus employed a trunk-trail foraging system. Energy gain per trip and per minute were not significantly different between species. There was also no interspecific difference in energy cost per trip, but energy

Jonathon A. Weier; Donald H. Feener

1995-01-01

203

Foraging and provisioning in Antarctic fur seals: interannual variability in time-energy budgets  

Microsoft Academic Search

This study examined three competing hypotheses to explain how lactating Antarctic fur seals (Arctocephalus gazella) respond to changes in the level of resource availability. Antarctic fur seals have episodic bouts of suckling (1-3 days), alternating with foraging trips (3-10 days). Foraging time budgets varied significantly (p , .001) among 8 consecutive years at Bird Island, South Georgia. Foraging trip duration

I. L. Boyd

1999-01-01

204

Fatty Acid Composition of Mixed-Rumen Bacteria: Effect of Concentration and Type of Forage  

Microsoft Academic Search

The effects of concentration and type of forage in the diet on lipid content and fatty acid (FA) composition of rumen bacteria were studied in 14 goats fitted with duodenal cannulas. The goats were fed a complete maintenance diet containing 40, 70, or 100% chopped forage (dry matter basis) in two equal meals. Forage was either corn stover or alfalfa

P. Bas; H. Archimčde; A. Rouzeau; D. Sauvant

2003-01-01

205

Interactions with Combined Chemical Cues Inform Harvester Ant Foragers' Decisions to Leave the Nest in Search of Food  

PubMed Central

Social insect colonies operate without central control or any global assessment of what needs to be done by workers. Colony organization arises from the responses of individuals to local cues. Red harvester ants (Pogonomyrmex barbatus) regulate foraging using interactions between returning and outgoing foragers. The rate at which foragers return with seeds, a measure of food availability, sets the rate at which outgoing foragers leave the nest on foraging trips. We used mimics to test whether outgoing foragers inside the nest respond to the odor of food, oleic acid, the odor of the forager itself, cuticular hydrocarbons, or a combination of both with increased foraging activity. We compared foraging activity, the rate at which foragers passed a line on a trail, before and after the addition of mimics. The combination of both odors, those of food and of foragers, is required to stimulate foraging. The addition of blank mimics, mimics coated with food odor alone, or mimics coated with forager odor alone did not increase foraging activity. We compared the rates at which foragers inside the nest interacted with other ants, blank mimics, and mimics coated with a combination of food and forager odor. Foragers inside the nest interacted more with mimics coated with combined forager/seed odors than with blank mimics, and these interactions had the same effect as those with other foragers. Outgoing foragers inside the nest entrance are stimulated to leave the nest in search of food by interacting with foragers returning with seeds. By using the combined odors of forager cuticular hydrocarbons and of seeds, the colony captures precise information, on the timescale of seconds, about the current availability of food.

Greene, Michael J.; Pinter-Wollman, Noa; Gordon, Deborah M.

2013-01-01

206

Manejo biotecnológico de gramíneas forrajeras Biotechnological manipulation of forage grasses  

Microsoft Academic Search

Biotechnological advances achieved in basic crops and model plants are currently being applied to practically all grasses, being them cereals, forages, turfs, ornamentals or species having industrial or pharmaceutical importance. An unprecedented revolution in possibilities for manipulating graminaceous species through current and coming technologies can be expected which should impact all areas and levels of knowledge and use of these

Gerardo Armando Aguado-Santacruz; Quintín Rascón Cruz; José Luis Pons Hernández; Oscar Grageda Cabrera; Edmundo García-Moya

207

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...

208

Unravelling the mechanisms of trapline foraging in bees.  

PubMed

Trapline foraging (repeated sequential visits to a series of feeding locations) is a taxonomically widespread but poorly understood behavior. Investigating these routing strategies in the field is particularly difficult, as it requires extensive tracking of animal movements to retrace their complete foraging history. In a recent study, we used harmonic radar and motion-triggered video cameras to track bumblebees foraging between artificial flowers in a large open field. We describe how all bees gradually developed a near optimal trapline to link all flowers and have identified a simple learning heuristic capable of replicating this optimisation behavior. Our results provide new perspectives to clarify the sequence of decisions made by pollinating insects during trapline foraging, and explore how spatial memory is organized in their small brains.   "I have always regretted that I did not mark the bees by attaching bits of cotton wool or eiderdown to them with rubber, because this would have made it much easier to follow their paths." Charles Darwin(1.) PMID:23750293

Lihoreau, Mathieu; Raine, Nigel E; Reynolds, Andrew M; Stelzer, Ralph J; Lim, Ka S; Smith, Alan D; Osborne, Juliet L; Chittka, Lars

2013-01-01

209

NEUROENDOCRINE FUNCTION IN HEIFERS CONSUMING LOW QUALITY DORMANT FORAGE  

Microsoft Academic Search

This study examined effects of low quality dormant forage on neuroendocrine function. Eighteen, 2- yr-old, rumen-cannulated, cyclic crossbred heifers (428 ± 44 kg) were stratified by BW and randomly assigned to 1 of 3 dietary treatments (n = 6) fed on a DM basis. Treatment 1 (Trt 1) was a 50% buffalo straw - 50% old world bluestem mix (CP%

J. D. Walsh; C. M. Gardner; S. I. Valverde-Saenz; M. B. Horvath; J. T. Mulliniks; D. M. Hallford; S. L. Lodge-Ivey; K. K. Kane; D. E. Hawkins

210

Liquid supplement and forage intake by range beef cows1  

Microsoft Academic Search

One hundred eighty crossbred cows were assigned to one of six native range pastures during two winters to evaluate forage and supplement intake as affected by liquid supplement (yr 1: 50% crude pro- tein, 84% from urea; yr 2: 57% crude protein, 91% from urea) delivery method and cow age (2, 3, 4, 5, or 6 yr). Treatments were: 1)

B. F. Sowell; J. G. P. Bowman; E. E. Grings; M. D. MacNeil

2010-01-01

211

Foraging Ecology of Pileated Woodpeckers in Coastal Forests of Washington  

Microsoft Academic Search

In the Pacific Northwest, providing adequate habitat forpileated woodpeckers (Dryocopus pileatus) has been a key component Of federal forest management strategies for over 20 years. Although their nesting and roosting ecology has been well studied, information on their foraging ecology is limited. From 1990 to 1995, we studied food habits of pileated woodpeckers in coastal forests (with scat analysis); estimated

CATHERINE M. RALEY; KEITH B. AUBRY

2006-01-01

212

Empty-headed dynamical model of infant visual foraging.  

PubMed

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. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 56: 1129-1133, 2014. PMID:24009070

Robertson, Steven S

2014-07-01

213

Space use by foraging Galápagos penguins during chick rearing  

Microsoft Academic Search

Between May 2004 and May 2005, we studied the horizontal and vertical movements of foraging Galápagos penguins Spheniscus mendiculus during their breeding season to examine space use at sea and to compare the volume of water exploited by this penguin to those of other penguin species. A total of 23 adult penguins (11 males and 12 females) brooding chicks were

Antje Steinfurth; F. Hernan Vargas; Rory P. Wilson; Michael Spindler; David W. Macdonald

2008-01-01

214

Genetic dissection of honeybee (Apis mellifera L.) foraging behavior.  

PubMed

We demonstrate the effects of a new quantitative trait locus (QTL), designated pln3, that was mapped in a backcross population derived from strains of bees selected for the amount of pollen they store in combs. We independently confirmed pln3 by demonstrating its effects on individual foraging behavior, as we did previously for QTLs pln1 and pln2 (Hunt et al. 1995). QTL pln2 is very robust in its effects on foraging behavior. In this study, pln2 was again shown to affect individual foraging behavior of workers derived from a hybrid backcross of the selected strains. In addition, pln2 was shown to affect the amount of pollen stored in combs of colonies derived from a wide cross of European and Africanized honeybees. This is noteworthy because it demonstrates that we can map QTLs for behavior in interstrain crosses derived from selective breeding and study their effects in unselected, natural populations. The results we present also demonstrate the repeatability of finding QTLs with measurable effects, even after outcrossing selected strains, suggesting that there is a relatively small subset of QTLs with major effects segregating in the population from which we selected our founding breeding populations. The different QTLs, pln1, pln2, and pln3, appear to have different effects, revealing the complex genetic architecture of honeybee foraging behavior. PMID:11218085

Page, R E; Fondrk, M K; Hunt, G J; Guzmán-Novoa, E; Humphries, M A; Nguyen, K; Greene, A S

2000-01-01

215

Foraging success of biological Lévy flights recorded in situ.  

PubMed

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

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

2012-05-01

216

Foraging by bats in cleared, thinned and unharvested boreal forest  

Microsoft Academic Search

Summary 1. Modern silvicultural methods employ various styles of selective harvesting in addi- tion to traditional clear-cutting. This can create a mosaic of patches with different tree densities that may influence habitat use by foraging bats. Use of forest patches may also vary among bat species due to variation in their manoeuvrability. Apart from studies investigating use of clear-cuts, few

Krista J. Patriquin; Robert M. R. Barclay

2003-01-01

217

ADAPTING TROPICAL FORAGES TO LOW-FERTILITY SOILS  

Microsoft Academic Search

Tropical forages growing in low-fertility acid soils usually increase the amount of dry matter partitioned to roots at the expense of shoot growth, but substantially different adaptive attributes to such soils have been found, both between and within species. By possessing the C 4 pathway of photosynthesis, grasses are more efficient than legumes in using N, Ca, and P, whereas

I. M. Rao

218

Potential energetic effects of mountain climbers on foraging grizzly bears  

USGS Publications Warehouse

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.

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

1999-01-01

219

Optimal foraging theory: a possible role for parasites  

Microsoft Academic Search

Summary. - The role of parasitism has, to date, been largely ignored in optimal foraging theory. The mechanisms necessary to allow animals to use their diet to protect themselves from potential or actual parasitism have been observed in various species. The inclusion of the effects of parasitism on diet choice may considerably improve the predictive powers of future opti- mal

George A. Lozano

220

Optimal management of MicroGrid using Bacterial Foraging Algorithm  

Microsoft Academic Search

This paper focused on optimal operating strategy and cost optimization scheme for a MicroGrid by using Bacterial Foraging Algorithm. Prior to the optimization of the microgrid itself, the system model components from some real manufactural data are constructed. The proposed cost function takes into consideration the costs of the emissions NOx, SO2, and CO2 as well as the operation and

R. Noroozian; H. Vahedi

2010-01-01

221

Cervid forage utilization in noncommercially thinned ponderosa pine forests  

USGS Publications Warehouse

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.

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

2004-01-01

222

Adaptive L?vy Walks in Foraging Fallow Deer  

PubMed Central

Background Lévy flights are random walks, the step lengths of which come from probability distributions with heavy power-law tails, such that clusters of short steps are connected by rare long steps. Lévy walks maximise search efficiency of mobile foragers. Recently, several studies raised some concerns about the reliability of the statistical analysis used in previous analyses. Further, it is unclear whether Lévy walks represent adaptive strategies or emergent properties determined by the interaction between foragers and resource distribution. Thus two fundamental questions still need to be addressed: the presence of Lévy walks in the wild and whether or not they represent a form of adaptive behaviour. Methodology/Principal Findings We studied 235 paths of solitary and clustered (i.e. foraging in group) fallow deer (Dama dama), exploiting the same pasture. We used maximum likelihood estimation for discriminating between a power-tailed distribution and the exponential alternative and rank/frequency plots to discriminate between Lévy walks and composite Brownian walks. We showed that solitary deer perform Lévy searches, while clustered animals did not adopt that strategy. Conclusion/Significance Our demonstration of the presence of Lévy walks is, at our knowledge, the first available which adopts up-to-date statistical methodologies in a terrestrial mammal. Comparing solitary and clustered deer, we concluded that the Lévy walks of solitary deer represent an adaptation maximising encounter rates with forage resources and not an epiphenomenon induced by a peculiar food distribution.

Focardi, Stefano; Montanaro, Paolo; Pecchioli, Elena

2009-01-01

223

In Vitro Digestion Rate of Forage Cell Wall Components  

Microsoft Academic Search

Linearity of the semilog plots of remain- ing digestible fiber on time and their corre- lations (r = .98 approximately) indicated first order digestion kinetics for each of the six forages even though composition and observed rates of fiber digestion were markedly different. Immature rye cell walls digested fastest (27.03 ± .81%\\/ hour, r 2 -- .999) and mature timothy

L. W. Smith; H. K. Goering; D. R. Waldo; C. H. Gordon

1971-01-01

224

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...

225

Sampling requirements for forage quality characterization of rectangular hay bales  

SciTech Connect

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.

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

2000-02-01

226

Nutrient compensatory foraging in a free-living social insect.  

PubMed

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. PMID:20689904

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

2010-10-01

227

Use of biosolids to enhance rangeland forage quality.  

PubMed

Biosolids land application was demonstrated to be a potentially cost-effective means for restoring forage productivity and enhancing soil-moisture-holding capacity on disturbed rangelands. By land-applying aerobically digested, anaerobically digested, composted, and lime-stabilized biosolids on rangeland test plots at rates of up to 20 times (20X) the estimated nitrogen-based agronomic rate, forage yields were found to increase from 132.8 kg/ha (118.2 lb/ac) (control plots) to 1182.3 kg/ha (1052.8 lb/ac). Despite the environmental benefits associated with increased forage yield (e.g., reduced soil erosion, improved drainage, and enhanced terrestrial carbon sequestration), the type of forage generated both before and after biosolids land application was found to be dominated by invasive weeds, all of which were characterized as having fair to poor nutritional value. Opportunistic and shallow rooting invasive weeds not only have marginal nutritional value, they also limit the establishment of native perennial grasses and thus biodiversity. Many of the identified invasive species (e.g., Cheatgrass) mature early, a characteristic that significantly increases the fuel loads that support the increased frequency and extent of western wildfires. PMID:20480767

McFarland, Michael J; Vasquez, Issaak Romero; Vutran, MaiAnh; Schmitz, Mark; Brobst, Robert B

2010-05-01

228

Mineral contents and their interrelationships in soil–forage system along a transhumant route of nomadic pastoralists in Southern Nigeria  

Microsoft Academic Search

A study was undertaken to determine the mineral status of selected soils and forage along a transhumant route of nomadic pastoralists in the derived savanna of Southern Nigeria. The interrelationships among nutrients in the soil–forage system were also determined. Thus, soil and forage samples were collected along the route at the same time. The forage sampled were Centrosema pubsescens and

A. U. Omoregie; A. A. Oshineye

2002-01-01

229

Foraging strategy quick response to temperature of Messor barbarus (Hymenoptera: Formicidae) in Mediterranean environments.  

PubMed

Animals principally forage to try to maximize energy intake per unit of feeding time, developing different foraging strategies. Temperature effects on foraging have been observed in diverse ant species; these effects are limited to the duration of foraging or the number of foragers involved. The harvester ant Messor barbarus L. 1767 has a specialized foraging strategy that consists in the formation of worker trails. Because of the high permeability of their body integument, we presume that the length, shape, and type of foraging trails of M. barbarus must be affected by temperature conditions. From mid-June to mid-August 1999, we tested the effect on these trail characteristics in a Mediterranean forest. We found that thermal stress force ants to use a foraging pattern based on the variation of the workers trail structure. Ants exploit earlier well-known sources using long physical trails, but as temperatures increases throughout the morning, foragers reduce the length of the foraging column gradually, looking for alternative food sources in nonphysical trails. This study shows that animal forage can be highly adaptable and versatile in environments with high daily variations. PMID:18801249

Doblas-Miranda, Enrique; Reyes-López, Joaquín

2008-08-01

230

Valuation of pollinator forage services provided by Eucalyptus cladocalyx.  

PubMed

We assess the monetary value of forage provisioning services for honeybees as provided by an alien tree species in the Western Cape province of South Africa. Although Eucalyptus cladocalyx is not an officially declared invader, it is cleared on a regular basis along with other invasive Eucalyptus species such as Eucalyptus camaldulensis, and Eucalyptus conferruminata (which have been prioritised for eradication in South Africa). We present some of the trade-offs associated with the clearing of E. cladocalyx by means of a practical example that illustrates a situation where the benefits of the species to certain stakeholders could support the containment of the species in demarcated areas, while allowing clearing outside such areas. Given the absence of market prices for such forage provisioning services, the replacement cost is used to present the value of the loss in forage as provided by E. cladocalyx if the alien tree species is cleared along with invasive alien tree species. Two replacement scenarios formed the basis for our calculations. The first scenario was an artificial diet as replacement for the forage provisioning service, which yielded a direct cost estimate of US$7.5 m per year. The second was based on a Fynbos cultivation/restoration initiative aimed at substituting the forage provisioning service of E. cladocalyx, which yielded a direct cost of US$20.2 m per year. These figures provide estimates of the potential additional cost burden on the beekeeping industry if E. cladocalyx is completely eradicated from the Western Cape. The cost estimates should be balanced against the negative impacts of E. cladocalyx on ecosystem services in order to make an informed decision with regard to appropriate management strategies for this species. The findings therefore serve as useful inputs to balance trade-offs for alien species that are considered as beneficial to some, but harmful to other. PMID:23629013

de Lange, Willem J; Veldtman, Ruan; Allsopp, Mike H

2013-08-15

231

Foraging Fidelity as a Recipe for a Long Life: Foraging Strategy and Longevity in Male Southern Elephant Seals  

PubMed Central

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 () 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.

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

2012-01-01

232

Look before you leap: is risk of injury a foraging cost?  

PubMed

Theory states that an optimal forager should exploit a patch so long as its harvest rate of resources from the patch exceeds its energetic, predation, and missed opportunity costs for foraging. However, for many foragers, predation is not the only source of danger they face while foraging. Foragers also face the risk of injuring themselves. To test whether risk of injury gives rise to a foraging cost, we offered red foxes pairs of depletable resource patches in which they experienced diminishing returns. The resource patches were identical in all respects, save for the risk of injury. In response, the foxes exploited the safe patches more intensively. They foraged for a longer time and also removed more food (i.e., had lower giving up densities) in the safe patches compared to the risky patches. Although they never sustained injury, video footage revealed that the foxes used greater care while foraging from the risky patches and removed food at a slower rate. Furthermore, an increase in their hunger state led foxes to allocate more time to foraging from the risky patches, thereby exposing themselves to higher risks. Our results suggest that foxes treat risk of injury as a foraging cost and use time allocation and daring-the willingness to risk injury-as tools for managing their risk of injury while foraging. This is the first study, to our knowledge, which explicitly tests and shows that risk of injury is indeed a foraging cost. While nearly all foragers may face an injury cost of foraging, we suggest that this cost will be largest and most important for predators. PMID:19779627

Berger-Tal, Oded; Mukherjee, Shomen; Kotler, Burt P; Brown, Joel S

2009-10-01

233

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

PubMed Central

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.

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

2014-01-01

234

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

PubMed Central

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.

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

2013-01-01

235

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

PubMed

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

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

2014-07-01

236

Effects of Selection for Honey Bee Worker Reproduction on Foraging Traits  

PubMed Central

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.

Oldroyd, Benjamin P; Beekman, Madeleine

2008-01-01

237

GPS tracking devices reveal foraging strategies of black-legged kittiwakes  

USGS Publications Warehouse

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.

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

2010-01-01

238

Persistence, reticence and the management of multiple time memories by forager honey bees.  

PubMed

Honey bee foragers form time memories that enable them to match their foraging activity to the time of day when a particular food source is most productive. Persistent foragers show food-anticipatory activity by making reconnaissance flights to the previously productive food source and may continue to inspect it for several days. In contrast, reticent foragers do not investigate the source but wait for confirmation from returning persistent foragers. To determine how persistent and reticent foragers might contribute to the colony's ability to rapidly reallocate foragers among sources, we trained foragers to collect sucrose from a feeder at a restricted time of day for several days and then observed their behavior for three consecutive days during which the feeder was empty. In two separate trials, video monitoring of the hive entrance during unrewarded test days in parallel with observing reconnaissance visits to the feeder revealed a high level of activity, in both persistent and reticent foragers, thought to be directed at other food sources. This 'extracurricular' activity showed a high degree of temporal overlap with reconnaissance visits to the feeder. In some cases, inspection flights to the unrewarded feeder were made within the same trip to an extracurricular source, indicating that honey bees have the ability to manage at least two different time memories despite coincidence with respect to time of day. The results have major implications for understanding flower fidelity throughout the day, flower constancy within individual foraging excursions, and the sophisticated cognitive management of spatiotemporal memories in honey bees. PMID:23197093

Wagner, Ashley E; Van Nest, Byron N; Hobbs, Caddy N; Moore, Darrell

2013-04-01

239

Foraging errors play a role in resource exploration by bumble bees (Bombus terrrestris).  

PubMed

If the cognitive performance of animals reflects their particular ecological requirements, how can we explain appreciable variation in learning ability amongst closely related individuals (e.g. foraging workers within a bumble bee colony)? One possibility is that apparent 'errors' in a learning task actually represent an alternative foraging strategy. In this study we investigate the potential relationship between foraging 'errors' and foraging success among bumble bee (Bombus terrestris) workers. Individual foragers were trained to choose yellow, rewarded flowers and ignore blue, unrewarded flowers. We recorded the number of errors (visits to unrewarded flowers) each bee made during training, then tested them to determine how quickly they discovered a more profitable food source (either familiar blue flowers, or novel green flowers). We found that error prone bees discovered the novel food source significantly faster than accurate bees. Furthermore, we demonstrate that the time taken to discover the novel, more profitable, food source is positively correlated with foraging success. These results suggest that foraging errors are part of an 'exploration' foraging strategy, which could be advantageous in changeable foraging environments. This could explain the observed variation in learning performance amongst foragers within social insect colonies. PMID:24838937

Evans, Lisa J; Raine, Nigel E

2014-06-01

240

Foraging location and site fidelity of the Double-crested Cormorant on Oneida Lake, New York  

USGS Publications Warehouse

We studied the foraging behavior of the Double-crested Cormorant (Phalacrocorax auritus) on Oneida Lake, New York, by monitoring the activities of 27 radio-tagged birds in July and August of 1999 and 2000. A total of 224 locations were obtained of cormorants actively diving, and presumed foraging, at the time of detection. A geographic information system was used to examine foraging distances from the nesting island, the water depth and type of substrate at preferred foraging sites, and to estimate kernel home ranges for analysis of individual foraging site fidelity. An explanatory model was developed to determine parameters affecting the distance to cormorant foraging sites. The mean distance to foraging locations of tagged cormorants from the colony site was 2,920 m (SE ?? 180 m, max = 14,190 m), and 52% of the locations were within 2,000 m of the nesting island. No cormorant was observed making daily foraging trips to outside water bodies. Mean foraging distance was greater during morning than in the afternoon, and there was a significant effect of the time of day on distance. There was no significant effect of sex date, a seasonal measure on distance to foraging location. Individual cormorants exhibited fidelity to specific foraging sites. Most cormorants foraged in close proximity to the nesting island much of the time, while those detected further from the island tended to return repeatedly to the same locations. Ninety percent of the foraging locations were in water depths ???7.5 m, and most were in water 2.5-5 m deep. Compositional analysis of habitat use revealed a preference for these depths, along with substrates of cobble with rubble, and silt with clay.

Coleman, J. T. H.; Richmond, M. E.; Rudstam, L. G.; Mattison, P. M.

2005-01-01

241

A molecular phylogeny of Dorylus army ants provides evidence for multiple evolutionary transitions in foraging niche  

PubMed Central

Background Army ants are the prime arthropod predators in tropical forests, with huge colonies and an evolutionary derived nomadic life style. Five of the six recognized subgenera of Old World Dorylus army ants forage in the soil, whereas some species of the sixth subgenus (Anomma) forage in the leaf-litter and some as conspicuous swarm raiders on the forest floor and in the lower vegetation (the infamous driver ants). Here we use a combination of nuclear and mitochondrial DNA sequences to reconstruct the phylogeny of the Dorylus s.l. army ants and to infer the evolutionary transitions in foraging niche and associated morphological adaptations. Results Underground foraging is basal and gave rise to leaf-litter foraging. Leaf-litter foraging in turn gave rise to two derived conditions: true surface foraging (the driver ants) and a reversal to subterranean foraging (a clade with most of the extant Dorylus s.s. species). This means that neither the subgenus Anomma nor Dorylus s.s. is monophyletic, and that one of the Dorylus s.s. lineages adopted subterranean foraging secondarily. We show that this latter group evolved a series of morphological adaptations to underground foraging that are remarkably convergent to the basal state. Conclusion The evolutionary transitions in foraging niche were more complex than previously thought, but our comparative analysis of worker morphology lends strong support to the contention that particular foraging niches have selected for very specific worker morphologies. The surprising reversal to underground foraging is therefore a striking example of convergent morphological evolution.

Kronauer, Daniel JC; Schoning, Caspar; Vilhelmsen, Lars B; Boomsma, Jacobus J

2007-01-01

242

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

PubMed Central

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.

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

2013-01-01

243

Long-Term Habitat Use by Mountain Gorillas ( Gorilla gorilla beringei ). 2. Reuse of Foraging Areas in Relation to Resource Abundance, Quality, and Depletion  

Microsoft Academic Search

Resource depression caused by current feeding and the rate of resource renewal should influence foragers' decisions about when to revisit foraging areas. Adjustment of foraging paths and revisit rates should be particularly important when resources renew slowly. Foragers can also benefit by returning more often to highly profitable than to less profitable foraging areas. Many highly frugivorous primates seem to

David P. Watts

1998-01-01

244

Responses of late-lactation cows to forage substitutes in low-forage diets supplemented with by-products.  

PubMed

In response to drought-induced forage shortages along with increased corn and soy prices, this study was conducted to evaluate lactation responses of dairy cows to lower-forage diets supplemented with forage substitutes. By-product feeds were used to completely replace corn grain and soybean feeds. Forty-eight late-lactation cows were assigned to 1 of 4 diets using a randomized complete block design with a 2-wk covariate period followed by a 4-wk experimental period. The covariate diet contained corn grain, soybean meal, and 61% forage. Experimental diets contained chopped wheat straw (WS)/sugar beet pulp at 0/12, 3/9, 6/6, or 9/3 percentages of diet dry matter (DM). Corn silage (20%), alfalfa silage (20%), pelleted corn gluten feed (25.5%), distillers grains (8%), whole cottonseed (5%), cane molasses/whey blend (7%), and vitamin and mineral mix with monensin (2.5%) comprised the rest of diet DM. The WS/sugar beet pulp diets averaged 16.5% crude protein, 35% neutral detergent fiber, and 11% starch (DM basis). Cows consuming the experimental diets maintained a 3.5% fat- and protein-corrected milk production (35.2kg; standard deviation=5.6kg) that was numerically similar to that measured in the covariate period (35.3kg; standard deviation=5.0kg). Intakes of DM and crude protein declined linearly as WS increased, whereas neutral detergent fiber intake increased linearly. Linear increases in time spent ruminating (from 409 to 502min/d) and eating (from 156 to 223min/d) were noted as WS inclusion increased. Yields of milk fat and 3.5% fat-and protein-corrected milk did not change as WS increased, but those of protein and lactose declined linearly. Phosphorous intakes were in excess of recommended levels and decreased linearly with increasing WS inclusion. Nutritional model predictions for multiparous cows were closest to actual performance for the National Research Council 2001 model when a metabolizable protein basis was used; primiparous cow performance was better predicted by energy-based predictions made with the National Research Council or Cornell Net Carbohydrate and Protein System models. Model predictions of performance showed a quadratic diet effect with increasing WS. Lactating dairy cows maintained production on low-forage diets that included forage substitutes, and in which by-product feeds fully replaced corn grain and soybean. However, longer-term studies are needed to evaluate animal performance and to improve model predictions of performance on these nontraditional diets. PMID:24612800

Hall, M B; Chase, L E

2014-05-01

245

Foraging costs drive female resistance to a sensory trap  

PubMed Central

Male ornaments can evolve through the exploitation of female perceptual biases such as those involved in responding to cues from food. This type of sensory exploitation may lead to confusion between the male signals and the cues that females use to find/recognize food. Such interference would be costly to females and may be one reason why females evolve resistance to the male ornaments. Using a group of species of viviparous fish where resistance to a sensory trap has evolved, we demonstrate that females exposed to an ornament that resembles food have a diminished foraging efficiency, that this effect is apparent when foraging on a food item with which the ornament shares visual attributes, and that not all species are equally affected by such confusion. Our results lend support to the model of ornamental evolution through chase-away sexual conflict.

Garcia, Constantino Macias; Lemus, Yolitzi Saldivar

2012-01-01

246

Protecting rain forests and forager's rights using LANDSAT imagery  

NASA Technical Reports Server (NTRS)

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.

Wilkie, David S.

1991-01-01

247

Prefrontal-parietal function: from foraging to foresight.  

PubMed

Comparative neuroanatomy shows that new prefrontal areas emerged during the evolution of anthropoid primates to augment prefrontal, parietal, and temporal areas that had evolved in earlier primates. We recently proposed that the new anthropoid areas reduce foraging errors by generating goals from current contexts and learning to do so rapidly, sometimes based on single events. Among the contexts used to generate these goals, the posterior parietal cortex provides the new prefrontal areas with information about relational metrics such as order, number, duration, length, distance and proportion, which play a crucial role in foraging choices. Here we propose that this specialized network later became adapted to support the human capacity for reasoning and general problem-solving. PMID:24378542

Genovesio, Aldo; Wise, Steven P; Passingham, Richard E

2014-02-01

248

Emerging technologies advancing forage and turf grass genomics.  

PubMed

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

Kopecký, David; Studer, Bruno

2014-01-01

249

Extrafloral nectar content alters foraging preferences of a predatory ant.  

PubMed

We tested whether the carbohydrate and amino acid content of extrafloral nectar affected prey choice by a predatory ant. Fire ants, Solenopsis invicta, were provided with artificial nectar that varied in the presence of carbohydrates and amino acids and were then provided with two prey items that differed in nutritional content, female and male crickets. Colonies of fire ants provided with carbohydrate supplements consumed less of the female crickets and frequently did not consume the high-lipid ovaries of female crickets. Colonies of fire ants provided with amino acid supplements consumed less of the male crickets. While a number of studies have shown that the presence of extrafloral nectar or honeydew can affect ant foraging activity, these results suggest that the nutritional composition of extrafloral nectar is also important and can affect subsequent prey choice by predatory ants. Our results suggest that, by altering the composition of extrafloral nectar, plants could manipulate the prey preferences of ants foraging on them. PMID:19864270

Wilder, Shawn M; Eubanks, Micky D

2010-04-23

250

Chemical compounds of the foraging recruitment pheromone in bumblebees  

NASA Astrophysics Data System (ADS)

When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees.

Granero, Angeles Mena; Sanz, José M. Guerra; Gonzalez, Francisco J. Egea; Vidal, José L. Martinez; Dornhaus, Anna; Ghani, Junaid; Serrano, Ana Roldán; Chittka, Lars

2005-08-01

251

PCNN document segmentation method based on bacterial foraging optimization algorithm  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

252

Extrafloral nectar content alters foraging preferences of a predatory ant  

PubMed Central

We tested whether the carbohydrate and amino acid content of extrafloral nectar affected prey choice by a predatory ant. Fire ants, Solenopsis invicta, were provided with artificial nectar that varied in the presence of carbohydrates and amino acids and were then provided with two prey items that differed in nutritional content, female and male crickets. Colonies of fire ants provided with carbohydrate supplements consumed less of the female crickets and frequently did not consume the high-lipid ovaries of female crickets. Colonies of fire ants provided with amino acid supplements consumed less of the male crickets. While a number of studies have shown that the presence of extrafloral nectar or honeydew can affect ant foraging activity, these results suggest that the nutritional composition of extrafloral nectar is also important and can affect subsequent prey choice by predatory ants. Our results suggest that, by altering the composition of extrafloral nectar, plants could manipulate the prey preferences of ants foraging on them.

Wilder, Shawn M.; Eubanks, Micky D.

2010-01-01

253

Activity Time Budget during Foraging Trips of Emperor Penguins  

PubMed Central

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.

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

2012-01-01

254

Methane Production of Different Forages in In vitro Ruminal Fermentation  

PubMed Central

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.

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

2012-01-01

255

Foraging of Scavenging Deep-Sea Lysianassoid Amphipods  

Microsoft Academic Search

\\u000a Literature on the biology and ecology of bait-attending, deep-sea lysianassoid amphipods was critically reviewed to assess\\u000a our current understanding of their foraging. Olfaction, possibly combined with a rheotactic swimming behavior, is probably\\u000a the principal means of detection and localization of bait, but alternative or complementary means have been proposed (territorial\\u000a collapse, mechanoreception of bait impact on bottom or of sounds

B. Sainte-Marie

256

Bee foraging in uncertain environments using predictive hebbian learning  

Microsoft Academic Search

RECENT work has identified a neuron with widespread projections to odour processing regions of the honeybee brain whose activity represents the reward value of gustatory stimuli1,2. We have constructed a model of bee foraging in uncertain environments based on this type of neuron and a predictive form of hebbian synaptic plasticity. The model uses visual input from a simulated three-dimensional

P. Read Montague; Peter Dayan; Christophe Person; Terrence J. Sejnowski

1995-01-01

257

Fine-Scale Variability in Harbor Seal Foraging Behavior  

PubMed Central

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.

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

2014-01-01

258

Genetic Variability for Mineral Element Concentration of Crested Wheatgrass Forage  

Microsoft Academic Search

ABSTRACT Grass tetany is a complex,metabolic disorder that causes sub- stantial livestock production losses and deaths in temperate regions of the world. It is caused by low levels of Mg or an imbalance of K, Ca, and Mg in forage consumed by animals. Development of grasses with improved,mineral balance would be an economical,means of minimizing,losses from this malady. This study

K. P. Vogel; H. F. Mayland; P. E. Reece; J. F. S. Lamb

1989-01-01

259

Polymodal foraging in adult female loggerheads ( Caretta caretta )  

Microsoft Academic Search

To determine whether loggerhead turtles (Caretta caretta) nesting in southeastern USA exhibit polymorphic foraging strategies, we evaluated skin samples for stable isotopes of carbon\\u000a (?13C) and nitrogen (?15N) from 310 loggerheads from four locations on the east coast of Florida and epibionts from 48 loggerheads. We found a dichotomy\\u000a between a depleted ?13C cluster and an enriched ?13C cluster. Epibionts

Kimberly J. Reich; Karen A. Bjorndal; Michael G. Frick; Blair E. Witherington; Chris Johnson; Alan B. Bolten

2010-01-01

260

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

PubMed

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

Batova, O N

2011-01-01

261

Lévy Flights in Dobe Ju\\/’hoansi Foraging Patterns  

Microsoft Academic Search

We analyzed data on Ju\\/’hoansi hunter–gatherer foraging patterns and found that their movements between residence camps can\\u000a be modeled as a Lvy flight. The step lengths of their movements scale as a power law with an exponent ??=?1.97. Their wait times (residence times) at the camps also scale as a power law (??=?1.45). A Lvy flight with step lengths ??=?2

Clifford T. Brown; Larry S. Liebovitch; Rachel Glendon

2007-01-01

262

Q-learning policies for a single agent foraging tasks  

Microsoft Academic Search

Policies play an important role in balancing the trade-off between exploration and exploitation problem in q-learning. Pure exploration degrades the performance of the q-learning but increases the flexibility to adapt in a dynamic environment. On the other hand pure exploitation drives the learning process to locally optimal solutions. In this paper, a single agent foraging task has been modeled incorporating

Yogeswaran Mohan; S. G. Ponnambalam

2010-01-01

263

Communal roosting and foraging behavior of staging sandhill cranes  

USGS Publications Warehouse

Each spring more than 300,000 Sandhill Cranes (Grus canadensis) roost communally at night in river channels in the Platte River Valley of Nebraska and disperse at dawn to forage in agricultural fields. Cranes with central roosts had activity ranges double the size of those with peripheral roosts; 42% of the birds changed activity ranges prior to the onset of migration. Minimum daily flight distance generally increased during the staging period. Cranes used native grassland and planted hayland more often than expected, relative to their percentage of occurrence, and fed longest there; cornfields were underutilized. These differences probably reflect, in part, (1) limited distribution of grasslands and haylands resulting in a greater energy expenditure to acquire protein in the form of macroinvertebrates and (2) wider distribution of cornfields with adequate energyrich foods but limited protein. Cranes probably forage more efficiently and conserve energy by following conspecifics from communal roosts to local feeding grounds, by settling in fields where foraging flocks are already present, and by establishing diurnal activity centers. Alert behavior varied with flock size but not as predicted from group size, presumably because predation of staging adult cranes is inconsequential.

Sparling, D.W.; Krapu, G.L.

1994-01-01

264

Imidacloprid Alters Foraging and Decreases Bee Avoidance of Predators  

PubMed Central

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.

Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C.

2014-01-01

265

Swimming speed and foraging strategies of northern elephant seals  

NASA Astrophysics Data System (ADS)

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.

Hassrick, Jason L.; Crocker, Daniel E.; Zeno, Ramona L.; Blackwell, Susanna B.; Costa, Daniel P.; Le Boeuf, Burney J.

2007-02-01

266

Olfactory eavesdropping by a competitively foraging stingless bee, Trigona spinipes.  

PubMed Central

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.

Nieh, James C.; Barreto, Lillian S.; Contrera, Felipe A. L.; Imperatriz-Fonseca, Vera L.

2004-01-01

267

Imidacloprid alters foraging and decreases bee avoidance of predators.  

PubMed

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

Tan, Ken; Chen, Weiwen; Dong, Shihao; Liu, Xiwen; Wang, Yuchong; Nieh, James C

2014-01-01

268

Piping Plover brood foraging ecology on New York barrier islands  

USGS Publications Warehouse

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.

Elias, S.P.; Fraser, J.D.; Buckley, P.A.

2000-01-01

269

Impact of forage clipping treatments on performance of winter wheat.  

PubMed

Farmers in northern parts of Pakistan face severe shortage of green forage for their livestock during the harsh winter season. Winter wheat has the potential to be used as a dual-purpose crop for forage plus grain production in these areas. Ten elite winter wheat lines from Oklahoma State University were evaluated at Hazara Research Station Abbottabad under unclipped and clipped treatment level during 2005-06. The material was planted in a randomized complete block design with three replications, with a row length of four meters and a row to row space of 25 cm. Data were recorded on green forage yield, plant height, spike length, spikelets/spike, days to maturity, spike weight, biological weight, and grain yield. Analysis of variance indicated significant differences among genotypes for all traits except spike length. Similarly all traits except spikelets/spike exhibited significant differences between unclipped and clipped treatment levels. Genotype x clipping interaction was non-significant for all traits except grain yield. Overall, winter wheat lines OK98G508W and OK00611W performed better for important traits such as early maturity, biological yield and grain yield, although over-environment testing is needed before recommendations can be made to the farmers. PMID:24301789

Jadoon, S A; Ullah, H; Mohammad, F; Khalil, I H; Alam, M; Shahwar, D; Malik, M F A; Jamal, Y

2013-01-01

270

COMMUNICATION: Stochastic resonance and the evolution of Daphnia foraging strategy  

NASA Astrophysics Data System (ADS)

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.

Dees, Nathan D.; Bahar, Sonya; Moss, Frank

2008-12-01

271

The impact of giant panda foraging on bamboo dynamics in an isolated environment  

Microsoft Academic Search

Wildlife species are threatened by massive habitat destruction worldwide. Habitat fragmentation and isolation spatially constrain\\u000a animals and in turn cause non-sustainable rates of animal foraging on plant populations. However, little empirical research\\u000a has been done in large controlled settings to investigate foraging impacts. We conducted an experiment to characterize the\\u000a impact of panda foraging on the sustainability of its food

Vanessa Hull; Ashton Shortridge; Bin Liu; Scott Bearer; Xiaoping Zhou; Jinyan Huang; Shiqiang Zhou; Hemin Zhang; Zhiyun Ouyang; Jianguo Liu

2011-01-01

272

Social foraging in stingless bees: how colonies of Melipona fasciata choose among nectar sources  

Microsoft Academic Search

In an experimental set-up, a colony of the stingless bee Melipona fasciata demonstrated its ability to choose the better of two nectar sources. This colony pattern was a result of the following individual\\u000a behavioural decisions: continue foraging, abandon the feeder, restart foraging and initiate foraging. Only very rarely did\\u000a individuals switch from one feeder to the other. With the first

Jacobus C. Biesmeijer; Marcel C. W. Ermers

1999-01-01

273

State-determinate foraging decisions and web architecture in the spider Dictyna volucripes (Araneae Dictynidae)  

Microsoft Academic Search

Foraging behaviors result from dynamic trade-offs made by organisms, incorporating factors such as past foraging success, reproductive effort, and predation risk. But, decision-making by animals occurs with incomplete information about the environment. We examined the relationship of web architecture and foraging decisions in the tangle web-building spider Dictyna volucripes Keyserling, a common spider in North American fields. Tangle webs are

T. A. Blackledge; J. W. Wenzel

2001-01-01

274

Spatial working memory for clustered and linear configurations of sites in a virtual reality foraging task.  

PubMed

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

De Lillo, Carlo; James, Frances C

2012-08-01

275

Quality-related characteristics of forages as influenced by plant environment and agronomic factors  

Microsoft Academic Search

The most important factor influencing forage quality is herbage maturity. For example, a 1-week delay in harvesting of alfalfa (Medicago sativa L.) will decrease digestibility and crude protein concentration by about 20 g kg?1 and increase cell-wall concentration by approximately 30 g kg?1. Forage quality also is influenced by the environment in which forages are grown and by soil fertility

Dwayne R. Buxton

1996-01-01

276

Colony nutritional status modulates worker responses to foraging recruitment pheromone in the bumblebee Bombus terrestris  

Microsoft Academic Search

Foraging activity in social insects should be regulated by colony nutritional status and food availability, such that both\\u000a the emission of, and response to, recruitment signals depend on current conditions. Using fully automatic radio-frequency\\u000a identification (RFID) technology to follow the foraging activity of tagged bumblebees (Bombus terrestris) during 16,000 foraging bouts, we tested whether the cue provided by stored food

Mathieu Molet; Lars Chittka; Ralph J. Stelzer; Sebastian Streit; Nigel E. Raine

2008-01-01

277

PERENNIAL FORAGE KOCHIA FOR IMPROVED PRODUCTIVITY OF GRASS DOMINATED WINTER GRAZING PASTURES  

Microsoft Academic Search

3 USDA-ARS Forage and Range Research Lab, Logan, Utah 84322 4 USDA-NRCS, 185 N. Main, Tooele, Utah 84074 ABSTRACT: Grazing forage kochia (Kochia prostrata) during fall\\/winter has been shown to improve livestock health and reduce winter feeding costs. The objectives of this study were to compare the differences of traditional winter pastures versus pastures with forage kochia. Fifty mature, pregnant,

L. K. Greenhalgh; K. C. Olson; D. R. ZoBell; B. L. Waldron; A. R. Moulton; B. W. Davenport

278

Reward rate and forager activation in honeybees: recruiting mechanisms and temporal distribution of arrivals  

Microsoft Academic Search

We analyzed the foraging and recruitment activity of single foragers ( Apis mellifera), exploiting low reward rates of sucrose solution. Single employed foragers (test bees) were allowed to collect 2.0 m sucrose solution delivered by a rate-feeder located at 160 m from the hive for 2 h. Flow rates varied between 1.4 and 5.5 µl\\/min. The individual behavior of the test bees was registered

P. C. Fernández; M. Gil; W. M. Farina

2003-01-01

279

Loggerhead turtles (Caretta caretta) use vision to forage on gelatinous prey in mid-water.  

PubMed

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

Narazaki, Tomoko; Sato, Katsufumi; Abernathy, Kyler J; Marshall, Greg J; Miyazaki, Nobuyuki

2013-01-01

280

Characterizing Variation of Isotopic Markers in Northern Alaskan Caribou Forages  

NASA Astrophysics Data System (ADS)

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.

VanSomeren, L.; Barboza, P. S.; Gustine, D. D.; Parrett, L. S.; Stricker, C. A.

2013-12-01

281

Mercury bioaccumulation and risk to three waterbird foraging guilds is influenced by foraging ecology and breeding stage  

USGS Publications Warehouse

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.

Eagles-Smith, C. A.; Ackerman, J. T.; De La, Cruz, S. E. W.; Takekawa, J. Y.

2009-01-01

282

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

USGS Publications Warehouse

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.

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

1998-01-01

283

The Dynamics of Foraging Trails in the Tropical Arboreal Ant Cephalotes goniodontus  

PubMed Central

The foraging behavior of the arboreal turtle ant, Cephalotes goniodontus, was studied in the tropical dry forest of western Mexico. The ants collected mostly plant-derived food, including nectar and fluids collected from the edges of wounds on leaves, as well as caterpillar frass and lichen. Foraging trails are on small pieces of ephemeral vegetation, and persist in exactly the same place for 4–8 days, indicating that food sources may be used until they are depleted. The species is polydomous, occupying many nests which are abandoned cavities or ends of broken branches in dead wood. Foraging trails extend from trees with nests to trees with food sources. Observations of marked individuals show that each trail is travelled by a distinct group of foragers. This makes the entire foraging circuit more resilient if a path becomes impassable, since foraging in one trail can continue while a different group of ants forms a new trail. The colony’s trails move around the forest from month to month; from one year to the next, only one colony out of five was found in the same location. There is continual searching in the vicinity of trails: ants recruited to bait within 3 bifurcations of a main foraging trail within 4 hours. When bait was offered on one trail, to which ants recruited, foraging activity increased on a different trail, with no bait, connected to the same nest. This suggests that the allocation of foragers to different trails is regulated by interactions at the nest.

Gordon, Deborah M.

2012-01-01

284

Forage selection by Royle's pika (Ochotona roylei) in the western Himalaya, India.  

PubMed

Forage selection decisions of herbivores are often complex and dynamic; they are modulated by multiple cues, such as quality, accessibility and abundance of forage plants. To advance the understanding of plant-herbivore interactions, we explored foraging behavior of the alpine lagomorph Royle's pika (Ochotona roylei) in Kedarnath Wildlife Sanctuary, India. Pika bite counts on food plants were recorded through focal sampling in three permanently marked plots. Food plant abundance was recorded by traditional quadrat procedures; forage selection was estimated with Jacob's selection index. Multiple food-choice experiments were conducted to determine whether forage selection criteria would change with variation in food plant composition. We also analyzed leaf morphology and nutrient content in both major food plants and abundantly available non-food plants. Linear regression models were used to test competing hypotheses in order to identify factors governing forage selection. Royle's pika fed primarily on 17 plant species and each forage selection decision was positively modulated by leaf area and negatively modulated by contents of avoided substances (neutral detergent fiber, acid detergent fiber, acid detergent lignin and tannin) in food plants. Furthermore, significance of the interaction term "leaf size × avoided substance" indicates that plants with large leaves were selected only when they had low avoided substance content. The forage selection criteria did not differ between field and laboratory experiments. The parameter estimates of best fit models indicate that the influence of leaf size or amount of avoided substance on pika forage selection was modulated by the magnitude of predation risk. PMID:23932023

Bhattacharyya, Sabuj; Adhikari, Bhupendra S; Rawat, Gopal S

2013-10-01

285

Pollen foraging: learning a complex motor skill by bumblebees (Bombus terrestris)  

NASA Astrophysics Data System (ADS)

To investigate how bumblebees (Bombus terrestris) learn the complex motor skills involved in pollen foraging, we observed naďve workers foraging on arrays of nectarless poppy flowers (Papaver rhoeas) in a greenhouse. Foraging skills were quantified by measuring the pollen load collected during each foraging bout and relating this to the number of flowers visited and bout duration on two consecutive days. The pollen standing crop (PSC) in each flower decreased drastically from 0530 to 0900 hours. Therefore, we related foraging performance to the changing levels of pollen available (per flower) and found that collection rate increased over the course of four consecutive foraging bouts (comprising between 277 and 354 individual flower visits), suggesting that learning to forage for pollen represents a substantial time investment for individual foragers. The pollen collection rate and size of pollen loads collected at the start of day 2 were markedly lower than at the end of day 1, suggesting that components of pollen foraging behaviour could be subject to imperfect overnight retention. Our results suggest that learning the necessary motor skills to collect pollen effectively from morphologically simple flowers takes three times as many visits as learning how to handle the most morphologically complex flowers to extract nectar, potentially explaining why bees are more specialised in their choice of pollen flowers.

Raine, Nigel E.; Chittka, Lars

2007-06-01

286

Simulating secondary succession of elk forage values in a managed forest landscape, western Washington  

USGS Publications Warehouse

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.

Jenkins, Kurt J.; Starkey, Edward E.

1996-01-01

287

Daily foraging pattern and proteinaceous food preferences of Solenopsis geminata (Fabricius) (Hymenoptera:Formicidae).  

PubMed

A field study on foraging activity and proteinacous food preference was performed on the tropical fire ant (Solenopsis geminata) (Fabricius) at the School of Biological Sciences and Desasiswa Bakti Permai, Universiti Sains Malaysia (USM), Penang. Foraging activity studies of 4 colonies of S. geminata were conducted in the field for 24 hours. Foraging activity significantly increased 4 hours before sunset and maximum foraging occurred at midnight until early morning. Three types of proteinacous food; anchovy, meat and egg yolk were tested among the five colonies of S. geminata in the field. The egg yolk was the most preferred food (100%) followed by meat (31%) and anchovy (15%). PMID:17322814

Norasmah, B; Abu Hassan, A; Che Salmah, M R; Nurita, A T; Nur Aida, H

2006-12-01

288

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

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.

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

2005-01-01

289

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).  

PubMed

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 degrees 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. PMID:16132417

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

2005-10-01

290

Differential regulation of the foraging gene associated with task behaviors in harvester ants  

PubMed Central

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.

2011-01-01

291

Bumblebee foraging rhythms under the midnight sun measured with radiofrequency identification  

PubMed Central

Background In the permanent daylight conditions north of the Arctic circle, there is a unique opportunity for bumblebee foragers to maximise intake, and therefore colony growth, by remaining active during the entire available 24-h period. We tested the foraging rhythms of bumblebee (Bombus terrestris and B. pascuorum) colonies in northern Finland during the summer, when the sun stays above the horizon for weeks. We used fully automatic radio-frequency identification to monitor the foraging activity of more than 1,000 workers and analysed their circadian foraging rhythms. Results Foragers did not use the available 24-h foraging period but exhibited robust diurnal rhythms instead. A mean of 95.2% of the tested B. terrestris workers showed robust diurnal rhythms with a mean period of 23.8 h. Foraging activity took place mainly between 08:00 and 23:00, with only low or almost no activity during the rest of the day. Activity levels increased steadily during the morning, reached a maximum around midday and decreased again during late afternoon and early evening. Foraging patterns of native B. pascuorum followed the same temporal organisation, with the foraging activity being restricted to the period between 06:00 and 22:00. Conclusions The results of the present study indicate that the circadian clock of the foragers must have been entrained by some external cue, the most prominent being daily cycles in light intensity and temperature. Daily fluctuations in the spectral composition of light, especially in the UV range, could also be responsible for synchronising the circadian clock of the foragers under continuous daylight conditions.

2010-01-01

292

The Importance of Predation Risk and Missed Opportunity Costs for Context-Dependent Foraging Patterns  

PubMed Central

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.

Eccard, Jana A.; Liesenjohann, Thilo

2014-01-01

293

Latitudinal Range Influences the Seasonal Variation in the Foraging Behavior of Marine Top Predators  

PubMed Central

Non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. Populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. We studied two species of resident central place foragers from temperate and equatorial regions with differing population trends and prey availability associated to season, the California sea lion (Zalophus californianus) (CSL) whose population is increasing and the endangered Galapagos sea lion (Zalophus wollebaeki) (GSL) whose population is declining. To determine their response to environmental change, we studied and compared their diving behavior using time-depth recorders and satellite location tags and their diet by measuring C and N isotope ratios during a warm and a cold season. Based on latitudinal differences in oceanographic productivity, we hypothesized that the seasonal variation in foraging behavior would differ for these two species. CSL exhibited greater seasonal variability in their foraging behavior as seen in changes to their diving behavior, foraging areas and diet between seasons. Conversely, GSL did not change their diving behavior between seasons, presenting three foraging strategies (shallow, deep and bottom divers) during both. GSL exhibited greater dive and foraging effort than CSL. We suggest that during the warm and less productive season a greater range of foraging behaviors in CSL was associated with greater competition for prey, which relaxed during the cold season when resource availability was greater. GSL foraging specialization suggests that resources are limited throughout the year due to lower primary production and lower seasonal variation in productivity compared to CSL. These latitudinal differences influence their foraging success, pup survival and population growth reflected in contrasting population trends in which CSL are more successful and potentially more resilient to climate change.

Villegas-Amtmann, Stella; Simmons, Samantha E.; Kuhn, Carey E.; Huckstadt, Luis A.; Costa, Daniel P.

2011-01-01

294

Liquid supplement and forage intake by range beef cows.  

PubMed

One hundred eighty crossbred cows were assigned to one of six native range pastures during two winters to evaluate forage and supplement intake as affected by liquid supplement (yr 1: 50% crude protein, 84% from urea; yr 2: 57% crude protein, 91% from urea) delivery method and cow age (2, 3, 4, 5, or 6 yr). Treatments were: 1) no supplement (Control); 2) a lick-wheel feeder containing liquid supplement (ADLIB); and 3) a computer-controlled lick-wheel feeder that dispensed 0.9 kg x cow(-1) x d(-1) of liquid supplement (average 0.5 kg of dry matter x cow(-1) x d(-1); Restricted). Each treatment was applied to two pastures. Forage digestibility was increased (P = 0.03) by supplementation. Supplemented cows lost less (P = 0.05) body condition than unsupplemented cows (average -0.3 vs -0.6). Blood urea nitrogen (BUN) was highest (P = 0.001) for ADLIB (8.7 mg/dL), intermediate for Restricted (6.2 mg/dL), and lowest for Control (2.3 mg/dL). Forage DMI was 31% higher (P = 0.01) in 1995 than in 1996, and was increased (P = 0.02) by supplementation both years. Cows supplemented with ADLIB consumed 23% more forage dry matter than Control cows, whereas Restricted cows consumed 21% more dry matter than ADLIB cows. Supplement intake by cows on ADLIB was greater (P = 0.001) than by cows on Restricted in both years. Supplement intake was lowest (P = 0.002) by 2-yr-old cows, intermediate by 3-yr-olds, and greatest by 4-, 5-, and 6-yr-old cows. Variation in supplement intake by individual cows was higher (P = 0.09) for cows in the Restricted treatment (coefficient of variation [CV] = 117%) than those on ADLIB (CV = 68%) during the first year, but did not differ between supplement treatments (average CV = 62%) in the second year. The proportions of cows consuming less than 0.3 kg/d of supplement dry matter intake (DMI) and consuming less than the target amount of supplement (0.5 kg DMI) were less (P = 0.001) for ADLIB than for Restricted during both years. ADLIB cows spent more (P = 0.001) time at the supplement feeder and had more (P < 0.002) supplement feeding bouts than Restricted cows during both years. During the first year, 2- and 3-yr-old cows spent less (P < 0.01) time at the feeder and had fewer feeding bouts per day than 6-yr-old cows. Age had no effect (P > 0.24) on feeding behavior during the second year. Supplementation of beef cows grazing winter range with 50 to 57% crude protein liquid supplement increased forage digestibility and intake. Restricting supplement access increased forage consumption and variability of supplement intake. PMID:12597401

Sowell, B F; Bowman, J G P; Grings, E E; MacNeil, M D

2003-01-01

295

Behavioral genomics of honeybee foraging and nest defense  

PubMed Central

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 (Am5HT7 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.

Amdam, Gro V.; Schlipalius, David; Emore, Christine; Sardesai, Nagesh; Williams, Christie E.; Rueppell, Olav; Guzman-Novoa, Ernesto; Arechavaleta-Velasco, Miguel; Chandra, Sathees; Fondrk, M. Kim; Beye, Martin; Page, Robert E.

2006-01-01

296

Behavioral genomics of honeybee foraging and nest defense  

NASA Astrophysics Data System (ADS)

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.

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

297

Foraging opportunity: a crucial criterion for horse welfare?  

PubMed

This study aimed at determining the effect of the increase of foraging opportunities on the behaviour and welfare of breeding mares housed in individual boxes but allowed outside 6 h a day in a bare paddock. One hundred Arab breeding mares were divided into two groups of 50 according to the treatment and allowed outside in two bare paddocks at the same density (115 mare/ha) where water and shelter were provided. The treatment consisted in providing the opportunity to forage on hay. Twenty-minute animal focal samplings and scan samplings were used to determine the time budget of the mares during the period from 0900 to 1500 h and study their social behaviour. A total of 300 focal sampling (6000 min), 3300 individual scan sampling (6000 min) and 62 group observations (1240 min) corresponding to the 100 mares were recorded. Non-parametric tests were used to analyse data. Results showed that experimental mares spent more time feeding (65.12% ± 2.40% v. 29.75% ± 2.45%, P < 0.01) and less time in locomotion (11.70% ± 1.31% v. 23.56% ± 1.34%, P < 0.01), stand resting (11.76% ± 2.57% v. 27.52% ± 2.62%, P < 0.01) and alert standing (5.23% ± 1.2% v. 14.71% ± 1.23%, P < 0.01). There was more bonding among experimental mares than control ones (26 v. 14, P < 0.05). Experimental mares showed more positive social interactions (P < 0.01) and less aggression (P < 0.01). These results suggest that giving densely housed mares foraging opportunities improves their welfare. PMID:22444907

Benhajali, H; Richard-Yris, M-A; Ezzaouia, M; Charfi, F; Hausberger, M

2009-09-01

298

The Bacterial Communities Associated with Honey Bee (Apis mellifera) Foragers.  

PubMed

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

Corby-Harris, Vanessa; Maes, Patrick; Anderson, Kirk E

2014-01-01

299

Spatial context influences patch residence time in foraging hierarchies.  

PubMed

Understanding responses of organisms to spatial heterogeneity in resources has emerged as a fundamentally important challenge in contemporary ecology. We examined responses of foraging herbivores to multi-scale heterogeneity in plants. We asked the question, "Is the behavior observed at coarse scales in a patch hierarchy the collective outcome of fine scale behaviors or, alternatively, does the spatial context at coarse scales entrain fine scale behavior?" To address this question we created a nested, two-level patch hierarchy. We examined the effects of the spatial context surrounding a patch on the amount of time herbivores resided in the patch. We developed a set of competing models predicting residence time as a function of the mass of plants contained in a patch and the distance between patches and examined the strength of evidence in our observations for these models. Models that included patch mass and inter-patch distance as independent variables successfully predicted observed residence times (bears: r (2)=0.67-0.76 and mule deer: r (2)=0.33-0.55). Residence times of grizzly bears (Ursus arctos) and mule deer (Odocoileus hemionus) responded to the spatial context surrounding a patch. Evidence ratios of Akaike weights demonstrated that models containing effects of higher levels in the hierarchy on residence time at lower levels received up to 34 times more support in the data than models that failed to consider the higher level context for grizzly bears and up to 48 times more support for mule deer. We conclude that foraging by large herbivores is influenced by more than one level of heterogeneity in patch hierarchies and that simple empirical models offer a viable alternative to optimal foraging models for the prediction of patch residence times. PMID:16705439

Searle, Kate R; Vandervelde, Thea; Hobbs, N Thompson; Shipley, Lisa A; Wunder, Bruce A

2006-07-01

300

Ants Can Learn to Forage on One-Way Trails  

PubMed Central

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.

Ribeiro, Pedro Leite; Helene, Andre Frazao; Xavier, Gilberto; Navas, Carlos; Ribeiro, Fernando Leite

2009-01-01

301

Implications of predator foraging on aphid pathogen dynamics.  

PubMed

The foraging behavior of starved and nonstarved second and fourth instar Coccinella septempunctata larvae on dead Acyrthosiphon pisum aphids, either infected with the entomopathogenic fungus Erynia neoaphidis (sporulating) or uninfected, was examined. Larvae searched for longer and fed less when presented with infected rather than uninfected A. pisum. Although no sporulating infected aphids were completely consumed, both adult and larval ladybirds can still be considered as intraguild predators. In a further study, fourth instar larvae fed on dying infected, dead infected (not sporulating), and dead uninfected aphids for similar periods of time but again the infected aphids were seldom entirely consumed. Live uninfected aphids were fed upon for significantly longer than any other prey. Infected aphids which were damaged at an early stage of infection (0, 1, or 2 days after inoculation) did not sporulate, whereas damaged moribund aphids (3 days after inoculation) did subsequently sporulate. Damaged sporulating cadavers continued to sporulate. However, damage to moribund and sporulating infected aphids, both mechanical or due to C. septempunctata feeding, reduced the number of conidia subsequently produced. Larval feeding caused the most significant reduction. Under laboratory conditions, C. septempunctata foraging on infected aphids did, therefore, reduce the pathogen density. However, conidia produced from a damaged cadaver resulted in levels of transmission to healthy aphids comparable to that resulting from an intact cadaver. Furthermore, the presence of a foraging adult ladybird resulted in a significant increase in transmission of the fungus to healthy aphids. Preliminary studies to assess the potential of other aphid natural enemies as intraguild predators illustrated that adults of the generalist carabid, Pterostichus madidus, entirely consumed sporulating cadavers. Third instar lacewing, Chrysoperla carnea, and hoverfly, Episyrphus balteatus, larvae never fed on sporulating cadavers. The ecological implications of these results are discussed. PMID:9538028

Roy, H E; Pell, J K; Clark, S J; Alderson, P G

1998-05-01

302

Harvest management of switchgrass for biomass feedstock and forage production  

SciTech Connect

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.

Sanderson, M.A.; Read, J.C.; Reed, R.L.

1999-02-01

303

Evolutionary and anthropological perspectives on optimal foraging in obesogenic environments.  

PubMed

The nutrition transition has created an obesogenic environment resulting in a growing obesity pandemic. An optimal foraging approach provides cost/benefit models of cognitive, behavioral and physiological strategies that illuminate the causes of caloric surfeit and consequent obesity in current environments of abundant food cues; easy-access and reliable food patches; low processing costs and enormous variety of energy-dense foods. Experimental and naturalistic observations demonstrate that obesogenic environments capitalize on human proclivities by displaying colorful advertising, supersizing meals, providing abundant variety, increasing convenience, and utilizing distractions that impede monitoring of food portions during consumption. The globalization of fast foods propels these trends. PMID:16806580

Lieberman, Leslie Sue

2006-07-01

304

Forage quality of western wheatgrass exposed to sulfur dioxide  

SciTech Connect

Effects of three exposure levels of SO/sub 2/ (55, 100, and 170 ..mu..m/sup -3/) on the nutritive value of western wheatgrass were investigated. Significant increases in plant sulfur content were observed, both with time and level of SO/sub 2/ exposure. Plant ash content paralled the trends observed for sulfur concentrations. Nitrogen concentrations in western wheatgrass were not affected by SO/sub 2/ treatments. The increased plant sulfur content and decreased N:S ratios across treatments did not significantly affect forage digestibility as measured by in vitro digestible dry matter.

Milchunas, D.G.; Lauenroth, W.K.; Dodd, J.L.

1981-07-01

305

Stand density index as a predictor of forage production in northern Arizona pine forests  

Microsoft Academic Search

Ponderosa pine (Pinus pondkrosu Laws.) overstory-forage understory relationships were studied on the Kaibab Plateau of northern Arizona to evaluate bow well forage (graminoid, forb, and current year shrub) production could be predicted by stand density index (SDI). Linear and nonlinear equations were used. Stand density index, a relative measure of stand density, was a useful predictor of understory production for

MARGARET M. MOORE; DALE A. DEITER

306

An integrated approch to the foraging ecology of marine birds and mammals  

Microsoft Academic Search

Birds and mammals are important components of pelagic marine ecosystems, but our knowledge of their foraging ecology is limited. We distinguish six distinct types of data that can be used in various combinations to understand their foraging behavior and ecology. We describe methods that combine concurrent dive recorder deployment, oceanographic sampling, and hydroacoustic surveys to generate hypotheses about interactions between

Donald A. Croll; Bernie R. Tershy; Roger P. Hewitt; David A. Demer; Paul C. Fiedler; Susan E. Smith; Wesley Armstrong; Jacqueline M. Popp; Thomas Kiekhefer; Vanesa R. Lopez; Jorge Urban; Diane Gendron

1998-01-01

307

Rhizobium inoculation trials designed to support a tropical forage legume selection programme  

Microsoft Academic Search

Summary Three phases of Rhizobium inoculation trials were carried out as part of a programme to select forage legume germplasm adapted to acid, infertile Oxisols of tropical America. Firstly, a range of tropical forage legumes were evaluated for their response to N fertilization or inoculation with strains previously shown to be effective in Leonard jars, using cores of undisturbed soil

Rosemary Sylvester-Bradley

1984-01-01

308

Predation risk and foraging behavior of the hoary marmot in Alaska  

Microsoft Academic Search

I observed hoary marmots for three field seasons to determine how the distribution of food and the risk of predation influenced marmots' foraging behavior. I quantified the amount of time Marmota caligata foraged in different patches of alpine meadows and assessed the distribution and abundance of vegetation eaten by marmots in these meadows. Because marmots dig burrows and run to

Warren G. Holmes

1984-01-01

309

Genetic diversity within honeybee colonies increases signal production by waggle-dancing foragers  

PubMed Central

Recent work has demonstrated considerable benefits of intracolonial genetic diversity for the productivity of honeybee colonies: single-patriline colonies have depressed foraging rates, smaller food stores and slower weight gain relative to multiple-patriline colonies. We explored whether differences in the use of foraging-related communication behaviour (waggle dances and shaking signals) underlie differences in foraging effort of genetically diverse and genetically uniform colonies. We created three pairs of colonies; each pair had one colony headed by a multiply mated queen (inseminated by 15 drones) and one colony headed by a singly mated queen. For each pair, we monitored the production of foraging-related signals over the course of 3 days. Foragers in genetically diverse colonies had substantially more information available to them about food resources than foragers in uniform colonies. On average, in genetically diverse colonies compared with genetically uniform colonies, 36% more waggle dances were identified daily, dancers performed 62% more waggle runs per dance, foragers reported food discoveries that were farther from the nest and 91% more shaking signals were exchanged among workers each morning prior to foraging. Extreme polyandry by honeybee queens enhances the production of worker–worker communication signals that facilitate the swift discovery and exploitation of food resources.

Mattila, Heather R; Burke, Kelly M; Seeley, Thomas D

2008-01-01

310

Geographic profiling applied to testing models of bumble-bee foraging  

PubMed Central

Geographic profiling (GP) was originally developed as a statistical tool to help police forces prioritize lists of suspects in investigations of serial crimes. GP uses the location of related crime sites to make inferences about where the offender is most likely to live, and has been extremely successful in criminology. Here, we show how GP is applicable to experimental studies of animal foraging, using the bumble-bee Bombus terrestris. GP techniques enable us to simplify complex patterns of spatial data down to a small number of parameters (2–3) for rigorous hypothesis testing. Combining computer model simulations and experimental observation of foraging bumble-bees, we demonstrate that GP can be used to discriminate between foraging patterns resulting from (i) different hypothetical foraging algorithms and (ii) different food item (flower) densities. We also demonstrate that combining experimental and simulated data can be used to elucidate animal foraging strategies: specifically that the foraging patterns of real bumble-bees can be reliably discriminated from three out of nine hypothetical foraging algorithms. We suggest that experimental systems, like foraging bees, could be used to test and refine GP model predictions, and that GP offers a useful technique to analyse spatial animal behaviour data in both the laboratory and field.

Raine, Nigel E.; Rossmo, D. Kim; Le Comber, Steven C.

2008-01-01

311

Detecting changes in habitat-scale bee foraging in a tropical fragmented landscape using stable isotopes  

Microsoft Academic Search

As the body of research on the ecosystem service of pollination grows, our ability to tackle a range of agricultural, conservation, and land management issues is limited by our understanding of pollinator foraging patterns and requirements. In particular, better knowledge of which habitats bees utilize for foraging over their lifetime would inform a range of applied and theoretical questions. Traditional

Berry J. Brosi; Gretchen C. Daily; C. Page Chamberlain; Matthew Mills

2009-01-01

312

How Information-Mapping Patterns Determine Foraging Behaviour of a Honey Bee Colony  

Microsoft Academic Search

We have developed a model of foraging behaviour of a honeybee colony based on reaction-diffusion equations and have studied how mapping the information about the explored environment to the hive determines this behaviour. The model utilizes two dominant components of colony's foraging behaviour — the recruitment to the located nectar sources and the abandonment of them. The recruitment is based

Valery Tereshko; Troy Lee

2002-01-01

313

Black-Capped Chickadees (Poecile atricapillus) Anticipate Future Outcomes of Foraging Choices  

Microsoft Academic Search

In 2 experiments we investigated the cognitive abilities of wild-caught black-capped chickadees (Poecile atricapillus) in future anticipation tasks. Chickadees were sensitive to anticipatory contrast effects over time horizons of 5, 10, and 30 min (Experiment 1). Chickadees also learned the order of events and anticipated that the quality of future foraging outcomes was contingent on current foraging choices. This behavior

Miranda C. Feeney; William A. Roberts; David F. Sherry

2011-01-01

314

Identifying leatherback turtle foraging behaviour from satellite telemetry using a switching state-space model  

Microsoft Academic Search

Abstract 1 Identifying foraging habitat of marine predators is vital to understanding the ecology of 2 these species and for their management,and conservation. Foraging habitat for many marine 3 predators is dynamic and this poses a serious challenge for understanding how oceanographic 4 features may shape the ecology of these animals. To help resolve this issue, we present a 5

Ian D. Jonsen; Ransom A. Myers; Michael C. James

2007-01-01

315

Reconstructing prehistoric hunter–gatherer foraging radii: a case study from California's southern Sierra Nevada  

Microsoft Academic Search

The concept of the foraging radius is essential to understanding hunter–gatherer settlement, subsistence, and sociocultural complexity yet is notoriously difficult to reconstruct archaeologically. Late prehistoric Western Mono foraging radii in the southern Sierra Nevada were reconstructed using GIS analysis of least-cost path distances between dispersed caching features and centralized residential features. Mean distances from settlements to caches exhibit a bimodal

Christopher Morgan

2008-01-01

316

In sacco NDF degradability and mineral release from selected forages in the rumen  

Microsoft Academic Search

An in sacco technique was used to measure NDF degradability and release of Mg, Ca, Zn, Cu, Fe from six forages - lucerne hay from the 1st cut (LH 1), from the 2 nd cut (LH 2), orchard grass (G), grass silage (GS), red clover silage treated with Feedtech (CSFT) and\\/or with Kofasil (CS KO ). The forages differed in

Z. ?EREŠ?ÁKOVÁ; P. F?AK; M. POLÁ?IKOVÁ; M. CHRENKOVÁ

317

THE ROLE OF ENDOPHYTIC FUNGI IN BRACHIARIA, A TROPICAL FORAGE GRASS  

Microsoft Academic Search

In temperate zones, endophytic fungi are widely used as biological protection agents for forage and turf grasses. They form nonpathogenic and intercellular associations with grasses and sedges, completing their entire life cycle within the plants' aerial parts. Our surveys and studies confirmed that various endophytic fungi, including Acremonium spp., also inhabit native savanna grasses and introduced tropical forage grasses. We

S. Kelemu; J. F. White; I. M. Rao

318

Pleiotropy, Epistasis and New QTL: The Genetic Architecture of Honey Bee Foraging Behavior  

Microsoft Academic Search

The regulation of division of labor in social insects, particularly in the honey bee (Apis mellifera L.), has received considerable attention from a number of biological subdisciplines, including quantitative and behavioral genetics, because of the high complexity of the behavioral traits involved. The foraging choices of honey bee workers can be accurately quantified, and previous studies have made the foraging

O. Ruppell; T. PANKIW; R. E. PAGE

2004-01-01

319

Comparing repeated forage bermudagrass harvest data to single, accumulated bioenergy feedstock harvests  

Microsoft Academic Search

Bermudagrass (Cynodon dactylon L.), widely grown for forage in the southeastern USA and throughout tropical and sub-tropical environments, is now being considered as a potential cellulosic bioenergy feedstock. The question is whether we can utilize extant forage data that seeks to balance yield with nutritive value to estimate its yield under single, yearly harvests designed purely for maximizing cellulosic biomass

James P. Muir; Barry D. Lambert; Amanda Greenwood; Angela Lee; Adrianna Riojas

2010-01-01

320

Exploration versus exploitation: a field study of time allocation to environmental tracking by foraging chipmunks  

Microsoft Academic Search

When food sources change unpredictably in time and space, animals may improve their foraging rate if they devote some of their foraging time to locating and assessing the quality of alternative sites, even after they have already discovered and begun to use one site. To test the hypothesis that the amount of time allocated to exploration would increase as the

DONALD L. KRAMER; DANIEL M. WEARY

1991-01-01

321

Foraging response of the ant Lasius pallitarsis to food sources with associated mortality risk  

Microsoft Academic Search

Summary Lasius pallitarsis (Provancher) ant colonies were offerred a choice between two food patches of equal nutritive quality but with one of the patches having associated with it one of several types of mortality risk indicators. Foraging decisions appeared to be affected only when theL. pallitarsis foragers could actually physically encounter a potential mortality agent (a largerFormica subnuda Emery). Odors

P. Nonacs; L. M. Dill

1988-01-01

322

Changes in learning and foraging behaviour within developing bumble bee (Bombus terrestris) colonies.  

PubMed

Organisation in eusocial insect colonies emerges from the decisions and actions of its individual members. In turn, these decisions and actions are influenced by the individual's behaviour (or temperament). Although there is variation in the behaviour of individuals within a colony, we know surprisingly little about how (or indeed if) the types of behaviour present in a colony change over time. Here, for the first time, we assessed potential changes in the behavioural type of foragers during colony development. Using an ecologically relevant foraging task, we measured the decision speed and learning ability of bumble bees (Bombus terrestris) at different stages of colony development. We determined whether individuals that forage early in the colony life cycle (the queen and early emerging workers) behaved differently from workers that emerge and forage at the end of colony development. Whilst we found no overall change in the foraging behaviour of workers with colony development, there were strong differences in foraging behaviour between queens and their workers. Queens appeared to forage more cautiously than their workers and were also quicker to learn. These behaviours could allow queens to maximise their nectar collecting efficiency whilst avoiding predation. Because the foundress queen is crucial to the survival and success of a bumble bee colony, more efficient foraging behaviour in queens may have strong adaptive value. PMID:24599144

Evans, Lisa J; Raine, Nigel E

2014-01-01

323

The energetic importance of night foraging for waders wintering in a temperate estuary  

NASA Astrophysics Data System (ADS)

Many species of waders forage extensively at night, but there is very little information on the relevance of this behaviour for the energy budget of waders wintering in estuarine wetlands. Quantitative data on diurnal and nocturnal intake rates can indicate the extent to which birds need to forage at night to supplement their diurnal energetic intake, or rather show a preference for nocturnal foraging. We compared day and night foraging behaviour, diet, and energy consumption of several wader species in the Tejo estuary, Portugal. There were significant differences between diurnal and nocturnal foraging behaviour. In general, birds moved less at night and scolopacid waders tended to use more tactile foraging methods. Although birds consumed the same type of prey in the two periods, the relative importance of each type changed. Overall, energy consumption was higher during the day except in grey plover, which achieved higher crude intake rates at night. Our results support the assertion that night foraging is an important part of the energy balance of waders during late winter, but that in most species it is less profitable than diurnal foraging.

Lourenço, Pedro M.; Silva, Andreia; Santos, Carlos D.; Miranda, Ana C.; Granadeiro, José P.; Palmeirim, Jorge M.

2008-07-01

324

Five Decades of Alfalfa Cultivar Improvement: Impact on Forage Yield, Persistence, and Nutritive Value  

Microsoft Academic Search

Previous research has implied that forage yield in released alfalfa (Medicago sativa L.) cultivars declined slightly between 1978 and 1996. Our objective was to compare alfalfa cultivars released during the past five decades side by side in replicated yield trials to test for any changes in forage yield across time. Ten cultivars, two from each of the five decades, four

JoAnn F. S. Lamb; Craig C. Sheaffer; Landon H. Rhodes; R. Mark Sulc; Daniel J. Undersander; E. Charles Brummer

325

Colony-based foraging segregation by Antarctic fur seals at the Kerguelen Archipelago  

Microsoft Academic Search

The foraging behaviour of conspecific female Antarctic fur seals (AFS) was compared simultaneously at 2 breeding colonies at Îles Kerguelen (S Indian Ocean). A remnant colony at ÎIes Nuageuses (IN) thought to have escaped sealing is hypothesized to be the source of increasing fur seal numbers at Cap Noir (CN) on the Kerguelen mainland. Inter-annual variability in foraging areas is

Mary-Anne Lea; Christophe Guinet; Yves Cherel; Mark Hindell; Laurent Dubroca; Sam Thalmann

2008-01-01

326

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

Microsoft Academic Search

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 rainfall. By minimizing the time

Donald Pate

1986-01-01

327

Adaptation of forage Kochia accessions across an environmental gradient in rush valley, Utah  

Microsoft Academic Search

Forage kochia (Kochia prostrata) is native to Eurasia. It is a useful plant for reclamation in semiarid and arid regions with mineral soils. Fourteen accessions representing both forage kochia subspecies and all known polyploid levels (2x?6x) were tested for adaptation over an environmental gradient represented by three study sites differing in native plant composition, average annual precipitation, and soil type.

E. Durant McArthur; Stewart C. Sanderson; James N. Davis

1996-01-01

328

Effects of simulated acid rain on uptake, accumulation, and retention of fluoride in forage crops  

Microsoft Academic Search

Forage crops accumulate F from exposures to the air pollutant HF and the rate and amount taken up can be affected by a number of external factors, one of which is precipitation. To assess how precipitation, including acidic precipitation, alters F uptake and retention in forage, alfalfa (Medicago sativa L. var. Saranac) and tall fescue (Festuca arundinacea Schreb. var. Kentucky

D. C. Maclean; R. E. Schneider; K. S. Hansen; J. J. Troiano

1989-01-01

329

Adaptive foraging does not always lead to more complex food webs.  

PubMed

Recent modeling studies exploring the effect of consumers' adaptivity in diet composition on food web complexity invariably suggest that adaptivity in foraging decisions of consumers makes food webs more complex. That is, it allows for survival of a higher number of species when compared with non-adaptive food webs. Population-dynamical models in these studies share two features: parameters are chosen uniformly for all species, i.e. they are species-independent, and adaptive foraging is described by the search image model. In this article, we relax both these assumptions. Specifically, we allow parameters to vary among the species and consider the diet choice model as an alternative model of adaptive foraging. Our analysis leads to three important predictions. First, for species-independent parameter values for which the search image model demonstrates a significant effect of adaptive foraging on food web complexity, the diet choice model produces no such effect. Second, the effect of adaptive foraging through the search image model attenuates when parameter values cease to be species-independent. Finally, for the diet choice model we observe no (significant) effect of adaptive foraging on food web complexity. All these observations suggest that adaptive foraging does not always lead to more complex food webs. As a corollary, future studies of food web dynamics should pay careful attention to the choice of type of adaptive foraging model as well as of parameter values. PMID:20600137

Berec, Ludek; Eisner, Jan; Krivan, Vlastimil

2010-09-21

330

Spatial patterns in army ant foraging and migration: Eciton burchelli on Barro Colorado Island, Panama  

Microsoft Academic Search

Eciton burchelli colonies alternate bouts of central place foraging with periods of migration according to a set rhythm. When these army ants forage from a central nest site they separate neigh-bouring raids by using a pattern similar to that used by many plants in spiral phyllotaxis. During the intervening periods of migration, raids and emigrations are orientated to lower the

Nigel R. Franks; Charles R. Fletcher

1983-01-01

331

Parasitic infection leads to decline in hemolymph sugar levels in honeybee foragers  

Microsoft Academic Search

Parasites by drawing nutrition from their hosts can exert an energetic stress on them. Honeybee foragers with their high metabolic demand due to flight are especially prone to such a stress when they are infected. We hypothesized that infection by the microsporidian gut parasite Nosema ceranae can lower the hemolymph sugar level of an individual forager and uncouple its energetic

Christopher Mayack; Dhruba Naug

2010-01-01

332

Annual variation in foraging ecology of prothonotary warblers during the breeding season  

USGS Publications Warehouse

We studied foraging ecology of Prothonotary Warblers (Protonotaria citrea) along the Tennessee River in west-central Tennessee during the breeding seasons of 1984-1987. We analyzed seven foraging variables to determine if this population exhibited annual variation in foraging behavior. Based on nearly 3,000 foraging maneuvers, most variables showed significant interyear variation during the four prenestling and three nestling periods we studied. This interyear variation probably was due -to proximate, environmental cues--such as distribution and abundance of arthropods--which, in turn, were influenced by local weather conditions. Researchers should consider the consequences of combining foraging behavior data collected in different years, because resolution of ecological trends may be sacrificed by considering only general patterns of foraging ecology and not the dynamics of those activities. In addition, because of annual variability, foraging data collected in only one year, regardless of the number of observations gathered, may not provide an accurate concept of the foraging ecology in insectivorous birds.

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

1990-01-01

333

Hunting and GatheringThe Human Sexual Division of Foraging Labor  

Microsoft Academic Search

Among human foragers, males and females target different foods and share them. Some view this division of labor as a cooperative enterprise to maximize household benefits; others question men's foraging goals. Women tend to target reliable foods. Men tend to target energy-dense foods that are difficult to acquire and are shared widely outside the household, perhaps to advertise their phenotypic

Frank W. Marlowe

2007-01-01

334

Foraging time of rutting bighorn rams varies with individual behavior, not mating tactic  

Microsoft Academic Search

Mate guarding is the primary mating tactic used by dominant males of many species of ungulates. Guarding males are thought to forage less during the rut than do nonguarding males, possibly leading to greater fitness costs. I observed bighorn rams foraging during the pre-rut and the rut. I compared how coursing (an alternative mating tactic) and tending (a form of

Fanie Pelletier

2005-01-01

335

Factors influencing mercury accumulation in three species of forage fish from Caddo Lake, Texas, USA  

Microsoft Academic Search

Most studies that have examined mercury (Hg) contamination of fish have focused on game species feeding near the top of the food web, while studies that examine forage fish that feed near the base of the food web are rare. We conducted a survey of Hg contamination in three species of forage fish, brook silverside (Labidesthes sicculus), threadfin shad (Dorosoma

Matthew M Chumchal; Ray W Drenner; David R Cross; K David Hambright

2010-01-01

336

Corticosterone and foraging behavior in a diving seabird: The Adélie penguin, Pygoscelis adeliae  

Microsoft Academic Search

Because hormones mediate physiological or behavioral responses to intrinsic or extrinsic stimuli, they can help us understand how animals adapt their foraging decisions to energetic demands of reproduction. Thus, the hormone corticosterone deserves specific attention because of its influence on metabolism, food intake and locomotor activities. We examined the relationships between baseline corticosterone levels and foraging behavior or mass gain

Frédéric Angelier; Charles-André Bost; Mathieu Giraudeau; Guillaume Bouteloup; Stéphanie Dano; Olivier Chastel

2008-01-01

337

Prey depletion by the foraging of the Eurasian treecreeper, Certhia familiaris , on tree-trunk arthropods  

Microsoft Academic Search

We examined to what extent breeding insectivorous treecreepers, Certhia familiaris, affect the abundance and the mean size of their prey population on the surface of tree trunks. In order to determine foraging pressure on tree trunks, we observed the parent birds' foraging behaviour in marked squares (25Ꭱ m) at a short (10 m) and long distance (90 m) from the

Ari Jäntti; Teija Aho; Harri Hakkarainen; Markku Kuitunen; Jukka Suhonen

2001-01-01

338

Effect of plant trichomes on the vertical migration of Haemonchus contortus infective larvae on five tropical forages  

Microsoft Academic Search

The influence of trichomes on vertical migration and survival of Haemonchus contortus infective larvae (L3) on different forages was investigated. Four different forages showing different distributions of trichomes\\u000a (Brachiaria brizantha cv. Marandu, Brachiaria brizantha cv. Xaraes, Andropogon gayanus, and Stylosanthes spp.), and one forage species without trichomes (Panicum maximum cv. Tanzania), were used. Forages cut at the post-grazing height were

Aruaque L. F. Oliveira; Ciniro Costa; Roberto A. Rodella; Bruna F. Silva; Alessandro F. T. Amarante

2009-01-01

339

Geographic structure of ade??lie penguin populations: Overlap in colony-specific foraging areas  

USGS Publications Warehouse

In an investigation of the factors leading to geographic structuring among Ade??lie Penguin (Pygoscelis adeliae) populations, we studied the size and overlap of colony-specific foraging areas within an isolated cluster of colonies. The study area, in the southwestern Ross Sea, included one large and three smaller colonies, ranging in size from 3900 to 135000 nesting pairs, clustered on Ross and Beaufort Islands. We used triangulation of radio signals from transmitters attached to breeding penguins to determine foraging locations and to define colony-specific foraging areas during the chick-provisioning period of four breeding seasons, 1997-2000. Colony populations (nesting pairs) were determined using aerial photography just after egg-laying; reproductive success was estimated by comparing ground counts of chicks fledged to the number of breeding pairs apparent in aerial photos. Foraging-trip duration, meal size, and adult body mass were estimated using RFID (radio frequency identification) tags and an automated reader and weighbridge. Chick growth was assessed by weekly weighing. We related the following variables to colony size: foraging distance, area, and duration; reproductive success; chick meal size and growth rate; and seasonal variation in adult body mass. We found that penguins foraged closest to their respective colonies, particularly at the smaller colonies. However, as the season progressed, foraging distance, duration, and area increased noticeably, especially at the largest colony. The foraging areas of the smaller colonies overlapped broadly, but very little foraging area overlap existed between the large colony and the smaller colonies, even though the foraging area of the large colony was well within range of the smaller colonies. Instead, the foraging areas of the smaller colonies shifted as that of the large colony grew. Colony size was not related to chick meal size, chick growth, or parental body mass. This differed from the year previous to the study, when foraging trips of the large colony were very long, parents lost mass, and chick meals were smaller. In light of existing data on prey abundance in neritic waters in Antarctica suggesting that krill are relatively evenly distributed and in high abundance in the Southern Ross Sea, we conclude that penguins depleted or changed the availability of their prey, that the degree of alteration was a function of colony size, and that the large colony affected the location (and perhaps ultimately the size) of foraging areas for the smaller colonies. It appears, therefore, that foraging dynamics play a role in the geographic structuring of colonies in this species. ?? 2004 by the Ecological Society of America.

Ainley, D. G.; Ribic, C. A.; Ballard, G.; Heath, S.; Gaffney, I.; Karl, B. J.; Barton, K. J.; Wilson, P. R.; Webb, S.

2004-01-01

340

Natural History of the Neotropical Arboreal Ant, Odontomachus hastatus: Nest Sites, Foraging Schedule, and Diet  

PubMed Central

The ecology of most arboreal ants remains poorly documented because of the difficulty in accessing ant nests and foragers in the forest canopy. This study documents the nesting and foraging ecology of a large (?13 mm total length) arboreal trap—jaw ant, Odontomachus hastatus (Fabricius) (Hymenoptera: Formicidae) in a sandy plain forest on Cardoso Island, off the coast of Southeast Brazil. The results showed that O. hastatus nested in root clusters of epiphytic bromeliads, most commonly Vriesea procera (70% of nest plants). Mature O. hastatus colonies include one to several queens and about 500 workers. Foraging by O. hastatus is primarily nocturnal year—round, with increased foraging activity during the wet/warm season. The foragers hunt singly in the trees, preying on a variety of canopy—dwelling arthropods, with flies, moths, ants, and spiders accounting for > 60% of the prey captured. Although predators often have impacts on prey populations, the ecological importance of O. hastatus remains to be studied.

Camargo, Rafael X.; Oliveira, Paulo S.

2012-01-01

341

Quantifying the Effect of Colony Size and Food Distribution on Harvester Ant Foraging  

PubMed Central

Desert seed-harvester ants, genus Pogonomyrmex, are central place foragers that search for resources collectively. We quantify how seed harvesters exploit the spatial distribution of seeds to improve their rate of seed collection. We find that foraging rates are significantly influenced by the clumpiness of experimental seed baits. Colonies collected seeds from larger piles faster than randomly distributed seeds. We developed a method to compare foraging rates on clumped versus random seeds across three Pogonomyrmex species that differ substantially in forager population size. The increase in foraging rate when food was clumped in larger piles was indistinguishable across the three species, suggesting that species with larger colonies are no better than species with smaller colonies at collecting clumped seeds. These findings contradict the theoretical expectation that larger groups are more efficient at exploiting clumped resources, thus contributing to our understanding of the importance of the spatial distribution of food sources and colony size for communication and organization in social insects.

Flanagan, Tatiana P.; Letendre, Kenneth; Burnside, William R.; Fricke, G. Matthew; Moses, Melanie E.

2012-01-01

342

Scale-free foraging by primates emerges from their interaction with a complex environment  

PubMed Central

Scale-free foraging patterns are widespread among animals. These may be the outcome of an optimal searching strategy to find scarce, randomly distributed resources, but a less explored alternative is that this behaviour may result from the interaction of foraging animals with a particular distribution of resources. We introduce a simple foraging model where individual primates follow mental maps and choose their displacements according to a maximum efficiency criterion, in a spatially disordered environment containing many trees with a heterogeneous size distribution. We show that a particular tree-size frequency distribution induces non-Gaussian movement patterns with multiple spatial scales (Lévy walks). These results are consistent with field observations of tree-size variation and spider monkey (Ateles geoffroyi) foraging patterns. We discuss the consequences that our results may have for the patterns of seed dispersal by foraging primates.

Boyer, Denis; Ramos-Fernandez, Gabriel; Miramontes, Octavio; Mateos, Jose L; Cocho, Germinal; Larralde, Hernan; Ramos, Humberto; Rojas, Fernando

2006-01-01

343

Effects of predatory risk and resource renewal on the timing of foraging activity in a gerbil community  

Microsoft Academic Search

The foraging decisions of animals are often influenced by risk of predation and by the renewal of resources. For example, seed-eating gerbils on sand dunes in the Negev Desert of Israel prefer to forage in the bush microhabitat and during darker hours due to risk of predation. Also, daily renewal of seed resource patches and timing of nightly foraging activity

Burt P. Kotler; Yoram Ayal; Aziz Subach

1994-01-01

344

ESTIMATION OF DIGESTA KINETICS OF FORAGE KOCHIA AND TALL WHEATGRASS USING YB AND DY WHEN FED ALONE OR MIXED TOGETHER  

Microsoft Academic Search

Little is known about the nutritional value of forage kochia (Kochia prostrata) for grazing beef cattle when mixed in low-quality forage diets. Our objectives were to evaluate digesta kinetics using different ratios of forage kochia and tall wheatgrass (Agropyron elongatum) and to examine the use of two rare earth markers to simultaneously measure the kinetics of each feedstuff. Five ruminally

A. R. Wall; K. C. Olson; C. A. Stonecipher; M. Stuart; M. A. Maughn; J. C. Malechek

345

Nocturnal foraging habitats of French and bluestriped grunts, Haemulon flavolineatum and H. sciurus , at Tobacco Caye, Belize  

Microsoft Academic Search

Nocturnal foraging habitats of Haemulon flavolineatum and H. sciurus were investigated in the backreef habitat around Tobacco Caye, Belize. Grunts leave the reef at dusk to forage in the grass beds and sand flats surrounding the reef. The hypothesis that French and bluestriped grunts use separate foraging habitats was examined by following tagged fishes from their diurnal territories or schooling

Nancy C. Burke

1995-01-01

346

Effects of forage:concentrate ratio and forage type on apparent digestibility, ruminal fermentation, and microbial growth in goats.  

PubMed

The effects of forage type and forage:concentrate ratio (F:C) on apparent nutrient digestibility, ruminal fermentation, and microbial growth were investigated in goats. A comparison between liquid (LAB) and solid (SAB)-associated bacteria to estimate microbial N flow (MNF) from urinary purine derivative excretion was also examined. Treatments were a 2 x 2 factorial arrangement of forage type (grass hay vs. alfalfa hay) and high vs. low F:C (70:30 and 30:70, respectively). Four ruminally cannulated goats were fed, at maintenance intake, 4 experimental diets according to a 4 x 4 Latin square design. High-concentrate diets resulted in greater (P < 0.001) nutrient digestibility except for ADF. However, CP digestibility increased (P < 0.001) only for the high-concentrate diets including grass hay. Likewise, N retention, ruminal NH(3)-N concentration, and urinary excretion of purine derivatives increased (P < 0.05) with increasing concentrate in animals fed diets based on grass hay (0.23 vs. 0.13 g of retained N/g of digested N, 30.1 vs. 12.9 mg of NH(3)-N/100 mL, and 11.5 vs. 8.40 mmol/d, respectively), but not (P > 0.05) when diets included alfalfa hay. Total protozoa numbers and holotricha proportion were greater and less (P < 0.001), respectively, in high- than in low-concentrate diets. The F:C affected (P < 0.001) ruminal pH but not total VFA concentration (P = 0.12). Ammonia-N concentration was similar (P = 0.13) over time, whereas pH, VFA concentration, and protozoa numbers differed (P < 0.001) among diets. Estimated MNF was strongly influenced by using either the purine bases:N ratio obtained in our experimental conditions or values reported in the literature for small ruminants. There was a F:C effect (P = 0.006) on MNF estimated from LAB but not from SAB. The effect of F:C shifting from 70:30 to 30:70 in goat diets depends on the type of forage used. The MNF measured in goats fed different diets was influenced by the bacterial pellet (LAB or SAB). In addition, the purine bases:N ratio values found were different from those reported in the literature, which underlines the need for these variables to be analyzed directly in pellets isolated from specific animals and experimental conditions. PMID:18952730

Cantalapiedra-Hijar, G; Yáńez-Ruiz, D R; Martín-García, A I; Molina-Alcaide, E

2009-02-01

347

Bias to pollen odors is affected by early exposure and foraging experience.  

PubMed

In many pollinating insects, foraging preferences are adjusted on the basis of floral cues learned at the foraging site. In addition, olfactory experiences gained at early adult stages might also help them to initially choose food sources. To understand pollen search behavior of honeybees, we studied how responses elicited by pollen-based odors are biased in foraging-age workers according to (i) their genetic predisposition to collect pollen, (ii) pollen related information gained during foraging and (iii) different experiences with pollen gained at early adult ages. Bees returning to the hive carrying pollen loads, were strongly biased to unfamiliar pollen bouquets when tested in a food choice device against pure odors. Moreover, pollen foragers' orientation response was specific to the odors emitted by the pollen type they were carrying on their baskets, which suggests that foragers retrieve pollen odor information to recognize rewarding flowers outside the hive. We observed that attraction to pollen odor was mediated by the exposure to a pollen diet during the first week of life. We did not observe the same attraction in foraging-age bees early exposed to an artificial diet that did not contain pollen. Contrary to the specific response observed to cues acquired during foraging, early exposure to single-pollen diets did not bias orientation response towards a specific pollen odor in foraging-age bees (i.e. bees chose equally between the exposed and the novel monofloral pollen odors). Our results show that pollen exposure at early ages together with olfactory experiences gained in a foraging context are both relevant to bias honeybees' pollen search behavior. PMID:24852672

Arenas, A; Farina, W M

2014-07-01

348

Assessing Lévy walks as models of animal foraging.  

PubMed

The hypothesis that the optimal search strategy is a Lévy walk (LW) or Lévy flight, originally suggested in 1995, has generated an explosion of interest and controversy. Long-standing empirical evidence supporting the LW hypothesis has been overturned, while new models and data are constantly being published. Statistical methods have been criticized and new methods put forward. In parallel with the empirical studies, theoretical search models have been developed. Some theories have been disproved while others remain. Here, we gather together the current state of the art on the role of LWs in optimal foraging theory. We examine the body of theory underpinning the subject. Then we present new results showing that deviations from the idealized one-dimensional search model greatly reduce or remove the advantage of LWs. The search strategy of an LW with exponent ? = 2 is therefore not as robust as is widely thought. We also review the available techniques, and their potential pitfalls, for analysing field data. It is becoming increasingly recognized that there is a wide range of mechanisms that can lead to the apparent observation of power-law patterns. The consequence of this is that the detection of such patterns in field data implies neither that the foragers in question are performing an LW, nor that they have evolved to do so. We conclude that LWs are neither a universal optimal search strategy, nor are they as widespread in nature as was once thought. PMID:21632609

James, Alex; Plank, Michael J; Edwards, Andrew M

2011-09-01

349

Foraging theory upscaled: the behavioural ecology of herbivore movement  

PubMed Central

We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.

Owen-Smith, N.; Fryxell, J. M.; Merrill, E. H.

2010-01-01

350

Forest type affects prey foraging of saddleback tamarins, Saguinus nigrifrons.  

PubMed

Callitrichids can persist in secondary forests where they may benefit from elevated prey abundance. However, how tamarins forage for prey in secondary forest compared to primary forest has not been examined. Using scan and focal sampling, we compared prey foraging and capture success of two groups of Saguinus nigrifrons in north-eastern Peru: one ranging in primary forest, the other with access to a 10-year-old anthropogenic secondary forest. There was a trend for more prey search in the secondary forest, but prey feeding, capture success and size were lower compared to the primary forest. Tamarins avoided the forest floor, used vertical supports less often and searched on a lower variety of substrates in the secondary forest. In the secondary forest, tamarins did not capture flushed prey, which make up a substantial part of the total prey captures biomass in primary forests. Reduced prey capture success is unlikely to reflect reduced prey availability, since more Orthoptera were found in secondary forest through ultrasonic surveys. Therefore, the prey search activity of S. nigrifrons in young secondary forests seemed rather opportunistic, presumably influenced by altered predation patterns, vegetation structure, as well as prey diversity. PMID:24687729

Kupsch, Denis; Waltert, Matthias; Heymann, Eckhard W

2014-07-01

351

Individual specialization in a shorebird population with narrow foraging niche  

NASA Astrophysics Data System (ADS)

Individual specialization in resource use is a widespread driver for intra-population trait variation, playing a crucial evolutionary role in free-living animals. We investigated the individual foraging specialization of Black-tailed Godwits (Limosa limosa islandica) during the wintering period. Godwits displayed distinct degrees of individual specialization in diet and microhabitat use, indicating the presence of both generalist and specialist birds. Females were overall more specialist than males, primarily consuming polychaetes. Specialist males consumed mainly bivalves, but some individuals also specialized on gastropods or polychaetes. Sexual dimorphism in bill length is probably important in determining the differences in specialization, as longer-billed individuals have access to deep-buried polychaetes inaccessible to most males. Different levels of specialization within the same sex, unrelated to bill length, were also found, suggesting that mechanisms other traits are involved in explaining individual specialization. Godwits specialized on bivalves achieved higher intake rates than non-specialist birds, supporting the idea that individual foraging choices or skills result in different short-term payoffs within the same population. Understanding whether short-term payoffs are good indicators of long-term fitness and how selection operates to favour the prevalence of specialist or generalist godwits is a major future challenge.

Catry, Teresa; Alves, José A.; Gill, Jennifer A.; Gunnarsson, Tómas G.; Granadeiro, José P.

2014-04-01

352

Year-Class Formation of Upper St. Lawrence River Northern Pike  

Microsoft Academic Search

Variables associated with year-class formation in upper St. Lawrence River northern pike Esox lucius were examined to explore population trends. A partial least-squares (PLS) regression model (PLS 1) was used to relate a year-class strength index (YCSI; 1974–1997) to explanatory variables associated with spawning and nursery areas (seasonal water level and temperature and their variability, number of ice days, and

Brian M. Smith; John M. Farrell; H. Brian Underwood; Stephen J. Smith

2007-01-01

353

Effects of Clam Shrimp on Production of Walleye and Northern Pike, and a Review of Clam Shrimp Control Strategies  

Microsoft Academic Search

The dynamics of clam shrimp, Caenestheriella belfragei, populations in fish culture ponds were studied to evaluate their effect on yield of fingerling northern pike, Esox lucius, or walleye, Stizostedion vitreum. The studies were carried out on twenty-three 0.64-ha ponds during the culture season for northern pike and on 19 of the same ponds during the season for walleye. Ponds were

James M. Luzier; Robert C. Summerfelt

1996-01-01

354

Behavior and Passage Performance of Northern Pike, Walleyes, and White Suckers in an Experimental Raceway  

Microsoft Academic Search

The willingness and ability of wild adult northern pike Esox lucius, walleyes Sander vitreus, and white suckers Catostomus commersonii to ascend a 25- or 50-m experimental raceway against various water velocities (35–120 cm\\/s at 8 cm from the bottom) was measured. The probability that a fish of any given species would enter the raceway from its holding tank was significantly

Stephan J. Peake

2008-01-01

355

Environmental Contaminants in Fish and Their Associated Risk to Piscivorous Wildlife in the Yukon River Basin, Alaska  

Microsoft Academic Search

Organochlorine chemical residues and elemental contaminants were measured in northern pike (Esox lucius), longnose sucker (Catostomus catostomus), and burbot (Lota lota) from 10 sites in the Yukon River Basin (YRB) during 2002. Contaminant concentrations were compared to historical YRB data\\u000a and to toxicity thresholds for fish and piscivorous wildlife from the scientific literature. A risk analysis was conducted\\u000a to screen

Jo Ellen Hinck; Christopher J. Schmitt; Kathy R. Echols; Tom W. May; Carl E. Orazio; Donald E. Tillitt

2006-01-01

356

Clearing lakes. An ecosystem approach to the restoration and management of shallow lakes in the Netherlands  

Microsoft Academic Search

In the 1950 s and 1960 s, most shallow lakes in the Netherlands shifted from macrophyte-dominated clear water lakes, towards algae-dominated turbid water lakes. Eutrophication, i.e. increased nutrient loading, is the main cause of the deterioration of the lake ecosystems. Other perturbations, such as the loss of lake-marginal wetlands (nutrient filters, habitat for pike, Esox lucius) and chemical pollution toxic

H. Hosper

1997-01-01

357

Shallow groundwater quality on dairy farms with irrigated forage crops.  

PubMed

California's dairies are the largest confined animal industry in the state. A major portion of these dairies, which have an average herd size of nearly 1000 animal units, are located in low-relief valleys and basins. Large amounts of liquid manure are generated and stored in these dairies. In the semi-arid climate, liquid manure is frequently applied via flood or furrow irrigation to forage crops that are grown almost year-round. Little is known about the impact of manure management practices on water quality of the extensive alluvial aquifers underlying these basins. The objective of this work is to assess nitrate and salt leaching to shallow groundwater in a relatively vulnerable hydrogeologic region and to quantify the impact from individual sources on dairies. The complex array of potential point and nonpoint sources was divided into three major source areas representing farm management units: (1) manure water lagoons (ponds); (2) feedlot or exercise yard, dry manure, and feed storage areas (corrals); and (3) manure irrigated forage fields (fields). An extensive shallow groundwater-monitoring network (44 wells) was installed in five representative dairy operations in the northeastern San Joaquin Valley, CA. Water quality (electrical conductivity, nitrate-nitrogen, total Kjehldahl nitrogen) was observed over a 4-year period. Nitrate-N, reduced nitrogen and electrical conductivity (EC, salinity) were subject to large spatial and temporal variability. The range of observed nitrate-N and salinity levels was similar on all five dairies. Average shallow groundwater nitrate-N concentrations within the dairies were 64 mg/l compared to 24 mg/l in shallow wells immediately upgradient of these dairies. Average EC levels were 1.9 mS/cm within the dairies and 0.8 mS/cm immediately upgradient. Within the dairies, nitrate-N levels did not significantly vary across dairy management units. However, EC levels were significantly higher in corral and pond areas (2.3 mS/cm) than in field areas (1.6 mS/cm) indicating leaching from those management units. Pond leaching was further inferred from the presence of reduced nitrogen in three of four wells located immediately downgradient of pond berms. The estimated minimum average annual groundwater nitrate-N and salt loading from manure-treated forage fields were 280 and 4300 kg/ha, respectively. Leaching rates for ponds are estimated to be on the order of 0.8 m/year, at least locally. Since manure-treated fields represent by far the largest land area of the dairy, proper nutrient management will be a key to protecting groundwater quality in dairy regions overlying alluvial aquifers. PMID:11999633

Harter, Thomas; Davis, Harley; Mathews, Marsha C; Meyer, Roland D

2002-04-01

358

Antennal proteome comparison of sexually mature drone and forager honeybees.  

PubMed

Honeybees have evolved an intricate system of chemical communication to regulate their complex social interactions. Specific proteins involved in odorant detection most likely supported this chemical communication. Odorant reception takes place mainly in the antennae within hairlike structures called olfactory sensilla. Antennal proteomes of sexually mature drone and forager worker bees (an age group of bees assigned to perform field tasks) were compared using two-dimensional electrophoresis, mass spectrometry, quantitative real-time polymerase chain reaction, and bioinformatics. Sixty-one differentially expressed proteins were identified in which 67% were highly upregulated in the drones' antennae whereas only 33% upregulated in the worker bees' antennae. The antennae of the worker bees strongly expressed carbohydrate and energy metabolism and molecular transporters signifying a strong demand for metabolic energy and odorant binding proteins for their foraging activities and other olfactory responses, while proteins related to fatty acid metabolism, antioxidation, and protein folding were strongly upregulated in the drones' antennae as an indication of the importance for the detection and degradation of sex pheromones during queen identification for mating. On the basis of both groups of altered antenna proteins, carbohydrate metabolism and energy production and molecular transporters comprised more than 80% of the functional enrichment analysis and 45% of the constructed biological interaction networks (BIN), respectively. This suggests these two protein families play crucial roles in the antennal olfactory function of sexually mature drone and forager worker bees. Several key node proteins in the BIN were validated at the transcript level. This first global proteomic comparative analysis of antennae reveals sex-biased protein expression in both bees, indicating that odorant response mechanisms are sex-specific because of natural selection for different olfactory functions. To the best of our knowledge, this result further provides extensive insight into the expression of the proteins in the antennae of drone and worker honeybees and adds vital information to the previous findings. It also provides a new angle for future detailed functional analysis of the antennae of the honeybee castes. PMID:21618965

Feng, Mao; Song, Feifei; Aleku, Dereje Woltedji; Han, Bin; Fang, Yu; Li, Jianke

2011-07-01

359

Shallow groundwater quality on dairy farms with irrigated forage crops  

NASA Astrophysics Data System (ADS)

California's dairies are the largest confined animal industry in the state. A major portion of these dairies, which have an average herd size of nearly 1000 animal units, are located in low-relief valleys and basins. Large amounts of liquid manure are generated and stored in these dairies. In the semi-arid climate, liquid manure is frequently applied via flood or furrow irrigation to forage crops that are grown almost year-round. Little is known about the impact of manure management practices on water quality of the extensive alluvial aquifers underlying these basins. The objective of this work is to assess nitrate and salt leaching to shallow groundwater in a relatively vulnerable hydrogeologic region and to quantify the impact from individual sources on dairies. The complex array of potential point and nonpoint sources was divided into three major source areas representing farm management units: (1) manure water lagoons (ponds); (2) feedlot or exercise yard, dry manure, and feed storage areas (corrals); and (3) manure irrigated forage fields (fields). An extensive shallow groundwater-monitoring network (44 wells) was installed in five representative dairy operations in the northeastern San Joaquin Valley, CA. Water quality (electrical conductivity, nitrate-nitrogen, total Kjehldahl nitrogen) was observed over a 4-year period. Nitrate-N, reduced nitrogen and electrical conductivity (EC, salinity) were subject to large spatial and temporal variability. The range of observed nitrate-N and salinity levels was similar on all five dairies. Average shallow groundwater nitrate-N concentrations within the dairies were 64 mg/l compared to 24 mg/l in shallow wells immediately upgradient of these dairies. Average EC levels were 1.9 mS/cm within the dairies and 0.8 mS/cm immediately upgradient. Within the dairies, nitrate-N levels did not significantly vary across dairy management units. However, EC levels were significantly higher in corral and pond areas (2.3 mS/cm) than in field areas (1.6 mS/cm) indicating leaching from those management units. Pond leaching was further inferred from the presence of reduced nitrogen in three of four wells located immediately downgradient of pond berms. The estimated minimum average annual groundwater nitrate-N and salt loading from manure-treated forage fields were 280 and 4300 kg/ha, respectively. Leaching rates for ponds are estimated to be on the order of 0.8 m/year, at least locally. Since manure-treated fields represent by far the largest land area of the dairy, proper nutrient management will be a key to protecting groundwater quality in dairy regions overlying alluvial aquifers.

Harter, Thomas; Davis, Harley; Mathews, Marsha C.; Meyer, Roland D.

2002-04-01

360

Rich pickings near large communal roosts favor 'gang' foraging by juvenile common ravens, Corvus corax.  

PubMed

Ravens (Corvus corax) feed primarily on rich but ephemeral carcasses of large animals, which are usually defended by territorial pairs of adults. Non-breeding juveniles forage socially and aggregate in communal winter roosts, and these appear to function as 'information centers' regarding the location of the rare food bonanzas: individuals search independently of one another and pool their effort by recruiting each other at roosts. However, at a large raven roost in Newborough on Anglesey, North Wales, some juveniles have been observed recently to forage in 'gangs' and to roost separately from other birds. Here we adapt a general model of juvenile common raven foraging behavior where, in addition to the typical co-operative foraging strategy, such gang foraging behavior could be evolutionarily stable near winter raven roosts. We refocus the model on the conditions under which this newly documented, yet theoretically anticipated, gang-based foraging has been observed. In the process, we show formally how the trade off between search efficiency and social opportunity can account for the existence of the alternative social foraging tactics that have been observed in this species. This work serves to highlight a number of fruitful avenues for future research, both from a theoretical and empirical perspective. PMID:19240813

Dall, Sasha R X; Wright, Jonathan

2009-01-01

361

The effects of spatially heterogeneous prey distributions on detection patterns in foraging seabirds.  

PubMed

Many attempts to relate animal foraging patterns to landscape heterogeneity are focused on the analysis of foragers movements. Resource detection patterns in space and time are not commonly studied, yet they are tightly coupled to landscape properties and add relevant information on foraging behavior. By exploring simple foraging models in unpredictable environments we show that the distribution of intervals between detected prey (detection statistics) is mostly determined by the spatial structure of the prey field and essentially distinct from predator displacement statistics. Detections are expected to be Poissonian in uniform random environments for markedly different foraging movements (e.g. Lévy and ballistic). This prediction is supported by data on the time intervals between diving events on short-range foraging seabirds such as the thick-billed murre (Uria lomvia). However, Poissonian detection statistics is not observed in long-range seabirds such as the wandering albatross (Diomedea exulans) due to the fractal nature of the prey field, covering a wide range of spatial scales. For this scenario, models of fractal prey fields induce non-Poissonian patterns of detection in good agreement with two albatross data sets. We find that the specific shape of the distribution of time intervals between prey detection is mainly driven by meso and submeso-scale landscape structures and depends little on the forager strategy or behavioral responses. PMID:22514629

Miramontes, Octavio; Boyer, Denis; Bartumeus, Frederic

2012-01-01

362

Evidence of Levy walk foraging patterns in human hunter-gatherers.  

PubMed

When searching for food, many organisms adopt a superdiffusive, scale-free movement pattern called a Lévy walk, which is considered optimal when foraging for heterogeneously located resources with little prior knowledge of distribution patterns [Viswanathan GM, da Luz MGE, Raposo EP, Stanley HE (2011) The Physics of Foraging: An Introduction to Random Searches and Biological Encounters]. Although memory of food locations and higher cognition may limit the benefits of random walk strategies, no studies to date have fully explored search patterns in human foraging. Here, we show that human hunter-gatherers, the Hadza of northern Tanzania, perform Lévy walks in nearly one-half of all foraging bouts. Lévy walks occur when searching for a wide variety of foods from animal prey to underground tubers, suggesting that, even in the most cognitively complex forager on Earth, such patterns are essential to understanding elementary foraging mechanisms. This movement pattern may be fundamental to how humans experience and interact with the world across a wide range of ecological contexts, and it may be adaptive to food distribution patterns on the landscape, which previous studies suggested for organisms with more limited cognition. Additionally, Lévy walks may have become common early in our genus when hunting and gathering arose as a major foraging strategy, playing an important role in the evolution of human mobility. PMID:24367098

Raichlen, David A; Wood, Brian M; Gordon, Adam D; Mabulla, Audax Z P; Marlowe, Frank W; Pontzer, Herman

2014-01-14

363

The contribution of private and public information in foraging by Australasian gannets.  

PubMed

Predators that forage on foods with temporally and spatially patchy distributions may rely on private or public sources of information to enhance their chances of foraging success. Using GPS tracking, field observations, and videography, we examined potential sites and mechanisms of information acquisition in departures for foraging trips by colonially breeding Australasian gannets (Morus serrator). Analyses of the bill-fencing ceremony between mated pairs of breeding gannets did not detect correlations between parameters of this reciprocal behavior and foraging trips, as would have been predicted if gannets used this behavior as a source of private information. Instead, 60 % of the departing birds flew directly to join water rafts of other conspecific en route to the feeding grounds. The departure of solitary birds from the water rafts was synchronized (within 60 s) with the arrival of incoming foragers and also among departing birds. Furthermore, solitary departing birds from the rafts left in the same directional quadrant (90ş slices) as the prior arriving (67 %) and also prior departing forager (79 %). When associated plunge dives of conspecific were visible from the colony, providing a public source of information, gannets more often departed from the water rafts in groups. Our study thus provides evidence for the use of water rafts, but not the nest site, as locations of information transfer, and also confirms the use of local enhancement as a strategy for foraging flights by Australasian gannets. PMID:24337907

Machovsky-Capuska, Gabriel E; Hauber, Mark E; Libby, Eric; Amiot, Christophe; Raubenheimer, David

2014-07-01

364

Daily foraging patterns in free-living birds: exploring the predation-starvation trade-off  

PubMed Central

Daily patterns in the foraging behaviour of birds are assumed to balance the counteracting risks of predation and starvation. Predation risks are a function of the influence of weight on flight performance and foraging behaviours that may expose individuals to predators. Although recent research sheds light on daily patterns in weight gain, little data exist on daily foraging routines in free-living birds. In order to test the predictions of various hypotheses about daily patterns of foraging, we quantified the activity of four species of passerines in winter using radio-frequency identification receivers built into supplemental feeding stations. From records of 472 368 feeder visits by tagged birds, we found that birds generally started to feed before sunrise and continued to forage at a steady to increasing rate throughout the day. Foraging in most species terminated well before sunset, suggesting their required level of energy reserves was being reached before the end of the day. These results support the risk-spreading theorem over a long-standing hypothesis predicting bimodality in foraging behaviour purportedly driven by a trade-off between the risks of starvation and predation. Given the increased energetic demands experienced by birds during colder weather, our results suggest that birds' perceptions of risk are biased towards starvation avoidance in winter.

Bonter, David N.; Zuckerberg, Benjamin; Sedgwick, Carolyn W.; Hochachka, Wesley M.

2013-01-01

365

Evidence of L?vy walk foraging patterns in human hunter-gatherers  

PubMed Central

When searching for food, many organisms adopt a superdiffusive, scale-free movement pattern called a Lévy walk, which is considered optimal when foraging for heterogeneously located resources with little prior knowledge of distribution patterns [Viswanathan GM, da Luz MGE, Raposo EP, Stanley HE (2011) The Physics of Foraging: An Introduction to Random Searches and Biological Encounters]. Although memory of food locations and higher cognition may limit the benefits of random walk strategies, no studies to date have fully explored search patterns in human foraging. Here, we show that human hunter–gatherers, the Hadza of northern Tanzania, perform Lévy walks in nearly one-half of all foraging bouts. Lévy walks occur when searching for a wide variety of foods from animal prey to underground tubers, suggesting that, even in the most cognitively complex forager on Earth, such patterns are essential to understanding elementary foraging mechanisms. This movement pattern may be fundamental to how humans experience and interact with the world across a wide range of ecological contexts, and it may be adaptive to food distribution patterns on the landscape, which previous studies suggested for organisms with more limited cognition. Additionally, Lévy walks may have become common early in our genus when hunting and gathering arose as a major foraging strategy, playing an important role in the evolution of human mobility.

Raichlen, David A.; Wood, Brian M.; Gordon, Adam D.; Mabulla, Audax Z. P.; Marlowe, Frank W.; Pontzer, Herman

2014-01-01

366

Comparison of laboratory and field remote sensing methods to measure forage quality.  

PubMed

Recent research in range ecology has emphasized the importance of forage quality as a key indicator of rangeland condition. However, we lack tools to evaluate forage quality at scales appropriate for management. Using canopy reflectance data to measure forage quality has been conducted at both laboratory and field levels separately, but little work has been conducted to evaluate these methods simultaneously. The objective of this study is to find a reliable way of assessing grassland quality through measuring forage chemistry with reflectance. We studied a mixed grass ecosystem in Grasslands National Park of Canada and surrounding pastures, located in southern Saskatchewan. Spectral reflectance was collected at both in-situ field level and in the laboratory. Vegetation samples were collected at each site, sorted into the green grass portion, and then sent to a chemical company for measuring forage quality variables, including protein, lignin, ash, moisture at 135 °C, Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Total Digestible, Digestible Energy, Net Energy for Lactation, Net Energy for Maintenance, and Net Energy for Gain. Reflectance data were processed with the first derivative transformation and continuum removal method. Correlation analysis was conducted on spectral and forage quality variables. A regression model was further built to investigate the possibility of using canopy spectral measurements to predict the grassland quality. Results indicated that field level prediction of protein of mixed grass species was possible (r˛ = 0.63). However, the relationship between canopy reflectance and the other forage quality variables was not strong. PMID:20948940

Guo, Xulin; Wilmshurst, John F; Li, Zhaoqin

2010-09-01

367

Spatial scale of the patchiness of plant poisons: a critical influence on foraging efficiency.  

PubMed

Generalist mammalian browsers and folivores feed on a range of chemically different plant species, which may assist them in diluting toxins and diversifying nutrient consumption. The frequency and order in which their diets are mixed are important determinants of intake. As a result, the degree of plant heterogeneity in an environment, and the spatial scale at which this occurs, should directly influence herbivore foraging decisions. We tested whether altering the Spatial scale of plants, and thus plant secondary metabolites (PSMs), affected foraging efficiency of a generalist folivore, the common brushtail possum (Trichosurus vulpecula). First, we demonstrated that possums were able to consume more from a mixed diet of two chemically different species, Eucalyptus globulus and E. tenuiramis, than when either of these species was offered alone. We then tested whether altering the spatial scale between E. globulus and E. tenuiramis, as small- or large-scale plant heterogeneity "patches," affected possum foraging behavior and, ultimately, their foraging efficiency. Possums increased their foraging efficiency when the spatial scale of plant heterogeneity was small rather than large. We argue that the ability to regularly switch diets, when plant spatial distribution is at a small scale, reduces the negative effects of PSM ingestion. We predict that the heterogeneity of plant patches, in relation to PSM distribution, and the scale at which this occurs across a landscape, are critical factors that influence foraging efficiency and, ultimately, fitness of mammalian herbivores. This research provides a fundamental link between plant chemistry, foraging, and habitat heterogeneity. PMID:16995624

Wiggins, Natasha L; McArthur, Clare; Davies, Noel W; McLean, Stuart

2006-09-01

368

Effect of plant trichomes on the vertical migration of Haemonchus contortus infective larvae on five tropical forages.  

PubMed

The influence of trichomes on vertical migration and survival of Haemonchus contortus infective larvae (L3) on different forages was investigated. Four different forages showing different distributions of trichomes (Brachiaria brizantha cv. Marandu, Brachiaria brizantha cv. Xaraes, Andropogon gayanus, and Stylosanthes spp.), and one forage species without trichomes (Panicum maximum cv. Tanzania), were used. Forages cut at the post-grazing height were contaminated with faeces containing L3. Samples of different grass strata (0-10, 10-20, >20 cm) and faeces were collected for L3 quantification once per week over four weeks. In all forages studied, the highest L3 recovery occurred seven days after contamination, with the lowest recovery on A. gayanus. In general, larvae were found on all forages' strata. However, most of the larvae were at the lower stratum. There was no influence of trichomes on migration and survival of H. contortus L3 on the forages. PMID:18975119

Oliveira, Aruaque L F; Costa, Ciniro; Rodella, Roberto A; Silva, Bruna F; Amarante, Alessandro F T

2009-06-01

369

Bat guilds, a concept to classify the highly diverse foraging and echolocation behaviors of microchiropteran bats.  

PubMed

Throughout evolution the foraging and echolocation behaviors as well as the motor systems of bats have been adapted to the tasks they have to perform while searching and acquiring food. When bats exploit the same class of environmental resources in a similar way, they perform comparable tasks and thus share similar adaptations independent of their phylogeny. Species with similar adaptations are assigned to guilds or functional groups. Habitat type and foraging mode mainly determine the foraging tasks and thus the adaptations of bats. Therefore, we use habitat type and foraging mode to define seven guilds. The habitat types open, edge and narrow space are defined according to the bats' echolocation behavior in relation to the distance between bat and background or food item and background. Bats foraging in the aerial, trawling, flutter detecting, or active gleaning mode use only echolocation to acquire their food. When foraging in the passive gleaning mode bats do not use echolocation but rely on sensory cues from the food item to find it. Bat communities often comprise large numbers of species with a high diversity in foraging areas, foraging modes, and diets. The assignment of species living under similar constraints into guilds identifies patterns of community structure and helps to understand the factors that underlie the organization of highly diverse bat communities. Bat species from different guilds do not compete for food as they differ in their foraging behavior and in the environmental resources they use. However, sympatric living species belonging to the same guild often exploit the same class of resources. To avoid competition they should differ in their niche dimensions. The fine grain structure of bat communities below the rather coarse classification into guilds is determined by mechanisms that result in niche partitioning. PMID:23840190

Denzinger, Annette; Schnitzler, Hans-Ulrich

2013-01-01

370

Foraging in space and time structure an African small mammal community.  

PubMed

We used live-trapping and foraging to test for the effect of habitat selection and diet on structuring a community of six small mammals and one bird within the Soutpansberg, South Africa. We established grids that straddled adjacent habitats: woodland, rocky hillside, and grassland. Trapping and foraging were used to estimate abundance, habitat use, and species-specific foraging costs. The species with the highest abundance and foraging activity in a habitat, activity time, or food was considered the most efficient and presumed to have a competitive advantage. All species exhibited distinct patterns of spatial and temporal habitat preference which provided the main mechanism of coexistence, followed by diet selection. The study species were organized into three assemblages (? diversity): grassland, Rhabdomys pumilio, Dendromus melanotis, and Mus minutoides.; woodland, Aethomys ineptus and Micaelamys namaquensis; and rock-dwelling, M. namaquensis and Elephantulus myurus. Francolinus natalensis foraged in open rocky areas and under wooded islands within the grassland. Species organization across the habitats suggested that feeding opportunities are available within all habitats; however, distinct habitat preferences resulted from differing foraging aptitudes and efficiencies of the competing species. At Lajuma, species distribution and coexistence are promoted through distinct habitat preferences that were shaped by competition and species-specific foraging costs. The combination of trapping and foraging provided a mechanistic approach that integrates behavior into community ecology by 'asking' the animal to reveal its perspective of the environment. Using spatial and temporal foraging decisions-as behavioral indicators-enables us to guide our understanding for across-taxa species coexistence. PMID:24648024

Abu Baker, Mohammad A; Brown, Joel S

2014-06-01

371

Foraging by forest ants under experimental climatic warming: a test at two sites  

PubMed Central

Climatic warming is altering the behavior of individuals and the composition of communities. However, recent studies have shown that the impact of warming on ectotherms varies geographically: species at warmer sites where environmental temperatures are closer to their upper critical thermal limits are more likely to be negatively impacted by warming than are species inhabiting relatively cooler sites. We used a large-scale experimental temperature manipulation to warm intact forest ant assemblages in the field and examine the impacts of chronic warming on foraging at a southern (North Carolina) and northern (Massachusetts) site in eastern North America. We examined the influence of temperature on the abundance and recruitment of foragers as well as the number of different species observed foraging. Finally, we examined the relationship between the mean temperature at which a species was found foraging and the critical thermal maximum temperature of that species, relating functional traits to behavior. We found that forager abundance and richness were related to the experimental increase in temperature at the southern site, but not the northern site. Additionally, individual species responded differently to temperature: some species foraged more under warmer conditions, whereas others foraged less. Importantly, these species-specific responses were related to functional traits of species (at least at the Duke Forest site). Species with higher critical thermal maxima had greater forager densities at higher temperatures than did species with lower critical thermal maxima. Our results indicate that while climatic warming may alter patterns of foraging activity in predictable ways, these shifts vary among species and between sites. More southerly sites and species with lower critical thermal maxima are likely to be at greater risk to ongoing climatic warming.

Stuble, Katharine L; Pelini, Shannon L; Diamond, Sarah E; Fowler, David A; Dunn, Robert R; Sanders, Nathan J

2013-01-01

372

Foraging Behaviour of Juvenile Female New Zealand Sea Lions (Phocarctos hookeri) in Contrasting Environments  

PubMed Central

Foragers can show adaptive responses to changes within their environment through morphological and behavioural plasticity. We investigated the plasticity in body size, at sea movements and diving behaviour of juvenile female New Zealand (NZ) sea lions (Phocarctos hookeri) in two contrasting environments. The NZ sea lion is one of the rarest pinnipeds in the world. Most of the species is based at the subantarctic Auckland Islands (AI; considered to be marginal foraging habitat), with a recolonizing population on the Otago Peninsula, NZ mainland (considered to be more optimal habitat). We investigated how juvenile NZ sea lions adjust their foraging behaviour in contrasting environments by deploying satellite-linked platform transmitting terminals (PTTs) and time-depth recorders (TDRs) on 2–3 year-old females at AI (2007–2010) and Otago (2009–2010). Juvenile female NZ sea lions exhibited plasticity in body size and behaviour. Otago juveniles were significantly heavier than AI juveniles. Linear mixed effects models showed that study site had the most important effect on foraging behaviour, while mass and age had little influence. AI juveniles spent more time at sea, foraged over larger areas, and dove deeper and longer than Otago juveniles. It is difficult to attribute a specific cause to the observed contrasts in foraging behaviour because these differences may be driven by disparities in habitat/prey characteristics, conspecific density levels or interseasonal variation. Nevertheless, the smaller size and increased foraging effort of AI juveniles, combined with the lower productivity in this region, support the hypothesis that AI are less optimal habitat than Otago. It is more difficult for juveniles to forage in suboptimal habitats given their restricted foraging ability and lower tolerance for food limitation compared to adults. Thus, effective management measures should consider the impacts of low resource environments, along with changes that can alter food availability such as potential resource competition with fisheries.

Leung, Elaine S.; Auge, Amelie A.; Chilvers, B. Louise; Moore, Antoni B.; Robertson, Bruce C.

2013-01-01

373

Occurrence of fumonisin in forage grass in new zealand.  

PubMed

Fumonisin B(1) (FB(1)) was isolated from samples of forage grass originating in paddocks associated with an idiopathic disease of Canadian wapiti and wapiti-red deer hybrids characterized by "ill thrift" and liver dysfunction. Four of 40 samples contained 1, 3, 6, and 9 ppm (micrograms per gram) of FB(1) and 4, 0.5, 2, and 0.5 ppm, respectively, of the methyl ester of FB(1). Analyses were done by ion spray mass spectrometry and confirmed by both fast atom bombardment (solids probe) and mass spectral analysis by electron impact ionization of the trifluoroacetate derivative of the base hydrolyzed product (pentolamine) of FB(1). This article contains the first report of the presence of fumonisin B(1) in grass. PMID:16348778

Mirocha, C J; Mackintosh, C G; Mirza, U A; Xie, W; Xu, Y; Chen, J

1992-09-01

374

Occurrence of Fumonisin in Forage Grass in New Zealand †  

PubMed Central

Fumonisin B1 (FB1) was isolated from samples of forage grass originating in paddocks associated with an idiopathic disease of Canadian wapiti and wapiti-red deer hybrids characterized by “ill thrift” and liver dysfunction. Four of 40 samples contained 1, 3, 6, and 9 ppm (micrograms per gram) of FB1 and 4, 0.5, 2, and 0.5 ppm, respectively, of the methyl ester of FB1. Analyses were done by ion spray mass spectrometry and confirmed by both fast atom bombardment (solids probe) and mass spectral analysis by electron impact ionization of the trifluoroacetate derivative of the base hydrolyzed product (pentolamine) of FB1. This article contains the first report of the presence of fumonisin B1 in grass.

Mirocha, C. J.; Mackintosh, C. G.; Mirza, U. A.; Xie, W.; Xu, Y.; Chen, J.

1992-01-01

375

Adaptive Nonlinear Signal Approximation Using Bacterial Foraging Strategy  

NASA Astrophysics Data System (ADS)

Uniform approximation of signals has been an area of interest for researchers working in different disciplines of science and engineering. This paper presents an adaptive algorithm based on E. coli bacteria foraging strategy (EBFS) for uniform approximation of signals by linear combinations of shifted nonlinear basis functions. New class of nonlinear basis functions has been derived from a sigmoid function. The weight factor of the newly proposed nonlinear basis functions has been optimized by using the EBFS to minimize the mean square error. Different test signals are considered for validation of the present technique. Results are also compared with Genetic algorithm approach. The proposed technique could also be useful in fractional signal processing applications.

Kumar, Naik Manoj; Rutuparna, Panda

376

Status-dependent foraging behaviour in coral reef wrasses  

NASA Astrophysics Data System (ADS)

Field observations using underwater video were used to reveal differences in the duration and frequency that fish engaged in daily behaviours such as chasing, searching, feeding, and travelling, according to their social patterns [passive or aggressive terminal phases (TPs), pair-spawning, or promiscuous groups] and intraspecific status (terminal or initial colour phases). Marked differences were apparent according to status, but this was not consistent among the three species; TP Cheilinus fasciatus tended to swim in longer bouts with less frequent searching or feeding than initial phase (IP) conspecifics; TP Cirrhilabrus punctatus exhibited less frequent feeding and travelling than IP conspecifics, while the most aggressive species Stethojulis bandanensis displayed no significant intraspecific differences. We highlight the importance of social context and individual status when examining fish foraging activities and the utility of underwater video for recording the duration and frequency that fish engage in essential daily activities.

Layton, Cayne; Fulton, Christopher J.

2014-06-01

377

Foraging behavior of three passerines in mature bottomland hardwood forests during summer.  

SciTech Connect

Attention has focused on forest management practices and the interactions between birds and their habitat, as a result of apparent declines in populations of many forest birds. Although avian diversity and abundance have been studied in various forest habitats, avian foraging behavior is less well known. Although there are published descriptions of avian foraging behaviors in the western United States descriptions from the southeastern United States are less common. This article reports on the foraging behavior of the White-eyed Vireo, Northern Parula, and Hooded Warbler in mature bottomland hardwood forests in South Carolina.

Buffington, J., Matthew; Kilgo, John, C.; Sargent, Robert, A.; Miller, Karl, V.; Chapman, Brian, R.

2001-08-01

378

Foraging across the life span: is there a reduction in exploration with aging?  

PubMed Central

Does foraging change across the life span, and in particular, with aging? We report data from two foraging tasks used to investigate age differences in search in external environments as well as internal search in memory. Overall, the evidence suggests that foraging behavior may undergo significant changes across the life span across internal and external search. In particular, we find evidence of a trend toward reduced exploration with increased age. We discuss these findings in light of theories that postulate a link between aging and reductions in novelty seeking and exploratory behavior.

Mata, Rui; Wilke, Andreas; Czienskowski, Uwe

2013-01-01

379

Observations of geese foraging for clam shells during spring on the Yukon-Kuskokwim Delta, Alaska  

USGS Publications Warehouse

We studied the behavior of geese on exposed river ice during spring on the Yukon-Kuskokwim Delta. The predominant behavior while on the ice for both sexes was foraging; however, females foraged more than males. Visual inspection of the ice revealed no potential plant or animal food items. However, numerous small (<20 man) clam shells (Macoma balthica) and pieces of shell were noted. It appeared that geese were foraging on empty clam shells. This potential source of calcium was available to breeding geese just prior to egg formation and geese likely stored this calcium in the form of medullary bone for use during egg formation.

Flint, P. L.; Fowler, A. C.; Bottitta, G. E.; Schamber, J.

1998-01-01

380

Testing olfactory foraging strategies in an Antarctic seabird assemblage.  

PubMed

Procellariiform seabirds (petrels, albatrosses and shearwaters) forage over thousands of square kilometres for patchily distributed prey resources. While these birds are known for their large olfactory bulbs and excellent sense of smell, how they use odour cues to locate prey patches in the vast ocean is not well understood. Here, we investigate species-specific responses to 3-methyl pyrazine in a sub-Antarctic species assemblage near South Georgia Island (54 degrees 00 ' S, 36 degrees 00 ' W). Pyrazines are scented compounds found in macerated Antarctic krill (Euphausia superba), a primary prey item for many seabird species in this region. To examine behavioural attraction to this odour, we presented birds with either scented or 'unscented' vegetable oil slicks at sea. As a positive control for our experiments, we also compared birds' responses to a general olfactory attractant, herring oil. Responses to pyrazine were both highly species specific and consistent with results from earlier studies investigating responses to crude krill extracts. For example, Cape petrels (Daption capense), giant petrels (Macronectes sp.) and white-chinned petrels (Procellaria aequinoctialis) were sighted at least 1.8-4 times as often at pyrazine-scented slicks than at control slicks. Black-browed albatrosses (Diomedea melanophris) were only sighted at pyrazine-scented slicks and never at control slicks. Wilson's storm-petrels (Oceanites oceanicus), black-bellied storm-petrels (Fregetta tropica), great shearwaters (Puffinus gravis) and prions (Pachyptila sp.) were sighted with equal frequency at control and pyrazine-scented slicks. As expected, responses to herring oil were more common. With the exception of great shearwaters (Puffinus gravis), each of these species was sighted up to five times as often at slicks scented with herring oil compared with control slicks. Together, the results support the hypothesis that Antarctic procellariiforms use species-specific foraging strategies that are inter-dependent and more complex than simply tracking prey by scent. PMID:15339950

Nevitt, Gabrielle; Reid, Keith; Trathan, Phil

2004-09-01

381

Hidden Markov models: the best models for forager movements?  

PubMed

One major challenge in the emerging field of movement ecology is the inference of behavioural modes from movement patterns. This has been mainly addressed through Hidden Markov models (HMMs). We propose here to evaluate two sets of alternative and state-of-the-art modelling approaches. First, we consider hidden semi-Markov models (HSMMs). They may better represent the behavioural dynamics of foragers since they explicitly model the duration of the behavioural modes. Second, we consider discriminative models which state the inference of behavioural modes as a classification issue, and may take better advantage of multivariate and non linear combinations of movement pattern descriptors. For this work, we use a dataset of >200 trips from human foragers, Peruvian fishermen targeting anchovy. Their movements were recorded through a Vessel Monitoring System (?1 record per hour), while their behavioural modes (fishing, searching and cruising) were reported by on-board observers. We compare the efficiency of hidden Markov, hidden semi-Markov, and three discriminative models (random forests, artificial neural networks and support vector machines) for inferring the fishermen behavioural modes, using a cross-validation procedure. HSMMs show the highest accuracy (80%), significantly outperforming HMMs and discriminative models. Simulations show that data with higher temporal resolution, HSMMs reach nearly 100% of accuracy. Our results demonstrate to what extent the sequential nature of movement is critical for accurately inferring behavioural modes from a trajectory and we strongly recommend the use of HSMMs for such purpose. In addition, this work opens perspectives on the use of hybrid HSMM-discriminative models, where a discriminative setting for the observation process of HSMMs could greatly improve inference performance. PMID:24058400

Joo, Rocio; Bertrand, Sophie; Tam, Jorge; Fablet, Ronan

2013-01-01

382

Predicting Forage Foodscapes with Spectroscopy and UAV Imagery  

NASA Astrophysics Data System (ADS)

A major goal in conservation biology is to predict habitat use by animals. This goal requires methods for identifying and mapping habitat quality features such as concealment, nitrogen (N) and chemical defenses across different spatial scales. Remote sensing has been used for landscape-scale analysis of habitat features to explain the spatial use and selection of habitat by large herbivores. However, studies that directly link specific parameters of habitat quality to selection by wildlife are needed at the microsite-scale before landscape-scale mapping can be validated. Herbivores appear to make foraging decisions based on the nutritional quality of plants. For example, previous research has shown that sagebrush preferentially browsed by pygmy rabbits (Brachylagus idahoensis), a sagebrush specialist mammal, contain relatively higher amounts of crude protein and lower amounts of monoterpenes. Other research has shown that sage grouse (Centrocercus urophasianus) select dwarf sagebrush (Artemisia arbuscula and A. nova) over big sagebrush (A. tridentata subsp wyomingensis) for forage. In this study we examine the use of spectroscopy from the visible to shortwave infrared for predicting sagebrush nutritional quality, as measured by N (crude protein). Predictions are compared across instruments (FOSS NIRSystem 5000 and ASD FieldSpec Pro), sampling methods (i.e., dried ground leaves and fresh whole leaves), and species (dwarf and big sagebrush). We also build a foundation for spatial upscaling from whole leaf and individual shrubs to collective patches in a landscape by acquiring and classifying unmanned aerial vehicle (UAV) imagery in terms of sagebrush food types. The resultant 'foodscape' map concept will ultimately provide a tool for rapid assessment of the dietary quality of sagebrush and facilitate more effective conservation of herbivores that rely on sagebrush for food.

Mitchell, J. J.; Olsoy, P.; Forbey, J.; Glenn, N. F.; Burgess, M. A.; Rachlow, J. L.; Shipley, L. A.

2013-12-01

383

Flight destinations and foraging behaviour of northern gannets ( Sula bassana) preying on a small forage fish in a low-Arctic ecosystem  

NASA Astrophysics Data System (ADS)

We applied data loggers (temperature-depth and GPS-temperature-depth) on individual birds in combination with dietary sampling and a vessel survey of prey availability to assess the foraging behaviour of northern gannets ( Sula bassana, Linnaeus 1758) in a low-Arctic ecosystem in the NW Atlantic. We demonstrate that the gannets foraged almost exclusively on inshore and coastal aggregations of capelin. There was a strong correspondence between the distributions of capelin and foraging gannets, and gannets exhibited persistence in successive foraging trips to the same foraging areas. The diving activity of gannets was highest during the early morning and evening, when capelin are known to be primarily available in the upper water column. Most of the gannets dive depths were less than 5 m. Flight speeds recorded by GPS were 9% higher than those estimated by previous methods and were shown to benefit from tail wind. This study shows how a combination of ship-based surveys and individually tagged birds can help understanding predator-prey intersection in a three-dimensional space in the marine environment.

Garthe, Stefan; Montevecchi, William A.; Davoren, Gail K.

2007-02-01

384

Foraging Habitat for Bird Species or Bird Diversity in Wetland Design.  

National Technical Information Service (NTIS)

This technical note provides guidelines for creating, restoring, or enhancing wetlands with foraging habitat intended to 1) support selected bird species, or 2) maximize bird diversity. Information in this technical note is applicable to wetlands ranging ...

B. Harrington B. Streever

1999-01-01

385

Sound Use, Sequential Behavior and Ecology of Foraging Bottlenose Dolphins, Tursiops Truncatus.  

National Technical Information Service (NTIS)

Odontocetes are assumed to use echolocation for navigation and foraging, but neither of these uses of biosonar has been conclusively demonstrated in free-ranging animals. A new observation platform combining underwater acoustic recording and a remote cont...

D. P. Nowacek

1999-01-01

386

Range-Wide Meta-Analysis of Red-Cockaded Woodpecker Foraging Habitat Suitability.  

National Technical Information Service (NTIS)

The work reported here describes the project 'Range-Wide Meta- Analysis of Red-Cockaded Woodpecker Foraging Habitat Suitability.' This project was conducted under a cooperative agreement between the Engineer Research and Development Center - Construction ...

A. E. McKellar D. C. Kesler D. K. Delancy J. R. Walters R. J. Mitchell

2013-01-01

387

Ad?lie Penguin Foraging Location Predicted by Tidal Regime Switching  

PubMed Central

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.

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

2013-01-01

388

Digestive utilization of ozone-exposed forage by rabbits (Oryctolagus cuniculus).  

PubMed

A mixture of common Southern Piedmont (USA) grassland species (Lolium arundinacea, Paspalum dilatatum, Cynodon dactylon and Trifolium repens) was exposed to O(3) [ambient (non-filtered; NF) and twice-ambient (2X) concentrations] and fed to individually caged New Zealand white rabbits (Oryctolagus cuniculus) in a digestibility experiment. Forages and feed refusals were analyzed for concentrations of total cell wall constituents, lignin, crude protein, and soluble and hydrolyzable phenolic fractions. Neutral detergent fiber and acid detergent fiber digestibility by rabbits were significantly lower for 2X than NF forage. Decreased digestibility could not be attributed to lignin concentrations, but was associated with increased concentrations of acid-hydrolyzable and saponifiable phenolics. Exposure of forage to elevated O(3) resulted in decreased digestible dry matter intake by rabbits. Elevated O(3) concentrations could be expected to have a negative impact on forage quality, resulting in decreased nutrient utilization by mammalian herbivores in Southern Piedmont grasslands under projected future climate scenarios. PMID:22296918

Gilliland, Nicholas J; Chappelka, Arthur H; Muntifering, Russell B; Booker, Fitzgerald L; Ditchkoff, Stephen S

2012-04-01

389

Process and Apparatus to Improve the Properties and Value of Forage Crops.  

National Technical Information Service (NTIS)

An apparatus and method for the treatment of forage material and other agricultural plants by crushing and impact maceration has been developed. The apparatus includes a pair of rotatable, generally cylindrical crushing rollers and a rotatable impact roto...

R. G. Koegel T. J. Kraus K. J. Shinners R. J. Straub

1991-01-01

390

Urban foragers wander around the city in search of food, communion, and conversation  

NSDL National Science Digital Library

Documentary about urban foragers in Chicagohttp://boingboing.net/2009/01/07/short-documentary-ab.htmlThe freegans' creed: waste not, want nothttp://www.guardian.co.uk/environment/2009/jul/19/freegan-environment-foodForage Oaklandhttp://forageoakland.blogspot.com/Urban Edibleshttp://urbanedibles.org/Wild Food Tourshttp://www.wildmanstevebrill.com/Wandering around sidewalks and alleys looking for edible plants like dandelions or goosefoot might not be appealing to everyone, but to urban foragers, it's just part of a more sustainable and environmentally friendly way of life. The urban foraging movement has been growing as of late, and there are numerous weblogs and websites dedicated to those who wish to learn more about the subject. Many urban foragers will often share information with others in order to share the wealth of an apple tree or a collection of edible plants. Urban foragers abide by a code of ethics that includes respect for private property (no trespassing, obviously), and they aim to treat people with respect and to also clean up after themselves. The practice is not without its perils, as many plants in and around cities can be sprayed with chemicals or grown in soil that is laden with heavy chemicals. Chicago-based urban forager Nancy Klehm recently noted that she does this in order "to slow down, to not follow the grid, to skip out of technoconsumerism. I do this to realize that the health of my body is connected to the health of the land." The first link will take visitors to a nice piece from the Reuters News Service on the practice of urban foraging. The second link leads to a delightful 17-minute documentary on urban foragers in Chicago titled "Sky Full of Bacon 07: Eat This City". Moving on, the third link will whisk users away to a great piece by William Skidelsky writing for The Observer. In the piece, Skidelsky investigates the world of "freegans" by spending some time with one of their kind, Tristram Stuart. The fourth link leads to the Forage Oakland weblog which contains "edible maps" of Oakland. The fifth link will take visitors to the Urban Edibles site, which is a "community database of wild food sources in Portland, OR". The last link leads to the homepage of "Wildman" Steve Brill, who is "America's best known forager."

Grinnell, Max

2009-07-31

391

The Effect of Forage Level and Oil Supplement on Butyrivibrio fibrisolvens and Anaerovibrio lipolytica in Continuous Culture Fermenters  

PubMed Central

The objective of this study was to evaluate the effects of forage level and oil supplement on selected strains of rumen bacteria believed to be involved in biohydrogenation (BH). A continuous culture system consisting of four fermenters was used in a 4×4 Latin square design with a factorial arrangement of treatments, with four 10 d consecutive periods. Treatment diets were: i) high forage diet (70:30 forage to concentrate (dry matter basis); HFC), ii) high forage plus oil supplement (HFO), iii) low forage diet (30:70 forage to concentrate; LFC), and iv) low forage plus oil supplement (LFO). The oil supplement was a blend of fish oil and soybean oil added at 1 and 2 g/100 g dry matter, respectively. Treatment diets were fed for 10 days and samples were collected from each fermenter on the last day of each period 3 h post morning feeding. The concentrations of vaccenic acid (t11C18:1; VA) and c9t11 conjugated linoleic acid (CLA) were greater with the high forage diet while the concentrations of t10 C18:1 and t10c12 CLA were greater with the low forage diet and addition of oil supplement increased their concentrations at both forage levels. The DNA abundance of Anaerovibrio lipolytica, and Butyrivibrio fibrisolvens vaccenic acid subgroup (Butyrivibrio VA) were lower with the low forage diets but not affected by oil supplement. The DNA abundance of Butyrivibrio fibrisolvens stearic acid producer subgroup (Butyrivibrio SA) was not affected by forage level or oil supplement. In conclusion, oil supplement had no effects on the tested rumen bacteria and forage level affected Anaerovibrio lipolytica and Butyrivibrio VA.

Gudla, P.; Ishlak, A.; AbuGhazaleh, A. A.

2012-01-01

392

Retinal Ganglion Cell Topography of Five Species of Ground-Foraging Birds  

PubMed Central

Birds that forage on the ground have been studied extensively in relation to behavioral trade-offs between foraging and scanning for predators; however, we know little about the topography of their retinas, which can influence how they gather visual information. We characterized the density of retinal ganglion cells across the retina and estimated visual acuity of four Passeriformes (European starling Sturnus vulgaris, brown-headed cowbird Molothrus ater, house sparrow Passer domesticus, house finch Carpodacus mexicanus) and one Columbiforme (mourning dove Zenaida macroura) that forage on the ground. We used cresyl violet to stain retinal ganglion cells and estimated visual acuity based on cell density and eye size. All species contained a single area centralis, where cell densities were >20,000 cells/mm2. The proportion of the retina that fell in each of five cell density ranges varied between species. European starlings and house finches had the largest area of high cell density, mourning doves had the smallest. The largest proportion of the retina (>35%) of brown-headed cowbird and house sparrow was in the second-lowest cell density range. Considering the 25th percentile of highest cell densities, house finches and European starlings showed the highest cell densities and mourning doves the lowest. Estimated visual acuity increased from house finch, house sparrow, brown-headed cowbird, European starling to mourning dove, and was associated with both retinal area and cell density. Our findings suggest that these ground foragers do not have highly specialized retinas in relation to other types of foragers (e.g. tree foragers), probably because foraging on seeds and insects from the ground is not as visually demanding; however, the studied species showed variability in retinal topography that may be related to foraging techniques, eye size constraints, and size of the area centralis.

Dolan, Tracy; Fernandez-Juricic, Esteban

2010-01-01

393

Forage radish and cereal rye cover crop effects on mycorrhizal fungus colonization of maize roots  

Microsoft Academic Search

Forage radish (Raphanus sativus L. var. longipinnatus) is being used by increasing numbers of farmers as a winter cover crop in the Mid-Atlantic USA. It is a non-host to arbuscular\\u000a mycorrhizal fungi (AMF) and releases anti-fungal isothiocyanates (ITCs) upon decomposition in the winter. Field experiments\\u000a were conducted to determine the effect of forage radish and cereal rye (Secale cereale L.)

Charles M. White; Ray R. Weil

2010-01-01

394

Distribution and foraging behaviour of the Peruvian Booby ( Sula variegata ) off northern Chile  

Microsoft Academic Search

The Peruvian Booby (Sula variegata) is one of the most numerous guano bird species in the Humboldt Current. We used a combination of data logger deployment,\\u000a at-sea observations and colony-based work to investigate the foraging and diving behaviour, as well as the at-sea distribution\\u000a and food choice of Peruvian Boobies breeding at Isla Pajaros, northern central Chile. Birds foraged in

Katrin Ludynia; Stefan Garthe; Guillermo Luna-Jorquera

2010-01-01

395

Plant compositional constituents affecting between-plant and animal species prediction of forage intake.  

PubMed

The purpose of the study was to identify plant compositional constituents that influence forage intake. Emphasis was put on the ratio in vitro digestibility of organic matter (IVDOM):NDF because preliminary work with cattle and a limited number of forages showed the ratio to account for more variation in intake than either IVDOM or NDF alone. The compositional constituents were tested in intake prediction models using local and published data (n = 302) on grass pastures, silages, hays, straws, legumes, grass-legume mixtures, and shrubs ingested by both browsing and grass-eating ruminants (goats, red deer, impala, blesbok, sheep, cattle, and blue wildebeest). In the local experiments, esophageally fistulated and fecal bag-harnessed animals were used to collect representative grazed forage samples from pastures and to determine OM excreted, respectively. Forage intake was calculated as OM excreted divided by (1-IVDOM). Intake of silages, hays, and straws was measured indoors in digestibility trials. Intakes among species were compared after scaling for size by BW raised to the power of .9. Major contributors to the variation in forage intake were ash, hemicellulose, IVDOM:NDF, ADL, and the interaction between DM content and, respectively, ash, N, and ADL. High tannin/phenol concentrations proved limiting to intake. The ratio of IVDOM:NDF accounted for 67% of the variation in forage intake if data for which the other constituents had an effect were omitted, and the equation, OMI, g.kg BW-.9.d-1 = 70-97e-.975(IVDOM:NDF), predicted intake across all forages and ruminant species with a Sy.x of 5.3 g.kg BW-.9.d-1 (CV = 15%). The ratio of IVDOM:NDF should be valuable as a relatively inexpensive and rapid method to screen forages and cultivars. PMID:8567482

Meissner, H H; Paulsmeier, D V

1995-08-01

396

Determination of Tropical Forage Preferences Using Two Offering Methods in Rabbits  

PubMed Central

Two methods of feed preference trials were compared to evaluate the acceptability of 5 fresh foliages: Leucaena leucocephala, Moringa oleifera, Portulaca oleracea, Guazuma ulmifolia, and Brosimum alicastrum that was included as control. The evaluation included chemical analyses and forage intake by rabbits. The first method was a cafeteria trial; 12 California growing rabbits aged 8 wk, allocated in individual cages, were offered the five forage plants at the same time inside the cage, while in the second trial 60 California growing rabbits aged 8 wk, allocated individually, were randomly distributed into 5 experimental groups (n = 12/group); for each group just one forage species was offered at a time. The testing period for each method lasted for 7 d, preceded by one week of adaptation. The results showed that B. alicastrum and L. lecocephala were the most preferred forages while on the contrary G. ulmifolia was the least preferred one by rabbits. The results also revealed that the CV% value for the 2nd method (16.32%), which the tested forages were presented separately to rabbits, was lower and methodologically more acceptable than such value for the 1st method (34.28%), which all forages were presented together at the same time. It can be concluded that a range of tropical forages were consumed in acceptable quantities by rabbits, suggesting that diets based on such forages with a concentrate supplement could be used successfully for rabbit production. However, growth performance studies are still needed before recommendations could be made on appropriate ration formulations for commercial use.

Safwat, A. M.; Sarmiento-Franco, L.; Santos-Ricalde, R. H.; Nieves, D.

2014-01-01

397

Life expectancy and onset of foraging in the honeybee ( Apis mellifera )  

Microsoft Academic Search

Predictions that precocious foraging in honeybee workers is a result of shortening of their life expectancy were tested in\\u000a both laboratory and field experiments. In the laboratory experiment, we assessed the impact of anaesthesia with CO2 and infection with Nosema apis on the lifespan of workers. In the field experiment, the age at onset of foraging was observed in groups

M. Woyciechowski; D. Moro?

2009-01-01

398

Plant Compositional Constituents Affecting Between-Plant and Animal Species Prediction of Forage Intake  

Microsoft Academic Search

The purpose of the study was to identify plant compositional constituents that in- fluence forage intake. Emphasis was put on the ratio in vitro digestibility of organic matter (1VDOM):NDF because preliminary work with cattle and a limited number of forages showed the ratio to account for more variation in intake than either rVDOM or NDF alone. The compositional constituents were

H. H. Meissner; D. V. Paulsmeiert

2010-01-01

399

Retinal ganglion cell topography of five species of ground-foraging birds.  

PubMed

Birds that forage on the ground have been studied extensively in relation to behavioral trade-offs between foraging and scanning for predators; however, we know little about the topography of their retinas, which can influence how they gather visual information. We characterized the density of retinal ganglion cells across the retina and estimated visual acuity of four Passeriformes (European starling Sturnus vulgaris, brown-headed cowbird Molothrus ater, house sparrow Passer domesticus, house finch Carpodacus mexicanus) and one Columbiforme (mourning dove Zenaida macroura) that forage on the ground. We used cresyl violet to stain retinal ganglion cells and estimated visual acuity based on cell density and eye size. All species contained a single area centralis, where cell densities were >20,000 cells/mm(2). The proportion of the retina that fell in each of five cell density ranges varied between species. European starlings and house finches had the largest area of high cell density, mourning doves had the smallest. The largest proportion of the retina (>35%) of brown-headed cowbird and house sparrow was in the second-lowest cell density range. Considering the 25th percentile of highest cell densities, house finches and European starlings showed the highest cell densities and mourning doves the lowest. Estimated visual acuity increased from house finch, house sparrow, brown-headed cowbird, European starling to mourning dove, and was associated with both retinal area and cell density. Our findings suggest that these ground foragers do not have highly specialized retinas in relation to other types of foragers (e.g. tree foragers), probably because foraging on seeds and insects from the ground is not as visually demanding; however, the studied species showed variability in retinal topography that may be related to foraging techniques, eye size constraints, and size of the area centralis. PMID:20516656

Dolan, Tracy; Fernández-Juricic, Esteban

2010-01-01

400

Adaptation of forage legume species and cultivars under grazing in two extensive livestock systems in Italy  

Microsoft Academic Search

Legume-based pastures can increase the forage feeding value, the self-provision of protein sources and the sustainability of grazing systems. This 4-year study provided further knowledge on adaptation of forage legume species and cultivars for pasture sowing in extensive livestock systems of inland Italian areas. Three cultivars of lucerne (Medicago sativa L.), two of birdsfoot trefoil (Lotus corniculatus L.) and two

L. Pecetti; P. Annicchiarico; F. Battini; S. Cappelli

2009-01-01

401

Forage digestibility and intake by lesser snow geese: effects of dominance and resource heterogeneity  

Microsoft Academic Search

We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches (\\u000a$$\\\\bar x$$\\u000a=21.5 m2) of forage that made up =3% of the study area and consisted of high-quality

Jerry W. Hupp; Robert G. White; James S. Sedinger; Donna G. Robertson

1996-01-01

402

Regulation of pollen foraging in honeybee colonies: effects of young brood, stored pollen, and empty space  

Microsoft Academic Search

Pollen storage in a colony of Apis mellifera is actively regulated by increasing and decreasing pollen foraging according to the “colony's needs.” It has been shown that\\u000a nectar foragers indirectly gather information about the nectar supply of the colony from nestmates without estimating the\\u000a amount of honey actually stored in the combs. Very little is known about how the actual

Claudia Dreller; Robert E. Page Jr.; M. Kim Fondrk

1999-01-01

403

Factors regulating the breeding and foraging activity of a tropical opisthobranch  

Microsoft Academic Search

This study investigated the influence of environmental factors on the foraging cycle, breeding activity, settlement and growth\\u000a of the opisthobranch Hydatina\\u000a physis using laboratory trials and field observations. Results showed that H. physis follows a nocturnal circadian rhythm mediated by photic intensity and modulated by food availability. The adults foraged\\u000a between 1900 and 0530 h, with an activity peak between 2000

Jean-François Hamel; Annie Mercier

2006-01-01

404

Meta-analysis of foraging and predation risk trade-offs in terrestrial systems  

Microsoft Academic Search

Although there is ample evidence for the generality of foraging and predation trade-offs in aquatic systems, its application\\u000a to terrestrial systems is less comprehensive. In this review, meta-analysis was used to analyze experiments on giving-up-densities\\u000a in terrestrial systems to evaluate the overall magnitude of predation risk on foraging behavior and experimental conditions\\u000a mediating its effect. Results indicate a large and

Jennifer L. Verdolin

2006-01-01

405

The strategy of fly-and-forage migration, illustrated for the osprey ( Pandion haliaetus )  

Microsoft Academic Search

Migrating birds often alternate between flight steps, when distance is covered and energy consumed, and stopover periods,\\u000a when energy reserves are restored. An alternative strategy is fly-and-forage migration, useful mainly for birds that hunt\\u000a or locate their prey in flight, and thus, enables birds to combine foraging with covering migration distance. The favourability\\u000a of this strategy in comparison with the

Roine Strandberg; Thomas Alerstam

2007-01-01

406

Western Fisheries Research Center--Forage fish studies in Puget Sound  

USGS Publications Warehouse

Researchers at the Western Fisheries Research Center are working with other U.S. Geological Survey (USGS) Centers to better understand the interconnected roles of forage fishes throughout the ecosystem of Puget Sound, Washington. Support for these studies primarily is from the USGS Coastal Habitats in Puget Sound (CHIPS) program, which supports studies of the nearshore areas of Puget Sound. Human perturbations in the nearshore area such as shoreline armoring or urban development can affect the nearshore habitats critical to forage fish.

Liedtke, Theresa L.

2012-01-01

407

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany1  

Microsoft Academic Search

Nitrogen fertilization of forage is often accompanied by an increased incidence of grass tetany. A field experi- ment was established on two calcareous soils to evaluate the effects of N fertilizer on forage quality indices of grass tetany. Nitrogen, as NH,N0 i, was applied at 0 and 150 kg N\\/ha in each of 2 years to separate plots. The crested

D. L. Grunes; H. Waggoner; A. Florence; D. A. Hewes; P. K. Joo

1975-01-01

408

A Simple Method for the Analysis of Particle Sizes of Forage and Total Mixed Rations  

Microsoft Academic Search

ABSTRACT,following metabolic disorders: reduced total DM digestibility, reduced milk fat percentage, displaced A simple separator was developed to determine($ruminal separation of wet forage into three fractions and also,drome,(20 j. cows,consuming,sufficient NDF with a allows plotting of the particle size distribution. The,finely chopped,forage can also exhibit the Same meta- bolic disorders as cows fed a diet deficient in fiber ( 5,

B. P. Lammers; D. R. Buckmaster; A. J. Heinrichs

1996-01-01

409

Inferring Foraging Areas of Nesting Loggerhead Turtles Using Satellite Telemetry and Stable Isotopes  

PubMed Central

In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nesting in Florida and (ii) examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1) a seasonal continental shelf–constrained migratory pattern along the northeast U.S. coastline, (2) a non-breeding residency in southern foraging areas and (3) a residency in the waters adjacent to the breeding area. Isotopic variability in both ?13C and ?15N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well ?13C and ?15N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61%) of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level.

Ceriani, Simona A.; Roth, James D.; Evans, Daniel R.; Weishampel, John F.; Ehrhart, Llewellyn M.

2012-01-01

410

Functional Genomics of Forage and Bioenergy Quality Traits in the Grasses  

Microsoft Academic Search

\\u000a Biomass from forage and energy crops can provide a renewable source of meat, milk, and wool, or power, heat, transport fuels\\u000a and platform chemicals, respectively. Whilst in forage grasses some improvements have been made, the potential of energy grasses\\u000a is limited because plant varieties have not yet been selected for this purpose. There are distinct challenges to determine\\u000a and improve

Iain S. Donnison; Kerrie Farrar; Gordon G. Allison; Edward Hodgson; Jessic Adams; Robert Hatch; Joe A. Gallagher; Paul R. Robson; John C. Clifton-Brown; Phillip Morris

411

Inferring foraging areas of nesting loggerhead turtles using satellite telemetry and stable isotopes.  

PubMed

In recent years, the use of intrinsic markers such as stable isotopes to link breeding and foraging grounds of migratory species has increased. Nevertheless, several assumptions still must be tested to interpret isotopic patterns found in the marine realm. We used a combination of satellite telemetry and stable isotope analysis to (i) identify key foraging grounds used by female loggerheads nesting in Florida and (ii) examine the relationship between stable isotope ratios and post-nesting migration destinations. We collected tissue samples for stable isotope analysis from 14 females equipped with satellite tags and an additional 57 untracked nesting females. Telemetry identified three post-nesting migratory pathways and associated non-breeding foraging grounds: (1) a seasonal continental shelf-constrained migratory pattern along the northeast U.S. coastline, (2) a non-breeding residency in southern foraging areas and (3) a residency in the waters adjacent to the breeding area. Isotopic variability in both ?(13)C and ?(15)N among individuals allowed identification of three distinct foraging aggregations. We used discriminant function analysis to examine how well ?(13)C and ?(15)N predict female post-nesting migration destination. The discriminant analysis classified correctly the foraging ground used for all but one individual and was used to predict putative feeding areas of untracked turtles. We provide the first documentation that the continental shelf of the Mid- and South Atlantic Bights are prime foraging areas for a large number (61%) of adult female loggerheads from the largest loggerhead nesting population in the western hemisphere and the second largest in the world. Our findings offer insights for future management efforts and suggest that this technique can be used to infer foraging strategies and residence areas in lieu of more expensive satellite telemetry, enabling sample sizes that are more representative at the population level. PMID:23028943

Ceriani, Simona A; Roth, James D; Evans, Daniel R; Weishampel, John F; Ehrhart, Llewellyn M

2012-01-01

412

Marker-assisted Selection in Forage Crops and Turf: A Review  

Microsoft Academic Search

\\u000a Researchers and breeders have long been aware that the combination of conventional breeding approaches and molecular tools\\u000a would benefit forage and turf cultivar development. In spite of this, the forage and turf cultivars currently released are\\u000a still conventionally bred. This contrasts with the increasing number of research reports about DNA-marker assisted characterization\\u000a of germplasm resources and QTL mapping for a

Isabel Roldán-Ruiz; Roland Kölliker

413

Kingeider foraging effort during the pre-breeding period in Alaska  

USGS Publications Warehouse

For reproduction, many arctic-nesting migratory birds rely on nutrients obtained on the breeding grounds, so they devote sufficient time to foraging immediately prior to nesting. However, little is known about the increase in foraging effort necessary to meet the energetic requirements of reproduction. In early June 2006 and 2008, we quantified the proportion of time spent foraging before breeding by a large sea duck, the King Eider (Somateria spectabilis), on its breeding grounds in northern Alaska. During >235 hours of behavioral observations, both male and female King Eiders spent > 50% of the day loafing (resting, sleeping, comfort behavior, or being alert). Females foraged on average 30% of the time (mean 7.2 hr day?1, 95% CI 6.0-8.4 hr day?1), three times as much as males (9%; 2.3 hr day?1, 95% CI 1.5-2.8 hr day?1). The most common prey in ponds where the eiders foraged were chironomid larvae and worms ranging in length from 1 to 30 mm. If the King Eider's daily energy expenditure on its breeding grounds is similar to values published for related species, it would need to ingest only 0.2-0.6 g dry mass of invertebrates per minute of foraging to meet its energetic requirements. Males did not lose body mass before breeding, and we assume that their foraging effort was sufficient for energy balance. Therefore, female King Eiders appear to triple their foraging effort over maintenance requirements to meet the energetic challenges of egg formation. Copyright ?? The Cooper Ornithological Society 2011.

Oppel, S.; Powell, A. N.; Butler, M. G.

2011-01-01

414

Time stress, predation risk and diurnal–nocturnal foraging trade-offs in larval prey  

Microsoft Academic Search

Insect larvae increase in size with several orders of magnitude throughout development making them more conspicuous to visually\\u000a hunting predators. This change in predation pressure is likely to impose selection on larval anti-predator behaviour and since\\u000a the risk of detection is likely to decrease in darkness, the night may offer safer foraging opportunities to large individuals.\\u000a However, forsaking day foraging

David Berger; Karl Gotthard

2008-01-01

415

Foraging Ecology of Fall-Migrating Shorebirds in the Illinois River Valley  

PubMed Central

Populations of many shorebird species appear to be declining in North America, and food resources at stopover habitats may limit migratory bird populations. We investigated body condition of, and foraging habitat and diet selection by 4 species of shorebirds in the central Illinois River valley during fall migrations 2007 and 2008 (Killdeer [Charadrius vociferus], Least Sandpiper [Calidris minutilla], Pectoral Sandpiper [Calidris melanotos], and Lesser Yellowlegs [Tringa flavipes]). All species except Killdeer were in good to excellent condition, based on size-corrected body mass and fat scores. Shorebird diets were dominated by invertebrate taxa from Orders Diptera and Coleoptera. Additionally, Isopoda, Hemiptera, Hirudinea, Nematoda, and Cyprinodontiformes contribution to diets varied by shorebird species and year. We evaluated diet and foraging habitat selection by comparing aggregate percent dry mass of food items in shorebird diets and core samples from foraging substrates. Invertebrate abundances at shorebird collection sites and random sites were generally similar, indicating that birds did not select foraging patches within wetlands based on invertebrate abundance. Conversely, we found considerable evidence for selection of some diet items within particular foraging sites, and consistent avoidance of Oligochaeta. We suspect the diet selectivity we observed was a function of overall invertebrate biomass (51.2±4.4 [SE] kg/ha; dry mass) at our study sites, which was greater than estimates reported in most other food selection studies. Diet selectivity in shorebirds may follow tenants of optimal foraging theory; that is, at low food abundances shorebirds forage opportunistically, with the likelihood of selectivity increasing as food availability increases. Nonetheless, relationships between the abundance, availability, and consumption of Oligochaetes for and by waterbirds should be the focus of future research, because estimates of foraging carrying capacity would need to be revised downward if Oligochaetes are truly avoided or unavailable for consumption.

Smith, Randolph V.; Stafford, Joshua D.; Yetter, Aaron P.; Horath, Michelle M.; Hine, Christopher S.; Hoover, Jeffery P.

2012-01-01

416

The Impact of Using Alternative Forages on the Nutrient Value within Slurry and Its Implications for Forage Productivity in Agricultural Systems.  

PubMed

Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha-1) with 100 kg N ha-1 inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha-1 year-1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (P<0.001). The estimated relative fertiliser N equivalence (FNE) (fertiliser-N needed to produce same yield as slurry N), was greatest for lucerne (114 kg) >red clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha-1 yr-1). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P?=?0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001). Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks. PMID:24830777

Crotty, Felicity V; Fychan, Rhun; Theobald, Vince J; Sanderson, Ruth; Chadwick, David R; Marley, Christina L

2014-01-01

417

The Impact of Using Alternative Forages on the Nutrient Value within Slurry and Its Implications for Forage Productivity in Agricultural Systems  

PubMed Central

Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha?1) with 100 kg N ha?1 inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha?1 year?1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (P<0.001). The estimated relative fertiliser N equivalence (FNE) (fertiliser-N needed to produce same yield as slurry N), was greatest for lucerne (114 kg) >red clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha?1 yr?1). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P?=?0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001). Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks.

Crotty, Felicity V.; Fychan, Rhun; Theobald, Vince J.; Sanderson, Ruth; Chadwick, David R.; Marley, Christina L.

2014-01-01

418

Honeybees learn floral odors while receiving nectar from foragers within the hive  

NASA Astrophysics Data System (ADS)

Recent studies showed that nectar odors brought back by honeybee foragers can be learned associatively inside the hive. In the present study, we focused on the learning abilities of bees, which directly interact via trophallaxis with the incoming nectar foragers: the workers that perform nectar-receiving tasks inside the hive. Workers that have received food directly from foragers coming back from a feeder offering either unscented or scented sugar solution [phenylacetaldehyde (PHE) or nonanal diluted] were captured from two observational hives, and their olfactory memories were tested using the proboscis extension response paradigm. Bees that have received scented solution from incoming foragers showed significantly increased response frequencies for the corresponding solution odor in comparison with those that have received unscented solution. No differences in the response frequencies were found between food odors and colonies. The results indicate that first-order receivers learn via trophallaxis the association between the scent and the sugar solution transferred by incoming foragers. The implications of these results should be considered at three levels: the operational cohesion of bees involved in foraging-related tasks, the information propagation inside the hive related to the floral type exploited, and the putative effect of these memories on future preferences for resources.

Farina, Walter M.; Grüter, Christoph; Acosta, Luis; Mc Cabe, Sofía

2007-01-01

419

Game-theoretic methods for functional response and optimal foraging behavior.  

PubMed

We develop a decision tree based game-theoretical approach for constructing functional responses in multi-prey/multi-patch environments and for finding the corresponding optimal foraging strategies. Decision trees provide a way to describe details of predator foraging behavior, based on the predator's sequence of choices at different decision points, that facilitates writing down the corresponding functional response. It is shown that the optimal foraging behavior that maximizes predator energy intake per unit time is a Nash equilibrium of the underlying optimal foraging game. We apply these game-theoretical methods to three scenarios: the classical diet choice model with two types of prey and sequential prey encounters, the diet choice model with simultaneous prey encounters, and a model in which the predator requires a positive recognition time to identify the type of prey encountered. For both diet choice models, it is shown that every Nash equilibrium yields optimal foraging behavior. Although suboptimal Nash equilibrium outcomes may exist when prey recognition time is included, only optimal foraging behavior is stable under evolutionary learning processes. PMID:24586390

Cressman, Ross; K?ivan, Vlastimil; Brown, Joel S; Garay, József

2014-01-01

420

Effects of Climate Change on Range Forage Production in the San Francisco Bay Area  

PubMed Central

The San Francisco Bay Area in California, USA is a highly heterogeneous region in climate, topography, and habitats, as well as in its political and economic interests. Successful conservation strategies must consider various current and future competing demands for the land, and should pay special attention to livestock grazing, the dominant non-urban land-use. The main objective of this study was to predict changes in rangeland forage production in response to changes in temperature and precipitation projected by downscaled output from global climate models. Daily temperature and precipitation data generated by four climate models were used as input variables for an existing rangeland forage production model (linear regression) for California’s annual rangelands and projected on 244 12 km x 12 km grid cells for eight Bay Area counties. Climate model projections suggest that forage production in Bay Area rangelands may be enhanced by future conditions in most years, at least in terms of peak standing crop. However, the timing of production is as important as its peak, and altered precipitation patterns could mean delayed germination, resulting in shorter growing seasons and longer periods of inadequate forage quality. An increase in the frequency of extremely dry years also increases the uncertainty of forage availability. These shifts in forage production will affect the economic viability and conservation strategies for rangelands in the San Francisco Bay Area.

Chaplin-Kramer, Rebecca; George, Melvin R.

2013-01-01

421

The effects of chlorpyrifos on cholinesterase activity and foraging behavior in the dragonfly, Anax junius (Odonata)  

USGS Publications Warehouse

We examined head capsule cholinesterase (ChE) and foraging behavior in nymphs of the dragonfly, Anax junius, exposed for 24 h to 0.2, 0.6 and 1.0 ??g l-1 of the organophosphorus (OP) insecticide, chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate]. The invertebrate community is an important component of the structure and function of wetland ecosystems, yet the potential effects of insecticides on wetland ecosystems are largely unknown. Our objectives were to determine if exposure to environmentally realistic concentrations of chlorpyrifos affected foraging behavior and ChE activity in head capsules of dragonfly nymphs. Nymphs were exposed to different concentrations of chlorpyrifos and different prey densities in a factorial design. ChE activities and foraging behaviors of treated nymphs were not statistically different (p ??? 0.05) from control groups. Prey density effects exerted a greater effect on dragonfly foraging than toxicant exposures. Nymphs offered higher prey densities exhibited more foraging behaviors but also missed their prey more often. High variability in ChE activities within the control group and across treated groups precluded determination of relationships between ChE and foraging behaviors. It appears that A. junius is relatively tolerant of chlorpyrifos, although the concentrations we tested have been shown in other work to adversely affect the prey base; therefore the introduction of this insecticide may have indirect adverse affects on top invertebrate predators such as Odonata.

Brewer, S. K.; Atchison, G. J.

1999-01-01

422

Viral infection affects sucrose responsiveness and homing ability of forager honey bees, Apis mellifera L.  

PubMed

Honey bee health is mainly affected by Varroa destructor, viruses, Nosema spp., pesticide residues and poor nutrition. Interactions between these proposed factors may be responsible for the colony losses reported worldwide in recent years. In the present study, the effects of a honey bee virus, Israeli acute paralysis virus (IAPV), on the foraging behaviors and homing ability of European honey bees (Apis mellifera L.) were investigated based on proboscis extension response (PER) assays and radio frequency identification (RFID) systems. The pollen forager honey bees originated from colonies that had no detectable level of honey bee viruses and were manually inoculated with IAPV to induce the viral infection. The results showed that IAPV-inoculated honey bees were more responsive to low sucrose solutions compared to that of non-infected foragers. After two days of infection, around 10? copies of IAPV were detected in the heads of these honey bees. The homing ability of IAPV-infected foragers was depressed significantly in comparison to the homing ability of uninfected foragers. The data provided evidence that IAPV infection in the heads may enable the virus to disorder foraging roles of honey bees and to interfere with brain functions that are responsible for learning, navigation, and orientation in the honey bees, thus, making honey bees have a lower response threshold to sucrose and lose their way back to the hive. PMID:24130876

Li, Zhiguo; Chen, Yanping; Zhang, Shaowu; Chen, Shenglu; Li, Wenfeng; Yan, Limin; Shi, Liangen; Wu, Lyman; Sohr, Alex; Su, Songkun

2013-01-01

423

The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants.  

PubMed

New methodology for measuring forage condensed tannin (CT) content is described and the effects of CT upon forage feeding and nutritive value for ruminant animals are reviewed. CT react with forage proteins in a pH-reversible manner, with reactivity determined by the concentration, structure and molecular mass of the CT. Increasing concentrations of CT in Lotus corniculatus and Lotus pedunculatus reduce the rates of solubilization and degradation of fraction 1 leaf protein in the rumen and increase duodenal non-NH3 N flow. Action of medium concentrations of total CT in Lotus corniculatus (30-40 g/kg DM) increased the absorption of essential amino acids from the small intestine and increased wool growth, milk secretion and reproductive rate in grazing sheep without affecting voluntary feed intake, thus improving the efficiency of food conversion. High concentrations of CT in Lotus pedunculatus (75-100 g/kg DM) depressed voluntary feed intake and rumen carbohydrate digestion and depressed rates of body and wool growth in grazing sheep. The minimum concentration of CT to prevent rumen frothy bloat in cattle is defined as 5 g/kg DM and sheep grazing CT-containing legumes were shown to better tolerate internal parasite infections than sheep grazing non CT-containing forages. It was concluded that defined concentrations of forage CT can be used to increase the efficiencies of protein digestion and animal productivity in forage-fed ruminants and to develop more ecologically sustainable systems of controlling some diseases under grazing. PMID:10999013

Barry, T N; McNabb, W C

1999-04-01

424

Foraging under conditions of short-term exploitative competition: the case of stock traders  

PubMed Central

Theory purports that animal foraging choices evolve to maximize returns, such as net energy intake. Empirical research in both human and non-human animals reveals that individuals often attend to the foraging choices of their competitors while making their own foraging choices. Owing to the complications of gathering field data or constructing experiments, however, broad facts relating theoretically optimal and empirically realized foraging choices are only now emerging. Here, we analyse foraging choices of a cohort of professional day traders who must choose between trading the same stock multiple times in a row—patch exploitation—or switching to a different stock—patch exploration—with potentially higher returns. We measure the difference between a trader's resource intake and the competitors' expected intake within a short period of time—a difference we call short-term comparative returns. We find that traders' choices can be explained by foraging heuristics that maximize their daily short-term comparative returns. However, we find no one-best relationship between different trading choices and net income intake. This suggests that traders' choices can be short-term win oriented and, paradoxically, maybe maladaptive for absolute market returns.

Saavedra, Serguei; Malmgren, R. Dean; Switanek, Nicholas; Uzzi, Brian

2013-01-01

425

Relative importance of social status and physiological need in determining leadership in a social forager.  

PubMed

Group decisions on the timing of mutually exclusive activities pose a dilemma: monopolized decision-making by a single leader compromises the optimal timing of activities by the others, while independent decision-making by all group members undermines group coherence. Theory suggests that initiation of foraging should be determined by physiological demand in social foragers, thereby resolving the dilemma of group coordination. However, empirical support is scant, perhaps because intrinsic qualities predisposing individuals to leadership (social status, experience or personality), or their interactions with satiation level, have seldom been simultaneously considered. Here, we examine which females initiated foraging in eider (Somateria mollissima) brood-rearing coalitions, characterized by female dominance hierarchies and potentially large individual differences in energy requirements due to strenuous breeding effort. Several physiological and social factors, except for female breeding experience and boldness towards predators, explained foraging initiation. Initiators spent a larger proportion of time submerged during foraging bouts, had poorer body condition and smaller structural size, but they were also aggressive and occupied central positions. Initiation probability also declined with female group size as expected given random assignment of initiators. However, the relative importance of physiological predictors of leadership propensity (active foraging time, body condition, structural size) exceeded those of social predictors (aggressiveness, spatial position) by an order of magnitude. These results confirm recent theoretical work suggesting that 'leading according to need' is an evolutionary viable strategy regardless of group heterogeneity or underlying dominance structure. PMID:23691258

Öst, Markus; Jaatinen, Kim

2013-01-01

426

Social learning in birds and its role in shaping a foraging niche  

PubMed Central

We briefly review the literature on social learning in birds, concluding that strong evidence exists mainly for predator recognition, song, mate choice and foraging. The mechanism of local enhancement may be more important than imitation for birds learning to forage, but the former mechanism may be sufficient for faithful transmission depending on the ecological circumstances. To date, most insights have been gained from birds in captivity. We present a study of social learning of foraging in two passerine birds in the wild, where we cross-fostered eggs between nests of blue tits, Cyanistes caeruleus and great tits, Parus major. Early learning causes a shift in the foraging sites used by the tits in the direction of the foster species. The shift in foraging niches was consistent across seasons, as showed by an analysis of prey items, and the effect lasted for life. The fact that young birds learn from their foster parents, and use this experience later when subsequently feeding their own offspring, suggests that foraging behaviour can be culturally transmitted over generations in the wild. It may therefore have both ecological and evolutionary consequences, some of which are discussed.

Slagsvold, Tore; Wiebe, Karen L.

2011-01-01

427

Forage to concentrate ratio in Jonica breed goats: influence on lactation curve and milk composition.  

PubMed

The aim of the work is to evaluate the effects of different forage to concentrate rations on milk yield, composition and renneting properties of milk of Jonica breed goats. Twenty-four Jonica goats received diets with forage to concentrate ratio of 35/65, 50/50 or 65/35, providing respectively a low, medium and high energy level. Goats were divided into three homogenous groups and confined in individual pens for 152 days to assess the daily feed intake and milk yield and composition. The main conclusions show that animal body weight did not change significantly with the increasing levels of forage, whereas significant differences (P<0.05) for daily dry matter intake were observed in relation to the evolution of lactation.