Science.gov

Sample records for prey protection measures

  1. Significance of Selective Predation and Development of Prey Protection Measures for Juvenile Salmonids in the Columbia and Snake River Reservoirs: Annual Progress Report, February 1991-February 1992.

    SciTech Connect

    Poe, Thomas P.

    1992-12-31

    This document is the 1991 annual report of progress for the Bonneville Power Administration (BPA) research Project conducted by the US Fish and Wildlife Service (FWS). Our approach was to present the progress achieved during 1991 in a series of separate reports for each major project task. Each report is prepared in the format of a scientific paper and is able to stand alone, whatever the state of progress or completion. This project has two major goals. One is to understand the significance of selective predation and prey vulnerability by determining if substandard juvenile salmonids (dead, injured, stressed, diseased, or naive) are more vulnerable to predation by northern squawfish, than standard or normal juvenile salmonids. The second goal is to develop and test prey protection measures to control predation on juvenile salmonids by reducing predator-smolt encounters or predator capture efficiency.

  2. Significance of Selective Predation and Development of Prey Protection Measures for Juvenile Salmonids in the Columbia and Snake River Reservoirs: Annual Progress Report, February 1993-February 1994.

    SciTech Connect

    Poe, Thomas P.

    1994-08-01

    This report addresses the problem of predator-prey interactions of juvenile salmonids in the Columbia and Snake River. Six papers are included on selective predation and prey protection. Attention is focused on monitoring the movements, the distribution, and the behavior of juvenile chinook salmon and northern squawfish.

  3. Significance of Selective Predation and Development of Prey Protection Measures for Juvenile Salmonids in the Columbia and Snake River Reservoirs: Annual Report, February 1992-February 1993.

    SciTech Connect

    Poe, Thomas P.; Gadomski, Dena M.

    1994-09-01

    This document is the 1992 annual report of progress for the Bonneville Power Administration (BPA) research Project No. 82-003 conducted by the U.S. Fish and Wildlife Service (FWS), the Oregon Cooperative Fishery Research Unit (OCFRU), and the Idaho Cooperative Fish and Wildlife Research Unit (ICFWRU). The approach was to present the progress achieved during 1992 in a series of separate reports for each major project task. Each report is prepared in the format of a scientific paper and is able to stand alone, whatever the state of progress or completion. Reports 1, 2, and 4 consist of the Abstract only (journal papers were submitted in lieu of reports). This project has two major goals. One is to understand the significance of selective predation and prey vulnerability by determining if substandard juvenile salmonids (dead, injured, stressed, diseased, or naive) are more vulnerable to predation by northern squawfish, Ptychocheilus oregonensis, than standard or normal juvenile salmonids. The second goal is to develop and test prey protection measures to control predation on juvenile salmonids by reducing predator-smolt encounters or predator capture efficiency. Separate abstracts have been submitted to the database for the seven articles in this report.

  4. Colour Polymorphism Protects Prey Individuals and Populations Against Predation

    PubMed Central

    Karpestam, Einat; Merilaita, Sami; Forsman, Anders

    2016-01-01

    Colour pattern polymorphism in animals can influence and be influenced by interactions between predators and prey. However, few studies have examined whether polymorphism is adaptive, and there is no evidence that the co-occurrence of two or more natural prey colour variants can increase survival of populations. Here we show that visual predators that exploit polymorphic prey suffer from reduced performance, and further provide rare evidence in support of the hypothesis that prey colour polymorphism may afford protection against predators for both individuals and populations. This protective effect provides a probable explanation for the longstanding, evolutionary puzzle of the existence of colour polymorphisms. We also propose that this protective effect can provide an adaptive explanation for search image formation in predators rather than search image formation explaining polymorphism. PMID:26902799

  5. Effect of a protection zone in the diffusive Leslie predator-prey model

    NASA Astrophysics Data System (ADS)

    Du, Yihong; Peng, Rui; Wang, Mingxin

    In this paper, we consider the diffusive Leslie predator-prey model with large intrinsic predator growth rate, and investigate the change of behavior of the model when a simple protection zone Ω for the prey is introduced. As in earlier work [Y. Du, J. Shi, A diffusive predator-prey model with a protection zone, J. Differential Equations 229 (2006) 63-91; Y. Du, X. Liang, A diffusive competition model with a protection zone, J. Differential Equations 244 (2008) 61-86] we show the existence of a critical patch size of the protection zone, determined by the first Dirichlet eigenvalue of the Laplacian over Ω and the intrinsic growth rate of the prey, so that there is fundamental change of the dynamical behavior of the model only when Ω is above the critical patch size. However, our research here reveals significant difference of the model's behavior from the predator-prey model studied in [Y. Du, J. Shi, A diffusive predator-prey model with a protection zone, J. Differential Equations 229 (2006) 63-91] with the same kind of protection zone. We show that the asymptotic profile of the population distribution of the Leslie model is governed by a standard boundary blow-up problem, and classical or degenerate logistic equations.

  6. The effectiveness of marine protected areas for predator and prey with varying mobility.

    PubMed

    Pilyugin, Sergei S; Medlock, Jan; De Leenheer, Patrick

    2016-08-01

    Marine protected areas (MPAs) are regions in the ocean where fishing is restricted or prohibited. Although several measures for MPA performance exist, here we focus on a specific one, namely the ratio of the steady state fish densities inside and outside the MPA. Several 2 patch models are proposed and analyzed mathematically. One patch represents the MPA, whereas the second patch represents the fishing ground. Fish move freely between both regions in a diffusive manner. Our main objective is to understand how fish mobility affects MPA performance. We show that MPA effectiveness decreases with fish mobility for single species models with logistic growth, and that densities inside and outside the MPA tend to equalize. This suggests that MPA performance is highest for the least mobile species. We then consider a 2 patch Lotka-Volterra predator-prey system. When one of the species moves, and the other does not, the ratio of the moving species first remains constant, and ultimately decreases with increased fish mobility, again with a tendency of equalization of the density in both regions. This suggests that MPA performance is not only highest for slow, but also for moderately mobile species. The discrepancy in MPA performance for single species models and for predator-prey models, confirms that MPA design requires an integrated, ecosystem-based approach. The mathematical approaches advocated here complement and enhance the numerical and theoretical approaches that are commonly applied to more complex models in the context of MPA design. PMID:27151107

  7. The economics of protecting tiger populations: Linking household behavior to poaching and prey depletion

    USGS Publications Warehouse

    Damania, R.; Stringer, R.; Karanth, K.U.; Stith, B.

    2003-01-01

    The tiger (Panthera tigris) is classified as endangered and populations continue to decline. This paper presents a formal economic analysis of the two most imminent threats to the survival of wild tigers: poaching tigers and hunting their prey. A model is developed to examine interactions between tigers and farm households living in and around tiger habitats. The analysis extends the existing literature on tiger demography, incorporating predator-prey interactions and exploring the sensitivity of tiger populations to key economic parameters. The analysis aims to contribute to policy debates on how best to protect one of the world's most endangered wild cats.

  8. Breaking and entering: predators invade the shelter of their prey and gain protection.

    PubMed

    Lemos, Felipe; Bernardo, Ana Maria Guimarães; Dias, Cleide Rosa; Sarmento, Renato Almeida; Pallini, Angelo; Venzon, Madelaine; Janssen, Arne

    2015-10-01

    Many herbivorous arthropods construct shelters on their host plant that offer protection against natural enemies. This has resulted in selection on natural enemies to enter these shelters, where they can feed on prey that are inaccessible for competing predators and parasitoids. The spider mite Tetranychus evansi produces a shelter consisting of a dense web that is impenetrable for most predators; the only known natural enemy that can penetrate the web and can forage efficiently on this pest is Phytoseiulus longipes. We show that this predator preferentially foraged and oviposited in the web of its prey. Moreover, intraguild predation on juveniles of these predators was significantly higher outside this web and in the less dense web of a closely related prey species (T. urticae) than inside the web of T. evansi. Although the production of shelters by herbivores may be profitable at first, their adapted natural enemies may reap the benefit in the end. PMID:26188859

  9. Predator-prey spatial game as a tool to understand the effects of protected areas on harvester-wildlife interactions.

    PubMed

    Tolon, Vincent; Martin, Jodie; Dray, Stéphane; Loison, Anne; Fischer, Claude; Baubet, Eric

    2012-03-01

    No-take reserves are sometimes implemented for sustainable population harvesting because they offer opportunities for animals to spatially avoid harvesters, whereas harvesters can benefit in return from the reserve spillover. Here, we used the framework of predator-prey spatial games to understand how protected areas shape spatial interactions between harvesters and target species and determine animal mortality. In these spatial games, the "predator" searches for "prey" and matches their habitat use, unless it meets spatial constraints offering the opportunity for prey to avoid the mortality source. However, such prey refuges could attract predators in the surroundings, which questions the potential benefits for prey. We located, in the Geneva Basin (France), hunting dogs and wild boar Sus scrofa L. during hunting seasons with global positioning systems and very-high-frequency collars. We quantified how the proximity of the reserve shaped the matching between both habitat uses using multivariate analyses and linked these patterns to animals' mortality with a Cox regression analysis. Results showed that habitat uses by both protagonists disassociated only when hunters were spatially constrained by the reserve. In response, hunters increased hunting efforts near the reserve boundary, which induced a higher risk exposure for animals settled over the reserve. The mortality of adult wild boar decreased near the reserve as the mismatch between both habitat uses increased. However the opposite pattern was determined for younger individuals that suffered from the high level of hunting close to the reserve. The predator-prey analogy was an accurate prediction of how the protected area modified spatial relationships between harvesters and target species. Prey-searching strategies adopted by hunters around reserves strongly impacted animal mortality and the efficiency of the protected area for this harvested species. Increasing reserve sizes and/or implementing buffer areas

  10. Do wildlife laws work? Species protection and the application of a prey choice model to poaching decisions.

    PubMed Central

    Rowcliffe, J. Marcus; de Merode, Emmanuel; Cowlishaw, Guy

    2004-01-01

    Legislation for the protection of species is a global conservation tool. However, in many developing countries lack of resources means that effectiveness relies on voluntary compliance, leading to contradictory assumptions. On one hand, laws introduced without effective enforcement mechanisms carry an implicit assumption that voluntary compliance will occur. On the other hand, it is often openly assumed that, without enforcement, there will in fact be no compliance. Which assumption holds has rarely been rigorously tested. Here we show that laws for the protection of some species of large mammal have no effect on the prey choice patterns of primarily commercial hunters in the Democratic Republic of Congo, confirming the second assumption. We established this result by using an optimal diet model to predict the pattern of prey choice in the absence of regulation. Prey choice patterns predicted by the model were accurate across a range of conditions defined by time, space and type of hunting weapon. Given that hunters will not comply voluntarily, the protection of vulnerable species can only take place through effective enforcement, for example by wildlife authorities restricting access to protected areas, or by traditional authorities restricting the sale of protected species in local markets. PMID:15615691

  11. Do wildlife laws work? Species protection and the application of a prey choice model to poaching decisions.

    PubMed

    Rowcliffe, J Marcus; de Merode, Emmanuel; Cowlishaw, Guy

    2004-12-22

    Legislation for the protection of species is a global conservation tool. However, in many developing countries lack of resources means that effectiveness relies on voluntary compliance, leading to contradictory assumptions. On one hand, laws introduced without effective enforcement mechanisms carry an implicit assumption that voluntary compliance will occur. On the other hand, it is often openly assumed that, without enforcement, there will in fact be no compliance. Which assumption holds has rarely been rigorously tested. Here we show that laws for the protection of some species of large mammal have no effect on the prey choice patterns of primarily commercial hunters in the Democratic Republic of Congo, confirming the second assumption. We established this result by using an optimal diet model to predict the pattern of prey choice in the absence of regulation. Prey choice patterns predicted by the model were accurate across a range of conditions defined by time, space and type of hunting weapon. Given that hunters will not comply voluntarily, the protection of vulnerable species can only take place through effective enforcement, for example by wildlife authorities restricting access to protected areas, or by traditional authorities restricting the sale of protected species in local markets. PMID:15615691

  12. Can measures of prey availability improve our ability to predict the abundance of large marine predators?

    PubMed

    Wirsing, Aaron J; Heithaus, Michael R; Dill, Lawrence M

    2007-09-01

    Apex marine predators can structure marine communities, so factors underlying their abundance are of broad interest. However, such data are almost completely lacking for large sharks. We assessed the relationship between tiger shark abundance, water temperature, and the availability of a variety of known prey over 5 years in Western Australia. Abundance of sharks in four size categories and the density of prey (cormorants, dugongs, sea snakes, sea turtles) were indexed using daily catch rates and transects, respectively. Across all sizes, thermal conditions were a determinant of abundance, with numerical peaks coinciding with periods of high water temperature. However, for sharks exceeding 300 cm total length, the inclusion of dugong density significantly improved temperature-based models, suggesting that use of particular areas by large tiger sharks is influenced by availability of this sirenian. We conclude that large marine predator population models may benefit from the inclusion of measures of prey availability, but only if such measures consider prey types separately and account for ontogenetic shifts in the diet of the predator in question. PMID:17549522

  13. Protective Measurement and Quantum Reality

    NASA Astrophysics Data System (ADS)

    Gao, Shan

    2015-01-01

    1. Protective measurements: an introduction Shan Gao; Part I. Fundamentals and Applications: 2. Protective measurements of the wave function of a single system Lev Vaidman; 3. Protective measurement, postselection and the Heisenberg representation Yakir Aharonov and Eliahu Cohen; 4. Protective and state measurement: a review Gennaro Auletta; 5. Determination of the stationary basis from protective measurement on a single system Lajos Diósi; 6. Weak measurements, the energy-momentum tensor and the Bohm approach Robert Flack and Basil J. Hiley; Part II. Meanings and Implications: 7. Measurement and metaphysics Peter J. Lewis; 8. Protective measurements and the explanatory gambit Michael Dickson; 9. Realism and instrumentalism about the wave function: how should we choose? Mauro Dorato and Frederico Laudisa; 10. Protective measurements and the PBR theorem Guy Hetzroni and Daniel Rohrlich; 11. The roads not taken: empty waves, waveform collapse and protective measurement in quantum theory Peter Holland; 12. Implications of protective measurements on de Broglie–Bohm trajectories Aurelien Drezet; 13. Entanglement, scaling, and the meaning of the wave function in protective measurement Maximilian Schlosshauer and Tangereen V. B. Claringbold; 14. Protective measurements and the nature of the wave function within the primitive ontology approach Vincent Lam; 15. Reality and meaning of the wave function Shan Gao; Index.

  14. Hierarchical multi-species modeling of carnivore responses to hunting, habitat and prey in a West African protected area.

    PubMed

    Burton, A Cole; Sam, Moses K; Balangtaa, Cletus; Brashares, Justin S

    2012-01-01

    Protected areas (PAs) are a cornerstone of global efforts to shield wildlife from anthropogenic impacts, yet their effectiveness at protecting wide-ranging species prone to human conflict--notably mammalian carnivores--is increasingly in question. An understanding of carnivore responses to human-induced and natural changes in and around PAs is critical not only to the conservation of threatened carnivore populations, but also to the effective protection of ecosystems in which they play key functional roles. However, an important challenge to assessing carnivore communities is the often infrequent and imperfect nature of survey detections. We applied a novel hierarchical multi-species occupancy model that accounted for detectability and spatial autocorrelation to data from 224 camera trap stations (sampled between October 2006 and January 2009) in order to test hypotheses about extrinsic influences on carnivore community dynamics in a West African protected area (Mole National Park, Ghana). We developed spatially explicit indices of illegal hunting activity, law enforcement patrol effort, prey biomass, and habitat productivity across the park, and used a Bayesian model selection framework to identify predictors of site occurrence for individual species and the entire carnivore community. Contrary to our expectation, hunting pressure and edge proximity did not have consistent, negative effects on occurrence across the nine carnivore species detected. Occurrence patterns for most species were positively associated with small prey biomass, and several species had either positive or negative associations with riverine forest (but not with other habitat descriptors). Influences of sampling design on carnivore detectability were also identified and addressed within our modeling framework (e.g., road and observer effects), and the multi-species approach facilitated inference on even the rarest carnivore species in the park. Our study provides insight for the conservation

  15. Hierarchical Multi-Species Modeling of Carnivore Responses to Hunting, Habitat and Prey in a West African Protected Area

    PubMed Central

    Burton, A. Cole; Sam, Moses K.; Balangtaa, Cletus; Brashares, Justin S.

    2012-01-01

    Protected areas (PAs) are a cornerstone of global efforts to shield wildlife from anthropogenic impacts, yet their effectiveness at protecting wide-ranging species prone to human conflict – notably mammalian carnivores – is increasingly in question. An understanding of carnivore responses to human-induced and natural changes in and around PAs is critical not only to the conservation of threatened carnivore populations, but also to the effective protection of ecosystems in which they play key functional roles. However, an important challenge to assessing carnivore communities is the often infrequent and imperfect nature of survey detections. We applied a novel hierarchical multi-species occupancy model that accounted for detectability and spatial autocorrelation to data from 224 camera trap stations (sampled between October 2006 and January 2009) in order to test hypotheses about extrinsic influences on carnivore community dynamics in a West African protected area (Mole National Park, Ghana). We developed spatially explicit indices of illegal hunting activity, law enforcement patrol effort, prey biomass, and habitat productivity across the park, and used a Bayesian model selection framework to identify predictors of site occurrence for individual species and the entire carnivore community. Contrary to our expectation, hunting pressure and edge proximity did not have consistent, negative effects on occurrence across the nine carnivore species detected. Occurrence patterns for most species were positively associated with small prey biomass, and several species had either positive or negative associations with riverine forest (but not with other habitat descriptors). Influences of sampling design on carnivore detectability were also identified and addressed within our modeling framework (e.g., road and observer effects), and the multi-species approach facilitated inference on even the rarest carnivore species in the park. Our study provides insight for the

  16. Bats as the main prey of wintering long-eared owl (Asio otus) in Beijing: Integrating biodiversity protection and urban management.

    PubMed

    Tian, Long; Zhou, Xuwei; Shi, Yang; Guo, Yumin; Bao, Weidong

    2015-03-01

    The loss of biodiversity from urbanized areas is a major environmental problem challenging policy-makers throughout the world. Solutions to this problem are urgently required in China. We carried out a case study of wintering long-eared owls (Asio otus) and their main prey to illustrate the negative effects of urbanization combined with ineffective conservation of biodiversity in Beijing. Field monitoring of owl numbers at two roosting sites from 2004 to 2012 showed that the owl population had fallen rapidly in metropolitan Beijing. Analysis of pellet contents identified only seven individuals of two species of shrew. The majority of mammalian prey comprised four bat and seven rodent species, making up 29.3% and 29.5% of the prey items, respectively. Prey composition varied significantly among years at the two sample sites. At the urban site the consumption of bats and rodents declined gradually over time, while predation on birds increased. In contrast, at the suburban site the prey composition showed an overall decrease in the number of bats, a sharp increase and a subsequent decrease in bird prey, and the number of rodent prey fell to a low point. Rapid development of real estate and inadequate greenfield management in city parks resulted in negative effects on the bird and small mammal habitat of urban areas in Beijing. We suggest that measures to conserve biodiversity should be integrated into future urban planning to maintain China's rich biodiversity while also achieving sustainable economic development. PMID:25316405

  17. In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies.

    PubMed

    Thums, Michele; Bradshaw, Corey J A; Hindelli, Mark A

    2011-06-01

    Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed "area-restricted search." However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity could also be spatially aware of suitable feeding areas based on prior experience; changes in movement patterns might therefore arise from the anticipation of higher prey density. We tested the hypothesis that regions of area-restricted search were associated with a higher number of daily speed spikes (a proxy for potential prey encounter rate) and foraging success in southern elephant seals (Mirounga leonina), a species exhibiting both area-restricted searches and high interannual foraging site fidelity. We used onshore morphological measurements and diving data from archival tags deployed during winter foraging trips. Foraging success was inferred from in situ changes in relative lipid content derived from measured changes in buoyancy, and first-passage time analysis was used to identify area-restricted search behavior. Seals exhibited relatively direct southerly movement on average, with intensive search behavior predominantly located at the distal end of tracks. The probability of being in search mode was positively related to changes in relative lipid content; thus, intensively searched areas were associated with the highest foraging success. However, there was high foraging success during the outward transit even though seals moved through quickly without slowing down and increasing turning rate to exploit these areas. In addition, the probability of being in search mode was negatively related to the number of daily speed spikes. These results suggest that movement patterns represent a response to prior expectation of the location of predictable and profitable resources. Shelf habitat was 4-9 times more profitable than the other habitats, emphasizing the importance

  18. Indirect effects of primary prey population dynamics on alternative prey.

    PubMed

    Barraquand, Frédéric; New, Leslie F; Redpath, Stephen; Matthiopoulos, Jason

    2015-08-01

    We develop a theory of generalist predation showing how alternative prey species are affected by changes in both mean abundance and variability (coefficient of variation) of their predator's primary prey. The theory is motivated by the indirect effects of cyclic rodent populations on ground-breeding birds, and developed through progressive analytic simplifications of an empirically-based model. It applies nonetheless to many other systems where primary prey have fast life-histories and can become superabundant, thus facilitating impact on alternative prey species and generating highly asymmetric interactions. Our results suggest that predator effects on alternative prey should generally decrease with mean primary prey abundance, and increase with primary prey variability (low to high CV)-unless predators have strong aggregative responses, in which case these results can be reversed. Approximations of models including predator dynamics (general numerical response with possible delays) confirm these results but further suggest that negative temporal correlation between predator and primary prey is harmful to alternative prey. Finally, we find that measurements of predator numerical responses are crucial to predict-even qualitatively-the response of ecosystems to changes in the dynamics of outbreaking prey species. PMID:25930160

  19. Variable wind, pack ice, and prey dispersion affect the long-term adequacy of protected areas for an Arctic sea duck.

    PubMed

    Lovvorn, James R; Anderson, Eric M; Rocha, Aariel R; Larned, William W; Grebmeier, Jacqueline M; Cooper, Lee W; Kolts, Jason M; North, Christopher A

    2014-03-01

    With changing climate, delineation of protected areas for sensitive species must account for long-term variability and geographic shifts of key habitat elements. Projecting the future adequacy of protected areas requires knowing major factors that drive such changes, and how readily the animals adjust to altered resources. In the Arctic, the viability of habitats for marine birds and mammals often depends on sea ice to dissipate storm waves and provide platforms for resting. However, some wind conditions (including weak winds during extreme cold) can consolidate pack ice into cover so dense that air-breathing divers are excluded from the better feeding areas. Spectacled Eiders (Somateria fischeri) winter among leads (openings) in pack ice in areas where densities of their bivalve prey are quite high. During winter 2009, however, prevailing winds created a large region of continuous ice with inadequate leads to allow access to areas of dense preferred prey. Stable isotope and fatty acid biomarkers indicated that, under these conditions, the eiders did not diversify their diet to include abundant non-bivalve taxa but did add a smaller, less preferred, bivalve species. Consistent with a computer model of eider energy balance, the body fat of adult eiders in 2009 was 33-35% lower than on the same date (19 March) in 2001 when ice conditions allowed access to higher bivalve densities. Ice cover data suggest that the eiders were mostly excluded from areas of high bivalve density from January to March in about 30% of 14 winters from 1998 to 2011. Thus, even without change in total extent of ice, shifts in prevailing winds can alter the areal density of ice to reduce access to important habitats. Because changes in wind-driven currents can also rearrange the dispersion of prey, the potential for altered wind patterns should be an important concern in projecting effects of climate change on the adequacy of marine protected areas for diving endotherms in the Arctic. PMID

  20. Predator-prey systems depend on a prey refuge.

    PubMed

    Chivers, W J; Gladstone, W; Herbert, R D; Fuller, M M

    2014-11-01

    Models of near-exclusive predator-prey systems such as that of the Canadian lynx and snowshoe hare have included factors such as a second prey species, a Holling Type II predator response and climatic or seasonal effects to reproduce sub-sets of six signature patterns in the empirical data. We present an agent-based model which does not require the factors or constraints of previous models to reproduce all six patterns in persistent populations. Our parsimonious model represents a generalised predator and prey species with a small prey refuge. The lack of the constraints of previous models, considered to be important for those models, casts doubt on the current hypothesised mechanisms of exclusive predator-prey systems. The implication for management of the lynx, a protected species, is that maintenance of an heterogeneous environment offering natural refuge areas for the hare is the most important factor for the conservation of this species. PMID:25058806

  1. Comparative magnetic measurements of migratory ant and its only termite prey

    NASA Astrophysics Data System (ADS)

    Esquivel, D. M. S.; Wajnberg, E.; Cernicchiaro, G. R.; Alves, O. C.

    2004-07-01

    Termites and ants are social insects living organized in nests in castes. Behavioral studies with the migratory ant Pachycondyla marginata have shown that it conducts well-organized predatory raids toward nests of its only prey, the termite Neocapritermes opacus. The magnetic materials in these two insects were studied using a SQUID magnetometer for two orientations. The Jr/ Js and Jr/ χ0, ratios were calculated from the two insects hysteresis curves. These ratios are in the range of magnetite pseudo-single or multi-domain particle values. The magnetic material are distinguishable by Hc values (30 Oe for ants and 100 Oe for termites) and by the magnetization magnitude, which is about two magnitude orders higher in the termite than in migratory ant. The Pachycondyla marginata SQUID results show an anisotropy in the magnetic material arrangement while for Neocapritermes opacus termite it is revealed by FMR spectra.

  2. Measuring cathodic protection under unbonded coatings

    SciTech Connect

    Orton, M.D.

    1986-03-01

    Corrosion protection of pipe lines by cathodic protection where unbonded coatings exist has concerned engineers for decades. Without more than theoretical considerations available, it is nearly impossible for a pipe line operator to make relevant economic decisions whether to apply additional cathodic protection or to recondition existing pipe lines. The savings realized from additional protective current versus reconditioning large diameter pipe can be significant provided adequate potentials can be achieved beneath unbonded coatings. Arabian American Oil Co. has developed a test procedure to make field measurements to determine the effectiveness of cathodic protection under unbonded coatings. The test site is in the northern part of the Eastern Province of Saudi Arabia.

  3. Adolescent use of sun-protection measures.

    PubMed

    Cockburn, J; Hennrikus, D; Scott, R; Sanson-Fisher, R

    1989-08-01

    This study sought to determine the prevalence of the use of sun-protection measures in adolescents, and the variables which predicted use of and failure to use such measures. Three thousand and two school students in Years 9 and 10 from 26 high schools in New South Wales were surveyed in the last term of 1986 and the first term of 1987 as part of the NSW Department of Health's Country Regions Skin Cancer Prevention Campaign. By means of standardized criteria, 70% of the sample were defined as not using adequate protection. Stepwise regression showed that the number of opportunities for sun protection, as well as sex, smoking status, skin-type and area of residence were significant predictors of whether a student used sun-protection measures. Further regression analyses indicated that the attitudes and beliefs of students also were significant predictors of sun-protection use, independent of sociodemographic variables and the number of opportunities for sun protection. Interventions to increase the use of sun protection are more likely to be effective if they are targeted at the modifying of beliefs about the benefits and barriers to sun-screening, the perceptions of an appropriate image for peers and parental influences about covering-up in the sun. PMID:2535601

  4. Spatial distribution of predator/prey interactions in the Scotia Sea: implications for measuring predator/fisheries overlap

    NASA Astrophysics Data System (ADS)

    Reid, Keith; Sims, Michelle; White, Richard W.; Gillon, Keith W.

    2004-06-01

    The measurement of spatial overlap between predators and fisheries exploiting a common prey source is dependent upon the measurement scale used; inappropriate scales may produce misleading results. Previous assessments of the level of overlap between predators and fisheries for Antarctic krill ( Euphausia superba) in the region of the South Shetland Islands used different measurement scales and arrived at contradictory conclusions. At-sea data from observations of krill predators during the CCAMLR 2000 Survey were used to identify the areas of potential overlap with fisheries in the Scotia Sea and to determine the scale at which such overlap should be measured. The relationship between autocorrelation and sampling distance was used to identify the characteristic scales of the distribution of predators, krill and krill fisheries, and an effort-corrected index of relative abundance as a function of distance from land was used to identify the characteristics of areas of high potential for overlap. Despite distinct differences in foraging ecology, a group of krill-dependent species including chinstrap penguin ( Pygoscelis antarctica), (Antarctic) fur seal ( Arctocephalus sp. ( gazella)) and white-chinned petrel ( Procellaria aequinoctialis) showed similar patterns of distribution; the relative abundances were highest at 60-120 km from land and decreased sharply at distances greater than 150 km from land. There were more inter-specific differences in the characteristic scales, which were of the order of 50-100 km. Antarctic krill had a characteristic scale of approximately 200 km and the relationship with distance from land showed a log-linear decline. Krill fisheries operate at a scale of 150 km and occur almost entirely within 100 km of land. The requirement of land for breeding and the biological and oceanographic conditions that produce the high concentrations of krill associated with those land areas produce a system in which the demand for Antarctic krill from

  5. When Optimal Strategy Matters to Prey Fish

    PubMed Central

    Soto, Alberto; Stewart, William J.; McHenry, Matthew J.

    2015-01-01

    Predator–prey interactions are commonly studied with an interest in determining the optimal strategy for prey. However, the implications of deviating from optimal strategy are often unclear. The present study considered these consequences by studying how the direction of an escape response affects the strategy of prey fish. We simulated these interactions with numerical and analytical mathematics and compared our predictions with measurements in zebrafish larvae (Danio rerio), which are preyed upon by adults of the same species. Consistent with existing theory, we treated the minimum distance between predator and prey as the strategic payoff that prey aim to maximize. We found that these interactions may be characterized by three strategic domains that are defined by the speed of predator relative to the prey. The “fast predator” domain occurs when the predator is more than an order of magnitude faster than the prey. The escape direction of the prey had only a small effect on the minimum distance under these conditions. For the “slow predator” domain, when the prey is faster than the predator, we found that differences in direction had no effect on the minimum distance for a broad range of escape angles. This was the regime in which zebrafish were found to operate. In contrast, the optimal escape angle offers a large benefit to the minimum distance in the intermediate strategic domain. Therefore, optimal strategy is most meaningful to prey fish when predators are faster than prey by less than a factor of 10. This demonstrates that the strategy of a prey animal does not matter under certain conditions that are created by the behavior of the predator. PMID:25964496

  6. Transient (lightning) protection for electronic measurement devices

    SciTech Connect

    Black, L.L.

    1995-12-01

    Electronic measurement devices have become a major part of the oil and gas business today. All of these devices operate on an electrical voltage. Any voltage introduced into the system that is beyond the predetermined tolerance will cause degradation of performance or in some cases failure of the device. The extent of the damage depends upon the dielectric strength of the circuit in question and upon the available energy. As electronic measurement devices are further developed to incorporate more solid state circuitry and operate at lower voltage levels the more susceptible they become to transients. Along with transient protection, the user must also be concerned with intrinsic safety requirements of the device to be protected. The devices and techniques used to protect the equipment from transients do not, in all cases, guarantee the user certification for use in hazardous environments. As a note of reference, some of the techniques listed in this paper as examples would not be allowed in hazardous areas without the addition of other devices to further isolate or clamp the available energy to a safe level. In other words, as the industry moves forward to improve the overall accuracy of the measurement system and adds data availability via communication networks, the transient protection scheme must become more sophisticated.

  7. Disentangling taste and toxicity in aposematic prey.

    PubMed

    Holen, Øistein Haugsten

    2013-02-22

    Many predators quickly learn to avoid attacking aposematic prey. If the prey vary in toxicity, the predators may alternatively learn to capture and taste-sample prey carefully before ingesting or rejecting them (go-slow behaviour). An increase in prey toxicity is generally thought to decrease predation on prey populations. However, while prey with a higher toxin load are more harmful to ingest, they may also be easier to recognize and reject owing to greater distastefulness, which can facilitate a taste-sampling foraging strategy. Here, the classic diet model is used to study the separate effects of taste and toxicity on predator preferences. The taste-sampling process is modelled using signal detection theory. The model is applicable to automimicry and batesian mimicry. It shows that when the defensive toxin is sufficiently distasteful, a mimicry complex may be less profitable to the predator and better protected against predation if the models are moderately toxic than if they are highly toxic. Moreover, taste mimicry can reduce the profitability of the mimicry complex and increase protection against predation. The results are discussed in relation to the selection pressures acting on prey defences and the evolution of mimicry. PMID:23256198

  8. Prey vulnerability to peacock cichlids and largemouth bass based on predator gape and prey body depth

    USGS Publications Warehouse

    Hill, Jeffrey E.; Nico, Leo G.; Cichra, Charles E.; Gilbert, Carter R.

    2005-01-01

    The interaction of prey fish body depth and predator gape size may produce prey assemblages dominated by invulnerable prey and excessive prey-to-predator biomass ratios. Peacock cichlids (Cichla ocellaris) were stocked into southeast Florida canals to consume excess prey fish biomass, particularly spotted tilapia (Tilapia mariae). The ecomorphologically similar largemouth bass (Micropterus salmoides) was already present in the canals. We present relations of length-specific gape size for peacock cichlids and largemouth bass. Both predators have broadly overlapping gape size, but largemouth bass ?126 mm total length have slightly larger gape sizes than peacock cichlids of the same length. Also, we experimentally tested the predictions of maximum prey size for peacock cichlids and determined that a simple method of measuring gape size used for largemouth bass also is appropriate for peacock cichlids. Lastly, we determined relations of body depth and length of prey species to investigate relative vulnerability. Using a simple predator-prey model and length frequencies of predators and bluegill (Lepomis macrochirus), redear sunfish (Lepomis microlophus), and spotted tilapia prey, we documented that much of the prey biomass in southeast Florida canals is unavailable for largemouth bass and peacock cichlid predation.

  9. Competing Conservation Objectives for Predators and Prey: Estimating Killer Whale Prey Requirements for Chinook Salmon

    PubMed Central

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A.; Clark, Steve; Hammond, Philip S.; Hoyt, Erich; Noren, Dawn P.; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada–US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  10. Competing conservation objectives for predators and prey: estimating killer whale prey requirements for Chinook salmon.

    PubMed

    Williams, Rob; Krkošek, Martin; Ashe, Erin; Branch, Trevor A; Clark, Steve; Hammond, Philip S; Hoyt, Erich; Noren, Dawn P; Rosen, David; Winship, Arliss

    2011-01-01

    Ecosystem-based management (EBM) of marine resources attempts to conserve interacting species. In contrast to single-species fisheries management, EBM aims to identify and resolve conflicting objectives for different species. Such a conflict may be emerging in the northeastern Pacific for southern resident killer whales (Orcinus orca) and their primary prey, Chinook salmon (Oncorhynchus tshawytscha). Both species have at-risk conservation status and transboundary (Canada-US) ranges. We modeled individual killer whale prey requirements from feeding and growth records of captive killer whales and morphometric data from historic live-capture fishery and whaling records worldwide. The models, combined with caloric value of salmon, and demographic and diet data for wild killer whales, allow us to predict salmon quantities needed to maintain and recover this killer whale population, which numbered 87 individuals in 2009. Our analyses provide new information on cost of lactation and new parameter estimates for other killer whale populations globally. Prey requirements of southern resident killer whales are difficult to reconcile with fisheries and conservation objectives for Chinook salmon, because the number of fish required is large relative to annual returns and fishery catches. For instance, a U.S. recovery goal (2.3% annual population growth of killer whales over 28 years) implies a 75% increase in energetic requirements. Reducing salmon fisheries may serve as a temporary mitigation measure to allow time for management actions to improve salmon productivity to take effect. As ecosystem-based fishery management becomes more prevalent, trade-offs between conservation objectives for predators and prey will become increasingly necessary. Our approach offers scenarios to compare relative influence of various sources of uncertainty on the resulting consumption estimates to prioritise future research efforts, and a general approach for assessing the extent of conflict

  11. Earthquake Protection Measures for People with Disabilities

    NASA Astrophysics Data System (ADS)

    Gountromichou, C.; Kourou, A.; Kerpelis, P.

    2009-04-01

    The problem of seismic safety for people with disabilities not only exists but is also urgent and of primary importance. Working towards disability equality, Earthquake Planning and Protection Organization of Greece (E.P.P.O.) has developed an educational scheme for people with disabilities in order to guide them to develop skills to protect themselves as well as to take the appropriate safety measures before, during and after an earthquake. The framework of this initiative includes a number of actions have been already undertaken, including the following: a. Recently, the main guidelines have been published to help people who have physical, cognitive, visual, or auditory disabilities to cope with a destructive earthquake. Of great importance, in case of people with disabilities, is to be prepared for the disaster, with several measures that must be taken starting today. In the pre-earthquake period, it is important that these people, in addition to other measures, do the following: - Create a Personal Support Network The Personal Support Network should be a group of at least three trustful people that can assist the disabled person to prepare for a disastrous event and to recover after it. - Complete a Personal Assessment The environment may change after a destructive earthquake. People with disabilities are encouraged to make a list of their personal needs and their resources for meeting them in a disaster environment. b. Lectures and training seminars on earthquake protection are given for students, teachers and educators in Special Schools for disabled people, mainly for informing and familiarizing them with earthquakes and with safety measures. c. Many earthquake drills have already taken place, for each disability, in order to share good practices and lessons learned to further disaster reduction and to identify gaps and challenges. The final aim of this action is all people with disabilities to be well informed and motivated towards a culture of earthquake

  12. Detecting frogs as prey in the diets of introduced mammals: a comparison between morphological and DNA-based diet analyses.

    PubMed

    Egeter, Bastian; Bishop, Phillip J; Robertson, Bruce C

    2015-03-01

    Amphibians are currently the most threatened group of vertebrates worldwide, and introduced fauna play a major role in their decline. The control of introduced predators to protect endangered species is often based on predation rates derived from diet studies of predators, but prey detection probabilities using different techniques are variable. We measured the detectability of frogs as prey, using morphological and DNA-based diet analyses, in the stomachs and faeces of four mammal species that have been introduced to many areas of the world. Frogs (Litoria raniformis) were fed to rats (Rattus norvegicus and R. rattus), mice (Mus musculus) and hedgehogs (Erinaceus europaeus). DNA-based analysis outperformed morphological analysis, increasing the prey detection rate from 2% to 70% in stomachs and from 0% to 53% in faeces. In most cases, utilizing either stomachs or faeces did not affect the success of prey DNA detection; however, using faeces extended the detectability half-life from 7 to 21 h. This study is the first to measure prey DNA detection periods in mammalian stomachs, and the first to compare prey DNA detection periods in the stomachs and faeces of vertebrates. The results indicate that DNA-based diet analysis provides a more reliable approach for detecting amphibians as prey and has the potential to be used to estimate the rate of predation by introduced mammals on endangered amphibians. PMID:25052066

  13. 29 CFR 1917.95 - Other protective measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial use... 29 Labor 7 2012-07-01 2012-07-01 false Other protective measures. 1917.95 Section 1917.95 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.95 Other protective measures. (a) Protective...

  14. 29 CFR 1917.95 - Other protective measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial use... 29 Labor 7 2014-07-01 2014-07-01 false Other protective measures. 1917.95 Section 1917.95 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.95 Other protective measures. (a) Protective...

  15. 29 CFR 1917.95 - Other protective measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial use... 29 Labor 7 2013-07-01 2013-07-01 false Other protective measures. 1917.95 Section 1917.95 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.95 Other protective measures. (a) Protective...

  16. 29 CFR 1917.95 - Other protective measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial use... 29 Labor 7 2011-07-01 2011-07-01 false Other protective measures. 1917.95 Section 1917.95 Labor... (CONTINUED) MARINE TERMINALS Personal Protection § 1917.95 Other protective measures. (a) Protective...

  17. 15 CFR 764.6 - Protective administrative measures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Protective administrative measures. 764.6 Section 764.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... ENFORCEMENT AND PROTECTIVE MEASURES § 764.6 Protective administrative measures. (a) License...

  18. 15 CFR 764.6 - Protective administrative measures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 2 2013-01-01 2013-01-01 false Protective administrative measures. 764.6 Section 764.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... ENFORCEMENT AND PROTECTIVE MEASURES § 764.6 Protective administrative measures. (a) License...

  19. 15 CFR 764.6 - Protective administrative measures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Protective administrative measures. 764.6 Section 764.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... ENFORCEMENT AND PROTECTIVE MEASURES § 764.6 Protective administrative measures. (a) License...

  20. 15 CFR 764.6 - Protective administrative measures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 2 2014-01-01 2014-01-01 false Protective administrative measures. 764.6 Section 764.6 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... ENFORCEMENT AND PROTECTIVE MEASURES § 764.6 Protective administrative measures. (a) License...

  1. Predators and Prey

    ERIC Educational Resources Information Center

    Kramm, Kenneth R.

    1975-01-01

    Reviews basic concepts of predator-prey interaction, encourages the presentation of the predator's role and describes a model of predator behavior to be used in secondary school or college classes. (LS)

  2. 29 CFR 1918.105 - Other protective measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pursuant to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial... 29 Labor 7 2014-07-01 2014-07-01 false Other protective measures. 1918.105 Section 1918.105 Labor... protective measures. (a) Protective clothing. (1) The employer shall provide and shall require the wearing...

  3. 29 CFR 1918.105 - Other protective measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pursuant to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial... 29 Labor 7 2010-07-01 2010-07-01 false Other protective measures. 1918.105 Section 1918.105 Labor... protective measures. (a) Protective clothing. (1) The employer shall provide and shall require the wearing...

  4. 29 CFR 1918.105 - Other protective measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pursuant to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial... 29 Labor 7 2013-07-01 2013-07-01 false Other protective measures. 1918.105 Section 1918.105 Labor... protective measures. (a) Protective clothing. (1) The employer shall provide and shall require the wearing...

  5. 29 CFR 1918.105 - Other protective measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pursuant to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial... 29 Labor 7 2011-07-01 2011-07-01 false Other protective measures. 1918.105 Section 1918.105 Labor... protective measures. (a) Protective clothing. (1) The employer shall provide and shall require the wearing...

  6. 29 CFR 1918.105 - Other protective measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pursuant to 46 CFR part 160 (Type I, II, III, or V PFD) and marked for use as a work vest, for commercial... 29 Labor 7 2012-07-01 2012-07-01 false Other protective measures. 1918.105 Section 1918.105 Labor... protective measures. (a) Protective clothing. (1) The employer shall provide and shall require the wearing...

  7. Protective sheath for a continuous measurement thermocouple

    DOEpatents

    Phillippi, R.M.

    1991-12-03

    Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device. 4 figures.

  8. Protective sheath for a continuous measurement thermocouple

    DOEpatents

    Phillippi, R. Michael

    1991-01-01

    Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device.

  9. Adult Prey Neutralizes Predator Nonconsumptive Limitation of Prey Recruitment.

    PubMed

    Ellrich, Julius A; Scrosati, Ricardo A; Romoth, Katharina; Molis, Markus

    2016-01-01

    Recent studies have shown that predator chemical cues can limit prey demographic rates such as recruitment. For instance, barnacle pelagic larvae reduce settlement where predatory dogwhelk cues are detected, thereby limiting benthic recruitment. However, adult barnacles attract conspecific larvae through chemical and visual cues, aiding larvae to find suitable habitat for development. Thus, we tested the hypothesis that the presence of adult barnacles (Semibalanus balanoides) can neutralize dogwhelk (Nucella lapillus) nonconsumptive effects on barnacle recruitment. We did a field experiment in Atlantic Canada during the 2012 and 2013 barnacle recruitment seasons (May-June). We manipulated the presence of dogwhelks (without allowing them to physically contact barnacles) and adult barnacles in cages established in rocky intertidal habitats. At the end of both recruitment seasons, we measured barnacle recruit density on tiles kept inside the cages. Without adult barnacles, the nearby presence of dogwhelks limited barnacle recruitment by 51%. However, the presence of adult barnacles increased barnacle recruitment by 44% and neutralized dogwhelk nonconsumptive effects on barnacle recruitment, as recruit density was unaffected by dogwhelk presence. For species from several invertebrate phyla, benthic adult organisms attract conspecific pelagic larvae. Thus, adult prey might commonly constitute a key factor preventing negative predator nonconsumptive effects on prey recruitment. PMID:27123994

  10. Adult Prey Neutralizes Predator Nonconsumptive Limitation of Prey Recruitment

    PubMed Central

    Scrosati, Ricardo A.; Romoth, Katharina; Molis, Markus

    2016-01-01

    Recent studies have shown that predator chemical cues can limit prey demographic rates such as recruitment. For instance, barnacle pelagic larvae reduce settlement where predatory dogwhelk cues are detected, thereby limiting benthic recruitment. However, adult barnacles attract conspecific larvae through chemical and visual cues, aiding larvae to find suitable habitat for development. Thus, we tested the hypothesis that the presence of adult barnacles (Semibalanus balanoides) can neutralize dogwhelk (Nucella lapillus) nonconsumptive effects on barnacle recruitment. We did a field experiment in Atlantic Canada during the 2012 and 2013 barnacle recruitment seasons (May–June). We manipulated the presence of dogwhelks (without allowing them to physically contact barnacles) and adult barnacles in cages established in rocky intertidal habitats. At the end of both recruitment seasons, we measured barnacle recruit density on tiles kept inside the cages. Without adult barnacles, the nearby presence of dogwhelks limited barnacle recruitment by 51%. However, the presence of adult barnacles increased barnacle recruitment by 44% and neutralized dogwhelk nonconsumptive effects on barnacle recruitment, as recruit density was unaffected by dogwhelk presence. For species from several invertebrate phyla, benthic adult organisms attract conspecific pelagic larvae. Thus, adult prey might commonly constitute a key factor preventing negative predator nonconsumptive effects on prey recruitment. PMID:27123994

  11. Sustainability and economic consequences of creating marine protected areas in multispecies multiactivity context.

    PubMed

    Kar, T K; Ghosh, Bapan

    2013-02-01

    The present study deals with harvesting of prey species in the presence of predator in a multispecies marine fishery. The total habitat is divided into two patches: one is reserve area where fishing is completely banned and other zone is called fishing area where only prey is exploited. We assume that the prey fish possesses heterogeneous intrinsic growth rate with uniform carrying capacity where as predator has constant intrinsic growth rate with prey dependent carrying capacity. The analytical conditions are derived to prevent the species extinction for larger employed effort in single (only prey) species fishery. Optimal equilibrium premium are presented for both monospecies and multispecies fishery for all degree of protection. Increasing standing stock (ISS) and protected standing stock (PSS) are measured in the presence of prey-predator interaction. PMID:23149287

  12. L-shaped prey isocline in the Gause predator-prey experiments with a prey refuge.

    PubMed

    Křivan, Vlastimil; Priyadarshi, Anupam

    2015-04-01

    Predator and prey isoclines are estimated from data on yeast-protist population dynamics (Gause et al., 1936). Regression analysis shows that the prey isocline is best fitted by an L-shaped function that has a vertical and a horizontal part. The predator isocline is vertical. This shape of isoclines corresponds with the Lotka-Volterra and the Rosenzweig-MacArthur predator-prey models that assume a prey refuge. These results further support the idea that a prey refuge changes the prey isocline of predator-prey models from a horizontal to an L-shaped curve. Such a shape of the prey isocline effectively bounds amplitude of predator-prey oscillations, thus promotes species coexistence. PMID:25644756

  13. Effect of light, prey density, and prey type on the feeding rates of Hemimysis anomala

    USGS Publications Warehouse

    Halpin, Kathleen E.; Boscarino, Brent T.; Rudstam, Lars G.; Walsh, Mureen G.; Lantry, Brian F.

    2013-01-01

    Hemimysis anomala is a near-shore mysid native to the Ponto-Caspian region that was discovered to have invaded Great Lakes ecosystems in 2006. We investigated feeding rates and prey preferences of adult and juvenile Hemimysis in laboratory experiments to gain insight on the potential for Hemimysis to disrupt food webs. For both age groups (AGs), we measured feeding rates as a function of prey abundance (Bosmina longirostris as prey), prey type (B. longirostris, Daphnia pulex, and Mesocyclops sp.), and light levels (no light and dim light). Mean feeding rates on Bosmina increased with prey density and reached 23 ind. (2 h)−1 for adults and 17 ind. (2 h)−1 for juveniles. Dim light had little effect on prey selection or feeding rate compared to complete darkness. When feeding rates on alternate prey were compared, both AGs fed at higher rates on Bosmina than Daphnia, but only juveniles fed at significantly higher rates on Bosmina relative to Mesocyclops. No significant differences were observed between feeding rates on Mesocyclops and on Daphnia. Hemimysis feeding rates were on the order of 30–60% of their body weight per day, similar to predatory cladocerans that have been implicated in zooplankton declines in Lakes Huron and Ontario.

  14. System for storing cathodic protection measurement data

    SciTech Connect

    Bowman, T.J., Westinghouse Hanford

    1996-12-02

    This paper describes a custom cathodic protection (CP) database, and discusses how this combination of data structure and software improves the ability to analyze cathodic protection. This may be a unique solution to the task of managing CP data, and may have value to others. This paper is primarily about the database design, and not about cathodic protection, per se. Every database project is a balancing act. A developer can create custom software that performs complex opcrafions requiring modest operator skills. On the other hand, custom software is expensive to both create and maintain. The Hanford CP data system will be used primarily by one person, the CP Engineer. It was concluded that this position could be trained to use off-the-shelf, general purpose database to store data, and spreadsheet software to perform analyses. The database product allows flexibility in data reporting, and enforces referential integrity. The spreadsheet allows many display options. Especially useful are the graphics. This solution entailed minimal computer coding and may lend itself to adoption by others. The data structure was designed by a database application developer, with close guidance from the CP engineer. The system will require modest amounts of attention from computer support staff, primarily for new query development. The data structures are provided in this report, and are available electronically.

  15. 46 CFR Sec. 5 - Measures to protect ship's payrolls.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Measures to protect ship's payrolls. Sec. 5 Section 5... SHIP'S PERSONNEL Sec. 5 Measures to protect ship's payrolls. (a) General Agents are not required to... paying off the crew should be either the Master, or purser, or some other member of the ship's...

  16. 46 CFR Sec. 5 - Measures to protect ship's payrolls.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Measures to protect ship's payrolls. Sec. 5 Section 5... SHIP'S PERSONNEL Sec. 5 Measures to protect ship's payrolls. (a) General Agents are not required to... paying off the crew should be either the Master, or purser, or some other member of the ship's...

  17. 46 CFR Sec. 5 - Measures to protect ship's payrolls.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Measures to protect ship's payrolls. Sec. 5 Section 5... SHIP'S PERSONNEL Sec. 5 Measures to protect ship's payrolls. (a) General Agents are not required to... paying off the crew should be either the Master, or purser, or some other member of the ship's...

  18. 30 CFR 282.28 - Environmental protection measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Environmental protection measures. 282.28 Section 282.28 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE... Responsibilities of Lessees § 282.28 Environmental protection measures. (a) Exploration, testing,...

  19. 30 CFR 282.28 - Environmental protection measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false Environmental protection measures. 282.28 Section 282.28 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE... Obligations and Responsibilities of Lessees § 282.28 Environmental protection measures. (a)-(b) (c)(1)...

  20. 30 CFR 282.28 - Environmental protection measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false Environmental protection measures. 282.28 Section 282.28 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE... Obligations and Responsibilities of Lessees § 282.28 Environmental protection measures. (a)-(b) (c)(1)...

  1. 30 CFR 282.28 - Environmental protection measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false Environmental protection measures. 282.28 Section 282.28 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE... Obligations and Responsibilities of Lessees § 282.28 Environmental protection measures. (a)-(b) (c)(1)...

  2. 46 CFR Sec. 5 - Measures to protect ship's payrolls.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Measures to protect ship's payrolls. Sec. 5 Section 5... SHIP'S PERSONNEL Sec. 5 Measures to protect ship's payrolls. (a) General Agents are not required to consider the amount of the payroll delivered to the Master at the conclusion of a voyage in determining...

  3. Measuring the effectiveness of protected area networks in reducing deforestation

    PubMed Central

    Andam, Kwaw S.; Ferraro, Paul J.; Pfaff, Alexander; Sanchez-Azofeifa, G. Arturo; Robalino, Juan A.

    2008-01-01

    Global efforts to reduce tropical deforestation rely heavily on the establishment of protected areas. Measuring the effectiveness of these areas is difficult because the amount of deforestation that would have occurred in the absence of legal protection cannot be directly observed. Conventional methods of evaluating the effectiveness of protected areas can be biased because protection is not randomly assigned and because protection can induce deforestation spillovers (displacement) to neighboring forests. We demonstrate that estimates of effectiveness can be substantially improved by controlling for biases along dimensions that are observable, measuring spatial spillovers, and testing the sensitivity of estimates to potential hidden biases. We apply matching methods to evaluate the impact on deforestation of Costa Rica's renowned protected-area system between 1960 and 1997. We find that protection reduced deforestation: approximately 10% of the protected forests would have been deforested had they not been protected. Conventional approaches to evaluating conservation impact, which fail to control for observable covariates correlated with both protection and deforestation, substantially overestimate avoided deforestation (by over 65%, based on our estimates). We also find that deforestation spillovers from protected to unprotected forests are negligible. Our conclusions are robust to potential hidden bias, as well as to changes in modeling assumptions. Our results show that, with appropriate empirical methods, conservation scientists and policy makers can better understand the relationships between human and natural systems and can use this to guide their attempts to protect critical ecosystem services. PMID:18854414

  4. Quantum state and quantum entanglement protection using quantum measurements

    NASA Astrophysics Data System (ADS)

    Wang, Shuchao; Li, Ying; Wang, Xiangbin; Kwek, Leong Chuan; Yu, Zongwen; Zou, Wenjie

    2015-03-01

    The time evolution of some quantum states can be slowed down or even stopped under frequent measurements. This is the usual quantum Zeno effect. Here we report an operator quantum Zeno effect, in which the evolution of some physical observables is slowed down through measurements even though thequantum state changes randomly with time. Based on the operator quantum Zeno effect, we show how we can protect quantum information from decoherence with two-qubit measurements, realizable with noisy two-qubit interactions. Besides, we report the quantum entanglement protection using weak measurement and measurement reversal scheme. Exposed in the nonzero temperature environment, a quantum system can both lose and gain excitations by interacting with the environment. In this work, we show how to optimally protect quantum states and quantum entanglement in such a situation based on measurement reversal from weak measurement. In particular, we present explicit formulas of protection. We find that this scheme can circumvent the entanglement sudden death in certain conditions.

  5. Protecting weak measurements against systematic errors

    NASA Astrophysics Data System (ADS)

    Pang, Shengshi; Alonso, Jose Raul Gonzalez; Brun, Todd A.; Jordan, Andrew N.

    2016-07-01

    In this work, we consider the systematic error of quantum metrology by weak measurements under decoherence. We derive the systematic error of maximum likelihood estimation in general to the first-order approximation of a small deviation in the probability distribution and study the robustness of standard weak measurement and postselected weak measurements against systematic errors. We show that, with a large weak value, the systematic error of a postselected weak measurement when the probe undergoes decoherence can be significantly lower than that of a standard weak measurement. This indicates another advantage of weak-value amplification in improving the performance of parameter estimation. We illustrate the results by an exact numerical simulation of decoherence arising from a bosonic mode and compare it to the first-order analytical result we obtain.

  6. The Allometry of Prey Preferences

    PubMed Central

    Kalinkat, Gregor; Rall, Björn Christian; Vucic-Pestic, Olivera; Brose, Ulrich

    2011-01-01

    The distribution of weak and strong non-linear feeding interactions (i.e., functional responses) across the links of complex food webs is critically important for their stability. While empirical advances have unravelled constraints on single-prey functional responses, their validity in the context of complex food webs where most predators have multiple prey remain uncertain. In this study, we present conceptual evidence for the invalidity of strictly density-dependent consumption as the null model in multi-prey experiments. Instead, we employ two-prey functional responses parameterised with allometric scaling relationships of the functional response parameters that were derived from a previous single-prey functional response study as novel null models. Our experiments included predators of different sizes from two taxonomical groups (wolf spiders and ground beetles) simultaneously preying on one small and one large prey species. We define compliance with the null model predictions (based on two independent single-prey functional responses) as passive preferences or passive switching, and deviations from the null model as active preferences or active switching. Our results indicate active and passive preferences for the larger prey by predators that are at least twice the size of the larger prey. Moreover, our approach revealed that active preferences increased significantly with the predator-prey body-mass ratio. Together with prior allometric scaling relationships of functional response parameters, this preference allometry may allow estimating the distribution of functional response parameters across the myriads of interactions in natural ecosystems. PMID:21998724

  7. The detectability half-life in predator-prey research: what it is, why we need it, how to measure it, and what it’s good for

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular gut-content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. However, gut-content assays produce qualitative results, necessitating care in using them to infer the impact of predators on prey populations. In order for gut-content assays to ...

  8. 50 CFR 622.10 - Conservation measures for protected resources.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ATLANTIC General Provisions § 622.10 Conservation measures for protected resources. (a) Atlantic dolphin... Atlantic dolphin and wahoo has been issued, as required under § 622.4(a)(2)(xii), and that has on board...

  9. 50 CFR 622.10 - Conservation measures for protected resources.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ATLANTIC General Provisions § 622.10 Conservation measures for protected resources. (a) Atlantic dolphin... Atlantic dolphin and wahoo has been issued, as required under § 622.4(a)(2)(xii), and that has on board...

  10. 50 CFR 622.10 - Conservation measures for protected resources.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ATLANTIC General Provisions § 622.10 Conservation measures for protected resources. (a) Atlantic dolphin... Atlantic dolphin and wahoo has been issued, as required under § 622.4(a)(2)(xii), and that has on board...

  11. SITE-SPECIFIC MEASUREMENTS OF RESIDENTIAL RADON PROTECTION CATEGORY

    EPA Science Inventory

    The report describes a series of benchmark measurements of soil radon potential at seven Florida sites and compares the measurements with regional estimates of radon potential from the Florida radon protection map. The measurements and map were developed under the Florida Radon R...

  12. Security Measures to Protect Mobile Agents

    NASA Astrophysics Data System (ADS)

    Dadhich, Piyanka; Govil, M. C.; Dutta, Kamlesh

    2010-11-01

    The security issues of mobile agent systems have embarrassed its widespread implementation. Mobile agents that move around the network are not safe because the remote hosts that accommodate the agents initiates all kinds of attacks. These hosts try to analyze the agent's decision logic and their accumulated data. So, mobile agent security is the most challenging unsolved problems. The paper analyzes various security measures deeply. Security especially the attacks performed by hosts to the visiting mobile agent (the malicious hosts problem) is a major obstacle that prevents mobile agent technology from being widely adopted. Being the running environment for mobile agent, the host has full control over them and could easily perform many kinds of attacks against them.

  13. Some applications of phasor measurements to adaptive protection

    SciTech Connect

    Thorp, J.S.; Phadke, A.G.; Horowitz, S.H.; Begovic, M.M.

    1987-01-01

    The application of microprocessor based phasor measurements to new adaptive protection schemes is presented. The concepts of digital adaptive protection in which relay characteristics are modified in response to external signals and conditions in the system are examined. The importance of real-time phasor measurements in adaptive protection systems is illustrated by two examples. The first involves obtaining synchronizing information about phasor measurements to be used in a new type of current differential protection for a multiterminal line. By estimating the reference angles for the phasor measurements the effect of synchronized sampling can be obtained without the expense of synchronizing equipment. The second use of phasor measurements in adaptive protection is the adaptive setting of out-of-step blocking and tripping. Traditional problems of setting out-of-step blocking and tripping are caused because the settings are, of necessity, compromises based on off-line studies. By reacting to real-time phasor measurements from selected buses in interconnection it is shown that improved out-of-step blocking and tripping is possible. 24 refs., 8 figs.

  14. Experimental determination of the spatial scale of a prey patch from the predator's perspective.

    PubMed

    Birk, Matthew A; White, J Wilson

    2014-03-01

    Foraging theory predicts that predators should prefer foraging in habitat patches with higher prey densities. However, density depends on the spatial scale at which a "patch" is defined by an observer. Ecologists strive to measure prey densities at the same scale that predators do, but many natural landscapes lack obvious, well-defined prey patches. Thus one must determine the scale at which predators define patches of prey. We estimated the scale at which guppies, Poecilia reticulata, selected patches of zooplankton prey using a behavioral assay. Guppies could choose between two prey arrays, each manipulated to have a density that depended on the spatial scale at which density was calculated. We estimated the scale of guppy foraging by comparing guppy preferences across a series of trials in which we systematically varied the scale associated with "high" prey density. This approach enables the application of foraging theory to non-discrete habitats and prey landscapes. PMID:24241641

  15. Measuring the skin dose protection afforded by protective apparel with a beta spectrometer

    SciTech Connect

    Martz, D.E.; Rich, B.L.; Johnson, L.O. )

    1986-10-01

    This paper reports that the protective apparel worn by radiation workers to avoid skin contamination also provides measurable protection against external beta sources. The beta contribution to the skin dose rate depends on the residual energy spectrum of the beta particles after they have penetrated the protective apparel. The shift in the beta energy spectra and consequent reduction in the shallow dose rates afforded by various items of protective apparel were investigated for a few laboratory beta sources using a beta spectrometer that is capable of dose calculations. The results presented here indicate that significant dose rates to the skin can occur despite the presence of protective apparel if high energy beta emitting isotopes are present.

  16. Goshawk prey have more bacteria than non-prey.

    PubMed

    Møller, A P; Peralta-Sánchez, J M; Nielsen, J T; López-Hernández, E; Soler, J J

    2012-03-01

    1. Predators often prey on individuals that are sick or otherwise weakened. Although previous studies have shown higher abundance of parasites in prey, whether prey have elevated loads of micro-organisms remains to be determined. 2. We quantified the abundance of bacteria and fungi on feathers of woodpigeons Columba palumbus L., jays Garrulus glandarius L. and blackbirds Turdus merula L. that either fell prey to goshawks Accipiter gentilis L. or were not depredated. 3. We found an almost three-fold increase in bacterial load of prey compared with non-prey, while there was no significant difference between prey and non-prey in level of fungal infection of the plumage. 4. The results were not confounded by differences in size or mass of feathers, date of collection of feathers, or date of analysis of feathers for micro-organisms. 5. These findings suggest a previously unknown contribution of bacteria to risk of predation, with important implications for behaviour, population ecology and community ecology. PMID:22039986

  17. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

    PubMed

    Clare, Elizabeth L; Holderied, Marc W

    2015-01-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism. PMID:26327624

  18. Ecoepidemic predator-prey model with feeding satiation, prey herd behavior and abandoned infected prey.

    PubMed

    Kooi, Bob W; Venturino, Ezio

    2016-04-01

    In this paper we analyse a predator-prey model where the prey population shows group defense and the prey individuals are affected by a transmissible disease. The resulting model is of the Rosenzweig-MacArthur predator-prey type with an SI (susceptible-infected) disease in the prey. Modeling prey group defense leads to a square root dependence in the Holling type II functional for the predator-prey interaction term. The system dynamics is investigated using simulations, classical existence and asymptotic stability analysis and numerical bifurcation analysis. A number of bifurcations, such as transcritical and Hopf bifurcations which occur commonly in predator-prey systems will be found. Because of the square root interaction term there is non-uniqueness of the solution and a singularity where the prey population goes extinct in a finite time. This results in a collapse initiated by extinction of the healthy or susceptible prey and thereafter the other population(s). When also a positive attractor exists this leads to bistability similar to what is found in predator-prey models with a strong Allee effect. For the two-dimensional disease-free (i.e. the purely demographic) system the region in the parameter space where bistability occurs is marked by a global bifurcation. At this bifurcation a heteroclinic connection exists between saddle prey-only equilibrium points where a stable limit cycle together with its basin of attraction, are destructed. In a companion paper (Gimmelli et al., 2015) the same model was formulated and analysed in which the disease was not in the prey but in the predator. There we also observed this phenomenon. Here we extend its analysis using a phase portrait analysis. For the three-dimensional ecoepidemic predator-prey system where the prey is affected by the disease, also tangent bifurcations including a cusp bifurcation and a torus bifurcation of limit cycles occur. This leads to new complex dynamics. Continuation by varying one parameter

  19. Public-private provision of protection measures against natural hazards

    NASA Astrophysics Data System (ADS)

    Gruber, M.

    2009-04-01

    Natural hazards threaten human lives as well as economic values of a society. Due to an increasing population density, augmenting property holdings in congested areas as well as higher frequencies of catastrophic events, the damage potential associated with natural hazards is growing. In order to safeguard societal assets against this threat, active and passive protection measures can be established. While passive protection measures provide for this type of risk by means of thorough land use planning, active protection measures aim at improving safety through technical or biological protective systems and structures. However, these provisions are costly and need to be handled prudentially. In most European countries protection measures against natural hazards are provided by the public. Specific governmental funds have been set up for the establishment of preventive systems as well as for damage compensation payments after the occurrence of catastrophic events. Though, additional capital is urgently needed in order to facilitate the realisation of all necessary projects in this field and to provide for maximal safety. One potential solution for such financial deficiencies can be found in Public Private Partnerships (PPP). PPPs have been implemented as attractive concepts for the funding of diverse projects in the fields of e.g. road construction, municipal, health and social services. In principle, they could also provide alternative funding solutions for the establishment of crucial protective infrastructure in respect of natural hazards, adding private financial means to the currently available public funds. Thereby, the entire capacities for catastrophe funding could be enhanced. Beside PPPs, also alternative funding mechanisms such as the emission of catastrophe bonds, contingent credit lines or leasing arrangements may enhance available capacities for the financing of protection measures. This contribution discusses innovative solutions for the funding of

  20. Birds of Prey of Wisconsin.

    ERIC Educational Resources Information Center

    Hamerstrom, Frances

    This copiously illustrated document is designed to be a field quide to birds of prey that are common to Wisconsin, as well as to some that enter the state occasionally. An introduction discusses birds of prey with regard to migration patterns, the relationship between common names and the attitudes of people toward certain birds, and natural signs…

  1. Predatory Bacteriovorax Communities Ordered by Various Prey Species

    PubMed Central

    Chen, Huan; Young, Shanterial; Berhane, Timkhite-Kulu; Williams, Henry N.

    2012-01-01

    The role of predation in altering microbial communities has been studied for decades but few examples are known for bacterial predators. Bacteriovorax are halophilic prokaryotes that prey on susceptible Gram-negative bacteria. We recently reported novel observations on the differential selection of Bacteriovorax phylotypes by two different prey, Vibrio parahaemolyticus and Vibrio vulnificus. However, the conclusion is restricted by the limited number of prey tested. In this study, we have conducted two independent investigations involving eight species of prey bacteria while using V. vulnificus and V. parahaemolytics as reference strains. Water samples collected from Dry Bar, Apalachicola Bay were used to establish microcosms which were respectively spiked with prey strains Vibrio cholerae, Escherichia coli or Pseudomonas putida to examine the response of native Bacteriovorax to freshwater bacteria. Indigenous Vibrio sp., Pseudoalteromonas sp., Photobacterium sp. and a clinical strain of V. vulnificus were also tested for the impact of saltwater prey on the Bacteriovorax community. At 24 hour intervals, optical density of the microcosm samples and the abundance of Bacteriovorax were measured over five days. The predominant Bacteriovorax plaques were selected and analyzed by 16S rRNA gene amplification and sequencing. In addition, the impacts of prey on predator population and bacterial community composition were investigated using culture independent denaturing gradient gel electrophoresis. Strikingly, Cluster IV was found consistently as the predominant phylotype produced by the freshwater prey. For all saltwater prey, subgroups of Bacteriovorax phylotype IX were the major predators recovered. The results suggest that prey is an important factor along with temperature, salinity and other environmental parameters in shaping Bacteriovorax communities in aquatic systems. PMID:22461907

  2. Predatory Bacteriovorax communities ordered by various prey species.

    PubMed

    Chen, Huan; Young, Shanterial; Berhane, Timkhite-Kulu; Williams, Henry N

    2012-01-01

    The role of predation in altering microbial communities has been studied for decades but few examples are known for bacterial predators. Bacteriovorax are halophilic prokaryotes that prey on susceptible gram-negative bacteria. We recently reported novel observations on the differential selection of Bacteriovorax phylotypes by two different prey, Vibrio parahaemolyticus and Vibrio vulnificus. However, the conclusion is restricted by the limited number of prey tested. In this study, we have conducted two independent investigations involving eight species of prey bacteria while using V. vulnificus and V. parahaemolytics as reference strains. Water samples collected from Dry Bar, Apalachicola Bay were used to establish microcosms which were respectively spiked with prey strains Vibrio cholerae, Escherichia coli or Pseudomonas putida to examine the response of native Bacteriovorax to freshwater bacteria. Indigenous Vibrio sp., Pseudoalteromonas sp., Photobacterium sp. and a clinical strain of V. vulnificus were also tested for the impact of saltwater prey on the Bacteriovorax community. At 24 hour intervals, optical density of the microcosm samples and the abundance of Bacteriovorax were measured over five days. The predominant Bacteriovorax plaques were selected and analyzed by 16S rRNA gene amplification and sequencing. In addition, the impacts of prey on predator population and bacterial community composition were investigated using culture independent denaturing gradient gel electrophoresis. Strikingly, Cluster IV was found consistently as the predominant phylotype produced by the freshwater prey. For all saltwater prey, subgroups of Bacteriovorax phylotype IX were the major predators recovered. The results suggest that prey is an important factor along with temperature, salinity and other environmental parameters in shaping Bacteriovorax communities in aquatic systems. PMID:22461907

  3. Personal Protection Measures Against Mosquitoes, Ticks, and Other Arthropods.

    PubMed

    Alpern, Jonathan D; Dunlop, Stephen J; Dolan, Benjamin J; Stauffer, William M; Boulware, David R

    2016-03-01

    Arthropod-associated diseases are a major cause of morbidity among travelers. Obtaining a detailed travel itinerary and understanding traveler-specific and destination-specific risk factors can help mitigate the risk of vector-borne diseases. DEET, picaridin, PMD, and IR3535 are insect repellents that offer sufficient protection against arthropod bites. IR3535 does not provide adequate protection against Anopheles mosquitoes, and should be avoided in malaria-endemic regions. General protective measures, such as bite avoidance, protective clothing, insecticide-treated bed nets, and insecticide-treated clothing, should be recommended, especially in malaria-endemic areas. Spatial repellents may prevent nuisance biting, but have not been shown to prevent against vector-borne disease. PMID:26900115

  4. Negotiating a noisy, information-rich environment in search of cryptic prey: olfactory predators need patchiness in prey cues.

    PubMed

    Carthey, Alexandra J R; Bytheway, Jenna P; Banks, Peter B

    2011-07-01

    1. Olfactory predator search processes differ fundamentally to those based on vision, particularly when odour cues are deposited rather than airborne or emanating from a point source. When searching for visually cryptic prey that may have moved some distance from a deposited odour cue, cue context and spatial variability are the most likely sources of information about prey location available to an olfactory predator. 2. We tested whether the house mouse (Mus domesticus), a model olfactory predator, would use cue context and spatial variability when searching for buried food items; specifically, we tested the effect of varying cue patchiness, odour strength, and cue-prey association on mouse foraging success. 3. Within mouse- and predator-proof enclosures, we created grids of 100 sand-filled Petri dishes and buried peanut pieces in a set number of these patches to represent visually cryptic 'prey'. By adding peanut oil to selected dishes, we varied the spatial distribution of prey odour relative to the distribution of prey patches in each grid, to reflect different levels of cue patchiness (Experiment 1), odour strength (Experiment 2) and cue-prey association (Experiment 3). We measured the overnight foraging success of individual mice (percentage of searched patches containing prey), as well as their foraging activity (percentage of patches searched), and prey survival (percentage of unsearched prey patches). 4. Mouse foraging success was highest where odour cues were patchy rather than uniform (Experiment 1), and where cues were tightly associated with prey location, rather than randomly or uniformly distributed (Experiment 3). However, when cues at prey patches were ten times stronger than a uniformly distributed weak background odour, mice did not improve their foraging success over that experienced when cues were of uniform strength and distribution (Experiment 2). 5. These results suggest that spatial variability and cue context are important means by which

  5. Predator-prey interactions mediated by prey personality and predator hunting mode.

    PubMed

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-04-13

    Predator-prey interactions are important drivers in structuring ecological communities. However, despite widespread acknowledgement that individual behaviours and predator species regulate ecological processes, studies have yet to incorporate individual behavioural variations in a multipredator system. We quantified a prevalent predator avoidance behaviour to examine the simultaneous roles of prey personality and predator hunting mode in governing predator-prey interactions. Mud crabs, Panopeus herbstii, reduce their activity levels and increase their refuge use in the presence of predator cues. We measured mud crab mortality and consistent individual variations in the strength of this predator avoidance behaviour in the presence of predatory blue crabs, Callinectes sapidus, and toadfish, Opsanus tau We found that prey personality and predator species significantly interacted to affect mortality with blue crabs primarily consuming bold mud crabs and toadfish preferentially selecting shy crabs. Additionally, the strength of the predator avoidance behaviour depended upon the predation risk from the predator species. Consequently, the personality composition of populations and predator hunting mode may be valuable predictors of both direct and indirect predator-prey interaction strength. These findings support theories postulating mechanisms for maintaining intraspecies diversity and have broad implications for community dynamics. PMID:27075257

  6. Protective measures, personal experience, and the affective psychology of time.

    PubMed

    Peters, E; Kunreuther, H; Sagara, N; Slovic, P; Schley, D R

    2012-12-01

    We examined the role of time and affect in intentions to purchase a risk-protective measure (Studies 1 and 2) and explored participant abilities to factor time into the likelihood judgments that presumably underlie such intentions (Study 3). Participants worried more about losing their possessions and were more likely to purchase a protective measure given a longer term lease than a short-term lease, but only if their belongings were described in affect-poor terms. If described instead as being particularly special and affect-rich, participants neglected time and were about equally likely to purchase a risk-protective measure for shorter and longer term leases. However, and consistent with prior literature, the cognitive mechanism underlying this time-neglect-with-affect-richness effect seemed to be the greater use of the affect heuristic in the shorter term than the longer term. Study 2 results demonstrated that prior experience with having been burglarized amplified the interactive effect of time and affect. Greater deliberation did not attenuate this effect as hypothesized whether deliberation was measured through numeracy or manipulated through instructions. The results of Study 3 indicated that few participants are able to calculate correctly the risk numbers necessary to take time into account. Two possible solutions to encourage more purchases of protective measures in the long term are discussed. PMID:22548249

  7. Acoustic mirror effect increases prey detection distance in trawling bats

    NASA Astrophysics Data System (ADS)

    Siemers, Björn M.; Baur, Eric; Schnitzler, Hans-Ulrich

    2005-06-01

    Many different and phylogenetically distant species of bats forage for insects above water bodies and take insects from and close to the surface; the so-called ‘trawling behaviour’. Detection of surface-based prey by echolocation is facilitated by acoustically smooth backgrounds such as water surfaces that reflect sound impinging at an acute angle away from the bat and thereby render a prey object acoustically conspicuous. Previous measurements had shown that the echo amplitude of a target on a smooth surface is higher than that of the same target in mid-air, due to an acoustic mirror effect. In behavioural experiments with three pond bats (Myotis dasycneme), we tested the hypothesis that the maximum distances at which bats can detect prey are larger for prey on smooth surfaces than for the same prey in an airborne situation. We determined the moment of prey detection from a change in echolocation behaviour and measured the detection distance in 3D space from IR-video recordings using stereo-photogrammetry. The bats showed the predicted increase in detection distance for prey on smooth surfaces. The acoustic mirror effect therefore increases search efficiency and contributes to the acoustic advantages encountered by echolocating bats when foraging at low heights above smooth water surfaces. These acoustic advantages may have favoured the repeated evolution of trawling behaviour.

  8. The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms

    USGS Publications Warehouse

    Humphries, Austin T.; La Peyre, Megan K.; Decossas, Gary A.

    2011-01-01

    Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

  9. Load Measurement on Foundations of Rockfall Protection Systems.

    PubMed

    Volkwein, Axel; Kummer, Peter; Bitnel, Hueseyin; Campana, Lorenzo

    2016-01-01

    Rockfall protection barriers are connected to the ground using steel cables fixed with anchors and foundations for the steel posts. It is common practice to measure the forces in the cables, while to date measurements of forces in the foundations have been inadequately resolved. An overview is presented of existing methods to measure the loads on the post foundations of rockfall protection barriers. Addressing some of the inadequacies of existing approaches, a novel sensor unit is presented that is able to capture the forces acting on post foundations in all six degrees of freedom. The sensor unit consists of four triaxial force sensors placed between two steel plates. To correctly convert the measurements into the directional forces acting on the foundation a special in-situ calibration procedure is proposed that delivers a corresponding conversion matrix. PMID:26840315

  10. Load Measurement on Foundations of Rockfall Protection Systems

    PubMed Central

    Volkwein, Axel; Kummer, Peter; Bitnel, Hueseyin; Campana, Lorenzo

    2016-01-01

    Rockfall protection barriers are connected to the ground using steel cables fixed with anchors and foundations for the steel posts. It is common practice to measure the forces in the cables, while to date measurements of forces in the foundations have been inadequately resolved. An overview is presented of existing methods to measure the loads on the post foundations of rockfall protection barriers. Addressing some of the inadequacies of existing approaches, a novel sensor unit is presented that is able to capture the forces acting on post foundations in all six degrees of freedom. The sensor unit consists of four triaxial force sensors placed between two steel plates. To correctly convert the measurements into the directional forces acting on the foundation a special in-situ calibration procedure is proposed that delivers a corresponding conversion matrix. PMID:26840315

  11. 50 CFR 622.273 - Conservation measures for protected species.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.273 Conservation measures for protected species. (a) Atlantic dolphin and wahoo pelagic longliners. The owner or operator of a vessel for which a commercial permit for Atlantic dolphin and wahoo has been issued, as required...

  12. 50 CFR 622.273 - Conservation measures for protected species.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.273 Conservation measures for protected species. (a) Atlantic dolphin and wahoo pelagic longliners. The owner or operator of a vessel for which a commercial permit for Atlantic dolphin and wahoo has been issued, as required...

  13. 30 CFR 582.28 - Environmental protection measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... evaluation of the approved Delineation, Testing, or Mining Plan. The Director's review of the air quality consequences of proposed OCS activities will follow the practices and procedures specified in 30 CFR 250.194... Responsibilities of Lessees § 582.28 Environmental protection measures. (a) Exploration, testing,...

  14. 30 CFR 582.28 - Environmental protection measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... evaluation of the approved Delineation, Testing, or Mining Plan. The Director's review of the air quality consequences of proposed OCS activities will follow the practices and procedures specified in 30 CFR 250.194... Responsibilities of Lessees § 582.28 Environmental protection measures. (a) Exploration, testing,...

  15. 30 CFR 582.28 - Environmental protection measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... evaluation of the approved Delineation, Testing, or Mining Plan. The Director's review of the air quality consequences of proposed OCS activities will follow the practices and procedures specified in 30 CFR 250.194... Responsibilities of Lessees § 582.28 Environmental protection measures. (a) Exploration, testing,...

  16. Constructing vulnerabilty and protective measures indices for the enhanced critical infrastructure protection program.

    SciTech Connect

    Fisher, R. E.; Buehring, W. A.; Whitfield, R. G.; Bassett, G. W.; Dickinson, D. C.; Haffenden, R. A.; Klett, M. S.; Lawlor, M. A.; Decision and Information Sciences; LANL

    2009-10-14

    The US Department of Homeland Security (DHS) has directed its Protective Security Advisors (PSAs) to form partnerships with the owners and operators of assets most essential to the Nation's well being - a subclass of critical infrastructure and key resources (CIKR) - and to conduct site visits for these and other high-risk assets as part of the Enhanced Critical Infrastructure Protection (ECIP) Program. During each such visit, the PSA documents information about the facility's current CIKR protection posture and overall security awareness. The primary goals for ECIP site visits (DHS 2009) are to: (1) inform facility owners and operators of the importance of their facilities as an identified high-priority CIKR and the need to be vigilant in light of the ever-present threat of terrorism; (2) identify protective measures currently in place at these facilities, provide comparisons of CIKR protection postures across like assets, and track the implementation of new protective measures; and (3) enhance existing relationships among facility owners and operators; DHS; and various Federal, State, local tribal, and territorial partners. PSAs conduct ECIP visits to assess overall site security; educate facility owners and operators about security; help owners and operators identify gaps and potential improvements; and promote communication and information sharing among facility owners and operators, DHS, State governments, and other security partners. Information collected during ECIP visits is used to develop metrics; conduct sector-by-sector and cross-sector vulnerability comparisons; identify security gaps and trends across CIKR sectors and subsectors; establish sector baseline security survey results; and track progress toward improving CIKR security through activities, programs, outreach, and training (Snyder 2009). The data being collected are used in a framework consistent with the National Infrastructure Protection Plan (NIPP) risk criteria (DHS 2009). The NIPP

  17. Prey-predator model with a nonlocal consumption of prey.

    PubMed

    Banerjee, M; Volpert, V

    2016-08-01

    The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology. PMID:27586616

  18. Predator size, prey size and threshold food densities of diving ducks: does a common prey base support fewer large animals?

    PubMed

    Richman, Samantha E; Lovvorn, James R

    2009-09-01

    1. Allometry predicts that a given habitat area or common prey biomass supports fewer numbers of larger than smaller predators; however, birds from related taxa or the same feeding guild often deviate from this pattern. In particular, foraging costs of birds may differ among locomotor modes, while intake rates vary with accessibility, handling times and energy content of different-sized prey. Such mechanisms might affect threshold prey densities needed for energy balance, and thus relative numbers of different-sized predators in habitats with varying prey patches. 2. We compared the foraging profitability (energy gain minus cost) of two diving ducks: smaller lesser scaup (Aythya affinis, 450-1090 g) and larger white-winged scoters (Melanitta fusca, 950-1800 g). Calculations were based on past measurements of dive costs with respirometry, and of intake rates of a common bivalve prey ranging in size, energy content and burial depth in sediments. 3. For scaup feeding on small prey <12 mm long, all clams buried deeper than 5 cm were unprofitable at realistic prey densities. For clams buried in the top 5 cm, the profitability threshold decreased from 216 to 34 clams m(-2) as energy content increased from 50 to 300 J clam(-1). 4. For larger scoters feeding on larger prey 18-24 mm long, foraging was profitable for clams buried deeper than 5 cm, with a threshold density of 147 m(-2) for clams containing 380 J clam(-1). For clams <5 cm deep, the threshold density decreased from 86 to 36 clams m(-2) as energy content increased from 380 to 850 J clam(-1). If scoters decreased dive costs by swimming with wings as well as feet (not an option for scaup), threshold prey densities were 11-12% lower. 5. Our results show that threshold densities of total prey numbers for different-sized ducks depend on prey size structure and depth in the sediments. Thus, heterogeneity in disturbance regimes and prey population dynamics can create a mosaic of patches favouring large or small

  19. Preference and prey switching in a generalist predator attacking local and invasive alien pests.

    PubMed

    Jaworski, Coline C; Bompard, Anaïs; Genies, Laure; Amiens-Desneux, Edwige; Desneux, Nicolas

    2013-01-01

    Invasive pest species may strongly affect biotic interactions in agro-ecosystems. The ability of generalist predators to prey on new invasive pests may result in drastic changes in the population dynamics of local pest species owing to predator-mediated indirect interactions among prey. On a short time scale, the nature and strength of such indirect interactions depend largely on preferences between prey and on predator behavior patterns. Under laboratory conditions we evaluated the prey preference of the generalist predator Macrolophus pygmaeus Rambur (Heteroptera: Miridae) when it encounters simultaneously the local tomato pest Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and the invasive alien pest Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). We tested various ratios of local vs. alien prey numbers, measuring switching by the predator from one prey to the other, and assessing what conditions (e.g. prey species abundance and prey development stage) may favor such prey switching. The total predation activity of M. pygmaeus was affected by the presence of T. absoluta in the prey complex with an opposite effect when comparing adult and juvenile predators. The predator showed similar preference toward T. absoluta eggs and B. tabaci nymphs, but T. absoluta larvae were clearly less attacked. However, prey preference strongly depended on prey relative abundance with a disproportionately high predation on the most abundant prey and disproportionately low predation on the rarest prey. Together with the findings of a recent companion study (Bompard et al. 2013, Population Ecology), the insight obtained on M. pygmaeus prey switching may be useful for Integrated Pest Management in tomato crops, notably for optimal simultaneous management of B. tabaci and T. absoluta, which very frequently co-occur on tomato. PMID:24312646

  20. Mechanical work as a determinant of prey-handling behavior in the tokay gecko (Gekko gecko).

    PubMed

    Andrews, C; Bertram, J E

    1997-01-01

    In this study an in vitro analysis of the force and mechanical work required to bite prey items of different size and physical character is combined with an in vivo analysis of prey-handling behavior in the tokay gecko (Gekko gecko). The force required to bite and the work of biting increase with prey size, but the rate of increase is prey specific, with crickets (Acheta domestica) requiring substantially more force and work per bite than larvae (Galleria mellonella and Manduca sexta) for all but the smallest prey. Prey-handling behavior is also prey specific. Geckos exert more bites per feeding event on small crickets than on small insect larvae, but the number of bites increases faster with prey mass for larvae than for crickets. Combination of the in vitro mechanical measurements with the in vivo behavior analysis allows the calculation of total mechanical work per feeding event and indicates that total work increases with prey size but that the difference between prey types is far less than predicted from the differences in structural properties of the prey. This occurs because the number of bites and work per bite relationships tend to cancel the differences in the total work necessary to process each prey type. Thus, when considering the effect of prey size, a 13-fold greater rate of increase in bite force and an 18-fold greater rate of increase of work per bit for crickets over larvae was partially compensated for by a threefold increase in the number of bites used on larvae relative to crickets. These results can be interpreted in two ways. The effect of mechanical work in feeding behavior suggests that the energetics of jaw adductor musculature could play a greater role in governing the feeding behavior of this lizard than has previously been expected. Alternatively, the scaling of work in feeding over a range of prey sizes suggests distinct differences in the geometric features of the prey that determine how they are processed. PMID:9231392

  1. Understanding spatial distributions: negative density-dependence in prey causes predators to trade-off prey quantity with quality.

    PubMed

    Bijleveld, Allert I; MacCurdy, Robert B; Chan, Ying-Chi; Penning, Emma; Gabrielson, Rich M; Cluderay, John; Spaulding, Eric L; Dekinga, Anne; Holthuijsen, Sander; ten Horn, Job; Brugge, Maarten; van Gils, Jan A; Winkler, David W; Piersma, Theunis

    2016-04-13

    Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The 'functional response' couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cockles Cerastoderma edule) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knots Calidris canutus). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators. PMID:27053747

  2. Restricting Prey Dispersal Can Overestimate the Importance of Predation in Trophic Cascades

    PubMed Central

    Geraldi, Nathan R.; Macreadie, Peter I.

    2013-01-01

    Predators can affect prey populations and, via trophic cascades, predators can indirectly impact resource populations (2 trophic levels below the predator) through consumption of prey (density-mediated indirect effects; DMIEs) and by inducing predator-avoidance behavior in prey (trait-mediated indirect effects; TMIEs). Prey often employ multiple predator-avoidance behaviors, such as dispersal or reduced foraging activity, but estimates of TMIEs are usually on individual behaviors. We assessed direct and indirect predator effects in a mesocosm experiment using a marine food chain consisting of a predator (toadfish – Opsanus tau), prey (mud crab - Panopeus herbstii) and resource (ribbed mussel – Geukensia demissa). We measured dispersal and foraging activity of prey separately by manipulating both the presence and absence of the predator, and whether prey could or could not disperse into a predator-free area. Consumption of prey was 9 times greater when prey could not disperse, probably because mesocosm boundaries increased predator capture success. Although predator presence did not significantly affect the number of crabs that emigrated, the presence of a predator decreased resource consumption by prey, which resulted in fewer resources consumed for each prey that emigrated in the presence of a predator, and reduced the overall TMIE. When prey were unable to disperse, TMIEs on mussel survival were 3 times higher than the DMIEs. When prey were allowed to disperse, the TMIEs on resource survival increased to 11-times the DMIEs. We found that restricting the ability of prey to disperse, or focusing on only one predator-avoidance behavior, may be underestimating TMIEs. Our results indicate that the relative contribution of behavior and consumption in food chain dynamics will depend on which predator-avoidance behaviors are allowed to occur and measured. PMID:23408957

  3. 14. Protective measures for activities in Chernobyl's radioactively contaminated territories.

    PubMed

    Nesterenko, Alexey V; Nesterenko, Vassily B

    2009-11-01

    Owing to internally absorbed radionuclides, radiation levels for individuals living in the contaminated territories of Belarus, Ukraine, and Russia have been increasing steadily since 1994. Special protective measures in connection with agriculture, forestry, hunting, and fishing are necessary to protect the health of people in all the radioactively contaminated territories. Among the measures that have proven to be effective in reducing levels of incorporated radionuclides in meat production are food additives with ferrocyanides, zeolites, and mineral salts. Significant decreases in radionuclide levels in crops are achieved using lime/Ca as an antagonist of Sr-90, K fertilizers as antagonists of Cs-137, and phosphoric fertilizers that form a hard, soluble phosphate with Sr-90. Disk tillage and replowing of hayfields incorporating applications of organic and mineral fertilizers reduces the levels of Cs-137 and Sr-90 three- to fivefold in herbage grown in mineral soils. Among food technologies to reduce radionuclide content are cleaning cereal seeds, processing potatoes into starch, processing carbohydrate-containing products into sugars, and processing milk into cream and butter. There are several simple cooking techniques that decrease radionuclides in foodstuffs. Belarus has effectively used some forestry operations to create "a live partition wall," to regulate the redistribution of radionuclides into ecosystems. All such protective measures will be necessary in many European territories for many generations. PMID:20002058

  4. Benefits of fish passage and protection measures at hydroelectric projects

    SciTech Connect

    Cada, G.F.; Jones, D.W.

    1993-06-01

    The US Department of Energy`s Hydropower Program is engaged in a multi-year study of the costs and benefits of environmental mitigation measures at nonfederal hydroelectric power plants. An initial report (Volume 1) reviewed and surveyed the status of mitigation methods for fish passage, instream flows, and water quality; this paper focuses on the fish passage/protection aspects of the study. Fish ladders were found to be the most common means of passing fish upstream; elevators/lifts were less common, but their use appears to be increasing. A variety of mitigative measures is employed to prevent fish from being drawn into turbine intakes, including spill flows, narrow-mesh intake screens, angled bar racks, and lightor sound-based guidance measures. Performance monitoring and detailed, quantifiable performance criteria were frequently lacking at non-federal hydroelectric projects. Volume 2 considers the benefits and costs of fish passage and protection measures, as illustrated by case studies for which performance monitoring has been conducted. The report estimates the effectiveness of particular measures, the consequent impacts on the fish populations that are being maintained or restored, and the resulting use and non-use values of the maintained or restored fish populations.

  5. Protecting entanglement from correlated amplitude damping channel using weak measurement and quantum measurement reversal

    NASA Astrophysics Data System (ADS)

    Xiao, Xing; Yao, Yao; Xie, Ying-Mao; Wang, Xing-Hua; Li, Yan-Ling

    2016-06-01

    Based on the quantum technique of weak measurement, we propose a scheme to protect the entanglement from correlated amplitude damping decoherence. In contrast to the results of memoryless amplitude damping channel, we show that the memory effects play a significant role in the suppression of entanglement sudden death and protection of entanglement under severe decoherence. Moreover, we find that the initial entanglement could be drastically amplified by the combination of weak measurement and quantum measurement reversal even under the correlated amplitude damping channel. The underlying mechanism can be attributed to the probabilistic nature of weak measurements.

  6. Foraging and vulnerability traits modify predator-prey body mass allometry: freshwater macroinvertebrates as a case study.

    PubMed

    Klecka, Jan; Boukal, David S

    2013-09-01

    1. Predation is often size selective, but the role of other traits of the prey and predators in their interactions is little known. This hinders our understanding of the causal links between trophic interactions and the structure of animal communities. Better knowledge of trophic traits underlying predator-prey interactions is also needed to improve models attempting to predict food web structure and dynamics from known species traits. 2. We carried out laboratory experiments with common freshwater macroinvertebrate predators (diving beetles, dragonfly and damselfly larvae and water bugs) and their prey to assess how body size and traits related to foraging (microhabitat use, feeding mode and foraging mode) and to prey vulnerability (microhabitat use, activity and escape behaviour) affect predation strength. 3. The underlying predator-prey body mass allometry characterizing mean prey size and total predation pressure was modified by feeding mode of the predators (suctorial or chewing). Suctorial predators fed upon larger prey and had ˜3 times higher mass-specific predation rate than chewing predators of the same size and may thus have stronger effect on prey abundance. 4. Strength of individual trophic links, measured as mortality of the focal prey caused by the focal predator, was determined jointly by the predator and prey body mass and their foraging and vulnerability traits. In addition to the feeding mode, interactions between prey escape behaviour (slow or fast), prey activity (sedentary or active) and predator foraging mode (searching or ambush) strongly affected prey mortality. Searching predators was ineffective in capturing fast-escape prey in comparison with the remaining predator-prey combinations, while ambush predators caused higher mortality than searching predators and the difference was larger in active prey. 5. Our results imply that the inclusion of the commonly available qualitative data on foraging traits of predators and vulnerability traits

  7. Nuclear fragmentation measurements for hadrontherapy and space radiation protection

    SciTech Connect

    De Napoli, M.; Agodi, C.; Blancato, A. A.; Cavallaro, M.; Cirrone, G. A. P.; Cuttone, G.; Sardina, D.; Scuderi, V.; Battistoni, G.; Bondi, M.; Cappuzzello, F.; Carbone, D.; Nicolosi, D.; Raciti, G.; Tropea, S.; Giacoppo, F.; Morone, M. C.; Pandola, L.; Rapisarda, E.; Romano, F.; and others

    2013-04-19

    Nuclear fragmentation measurements are necessary in hadrontherapy and space radiation protection, to predict the effects of the ion nuclear interactions within the human body. Nowadays, a very limited set of carbon fragmentation cross sections has been measured and in particular, to our knowledge, no double differential fragmentation cross sections at intermediate energies are available in literature. We have measured the double differential cross sections and the angular distributions of the secondary fragments produced in the {sup 12}C fragmentation at 62 AMeV on a thin carbon target. The experimental data have been also used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before.

  8. Factors mediating co-occurrence of an economically valuable introduced fish and its native frog prey.

    PubMed

    Hartman, Rosemary; Pope, Karen; Lawler, Sharon

    2014-06-01

    Habitat characteristics mediate predator-prey coexistence in many ecological systems but are seldom considered in species introductions. When economically important introduced predators are stocked despite known negative impacts on native species, understanding the role of refuges, landscape configurations, and community interactions can inform habitat management plans. We measured these factors in basins with introduced trout (Salmonidae) and the Cascades frog (Rana cascadae) to determine, which are responsible for observed patterns of co-occurrence of this economically important predator and its native prey. Large, vegetated shallows were strongly correlated to co-occurrence, and R. cascadae larvae occur in shallower water when fish are present, presumably to escape predation. The number of nearby breeding sites of R. cascadae was also correlated to co-occurrence, but only when the western toad (Anaxyrus boreas) was present. Because A. boreas larvae are unpalatable to fish and resemble R. cascadae, they may provide protection from trout via Batesian mimicry. Although rescue-effect dispersal from nearby populations may maintain co-occurrence, within-lake factors proved more important for predicting co-occurrence. Learning which factors allow co-occurrence between economically important introduced species and their native prey enables managers to make better-informed stocking decisions. PMID:24372671

  9. Prey size structure diminishes cascading effects by increasing interference competition and predation among prey.

    PubMed

    Geraldii, Nathan R

    2015-09-01

    The size of an organism can change by orders of magnitude during its lifespan. Size can determine whether an individual consumes, is consumed, competes, or avoids individuals of the same or different species. Two complementary mesocosm experiments with a tri-trophic food chain (top predator, toadfish, Opsanus tau; intermediate prey, mud crab, family Xanthidae; basal resource, oyster, Crassostrea virginica) were conducted to measure how the size of both the top predator and the intermediate prey affects consumptive and behavioral interactions in trophic cascades. In the first experiment, I systematically varied the sizes of predators and prey, respectively. The amount of crab biomass consumed was dependent on crab size and not toadfish size, but the effect of crab size did not cascade to alter oyster survival. Increased oyster survival from crab interference competition in the absence of toadfish was similar to oyster survival,from predator-avoidance behavior in the presence of a toadfish. When all crab size classes were present, crab mortality was similar in the presence and absence of toadfish, highlighting the importance of intraguild predation in food-web dynamics. The second experiment separated crab mortality by other crabs from crab mortality by predatory toadfish and found that crab mortality generally switched from intra- to interguild predation when a toadfish was present. In addition, field surveys indicated mud crab abundance and size was primarily influenced by mud crab recruitment, but not by toadfish abundance, which supports our experimental results that interactions among mud crabs have similar effects to predator-prey interactions. These findings indicate that changes in size or abundance of intermediate prey may be comparable to changes in top predator abundance in terms of trophic interactions and their transmission to lower levels, which suggests that certain types of relatively simple food chains can be resilient to the loss of higher trophic

  10. Chemotactic predator-prey dynamics.

    PubMed

    Sengupta, Ankush; Kruppa, Tobias; Löwen, Hartmut

    2011-03-01

    A discrete chemotactic predator-prey model is proposed in which the prey secrets a diffusing chemical which is sensed by the predator and vice versa. Two dynamical states corresponding to catching and escaping are identified and it is shown that steady hunting is unstable. For the escape process, the predator-prey distance is diffusive for short times but exhibits a transient subdiffusive behavior which scales as a power law t¹/³ with time t and ultimately crosses over to diffusion again. This allows us to classify the motility and dynamics of various predatory microbes and phagocytes. In particular, there is a distinct region in the parameter space where they prove to be infallible predators. PMID:21517532

  11. Sensing the strike of a predator fish depends on the specific gravity of a prey fish.

    PubMed

    Stewart, William J; McHenry, Matthew J

    2010-11-15

    The ability of a predator fish to capture a prey fish depends on the hydrodynamics of the prey and its behavioral response to the predator's strike. Despite the importance of this predator-prey interaction to the ecology and evolution of a diversity of fish, it is unclear what factors dictate a fish's ability to evade capture. The present study evaluated how the specific gravity of a prey fish's body affects the kinematics of prey capture and the signals detected by the lateral line system of the prey during the strike of a suction-feeding predator. The specific gravity of zebrafish (Danio rerio) larvae was measured with high precision from recordings of terminal velocity in solutions of varying density. This novel method found that specific gravity decreased by ∼5% (from 1.063, N=8, to 1.011, N=35) when the swim bladder inflates. To examine the functional consequences of this change, we developed a mathematical model of the hydrodynamics of prey in the flow field created by a suction-feeding predator. This model found that the observed decrease in specific gravity due to swim bladder inflation causes an 80% reduction of the flow velocity around the prey's body. Therefore, swim bladder inflation causes a substantial reduction in the flow signal that may be sensed by the lateral line system to evade capture. These findings demonstrate that the ability of a prey fish to sense a predator depends crucially on the specific gravity of the prey. PMID:21037055

  12. Implementing planetary protection measures on the Mars Science Laboratory.

    PubMed

    Benardini, James N; La Duc, Myron T; Beaudet, Robert A; Koukol, Robert

    2014-01-01

    The Mars Science Laboratory (MSL), comprising a cruise stage; an aeroshell; an entry, descent, and landing system; and the radioisotope thermoelectric generator-powered Curiosity rover, made history with its unprecedented sky crane landing on Mars on August 6, 2012. The mission's primary science objective has been to explore the area surrounding Gale Crater and assess its habitability for past life. Because microbial contamination could profoundly impact the integrity of the mission and compliance with international treaty was required, planetary protection measures were implemented on MSL hardware to verify that bioburden levels complied with NASA regulations. By applying the proper antimicrobial countermeasures throughout all phases of assembly, the total bacterial endospore burden of MSL at the time of launch was kept to 2.78×10⁵ spores, well within the required specification of less than 5.0×10⁵ spores. The total spore burden of the exposed surfaces of the landed MSL hardware was 5.64×10⁴, well below the allowed limit of 3.0×10⁵ spores. At the time of launch, the MSL spacecraft was burdened with an average of 22 spores/m², which included both planned landed and planned impacted hardware. Here, we report the results of a campaign to implement and verify planetary protection measures on the MSL flight system. PMID:24432776

  13. Tigers and their prey: Predicting carnivore densities from prey abundance

    USGS Publications Warehouse

    Karanth, K.U.; Nichols, J.D.; Kumar, N.S.; Link, W.A.; Hines, J.E.

    2004-01-01

    The goal of ecology is to understand interactions that determine the distribution and abundance of organisms. In principle, ecologists should be able to identify a small number of limiting resources for a species of interest, estimate densities of these resources at different locations across the landscape, and then use these estimates to predict the density of the focal species at these locations. In practice, however, development of functional relationships between abundances of species and their resources has proven extremely difficult, and examples of such predictive ability are very rare. Ecological studies of prey requirements of tigers Panthera tigris led us to develop a simple mechanistic model for predicting tiger density as a function of prey density. We tested our model using data from a landscape-scale long-term (1995-2003) field study that estimated tiger and prey densities in 11 ecologically diverse sites across India. We used field techniques and analytical methods that specifically addressed sampling and detectability, two issues that frequently present problems in macroecological studies of animal populations. Estimated densities of ungulate prey ranged between 5.3 and 63.8 animals per km2. Estimated tiger densities (3.2-16.8 tigers per 100 km2) were reasonably consistent with model predictions. The results provide evidence of a functional relationship between abundances of large carnivores and their prey under a wide range of ecological conditions. In addition to generating important insights into carnivore ecology and conservation, the study provides a potentially useful model for the rigorous conduct of macroecological science.

  14. A fluid mechanical model for mixing in a plankton predator-prey system

    NASA Astrophysics Data System (ADS)

    Peng, J.; Dabiri, J. O.

    2009-04-01

    A Lagrangian method is developed to study mixing of small particles in open flows. Particle Lagrangian Coherent Structures (pLCS) are identified as transport barriers in the dynamical systems of particles. We apply this method to a planktonic predator-prey system in which moon jellyfish Aurelia aurita uses its body motion to generate fluid currents which carry their prey to the vicinity of their capture appendages. With the flow generated by the jellyfish experimentally measured and the dynamics of prey particles in the flow described by a modified Maxey-Riley equation, we use pLCS to identify the capture region in which prey can be captured. The properties of the capture region enable analysis of the effects of several physiological and mechanical parameters on the predator-prey interaction, such as prey size, escape force, predator perception, etc. The method provides a new methodology to study dynamics and mixing of small organisms in general.

  15. Innate prey preference overridden by familiarisation with detrimental prey in a specialised myrmecophagous predator

    NASA Astrophysics Data System (ADS)

    Pekár, Stano; Cárdenas, Manuel

    2015-02-01

    Prey-specialised spiders often do not have brood care and may not deposit eggs in the proximity of the preferred prey. Thus, naïve spiderlings are left to their own to find their focal prey. Our aim was to reveal whether the choice of a specific prey is innate and whether familiarisation with a certain prey will condition prey choice. We used the myrmecophagous spider Euryopis episinoides, which specialises on Messor ants. It finds ants using chemical cues deposited on the substrate. Naïve spiderlings were offered chemical cues from Messor and Myrmica ants and Drosophila flies. They chose significantly more chemical cues from Messor ants than those from Drosophila flies. Then spiderlings were assigned to three prey treatments: fed with Messor ants only (optimal prey), fed with Myrmica ants only (suboptimal prey) or fed with Drosophila flies only (detrimental prey) until adulthood. Every 2 weeks, all spiders from all treatments were offered chemical cues from the three prey types and the frequency of choice and latency to assuming a posture were recorded. Experienced spiderlings preferred chemical cues from the prey in which they were raised. They suffered high mortality on Drosophila flies and attained largest size on the optimal prey. We show here that majority of spiderlings are born with an innate preference to their focal prey, which can be altered by familiarisation with alternative prey, irrespective of whether such a prey is beneficial.

  16. [Personal protection measures against blood-sucking insects and ticks].

    PubMed

    Orshan, Laor; Wilamowski, Amos; Pener, Hedva

    2010-09-01

    Blood-sucking arthropods are major vectors of various pathogens like viruses, bacteria, protozoa and nematodes. Preventing exposure to the vector is imperative especially when vaccine and prophylactic treatments are not available. Personal protection measures (PPM) are essential and often the only means available when dealing with blood-sucking disease transmitting arthropods. Awareness of the risk in the specific areas of travel is the first step to be taken before and while traveling. PPM include preventive personal behavior, suitable clothing, application of insect repellents to the skin, the use of space repellents, impregnation of clothing, camping gear and bed nets and, when necessary, ground spraying of insecticides. The registered and recommended active ingredients for skin application are Deet, picaridin (icaridin), p-menthane-3,8-diol (PMD) and IR3535. Volatile pyrethrins are used as space repellents while pyrethroids, especially permethrin, are employed for impregnation and for ground spraying. It is recommended to purchase only products registered in Israel or other developed countries. These products should have a detailed label specifying the concentration of the active ingredient, application instructions and the duration of protection. PMID:21302476

  17. Does colour polymorphism enhance survival of prey populations?

    PubMed

    Wennersten, Lena; Forsman, Anders

    2009-06-22

    That colour polymorphism may protect prey populations from predation is an old but rarely tested hypothesis. We examine whether colour polymorphic populations of prey exposed to avian predators in an ecologically valid visual context were exposed to increased extinction risk compared with monomorphic populations. We made 2976 artificial pastry prey, resembling Lepidoptera larvae, in four different colours and presented them in 124 monomorphic and 124 tetramorphic populations on tree trunks and branches such that they would be exposed to predation by free-living birds, and monitored their 'survival'. Among monomorphic populations, there was a significant effect of prey coloration on survival, confirming that coloration influenced susceptibility to visually oriented predators. Survival of polymorphic populations was inferior to that of monomorphic green populations, but did not differ significantly from monomorphic brown, yellow or red populations. Differences in survival within polymorphic populations paralleled those seen among monomorphic populations; the red morph most frequently went extinct first and the green morph most frequently survived the longest. Our findings do not support the traditional protective polymorphism hypothesis and are in conflict with those of earlier studies. As a possible explanation to our findings, we offer a competing 'giveaway cue' hypothesis: that polymorphic populations may include one morph that attracts the attention of predators and that polymorphic populations therefore may suffer increased predation compared with some monomorphic populations. PMID:19324729

  18. Effects of prey size and mobility on prey-capture kinematics in leopard sharks triakis semifasciata

    PubMed

    Ferry-Graham

    1998-08-01

    Recent work on teleosts suggests that attack behaviors or kinematics may be modified by a predator on the basis of the size of the prey or the ability of the prey to sense predators and escape capture (elusivity). Sharks are generally presumed to be highly visual predators; thus, it is reasonable to expect that they might also be capable of such behavioral modulation. In this study, I investigated the effect of prey item size and type on prey-capture behavior in leopard sharks (Triakis semifasciata) that had been acclimated to feeding in the laboratory. Using high-speed video, sharks were filmed feeding on two sizes of the same prey item (thawed shrimp pieces) and two potentially more elusive prey items (live earthworms and live mud shrimp). In leopard sharks, little effect of prey elusivity was found for kinematic variables during prey capture. However, the large proportion of successful captures of the live prey suggests that they did not prove to be truly elusive prey items for the leopard shark. There were significant size effects on prey-capture kinematics, with the larger non-elusive items inducing greater head expansion during prey capture. Ram-suction index values also indicated that strikes on large, non-elusive prey had a significantly larger suction component than strikes on similar small prey items. This finding is interesting given that the two sizes of non-elusive prey item offered no differential challenge in terms of a performance consequence (reduced capture success). PMID:9679105

  19. When attempts at robbing prey turn fatal

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Corbara, Bruno; Azémar, Frédéric; Carpenter, James M.

    2012-07-01

    Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1 %) were captured in turn. The ant workers hunt in a group and use the "Velcro®" principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases.

  20. Feeding by the newly described mixotrophic dinoflagellate Paragymnodinium shiwhaense: feeding mechanism, prey species, and effect of prey concentration.

    PubMed

    Yoo, Yeong Du; Jeong, Hae Jin; Kang, Nam Seon; Song, Jae Yoon; Kim, Kwang Young; Lee, Gitack; Kim, Juhyoung

    2010-01-01

    To investigate the feeding by the newly described mixotrophic dinoflagellate Paragymnodinium shiwhaense (GenBank accession number=AM408889), we explored the feeding process and the kinds of prey species that P. shiwhaense is able to feed on using several different types of microscopes, including a transmission electron microscope and high-resolution video-microscopy. In addition, we measured the growth and ingestion rates of P. shiwhaense on its optimal algal prey Amphidinium carterae as a function of prey concentration. We also measured these parameters for edible prey at a single concentration at which the growth and ingestion rates of P. shiwhaense on A. carterae were saturated. Paragymnodinium shiwhaense feed on algal prey using a peduncle after anchoring the prey by a tow filament. Among the algal prey offered, P. shiwhaense ingested small algal species that had equivalent spherical diameters (ESDs) < or =11 microm (e.g. the prymnesiophyte Isochrysis galbana, the cryptophytes Teleaulax sp. and Rhodomonas salina, the raphidophyte Heterosigma akashiwo, and the dinoflagellates Heterocapsa rotundata and A. carterae). However, it did not feed on larger algal species that had ESDs > or =12 microm (e.g. the dinoflagellates Prorocentrum minimum, Heterocapsa triquetra, Scrippsiella trochoidea, Alexandrium tamarense, Prorocentrum micans, Gymnodinium catenatum, Akashiwo sanguinea, and Lingulodinium polyedrum) or the small diatom Skeletonema costatum. The specific growth rates for P. shiwhaense feeding upon A. carterae increased rapidly with increasing mean prey concentration before saturating at concentrations of ca. 350 ng C/ml (5,000 cells/ml). The maximum specific growth rate (i.e. mixotrophic growth) of P. shiwhaense on A. carterae was 1.097/d at 20 degrees C under a 14:10 h light-dark cycle of 20 microE/m(2)/s, while its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was -0.224/d. The maximum ingestion and clearance rates

  1. Protective measurement of the wave function of a single squeezed harmonic-oscillator state

    NASA Astrophysics Data System (ADS)

    Alter, Orly; Yamamoto, Yoshihisa

    1996-05-01

    A scheme for the "protective measurement"

    [Phys. Rev. A 47, 4616 (1993)]
    of the wave function of a squeezed harmonic-oscillator state is described. This protective measurement is shown to be equivalent to a measurement of an ensemble of states. The protective measurement, therefore, allows for a definition of the quantum wave function on a single system. Yet, this equivalency also suggests that both measurement schemes account for the epistemological meaning of the wave function only. The protective measurement requires a full a priori knowledge of the measured state. The intermediate cases, in which only partial a priori information is given, are also discussed.

  2. From Cues to Signals: Evolution of Interspecific Communication via Aposematism and Mimicry in a Predator-Prey System

    PubMed Central

    Lehmann, Kenna D. S.; Goldman, Brian W.; Dworkin, Ian; Bryson, David M.; Wagner, Aaron P.

    2014-01-01

    Current theory suggests that many signaling systems evolved from preexisting cues. In aposematic systems, prey warning signals benefit both predator and prey. When the signal is highly beneficial, a third species often evolves to mimic the toxic species, exploiting the signaling system for its own protection. We investigated the evolutionary dynamics of predator cue utilization and prey signaling in a digital predator-prey system in which prey could evolve to alter their appearance to mimic poison-free or poisonous prey. In predators, we observed rapid evolution of cue recognition (i.e. active behavioral responses) when presented with sufficiently poisonous prey. In addition, active signaling (i.e. mimicry) evolved in prey under all conditions that led to cue utilization. Thus we show that despite imperfect and dishonest signaling, given a high cost of consuming poisonous prey, complex systems of interspecific communication can evolve via predator cue recognition and prey signal manipulation. This provides evidence supporting hypotheses that cues may serve as stepping-stones in the evolution of more advanced communication and signaling systems that incorporate information about the environment. PMID:24614755

  3. Relative availability of natural prey versus livestock predicts landscape suitability for cheetahs Acinonyx jubatus in Botswana

    PubMed Central

    Winterbach, Christiaan W.; Boast, Lorraine K.; Klein, Rebecca; Somers, Michael J.

    2015-01-01

    Prey availability and human-carnivore conflict are strong determinants that govern the spatial distribution and abundance of large carnivore species and determine the suitability of areas for their conservation. For wide-ranging large carnivores such as cheetahs (Acinonyx jubatus), additional conservation areas beyond protected area boundaries are crucial to effectively conserve them both inside and outside protected areas. Although cheetahs prefer preying on wild prey, they also cause conflict with people by predating on especially small livestock. We investigated whether the distribution of cheetahs’ preferred prey and small livestock biomass could be used to explore the potential suitability of agricultural areas in Botswana for the long-term persistence of its cheetah population. We found it gave a good point of departure for identifying priority areas for land management, the threat to connectivity between cheetah populations, and areas where the reduction and mitigation of human-cheetah conflict is critical. Our analysis showed the existence of a wide prey base for cheetahs across large parts of Botswana’s agricultural areas, which provide additional large areas with high conservation potential. Twenty percent of wild prey biomass appears to be the critical point to distinguish between high and low probable levels of human-cheetah conflict. We identified focal areas in the agricultural zones where restoring wild prey numbers in concurrence with effective human-cheetah conflict mitigation efforts are the most immediate conservation strategies needed to maintain Botswana’s still large and contiguous cheetah population. PMID:26213646

  4. Relative availability of natural prey versus livestock predicts landscape suitability for cheetahs Acinonyx jubatus in Botswana.

    PubMed

    Winterbach, Hanlie E K; Winterbach, Christiaan W; Boast, Lorraine K; Klein, Rebecca; Somers, Michael J

    2015-01-01

    Prey availability and human-carnivore conflict are strong determinants that govern the spatial distribution and abundance of large carnivore species and determine the suitability of areas for their conservation. For wide-ranging large carnivores such as cheetahs (Acinonyx jubatus), additional conservation areas beyond protected area boundaries are crucial to effectively conserve them both inside and outside protected areas. Although cheetahs prefer preying on wild prey, they also cause conflict with people by predating on especially small livestock. We investigated whether the distribution of cheetahs' preferred prey and small livestock biomass could be used to explore the potential suitability of agricultural areas in Botswana for the long-term persistence of its cheetah population. We found it gave a good point of departure for identifying priority areas for land management, the threat to connectivity between cheetah populations, and areas where the reduction and mitigation of human-cheetah conflict is critical. Our analysis showed the existence of a wide prey base for cheetahs across large parts of Botswana's agricultural areas, which provide additional large areas with high conservation potential. Twenty percent of wild prey biomass appears to be the critical point to distinguish between high and low probable levels of human-cheetah conflict. We identified focal areas in the agricultural zones where restoring wild prey numbers in concurrence with effective human-cheetah conflict mitigation efforts are the most immediate conservation strategies needed to maintain Botswana's still large and contiguous cheetah population. PMID:26213646

  5. Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces

    PubMed Central

    Clare, Elizabeth L; Holderied, Marc W

    2015-01-01

    Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an ‘acoustic shadow’ cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for ‘acoustic camouflage’ as an anti-predator defence mechanism. DOI: http://dx.doi.org/10.7554/eLife.07404.001 PMID:26327624

  6. Prey patch patterns predict habitat use by top marine predators with diverse foraging strategies.

    PubMed

    Benoit-Bird, Kelly J; Battaile, Brian C; Heppell, Scott A; Hoover, Brian; Irons, David; Jones, Nathan; Kuletz, Kathy J; Nordstrom, Chad A; Paredes, Rosana; Suryan, Robert M; Waluk, Chad M; Trites, Andrew W

    2013-01-01

    Spatial coherence between predators and prey has rarely been observed in pelagic marine ecosystems. We used measures of the environment, prey abundance, prey quality, and prey distribution to explain the observed distributions of three co-occurring predator species breeding on islands in the southeastern Bering Sea: black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and northern fur seals (Callorhinus ursinus). Predictions of statistical models were tested using movement patterns obtained from satellite-tracked individual animals. With the most commonly used measures to quantify prey distributions--areal biomass, density, and numerical abundance--we were unable to find a spatial relationship between predators and their prey. We instead found that habitat use by all three predators was predicted most strongly by prey patch characteristics such as depth and local density within spatial aggregations. Additional prey patch characteristics and physical habitat also contributed significantly to characterizing predator patterns. Our results indicate that the small-scale prey patch characteristics are critical to how predators perceive the quality of their food supply and the mechanisms they use to exploit it, regardless of time of day, sampling year, or source colony. The three focal predator species had different constraints and employed different foraging strategies--a shallow diver that makes trips of moderate distance (kittiwakes), a deep diver that makes trip of short distances (murres), and a deep diver that makes extensive trips (fur seals). However, all three were similarly linked by patchiness of prey rather than by the distribution of overall biomass. This supports the hypothesis that patchiness may be critical for understanding predator-prey relationships in pelagic marine systems more generally. PMID:23301063

  7. Prey Patch Patterns Predict Habitat Use by Top Marine Predators with Diverse Foraging Strategies

    PubMed Central

    Benoit-Bird, Kelly J.; Battaile, Brian C.; Heppell, Scott A.; Hoover, Brian; Irons, David; Jones, Nathan; Kuletz, Kathy J.; Nordstrom, Chad A.; Paredes, Rosana; Suryan, Robert M.; Waluk, Chad M.; Trites, Andrew W.

    2013-01-01

    Spatial coherence between predators and prey has rarely been observed in pelagic marine ecosystems. We used measures of the environment, prey abundance, prey quality, and prey distribution to explain the observed distributions of three co-occurring predator species breeding on islands in the southeastern Bering Sea: black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and northern fur seals (Callorhinus ursinus). Predictions of statistical models were tested using movement patterns obtained from satellite-tracked individual animals. With the most commonly used measures to quantify prey distributions - areal biomass, density, and numerical abundance - we were unable to find a spatial relationship between predators and their prey. We instead found that habitat use by all three predators was predicted most strongly by prey patch characteristics such as depth and local density within spatial aggregations. Additional prey patch characteristics and physical habitat also contributed significantly to characterizing predator patterns. Our results indicate that the small-scale prey patch characteristics are critical to how predators perceive the quality of their food supply and the mechanisms they use to exploit it, regardless of time of day, sampling year, or source colony. The three focal predator species had different constraints and employed different foraging strategies – a shallow diver that makes trips of moderate distance (kittiwakes), a deep diver that makes trip of short distances (murres), and a deep diver that makes extensive trips (fur seals). However, all three were similarly linked by patchiness of prey rather than by the distribution of overall biomass. This supports the hypothesis that patchiness may be critical for understanding predator-prey relationships in pelagic marine systems more generally. PMID:23301063

  8. Prey capture in long-jawed butterflyfishes (Chaetodontidae): the functional basis of novel feeding habits.

    PubMed

    Ferry-Graham, L A.; Wainwright, P C.; Bellwood, D R.

    2001-01-31

    Several species of butterflyfishes (Chaetodontidae) possess extremely elongate jaws, and feed mostly by probing the benthos and biting off pieces of attached invertebrates. In contrast, Forcipiger longirostris, the longest-jawed chaetodontid, exhibits a novel pattern of prey use, feeding almost exclusively on small caridean shrimp, a mobile and highly elusive prey type that lives within the structure of coral reefs. We explored the functional basis of this novel pattern of prey use by comparing prey capture kinematics in this and four other butterflyfish species, including two other species that possess elongate jaws. High speed video recordings of feeding events on live adult brine shrimp were analyzed from individuals of five species: Forcipiger longirostris, F. flavissimus, Chelmon rostratus, Heniochus acuminatus, and Chaetodon xanthurus. We focused on a comparison among species of the relative contribution of "suction", measured as the amount of movement of the prey toward the predator's mouth, and "ram", measured as the distance moved by the predator toward the prey during the strike. All five species utilized a combination of suction and ram while feeding on brine shrimp. The contribution of suction did not differ significantly among species. However, F. longirostris exhibited a ram contribution to the strike that was more than twice that seen in any of the other species, permitting this species to initiate strikes from the greatest initial predator-prey distance. F. longirostris is known to possess a major structural novelty in the feeding mechanism that permits anterior movement of the entire jaw apparatus. The ability of this species to feed successfully on elusive prey appears to be related to exceptional jaw protrusion, resulting in greater use of ram during prey capture. This ability to protrude long, slender jaws toward the prey may allow it to move the jaws without detection within close enough proximity of the prey to then permit the effective use of

  9. Measuring the Impact of Child Protection through Activation States

    ERIC Educational Resources Information Center

    Brackenridge, Celia H.; Pawlaczek, Zofia; Bringer, Joy D.; Cockburn, Claudi; Nutt, Gareth; Pitchford, Andy; Russell, Kate

    2005-01-01

    Child protection (CP) has risen to the top of the UK sports policy agenda in the past four years and the Football Association has invested in this major strategy as part of its commitment to "use the power of football to build a better future" (Football Association, 2000a). Evidencing the impact of child protection is, however, a complex task,…

  10. Flocking and feeding in the fiddler crab ( UCA tangeri): Prey availability as risk-taking behaviour

    NASA Astrophysics Data System (ADS)

    Ens, B. J.; Klaassen, M.; Zwarts, L.

    For a full understanding of prey availability, it is necessary to study risk-taking behaviour of the prey. Fiddler crabs are ideally suited for such a study, as they have to leave their safe burrow to feed on the surface of the intertidal flats during low tide, thereby exposing themselves to avian predators. A study in an intertidal area along the coast of Mauritania showed that small crabs always stayed in the vicinity of their burrow, but large crabs wandered in large flocks (also referred to as droves) to feed on sea-grass beds downshore. Transplanting downshore feeding substrate to the burrowing zone of the small crabs proved that they too preferred to feed on it. Since small crabs can be preyed upon by more species of birds, this suggests that the decision not to leave the burrowing zone might be related to the risk of being fed upon by birds. We calculated predation risk from measurements on the density and feeding activity of the crabs, as well as the feeding density, the intake rate and the size selection of the avian predators. Per hour on the surface, crabs in a flock were more at risk than crabs feeding near their burrow. Thus, though flocking crabs may have benefited from 'swamping the predator' by emerging in maximum numbers during some tides only, this did not reduce their risk of predation below that of non-flocking crabs. Furthermore we found that irrespective of activity, large crabs suffered a higher mortality per tide from avian predators than small crabs. This suggests that large crabs could not sufficiently reduce their foraging time to compensate for the increased risk while foraging in a flock, even though they probably experienced better feeding conditions than small crabs staying near their burrow. The greater energy demands of large crabs were reflected in a greater surface area grazed. Thus, with increasing size a fiddler crab has to feed further away from its burrow and so may derive less protection from staying near to it. It seems that

  11. A Sensory-Driven Trade-Off between Coordinated Motion in Social Prey and a Predator's Visual Confusion.

    PubMed

    Lemasson, Bertrand H; Tanner, Colby J; Dimperio, Eric

    2016-02-01

    Social animals are capable of enhancing their awareness by paying attention to their neighbors, and prey found in groups can also confuse their predators. Both sides of these sensory benefits have long been appreciated, yet less is known of how the perception of events from the perspectives of both prey and predator can interact to influence their encounters. Here we examined how a visual sensory mechanism impacts the collective motion of prey and, subsequently, how their resulting movements influenced predator confusion and capture ability. We presented virtual prey to human players in a targeting game and measured the speed and accuracy with which participants caught designated prey. As prey paid more attention to neighbor movements their collective coordination increased, yet increases in prey coordination were positively associated with increases in the speed and accuracy of attacks. However, while attack speed was unaffected by the initial state of the prey, accuracy dropped significantly if the prey were already organized at the start of the attack, rather than in the process of self-organizing. By repeating attack scenarios and masking the targeted prey's neighbors we were able to visually isolate them and conclusively demonstrate how visual confusion impacted capture ability. Delays in capture caused by decreased coordination amongst the prey depended upon the collection motion of neighboring prey, while it was primarily the motion of the targets themselves that determined capture accuracy. Interestingly, while a complete loss of coordination in the prey (e.g., a flash expansion) caused the greatest delay in capture, such behavior had little effect on capture accuracy. Lastly, while increases in collective coordination in prey enhanced personal risk, traveling in coordinated groups was still better than appearing alone. These findings demonstrate a trade-off between the sensory mechanisms that can enhance the collective properties that emerge in social

  12. Condenser Microphone Protective Grid Correction for High Frequency Measurements

    NASA Technical Reports Server (NTRS)

    Lee, Erik; Bennett, Reginald

    2010-01-01

    Use of a protective grid on small diameter microphones can prolong the lifetime of the unit, but the high frequency effects can complicate data interpretation. Analytical methods have been developed to correct for the grid effect at high frequencies. Specifically, the analysis pertains to quantifying the microphone protective grid response characteristics in the acoustic near field of a rocket plume noise source. A frequency response function computation using two microphones will be explained. Experimental and instrumentation setup details will be provided. The resulting frequency response function for a B&K 4944 condenser microphone protective grid will be presented, along with associated uncertainties

  13. A METHOD TO MEASURE PROTECTIVE CLOTHING PERMEATION UNDER INTERMITTENT CHEIMCAL CONTACT CONDITIONS

    EPA Science Inventory

    A preliminary method was developed to measure chemical permeation under intermittent chemical contact conditions. Protective clothing permeation is presently measured using ASTM Method F739-85. Because this test measures permeation when the clothing material is in continuous cont...

  14. The Development and Validation of the Protective Factors Survey: A Self-Report Measure of Protective Factors against Child Maltreatment

    ERIC Educational Resources Information Center

    Counts, Jacqueline M.; Buffington, Elenor S.; Chang-Rios, Karin; Rasmussen, Heather N.; Preacher, Kristopher J.

    2010-01-01

    Objective: The objective of this study was to evaluate the internal structure of a self-report measure of multiple family-level protective factors against abuse and neglect and explore the relationship of this instrument to other measures of child maltreatment. Methods: For the exploratory factor analysis, 11 agencies from 4 states administered…

  15. Influence of time-dependent factors in the evaluation of critical infrastructure protection measures.

    SciTech Connect

    Buehring, W. A.; Samsa, M. E.; Decision and Information Sciences

    2008-03-28

    The examination of which protective measures are the most appropriate to be implemented in order to prevent, protect against, respond to, and recover from attacks on critical infrastructures and key resources typically involves a comparison of the consequences that could occur when the protective measure is implemented to those that could occur when it is not. This report describes a framework for evaluation that provides some additional capabilities for comparing optional protective measures. It illustrates some potentially important time-dependent factors, such as the implementation rate, that affect the relative pros and cons associated with widespread implementation of protective measures. It presents example results from the use of protective measures, such as detectors and pretrained responders, for an illustrative biological incident. Results show that the choice of an alternative measure can depend on whether or not policy and financial support can be maintained for extended periods of time. Choice of a time horizon greatly influences the comparison of alternatives.

  16. Coevolution can reverse predator–prey cycles

    PubMed Central

    Cortez, Michael H.; Weitz, Joshua S.

    2014-01-01

    A hallmark of Lotka–Volterra models, and other ecological models of predator–prey interactions, is that in predator–prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator–prey coevolution can also drive population cycles where the opposite of canonical Lotka–Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage–cholera, mink–muskrat, and gyrfalcon–rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator–prey coevolution and reveal unique ways in which predator–prey coevolution can shape, and possibly reverse, community dynamics. PMID:24799689

  17. Coevolution can reverse predator-prey cycles.

    PubMed

    Cortez, Michael H; Weitz, Joshua S

    2014-05-20

    A hallmark of Lotka-Volterra models, and other ecological models of predator-prey interactions, is that in predator-prey cycles, peaks in prey abundance precede peaks in predator abundance. Such models typically assume that species life history traits are fixed over ecologically relevant time scales. However, the coevolution of predator and prey traits has been shown to alter the community dynamics of natural systems, leading to novel dynamics including antiphase and cryptic cycles. Here, using an eco-coevolutionary model, we show that predator-prey coevolution can also drive population cycles where the opposite of canonical Lotka-Volterra oscillations occurs: predator peaks precede prey peaks. These reversed cycles arise when selection favors extreme phenotypes, predator offense is costly, and prey defense is effective against low-offense predators. We present multiple datasets from phage-cholera, mink-muskrat, and gyrfalcon-rock ptarmigan systems that exhibit reversed-peak ordering. Our results suggest that such cycles are a potential signature of predator-prey coevolution and reveal unique ways in which predator-prey coevolution can shape, and possibly reverse, community dynamics. PMID:24799689

  18. Theory of Arachnid Prey Localization

    NASA Astrophysics Data System (ADS)

    Stürzl, W.; Kempter, R.; van Hemmen, J. L.

    2000-06-01

    Sand scorpions and many other arachnids locate their prey through highly sensitive slit sensilla at the tips (tarsi) of their eight legs. This sensor array responds to vibrations with stimulus-locked action potentials encoding the target direction. We present a neuronal model to account for stimulus angle determination using a population of second-order neurons, each receiving excitatory input from one tarsus and inhibition from a triad opposite to it. The input opens a time window whose width determines a neuron's firing probability. Stochastic optimization is realized through tuning the balance between excitation and inhibition. The agreement with experiments on the sand scorpion is excellent.

  19. The effects of prey species on food conversion efficiency and growth of an insectivorous lizard.

    PubMed

    Rich, C Nelson; Talent, Larry G

    2008-05-01

    Little is known about the effects of different prey species on lizard growth. We conducted a 6-week study to determine the relative effects of prey species on growth parameters of hatchling western fence lizards, Sceloporus occidentalis. Lizards were fed house cricket nymphs, Acheta domesticus, or mealworm larvae, Tenebrio molitor. The effects of prey species on growth were determined by measuring prey consumption, gross conversion efficiency of food [gain in mass (g)/food consumed (g)], gain in mass, and gain in snout-vent length. Lizards grew well on both the prey species. However, lizards that fed on crickets consumed a significantly higher percentage of their body mass per day than those fed mealworms. Nevertheless, lizards that consumed mealworms ingested significantly more metabolizable energy, had significantly higher food conversion efficiencies, significantly higher daily gains in mass, and significantly greater total growth in mass than lizards that fed on crickets. PMID:19360616

  20. "Prey Play": Learning about Predators and Prey through an Interactive, Role-Play Game

    ERIC Educational Resources Information Center

    Deaton, Cynthia C. M.; Dodd, Kristen; Drennon, Katherine; Nagle, Jack

    2012-01-01

    "Prey Play" is an interactive role-play activity that provides fifth-grade students with opportunities to examine predator-prey interactions. This four-part, role-play activity allows students to take on the role of a predator and prey as they reflect on the behaviors animals exhibit as they collect food and interact with one another, as well as…

  1. Deterministic and Stochastic Analysis of a Prey-Dependent Predator-Prey System

    ERIC Educational Resources Information Center

    Maiti, Alakes; Samanta, G. P.

    2005-01-01

    This paper reports on studies of the deterministic and stochastic behaviours of a predator-prey system with prey-dependent response function. The first part of the paper deals with the deterministic analysis of uniform boundedness, permanence, stability and bifurcation. In the second part the reproductive and mortality factors of the prey and…

  2. Controllability and Optimal Harvesting of a Prey-Predator Model Incorporating a Prey Refuge

    ERIC Educational Resources Information Center

    Kar, Tapan Kumar

    2006-01-01

    This paper deals with a prey-predator model incorporating a prey refuge and harvesting of the predator species. A mathematical analysis shows that prey refuge plays a crucial role for the survival of the species and that the harvesting effort on the predator may be used as a control to prevent the cyclic behaviour of the system. The optimal…

  3. Application of radiological protection measures to meet different environmental protection criteria.

    PubMed

    Copplestone, D

    2012-01-01

    The International Commission on Radiological Protection (ICRP) recognises that there is no simple or single universal definition of 'environmental protection', and that the concept differs from country to country and from one circumstance to another. However, there is an increasing need to be able to demonstrate that the environment is protected from radioactive substances released under authorisation for various reasons, such as for wildlife conservation requirements, or wildlife management for commercial reasons, or simply as part of pollution control. The Commission is developing the concept of Representative Organisms, which may be identified from any specific legal requirements or from more general requirements to protect local habitats or ecosystems. Such organisms may be the actual objects of protection or they may be hypothetical, depending on the objectives of the assessment. They may be similar to, or even congruent with, one or more of the Reference Animals and Plants (RAPs). Where this is not the case, attempts can be made to consider the extent to which the Representative Organisms differ from the nearest RAP in terms of known radiation effects upon it, basic biology, radiation dosimetry, and pathways of exposure. This paper discusses the practical implications of such an approach. PMID:23089025

  4. Financial Risk Protection and Universal Health Coverage: Evidence and Measurement Challenges

    PubMed Central

    Saksena, Priyanka; Hsu, Justine; Evans, David B.

    2014-01-01

    Financial risk protection is a key component of universal health coverage (UHC), which is defined as access to all needed quality health services without financial hardship. As part of the PLOS Medicine Collection on measurement of UHC, the aim of this paper is to examine and to compare and contrast existing measures of financial risk protection. The paper presents the rationale behind the methodologies for measuring financial risk protection and how this relates to UHC as well as some empirical examples of the types of measures. Additionally, the specific challenges related to monitoring inequalities in financial risk protection are discussed. The paper then goes on to examine and document the practical challenges associated with measurement of financial risk protection. This paper summarizes current thinking on the area of financial risk protection, provides novel insights, and suggests future developments that could be valuable in the context of monitoring progress towards UHC. PMID:25244520

  5. The Many Faces of Fear: Comparing the Pathways and Impacts of Nonconsumptive Predator Effects on Prey Populations

    PubMed Central

    Preisser, Evan L.; Bolnick, Daniel I.

    2008-01-01

    Background Most ecological models assume that predator and prey populations interact solely through consumption: predators reduce prey densities by killing and consuming individual prey. However, predators can also reduce prey densities by forcing prey to adopt costly defensive strategies. Methodology/Principal Findings We build on a simple Lotka-Volterra predator-prey model to provide a heuristic tool for distinguishing between the demographic effects of consumption (consumptive effects) and of anti-predator defenses (nonconsumptive effects), and for distinguishing among the multiple mechanisms by which anti-predator defenses might reduce prey population growth rates. We illustrate these alternative pathways for nonconsumptive effects with selected empirical examples, and use a meta-analysis of published literature to estimate the mean effect size of each pathway. Overall, predation risk tends to have a much larger impact on prey foraging behavior than measures of growth, survivorship, or fecundity. Conclusions/Significance While our model provides a concise framework for understanding the many potential NCE pathways and their relationships to each other, our results confirm empirical research showing that prey are able to partially compensate for changes in energy income, mitigating the fitness effects of defensive changes in time budgets. Distinguishing the many facets of nonconsumptive effects raises some novel questions, and will help guide both empirical and theoretical studies of how predation risk affects prey dynamics. PMID:18560575

  6. Examining self-protection measures guarding Adult Protective Services social workers against compassion fatigue.

    PubMed

    Bourassa, Dara

    2012-06-01

    Little research has focused on the risk factors, effects, and experiences of compassion fatigue among gerontological social workers. This qualitative study explores the experiences and perspectives of nine Adult Protective Services (APS) social workers in relation to compassion fatigue. Results show that the APS social workers combined personal characteristics and professional factors to develop boundary-setting mechanisms that protected them from experiencing the deleterious symptoms and effects of compassion fatigue. Implications center around the elements needed to implement boundaries in order to maintain a separation between the work and home environment. Suggestions for future research are provided. PMID:22203624

  7. 50 CFR 622.29 - Conservation measures for protected resources.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... protected resources. (a) Gulf reef fish commercial vessels and charter vessels/headboats—(1) Sea turtle... Turtle Release With Minimal Injury,” and must post inside the wheelhouse, or in an easily viewable area if no wheelhouse, the sea turtle handling and release guidelines provided by NMFS. (ii) Such owner...

  8. 50 CFR 622.29 - Conservation measures for protected resources.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... protected resources. (a) Gulf reef fish commercial vessels and charter vessels/headboats—(1) Sea turtle... Turtle Release With Minimal Injury,” and must post inside the wheelhouse, or in an easily viewable area if no wheelhouse, the sea turtle handling and release guidelines provided by NMFS. (ii) Such owner...

  9. Aquatic feeding in pipid frogs: the use of suction for prey capture

    PubMed Central

    Carreño, Carrie A.; Nishikawa, Kiisa C.

    2010-01-01

    Inertial suction feeding is the most common method of prey capture among aquatic vertebrates. However, it had been unclear whether the aquatic frogs in the family Pipidae also used inertial suction for prey capture. In this study, we examined feeding behavior in four species of pipids, Pipa pipa, Xenopus laevis, Hymenochirus boettgeri and Pseudhymenochirus merlini. Pressure in the buccopharyngeal cavity was measured during prey capture. These pressure measurements were coupled with high-speed recordings of feeding behavior. For each species, the internal buccopharyngeal pressure was found to drop significantly below ambient pressure, and changes in pressure corresponded with the onset of mouth opening. Kinematic analysis revealed that all species of pipids generated subambient pressure during prey capture; H. boettgeri and P. merlini relied solely on inertial suction feeding. Pipa pipa and X. laevis additionally employed forelimb scooping during prey capture but both of these species demonstrated the ability to capture prey with inertial suction alone. Based on buccopharyngeal pressure measurements as well as kinematic analyses, we conclude that inertial suction feeding is used during prey capture in these four species of pipids. PMID:20511513

  10. Examining Self-Protection Measures Guarding Adult Protective Services Social Workers against Compassion Fatigue

    ERIC Educational Resources Information Center

    Bourassa, Dara

    2012-01-01

    Little research has focused on the risk factors, effects, and experiences of compassion fatigue among gerontological social workers. This qualitative study explores the experiences and perspectives of nine Adult Protective Services (APS) social workers in relation to compassion fatigue. Results show that the APS social workers combined personal…

  11. A Sensory-Driven Trade-Off between Coordinated Motion in Social Prey and a Predator’s Visual Confusion

    PubMed Central

    Lemasson, Bertrand H.; Tanner, Colby J.; Dimperio, Eric

    2016-01-01

    Social animals are capable of enhancing their awareness by paying attention to their neighbors, and prey found in groups can also confuse their predators. Both sides of these sensory benefits have long been appreciated, yet less is known of how the perception of events from the perspectives of both prey and predator can interact to influence their encounters. Here we examined how a visual sensory mechanism impacts the collective motion of prey and, subsequently, how their resulting movements influenced predator confusion and capture ability. We presented virtual prey to human players in a targeting game and measured the speed and accuracy with which participants caught designated prey. As prey paid more attention to neighbor movements their collective coordination increased, yet increases in prey coordination were positively associated with increases in the speed and accuracy of attacks. However, while attack speed was unaffected by the initial state of the prey, accuracy dropped significantly if the prey were already organized at the start of the attack, rather than in the process of self-organizing. By repeating attack scenarios and masking the targeted prey’s neighbors we were able to visually isolate them and conclusively demonstrate how visual confusion impacted capture ability. Delays in capture caused by decreased coordination amongst the prey depended upon the collection motion of neighboring prey, while it was primarily the motion of the targets themselves that determined capture accuracy. Interestingly, while a complete loss of coordination in the prey (e.g., a flash expansion) caused the greatest delay in capture, such behavior had little effect on capture accuracy. Lastly, while increases in collective coordination in prey enhanced personal risk, traveling in coordinated groups was still better than appearing alone. These findings demonstrate a trade-off between the sensory mechanisms that can enhance the collective properties that emerge in social

  12. The effectiveness of post-contact defenses in a prey with no pre-contact detection.

    PubMed

    Dias, Barbara C; Willemart, Rodrigo H

    2013-06-01

    Most empirical and theoretical papers on prey-predator interactions are for animals with long-range detection, animals that can detect and react to predators long before these touch the prey. Heavy-bodied and chemically defended harvestmen (Arachnida, Opiliones) are an exception to this general pattern and rely on contact to detect arthropod predators. We examined the interactions between the Brazilian wandering spider Ctenus ornatus with harvestmen (Mischonyx cuspidatus) or control prey (Gryllus sp. and M. cuspidatus immature, both with soft integuments). Considering a prey-predator system in which fleeing from or reacting to a predator at a distance is not possible, we predicted both a high survival value of near-range defense mechanisms and that mortality would be higher in the absence of such defense mechanisms. We also expected the predator to behave differently when interacting with harvestmen or with a control prey without such defense mechanisms. Our results from laboratory experiments partially matched our predictions: First of all, histological sections showed that the integument of adult harvestmen is thicker than that of immature harvestmen and that of crickets. Adult harvestmen were less preyed upon than the control prey; the heavy armature increases the survival rate but the secretions from the scent glands do not. The predator did behave differently when attacking harvestmen compared to crickets. Despite the large size difference between predator and harvestmen, the protection provided by the armature allowed some of the harvestmen to survive encounters without pre-contact detection, thus greatly reducing the reliance on long-range detection to survive encounters with predators. Harvestmen call for theoretical and empirical work on prey-predator interactions that take into account the possibility that prey may not detect the predator before contact is established. PMID:23669196

  13. Coexistence in a predator-prey system

    NASA Astrophysics Data System (ADS)

    Droz, Michel; Pȩkalski, Andrzej

    2001-05-01

    We propose a lattice model of two populations, predators and prey. The model is solved via Monte Carlo simulations. Each species moves randomly on the lattice and can live only a certain time without eating. The lattice cells are either grass (eaten by prey) or tree (giving cover for prey). Each animal has a reserve of food that is increased by eating (prey or grass) and decreased after each Monte Carlo step. To breed, a pair of animals must be adjacent and have a certain minimum of food supply. The number of offspring produced depends on the number of available empty sites. We show that such a predator-prey system may finally reach one of the following three steady states: coexisting, with predators and prey; pure prey; or an empty one, in which both populations become extinct. We demonstrate that the probability of arriving at one of the above states depends on the initial densities of the prey and predator populations, the amount of cover, and the way it is spatially distributed.

  14. 78 FR 45573 - Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-29

    ... COMMISSION Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE) AGENCY: Nuclear Regulatory Commission. ACTION: Notice of availability; request for public comment.../CR-7135, ``Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire...

  15. 43 CFR 3272.12 - What environmental protection measures must I include in my utilization plan?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false What environmental protection measures... What environmental protection measures must I include in my utilization plan? (a) Describe, at a... resources; (6) Minimize air and noise pollution; and (7) Minimize hazards to public health and safety...

  16. 43 CFR 3272.12 - What environmental protection measures must I include in my utilization plan?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false What environmental protection measures... What environmental protection measures must I include in my utilization plan? (a) Describe, at a... resources; (6) Minimize air and noise pollution; and (7) Minimize hazards to public health and safety...

  17. 43 CFR 3162.2-14 - May I appeal BLM's decision to require drainage protective measures?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... drainage protective measures? 3162.2-14 Section 3162.2-14 Public Lands: Interior Regulations Relating to...) ONSHORE OIL AND GAS OPERATIONS Requirements for Operating Rights Owners and Operators § 3162.2-14 May I... you take drainage protective measures. You may request BLM State Director review under 43 CFR...

  18. Use of diagnostic bones to identify and estimate original lengths of ingested prey fishes

    USGS Publications Warehouse

    Hansel, H.C.; Duke, S.D.; Lofy, P.T.; Gray, G.A.

    1988-01-01

    We examined and measured cleithra, dentaries, opercles, and pharyngeal arches – bones found to persist during digestion of most prey fish – to identify 24 prey fish species and back-calculate their original fork length. Eighteen of the 24 species examined could be easily distinguished; however, for certain congenerics, identification was neither consistent nor reliable for all bones within the size ranges examined. Relations between bone length and fish length were linear for 14 species for which the sample sizes were adequate (N > 30); coefficients of determination (r 2) ranged from 0.79 to 0.99. Diagnostic characteristics and measurements of these bones provided reliable identification of genera and species and estimates of original fork lengths of partly digested prey fish from three predators. This method, compared with that of examining only prey fish in a measurable condition, greatly increased the amount of dietary information available from gut analysis.

  19. Cryptic differences in colour among Müllerian mimics: how can the visual capacities of predators and prey shape the evolution of wing colours?

    PubMed

    Llaurens, V; Joron, M; Théry, M

    2014-03-01

    Antagonistic interactions between predators and prey often lead to co-evolution. In the case of toxic prey, aposematic colours act as warning signals for predators and play a protective role. Evolutionary convergence in colour patterns among toxic prey evolves due to positive density-dependent selection and the benefits of mutual resemblance in spreading the mortality cost of educating predators over a larger prey assemblage. Comimetic species evolve highly similar colour patterns, but such convergence may interfere with intraspecific signalling and recognition in the prey community, especially for species involved in polymorphic mimicry. Using spectrophotometry measures, we investigated the variation in wing coloration among comimetic butterflies from distantly related lineages. We focused on seven morphs of the polymorphic species Heliconius numata and the seven corresponding comimetic species from the genus Melinaea. Significant differences in the yellow, orange and black patches of the wing were detected between genera. Perceptions of these cryptic differences by bird and butterfly observers were then estimated using models of animal vision based on physiological data. Our results showed that the most strikingly perceived differences were obtained for the contrast of yellow against a black background. The capacity to discriminate between comimetic genera based on this colour contrast was also evaluated to be higher for butterflies than for birds, suggesting that this variation in colour, likely undetectable to birds, might be used by butterflies for distinguishing mating partners without losing the benefits of mimicry. The evolution of wing colour in mimetic butterflies might thus be shaped by the opposite selective pressures exerted by predation and species recognition. PMID:24444083

  20. Measuring benefits of protected area management: trends across realms and research gaps for freshwater systems.

    PubMed

    Adams, Vanessa M; Setterfield, Samantha A; Douglas, Michael M; Kennard, Mark J; Ferdinands, Keith

    2015-11-01

    Protected areas remain a cornerstone for global conservation. However, their effectiveness at halting biodiversity decline is not fully understood. Studies of protected area benefits have largely focused on measuring their impact on halting deforestation and have neglected to measure the impacts of protected areas on other threats. Evaluations that measure the impact of protected area management require more complex evaluation designs and datasets. This is the case across realms (terrestrial, freshwater, marine), but measuring the impact of protected area management in freshwater systems may be even more difficult owing to the high level of connectivity and potential for threat propagation within systems (e.g. downstream flow of pollution). We review the potential barriers to conducting impact evaluation for protected area management in freshwater systems. We contrast the barriers identified for freshwater systems to terrestrial systems and discuss potential measurable outcomes and confounders associated with protected area management across the two realms. We identify key research gaps in conducting impact evaluation in freshwater systems that relate to three of their major characteristics: variability, connectivity and time lags in outcomes. Lastly, we use Kakadu National Park world heritage area, the largest national park in Australia, as a case study to illustrate the challenges of measuring impacts of protected area management programmes for environmental outcomes in freshwater systems. PMID:26460127

  1. Developing measurement indices to enhance protection and resilience of critical infrastructure and key resources.

    PubMed

    Fisher, Ronald E; Norman, Michael

    2010-07-01

    The US Department of Homeland Security (DHS) is developing indices to better assist in the risk management of critical infrastructures. The first of these indices is the Protective Measures Index - a quantitative index that measures overall protection across component categories: physical security, security management, security force, information sharing, protective measures and dependencies. The Protective Measures Index, which can also be recalculated as the Vulnerability Index, is a way to compare differing protective measures (eg fence versus security training). The second of these indices is the Resilience Index, which assesses a site's resilience and consists of three primary components: robustness, resourcefulness and recovery. The third index is the Criticality Index, which assesses the importance of a facility. The Criticality Index includes economic, human, governance and mass evacuation impacts. The Protective Measures Index, Resilience Index and Criticality Index are being developed as part of the Enhanced Critical Infrastructure Protection initiative that DHS protective security advisers implement across the nation at critical facilities. This paper describes two core themes: determination of the vulnerability, resilience and criticality of a facility and comparison of the indices at different facilities. PMID:20826384

  2. Fluorescent prey traps in carnivorous plants.

    PubMed

    Kurup, R; Johnson, A J; Sankar, S; Hussain, A A; Sathish Kumar, C; Sabulal, B

    2013-05-01

    Carnivorous plants acquire most of their nutrients by capturing ants, insects and other arthropods through their leaf-evolved biological traps. So far, the best-known attractants in carnivorous prey traps are nectar, colour and olfactory cues. Here, fresh prey traps of 14 Nepenthes, five Sarracenia, five Drosera, two Pinguicula species/hybrids, Dionaea muscipula and Utricularia stellaris were scanned at UV 366 nm. Fluorescence emissions of major isolates of fresh Nepenthes khasiana pitcher peristomes were recorded at an excitation wavelength of 366 nm. N. khasiana field pitcher peristomes were masked by its slippery zone extract, and prey capture rates were compared with control pitchers. We found the existence of distinct blue fluorescence emissions at the capture spots of Nepenthes, Sarracenia and Dionaea prey traps at UV 366 nm. These alluring blue emissions gradually developed with the growth of the prey traps and diminished towards their death. On excitation at 366 nm, N. khasiana peristome 3:1 CHCl3–MeOH extract and its two major blue bands showed strong fluorescence emissions at 430–480 nm. Masking of blue emissions on peristomes drastically reduced prey capture in N. khasiana pitchers. We propose these molecular emissions as a critical factor attracting arthropods and other visitors to these carnivorous traps. Drosera, Pinguicula and Utricularia prey traps showed only red chlorophyll emissions at 366 nm. PMID:23696970

  3. Group formation stabilizes predator-prey dynamics.

    PubMed

    Fryxell, John M; Mosser, Anna; Sinclair, Anthony R E; Packer, Craig

    2007-10-25

    Theoretical ecology is largely founded on the principle of mass action, in which uncoordinated populations of predators and prey move in a random and well-mixed fashion across a featureless landscape. The conceptual core of this body of theory is the functional response, predicting the rate of prey consumption by individual predators as a function of predator and/or prey densities. This assumption is seriously violated in many ecosystems in which predators and/or prey form social groups. Here we develop a new set of group-dependent functional responses to consider the ecological implications of sociality and apply the model to the Serengeti ecosystem. All of the prey species typically captured by Serengeti lions (Panthera leo) are gregarious, exhibiting nonlinear relationships between prey-group density and population density. The observed patterns of group formation profoundly reduce food intake rates below the levels expected under random mixing, having as strong an impact on intake rates as the seasonal migratory behaviour of the herbivores. A dynamical system model parameterized for the Serengeti ecosystem (using wildebeest (Connochaetes taurinus) as a well-studied example) shows that grouping strongly stabilizes interactions between lions and wildebeest. Our results suggest that social groups rather than individuals are the basic building blocks around which predator-prey interactions should be modelled and that group formation may provide the underlying stability of many ecosystems. PMID:17960242

  4. Measuring the integrity of totally encapsulating chemical protective suits

    SciTech Connect

    Johnson, J.S.; Stull, J.O.

    1987-01-01

    To date, there is one completed ASTM TECP suit test, ''Practice for Pressure Testing of Gas Tight Totally Encapsulating Chemical Protective Suits.'' The other three tests described in this article, a quantitative test, a worst-case chemical exposure test, and a chemical leak rate test are in various stages of development. When they are finished and available as ASTM standard test methods or practices, a complete and reproducible battery of tests can be completed on commercially available TECP suits. Results from these tests, along with information presently being generated using ASTM test methods for permeation and penetration, will provide the user with a sound technical data base. This will allow the user to effectively evaluate the performance of the TECP suits he purchases and uses. By using these, TECP suit tests and related data can assure a high degree of TECP suit reliability. 2 refs., 9 figs.

  5. Cheetahs, Acinonyx jubatus, balance turn capacity with pace when chasing prey

    PubMed Central

    Wilson, John W.; Mills, Michael G. L.; Wilson, Rory P.; Peters, Gerrit; Mills, Margaret E. J.; Speakman, John R.; Durant, Sarah M.; Bennett, Nigel C.; Marks, Nikki J.; Scantlebury, Michael

    2013-01-01

    Predator–prey interactions are fundamental in the evolution and structure of ecological communities. Our understanding, however, of the strategies used in pursuit and evasion remains limited. Here, we report on the hunting dynamics of the world's fastest land animal, the cheetah, Acinonyx jubatus. Using miniaturized data loggers, we recorded fine-scale movement, speed and acceleration of free-ranging cheetahs to measure how hunting dynamics relate to chasing different sized prey. Cheetahs attained hunting speeds of up to 18.94 m s−1 and accelerated up to 7.5 m s−2 with greatest angular velocities achieved during the terminal phase of the hunt. The interplay between forward and lateral acceleration during chases showed that the total forces involved in speed changes and turning were approximately constant over time but varied with prey type. Thus, rather than a simple maximum speed chase, cheetahs first accelerate to decrease the distance to their prey, before reducing speed 5–8 s from the end of the hunt, so as to facilitate rapid turns to match prey escape tactics, varying the precise strategy according to prey species. Predator and prey thus pit a fine balance of speed against manoeuvring capability in a race for survival. PMID:24004493

  6. Musculoskeletal anatomy of the Eurasian lynx, Lynx lynx (Carnivora: Felidae) forelimb: Adaptations to capture large prey?

    PubMed

    Viranta, Suvi; Lommi, Hanna; Holmala, Katja; Laakkonen, Juha

    2016-06-01

    Mammalian carnivores adhere to two different feeding strategies relative to their body masses. Large carnivores prey on animals that are the same size or larger than themselves, whereas small carnivores prey on smaller vertebrates and invertebrates. The Eurasian lynx (Lynx lynx) falls in between these two categories. Lynx descend from larger forms that were probably large prey specialists, but during the Pleistocene became predators of small prey. The modern Eurasian lynx may be an evolutionary reversal toward specializing in large prey again. We hypothesized that the musculoskeletal anatomy of lynx should show traits for catching large prey. To test our hypothesis, we dissected the forelimb muscles of six Eurasian lynx individuals and compared our findings to results published for other felids. We measured the bones and compared their dimensions to the published material. Our material displayed a well-developed pectoral girdle musculature with some uniquely extensive muscle attachments. The upper arm musculature resembled that of the pantherine felids and probably the extinct sabertooths, and also the muscles responsible for supination and pronation were similar to those in large cats. The muscles controlling the pollex were well-developed. However, skeletal indices were similar to those of small prey predators. Our findings show that lynx possess the topographic pattern of muscle origin and insertion like in large felids. J. Morphol. 277:753-765, 2016. © 2016 Wiley Periodicals, Inc. PMID:26997516

  7. Cheetahs, Acinonyx jubatus, balance turn capacity with pace when chasing prey.

    PubMed

    Wilson, John W; Mills, Michael G L; Wilson, Rory P; Peters, Gerrit; Mills, Margaret E J; Speakman, John R; Durant, Sarah M; Bennett, Nigel C; Marks, Nikki J; Scantlebury, Michael

    2013-10-23

    Predator-prey interactions are fundamental in the evolution and structure of ecological communities. Our understanding, however, of the strategies used in pursuit and evasion remains limited. Here, we report on the hunting dynamics of the world's fastest land animal, the cheetah, Acinonyx jubatus. Using miniaturized data loggers, we recorded fine-scale movement, speed and acceleration of free-ranging cheetahs to measure how hunting dynamics relate to chasing different sized prey. Cheetahs attained hunting speeds of up to 18.94 m s(-1) and accelerated up to 7.5 m s(-2) with greatest angular velocities achieved during the terminal phase of the hunt. The interplay between forward and lateral acceleration during chases showed that the total forces involved in speed changes and turning were approximately constant over time but varied with prey type. Thus, rather than a simple maximum speed chase, cheetahs first accelerate to decrease the distance to their prey, before reducing speed 5-8 s from the end of the hunt, so as to facilitate rapid turns to match prey escape tactics, varying the precise strategy according to prey species. Predator and prey thus pit a fine balance of speed against manoeuvring capability in a race for survival. PMID:24004493

  8. Ecoepidemics with Two Strains: Diseased Prey.

    NASA Astrophysics Data System (ADS)

    Elena, Elisa; Grammauro, Maria; Venturino, Ezio

    2011-09-01

    In this work we present a minimal model for an ecoepidemic situation with two diseases affecting the prey population. The main assumptions are the following ones. The predators recognize and hunt only the healthy prey. An infected prey of one strain becomes immune to the other one. The major finding shows that the two strains cannot simultaneously thrive in the system, contrary to the standard assumptions in epidemiology. But this rather unexpected and remarkable result, paralleling another one when the epidemics affects the predators, is most likely due to the assumptions made.

  9. Usage and Perceived Side Effects of Personal Protective Measures against Mosquitoes among Current Users in Delhi

    PubMed Central

    Kumar, Rajesh; Meena, G. S.; Singh, M. M.; Sahoo, Jyotiranjan; Ingle, G. K.

    2014-01-01

    Background. Mosquito-borne diseases constitute an important cause of morbidity and mortality. The use of personal protective measures (PPM) like mats, bednets, screening, repellents, liquid vaporizers, mosquito coils, and so forth has been advocated as an effective tool in control of mosquito-borne diseases, but data about the safety profile of personal protective measures is still scarce. Objective. To study the usage and side effects of personal protective measures against mosquitoes among current users in Delhi. Materials and Methods. A community-based cross-sectional study among 350 adult individuals selected by systematic sampling method. Data was collected using pretested semistructured questionnaire after taking written informed consent. Data was analysed using SPSS version 17. Chi-square/Fisher's Exact test was used for qualitative variables to find association and P value <0.05 was considered significant. Results. Out of 350 families selected, 210 belonged to rural area and 140 to urban area. Personal protective measures were used by 219 (62.5%) subjects. Liquid vaporizer was the most preferred method (41.4%). Most common perceived side effect of personal protective measures was headache (7.7%). Other perceived side effects were cough (3.2%), sore throat (2.7%), allergy (1.3%), and eye irritation (0.9%) predominantly among coil users. Conclusion. There is a need to have a close watch for side effects of personal protective measures among users. Further research is also needed to develop safe and effective personal protective measures against mosquitoes. PMID:24616805

  10. Cats protecting birds revisited.

    PubMed

    Fan, Meng; Kuang, Yang; Feng, Zhilan

    2005-09-01

    In this paper, we revisit the dynamical interaction among prey (bird), mesopredator (rat), and superpredator (cat) discussed in [Courchamp, F., Langlais, M., Sugihara, G., 1999. Cats protecting birds: modelling the mesopredator release effect. Journal of Animal Ecology 68, 282-292]. First, we develop a prey-mesopredator-superpredator (i.e., bird-rat-cat, briefly, BRC) model, where the predator's functional responses are derived based on the classical Holling's time budget arguments. Our BRC model overcomes several model construction problems in Courchamp et al. (1999), and admits richer, reasonable and realistic dynamics. We explore the possible control strategies to save or restore the bird by controlling or eliminating the rat or the cat when the bird is endangered. We establish the existence of two types of mesopredator release phenomena: severe mesopredator release, where once superpredators are suppressed, a burst of mesopredators follows which leads their shared prey to extinction; and mild mesopredator release, where the mesopredator release could assert more negative impact on the endemic prey but does not lead the endemic prey to extinction. A sharp sufficient criterion is established for the occurrence of severe mesopredator release. We also show that, in a prey-mesopredator-superpredator trophic food web, eradication of introduced superpredators such as feral domestic cats in the BRC model, is not always the best solution to protect endemic insular prey. The presence of a superpredator may have a beneficial effect in such systems. PMID:15998496

  11. Measurements of the UVR protection provided by hats used at school.

    PubMed

    Gies, Peter; Javorniczky, John; Roy, Colin; Henderson, Stuart

    2006-01-01

    The importance of protection against solar ultraviolet radiation (UVR) in childhood has lead to SunSmart policies at Australian schools, in particular primary schools, where children are encouraged and in many cases required to wear hats at school. Hat styles change regularly and the UVR protection provided by some of the hat types currently used and recommended for sun protection by the various Australian state cancer councils had not been previously evaluated. The UVR protection of the hats was measured using UVR sensitive polysulphone film badges attached to different facial sites on rotating headforms. The sun protection type hats included in this study were broad-brimmed hats, "bucket hats" and legionnaires hats. Baseball caps, which are very popular, were also included. The broad-brimmed hats and bucket hats provided the most UVR protection for the six different sites about the face and head. Legionnaires hats also provided satisfactory UVR protection, but the caps did not provide UVR protection to many of the facial sites. The highest measured UVR protection factors for facial sites other than the forehead were 8 to 10, indicating that, while some hats can be effective, they need to be used in combination with other forms of UVR protection. PMID:16483247

  12. Relative Preference and Localized Food Affect Predator Space Use and Consumption of Incidental Prey.

    PubMed

    Schartel, Tyler E; Schauber, Eric M

    2016-01-01

    Abundant, localized foods can concentrate predators and their foraging efforts, thus altering both the spatial distribution of predation risk and predator preferences for prey that are encountered incidentally. However, few investigations have quantified the spatial scale over which localized foods affect predator foraging behavior and consumption of incidental prey. In spring 2010, we experimentally tested how point-source foods altered how generalist predators (white-footed mice, Peromyscus leucopus) utilized space and depredated two incidental prey items: almonds (Prunus dulcis; highly profitable) and maple seeds (Acer saccharum; less profitable). We estimated mouse population densities with trapping webs, quantified mouse consumption rates of these incidental prey items, and measured local mouse activity with track plates. We predicted that 1) mouse activity would be elevated near full feeders, but depressed at intermediate distances from the feeder, 2) consumption of both incidental prey would be high near feeders providing less-preferred food and, 3) consumption of incidental prey would be contingent on predator preference for prey relative to feeders providing more-preferred food. Mouse densities increased significantly from pre- to post-experiment. Mean mouse activity was unexpectedly greatest in control treatments, particularly <15 m from the control (empty) feeder. Feeders with highly preferred food (sunflower seeds) created localized refuges for incidental prey at intermediate distances (15 to 25m) from the feeder. Feeders with less-preferred food (corn) generated localized high risk for highly preferred almonds <10 m of the feeder. Our findings highlight the contingent but predictable effects of locally abundant food on risk experienced by incidental prey, which can be positive or negative depending on both spatial proximity and relative preference. PMID:26978659

  13. Relative Preference and Localized Food Affect Predator Space Use and Consumption of Incidental Prey

    PubMed Central

    Schartel, Tyler E.; Schauber, Eric M.

    2016-01-01

    Abundant, localized foods can concentrate predators and their foraging efforts, thus altering both the spatial distribution of predation risk and predator preferences for prey that are encountered incidentally. However, few investigations have quantified the spatial scale over which localized foods affect predator foraging behavior and consumption of incidental prey. In spring 2010, we experimentally tested how point-source foods altered how generalist predators (white-footed mice, Peromyscus leucopus) utilized space and depredated two incidental prey items: almonds (Prunus dulcis; highly profitable) and maple seeds (Acer saccharum; less profitable). We estimated mouse population densities with trapping webs, quantified mouse consumption rates of these incidental prey items, and measured local mouse activity with track plates. We predicted that 1) mouse activity would be elevated near full feeders, but depressed at intermediate distances from the feeder, 2) consumption of both incidental prey would be high near feeders providing less-preferred food and, 3) consumption of incidental prey would be contingent on predator preference for prey relative to feeders providing more-preferred food. Mouse densities increased significantly from pre- to post-experiment. Mean mouse activity was unexpectedly greatest in control treatments, particularly <15 m from the control (empty) feeder. Feeders with highly preferred food (sunflower seeds) created localized refuges for incidental prey at intermediate distances (15 to 25m) from the feeder. Feeders with less-preferred food (corn) generated localized high risk for highly preferred almonds <10 m of the feeder. Our findings highlight the contingent but predictable effects of locally abundant food on risk experienced by incidental prey, which can be positive or negative depending on both spatial proximity and relative preference. PMID:26978659

  14. Inferring Predator Behavior from Attack Rates on Prey-Replicas That Differ in Conspicuousness

    PubMed Central

    2012-01-01

    Behavioral ecologists and evolutionary biologists have long studied how predators respond to prey items novel in color and pattern. Because a predatory response is influenced by both the predator’s ability to detect the prey and a post-detection behavioral response, variation among prey types in conspicuousness may confound inference about post-prey-detection predator behavior. That is, a relatively high attack rate on a given prey type may result primarily from enhanced conspicuousness and not predators’ direct preference for that prey. Few studies, however, account for such variation in conspicuousness. In a field experiment, we measured predation rates on clay replicas of two aposematic forms of the poison dart frog Dendrobates pumilio, one novel and one familiar, and two cryptic controls. To ask whether predators prefer or avoid a novel aposematic prey form independently of conspicuousness differences among replicas, we first modeled the visual system of a typical avian predator. Then, we used this model to estimate replica contrast against a leaf litter background to test whether variation in contrast alone could explain variation in predator attack rate. We found that absolute predation rates did not differ among color forms. Predation rates relative to conspicuousness did, however, deviate significantly from expectation, suggesting that predators do make post-detection decisions to avoid or attack a given prey type. The direction of this deviation from expectation, though, depended on assumptions we made about how avian predators discriminate objects from the visual background. Our results show that it is important to account for prey conspicuousness when investigating predator behavior and also that existing models of predator visual systems need to be refined. PMID:23119039

  15. Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

    PubMed

    Millett, J; Foot, G W; Svensson, B M

    2015-04-15

    Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. PMID:25655989

  16. 50 CFR 622.179 - Conservation measures for protected resources.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    .../headboats—(1) Sea turtle conservation measures. (i) The owner or operator of a vessel for which a commercial... for Sea Turtle Release With Minimal Injury,” and must post inside the wheelhouse, or in an easily viewable area if no wheelhouse, the sea turtle handling and release guidelines provided by NMFS. (ii)...

  17. 50 CFR 622.179 - Conservation measures for protected resources.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .../headboats—(1) Sea turtle conservation measures. (i) The owner or operator of a vessel for which a commercial... for Sea Turtle Release With Minimal Injury,” and must post inside the wheelhouse, or in an easily viewable area if no wheelhouse, the sea turtle handling and release guidelines provided by NMFS. (ii)...

  18. 30 CFR 282.28 - Environmental protection measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... measures. (a) Exploration, testing, development, production, and processing activities proposed to be... prepared in association with the review and evaluation of the approved Delineation, Testing, or Mining Plan. The Director's review of the air quality consequences of proposed OCS activities will follow...

  19. Beaked whales echolocate on prey.

    PubMed

    Johnson, Mark; Madsen, Peter T; Zimmer, Walter M X; de Soto, Natacha Aguilar; Tyack, Peter L

    2004-12-01

    Beaked whales (Cetacea: Ziphiidea) of the genera Ziphius and Mesoplodon are so difficult to study that they are mostly known from strandings. How these elusive toothed whales use and react to sound is of concern because they mass strand during naval sonar exercises. A new non-invasive acoustic ording tag was attached to four beaked whales(two Mesoplodon densirostris and two Ziphius cavirostris) and recorded high-frequency clicks during deep dives. The tagged whales only clicked at depths below 200 m, down to a maximum depth of 1267 m. Both species produced a large number of short, directional, ultrasonic clicks with significant energy below 20 kHz. The tags recorded echoes from prey items; to our knowledge, a first for any animal echolocating in the wild. As far as we are aware, these echoes provide the first direct evidence on how free-ranging toothed whales use echolocation in foraging. The strength of these echoes suggests that the source level of Mesoplodon clicks is in the range of 200-220 dB re 1 microPa at 1 m. This paper presents conclusive data on the normal vocalizations of these beaked whale species, which may enable acoustic monitoring to mitigate exposure to sounds intense enough to harm them. PMID:15801582

  20. Beaked whales echolocate on prey.

    PubMed Central

    Johnson, Mark; Madsen, Peter T; Zimmer, Walter M X; de Soto, Natacha Aguilar; Tyack, Peter L

    2004-01-01

    Beaked whales (Cetacea: Ziphiidea) of the genera Ziphius and Mesoplodon are so difficult to study that they are mostly known from strandings. How these elusive toothed whales use and react to sound is of concern because they mass strand during naval sonar exercises. A new non-invasive acoustic ording tag was attached to four beaked whales(two Mesoplodon densirostris and two Ziphius cavirostris) and recorded high-frequency clicks during deep dives. The tagged whales only clicked at depths below 200 m, down to a maximum depth of 1267 m. Both species produced a large number of short, directional, ultrasonic clicks with significant energy below 20 kHz. The tags recorded echoes from prey items; to our knowledge, a first for any animal echolocating in the wild. As far as we are aware, these echoes provide the first direct evidence on how free-ranging toothed whales use echolocation in foraging. The strength of these echoes suggests that the source level of Mesoplodon clicks is in the range of 200-220 dB re 1 microPa at 1 m.This paper presents conclusive data on the normal vocalizations of these beaked whale species, which may enable acoustic monitoring to mitigate exposure to sounds intense enough to harm them. PMID:15801582

  1. Are lemmings prey or predators?

    NASA Astrophysics Data System (ADS)

    Turchin, P.; Oksanen, L.; Ekerholm, P.; Oksanen, T.; Henttonen, H.

    2000-06-01

    Large oscillations in the populations of Norwegian lemmings have mystified both professional ecologists and lay public. Ecologists suspect that these oscillations are driven by a trophic mechanism: either an interaction between lemmings and their food supply, or an interaction between lemmings and their predators. If lemming cycles are indeed driven by a trophic interaction, can we tell whether lemmings act as the resource (`prey') or the consumer (`predator')? In trophic interaction models, peaks of resource density generally have a blunt, rounded shape, whereas peaks of consumer density are sharp and angular. Here we have applied several statistical tests to three lemming datasets and contrasted them with comparable data for cyclic voles. We find that vole peaks are blunt, consistent with their cycles being driven by the interaction with predators. In contrast, the shape of lemming peaks is consistent with the hypothesis that lemmings are functional predators, that is, their cycles are driven by their interaction with food plants. Our findings suggest that a single mechanism, such as interaction between rodents and predators, is unlikely to provide the `universal' explanation of all cyclic rodent dynamics.

  2. Effects of the prey refuge distribution on a predator-prey system

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hee; Kwon, Ohsung; Song, Hark-Soo

    2016-03-01

    The existence of prey refuges in a predator-prey system is known to be strongly related to the ecosystem's stability. In this study, we explored how the prey refuge distribution affects the predator-prey system. To do so, we constructed a spatial lattice model to simulate an integrative predator (wolf) - prey (rabbit) - plant (grass) relationship. When a wolf (rabbit) encountered a rabbit (grass), the wolf (rabbit) tended to move to the rabbit (grass) for foraging while the rabbit tended to escape from the wolf. These behaviors were mathematically described by the degrees of willingness for hunting ( H) and escaping ( E). Initially, n refuges for prey were heterogeneously distributed in the lattice space. The heterogeneity was characterized as variable A. Higher values of A equate to higher aggregation in the refuge. We investigated the mean population density for different values of H, E, and A. To simply characterize the refuge distribution effect, we built an H-E grid map containing the population density for each species. Then, we counted the number of grids, N, with a population density ≥ 0.25. Simulation results showed that an appropriate value of A positively affected prey survival while values of A were too high had a negative effect on prey survival. The results were explained by using the trade-off between the staying time of the prey in the refuge and the cluster size of the refuge.

  3. Visual illusions in predator-prey interactions: birds find moving patterned prey harder to catch.

    PubMed

    Hämäläinen, Liisa; Valkonen, Janne; Mappes, Johanna; Rojas, Bibiana

    2015-09-01

    Several antipredator strategies are related to prey colouration. Some colour patterns can create visual illusions during movement (such as motion dazzle), making it difficult for a predator to capture moving prey successfully. Experimental evidence about motion dazzle, however, is still very scarce and comes only from studies using human predators capturing moving prey items in computer games. We tested a motion dazzle effect using for the first time natural predators (wild great tits, Parus major). We used artificial prey items bearing three different colour patterns: uniform brown (control), black with elongated yellow pattern and black with interrupted yellow pattern. The last two resembled colour patterns of the aposematic, polymorphic dart-poison frog Dendrobates tinctorius. We specifically tested whether an elongated colour pattern could create visual illusions when combined with straight movement. Our results, however, do not support this hypothesis. We found no differences in the number of successful attacks towards prey items with different patterns (elongated/interrupted) moving linearly. Nevertheless, both prey types were significantly more difficult to catch compared to the uniform brown prey, indicating that both colour patterns could provide some benefit for a moving individual. Surprisingly, no effect of background (complex vs. plain) was found. This is the first experiment with moving prey showing that some colour patterns can affect avian predators' ability to capture moving prey, but the mechanisms lowering the capture rate are still poorly understood. PMID:25947086

  4. Influence of predator mutual interference and prey refuge on Lotka-Volterra predator-prey dynamics

    NASA Astrophysics Data System (ADS)

    Chen, Liujuan; Chen, Fengde; Wang, Yiqin

    2013-11-01

    A Lotka-Volterra predator-prey model incorporating a constant number of prey using refuges and mutual interference for predator species is presented. By applying the divergency criterion and theories on exceptional directions and normal sectors, we show that the interior equilibrium is always globally asymptotically stable and two boundary equilibria are both saddle points. Our results indicate that prey refuge has no influence on the coexistence of predator and prey species of the considered model under the effects of mutual interference for predator species, which differently from the conclusion without predator mutual interference, thus improving some known ones. Numerical simulations are performed to illustrate the validity of our results.

  5. National Council on Radiation Protection and Measurements semiannual technical progress report, March 1989--August 1989

    SciTech Connect

    Ney, W.R.

    1991-01-01

    This semiannual technical progress report is for the period 1 March 1989 through 31 August 1989. This National Council on Radiation Protection and Measurements (NCRP) program is designed to provide recommendations for radiation protection based on scientific principles. During this period several reports were published covering the topics of occupational radiation exposure, medical exposure, radon control, dosimetry, and radiation protection standards. Accomplishments of various committees are also reported; including the committees on dental x-ray protection, radiation safety in uranium mining and milling, ALARA, instrumentation, records maintenance, occupational exposures of medical personnel, emergency planning, and others. (SM)

  6. Predator fitness increases with selectivity for odd prey.

    PubMed

    Rutz, Christian

    2012-05-01

    The fundamental currency of normative models of animal decision making is Darwinian fitness. In foraging ecology, empirical studies typically assess foraging strategies by recording energy intake rates rather than realized reproductive performance. This study provides a rare empirical link, in a vertebrate predator-prey system, between a predator's foraging behavior and direct measures of its reproductive fitness. Goshawks Accipiter gentilis selectively kill rare color variants of their principal prey, the feral pigeon Columba livia, presumably because targeting odd-looking birds in large uniform flocks helps them overcome confusion effects and enhances attack success. Reproductive performance of individual hawks increases significantly with their selectivity for odd-colored pigeons, even after controlling for confounding age effects. Older hawks exhibit more pronounced dietary preferences, suggesting that hunting performance improves with experience. Intriguingly, although negative frequency-dependent predation by hawks exerts strong selection against rare pigeon phenotypes, pigeon color polymorphism is maintained through negative assortative mating. PMID:22503502

  7. 49 CFR Appendix D to Part 192 - Criteria for Cathodic Protection and Determination of Measurements

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of Measurements D Appendix D to Part 192 Transportation Other Regulations Relating to Transportation.... 192, App. D Appendix D to Part 192—Criteria for Cathodic Protection and Determination of Measurements... appendix. D. Metals of different anodic potentials. A negative (cathodic) voltage, measured in...

  8. 49 CFR Appendix D to Part 192 - Criteria for Cathodic Protection and Determination of Measurements

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of Measurements D Appendix D to Part 192 Transportation Other Regulations Relating to Transportation.... 192, App. D Appendix D to Part 192—Criteria for Cathodic Protection and Determination of Measurements... appendix. D. Metals of different anodic potentials. A negative (cathodic) voltage, measured in...

  9. 49 CFR Appendix D to Part 192 - Criteria for Cathodic Protection and Determination of Measurements

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of Measurements D Appendix D to Part 192 Transportation Other Regulations Relating to Transportation.... 192, App. D Appendix D to Part 192—Criteria for Cathodic Protection and Determination of Measurements... appendix. D. Metals of different anodic potentials. A negative (cathodic) voltage, measured in...

  10. Measuring impact of protected area management interventions: current and future use of the Global Database of Protected Area Management Effectiveness

    PubMed Central

    Coad, Lauren; Leverington, Fiona; Knights, Kathryn; Geldmann, Jonas; Eassom, April; Kapos, Valerie; Kingston, Naomi; de Lima, Marcelo; Zamora, Camilo; Cuardros, Ivon; Nolte, Christoph; Burgess, Neil D.; Hockings, Marc

    2015-01-01

    Protected areas (PAs) are at the forefront of conservation efforts, and yet despite considerable progress towards the global target of having 17% of the world's land area within protected areas by 2020, biodiversity continues to decline. The discrepancy between increasing PA coverage and negative biodiversity trends has resulted in renewed efforts to enhance PA effectiveness. The global conservation community has conducted thousands of assessments of protected area management effectiveness (PAME), and interest in the use of these data to help measure the conservation impact of PA management interventions is high. Here, we summarize the status of PAME assessment, review the published evidence for a link between PAME assessment results and the conservation impacts of PAs, and discuss the limitations and future use of PAME data in measuring the impact of PA management interventions on conservation outcomes. We conclude that PAME data, while designed as a tool for local adaptive management, may also help to provide insights into the impact of PA management interventions from the local-to-global scale. However, the subjective and ordinal characteristics of the data present significant limitations for their application in rigorous scientific impact evaluations, a problem that should be recognized and mitigated where possible. PMID:26460133

  11. Measuring impact of protected area management interventions: current and future use of the Global Database of Protected Area Management Effectiveness.

    PubMed

    Coad, Lauren; Leverington, Fiona; Knights, Kathryn; Geldmann, Jonas; Eassom, April; Kapos, Valerie; Kingston, Naomi; de Lima, Marcelo; Zamora, Camilo; Cuardros, Ivon; Nolte, Christoph; Burgess, Neil D; Hockings, Marc

    2015-11-01

    Protected areas (PAs) are at the forefront of conservation efforts, and yet despite considerable progress towards the global target of having 17% of the world's land area within protected areas by 2020, biodiversity continues to decline. The discrepancy between increasing PA coverage and negative biodiversity trends has resulted in renewed efforts to enhance PA effectiveness. The global conservation community has conducted thousands of assessments of protected area management effectiveness (PAME), and interest in the use of these data to help measure the conservation impact of PA management interventions is high. Here, we summarize the status of PAME assessment, review the published evidence for a link between PAME assessment results and the conservation impacts of PAs, and discuss the limitations and future use of PAME data in measuring the impact of PA management interventions on conservation outcomes. We conclude that PAME data, while designed as a tool for local adaptive management, may also help to provide insights into the impact of PA management interventions from the local-to-global scale. However, the subjective and ordinal characteristics of the data present significant limitations for their application in rigorous scientific impact evaluations, a problem that should be recognized and mitigated where possible. PMID:26460133

  12. Porpoises: From predators to prey

    NASA Astrophysics Data System (ADS)

    Leopold, Mardik F.; Begeman, Lineke; Heße, Eileen; van der Hiele, Jaap; Hiemstra, Sjoukje; Keijl, Guido; Meesters, Erik H.; Mielke, Lara; Verheyen, Dorien; Gröne, Andrea

    2015-03-01

    Along the Dutch shores hundreds of harbour porpoises Phocoena phocoena are stranded each year. A recurrent phenomenon in the Netherlands is a surge of strandings in late winter and early spring of severely mutilated porpoises, that are mostly in good nutritional body condition (thick blubber layer). These mutilated porpoises have parts of the skin and blubber, and sometimes of the muscle tissue missing. By reviewing photographs of stranded animals taken at the stranding sites as well as autopsy results we found 273 mutilated animals from 2005 to 2012. Mutilations could be classified into several categories, but wounds had been mostly inflicted to the sides of these animals, in a zigzag fashion, or to the throat/cheek region. The stomach contents of 31 zigzags, 12 throats/cheeks and 31 control animals that were not mutilated, from the same age and blubber thickness categories were compared; all these animals had stranded between December and April, 2006-2012. The diet of individuals with zigzag lesions to their sides consisted for a large part of gobies, while animals that had wounds at the throat/cheek had been feeding predominately on clupeids. In comparison, animals without mutilations had a more varied diet, including gobies and clupeids, but also a large proportion of sandeels and gadoids. The finding that the type of mutilation corresponds to a certain diet suggests that porpoises that were feeding on different prey, or in different micro-habitats, were hit in different ways. Animals feeding at the sea floor (on gobies) apparently run a risk of being hit from the side, while animals supposedly feeding higher in the water column (on schooling clupeids), were predominantly hit from below, in the throat region. The wider variation in the diets of non-mutilated porpoises is suggestive of them using a larger variety of micro-habitats.

  13. Contribution of pitcher fragrance and fluid viscosity to high prey diversity in a Nepenthes carnivorous plant from Borneo.

    PubMed

    Giusto, Bruno Di; Grosbois, Vladimir; Fargeas, Elodie; Marshall, David J; Gaume, Laurence

    2008-03-01

    Mechanisms that improve prey richness in carnivorous plants may involve three crucial phases of trapping:attraction, capture and retention. Nepenthes rafflesiana var. typica is an insectivorous pitcher plant that is widespread in northern Borneo. It exhibits ontogenetic pitcher dimorphism with the upper pitchers trapping more flying prey than the lower pitchers. While this difference in prey composition has been ascribed to differences in attraction,the contribution of capture and retention has been overlooked. This study focused on distinguishing between the prey trapping mechanisms, and assessing their relative contribution to prey diversity. Arthropod richness and diversity of both visitors and prey in the two types of pitchers were analysed to quantify the relative contribution of attraction to prey trapping. Rate of insect visits to the different pitcher parts and the presence or absence of a sweet fragrance was recorded to clarify the origin and mechanism of attraction. The mechanism of retention was studied by insect bioassays and measurements of fluid viscosity. Nepenthes rafflesiana was found to trap a broader prey spectrum than that previously described for any Nepenthes species,with the upper pitchers attracting and trapping a greater quantity and diversity of prey items than the lower pitchers. Capture efficiency was low compared with attraction or retention efficiency. Fragrance of the peristome,or nectar rim,accounted mainly for the observed non-specific, better prey attraction by the upper pitchers, while the retentive properties of the viscous fluid in these upper pitchers arguably explains the species richness of their flying prey. The pitchers of N. rafflesiana are therefore more than simple pitfall traps and the digestive fluid plays an important yet unsuspected role in the ecological success of the species. PMID:18376077

  14. Restructuring fundamental predator-prey models by recognising prey-dependent conversion efficiency and mortality rates.

    PubMed

    Li, Jiqiu; Montagnes, David J S

    2015-05-01

    Incorporating protozoa into population models (from simple predator-prey explorations to complex food web simulations) is of conceptual, ecological, and economic importance. From theoretical and empirical perspectives, we expose unappreciated complexity in the traditional predator-prey model structure and provide a parsimonious solution, especially for protistologists. We focus on how prey abundance alters two key components of models: predator conversion efficiency (e, the proportion of prey converted to predator, before mortality loss) and predator mortality (δ, the portion of the population lost though death). Using a well-established model system (Paramecium and Didinium), we collect data to parameterize a range of existing and novel population models that differ in the functional forms of e and δ. We then compare model simulations to an empirically obtained time-series of predator-prey population dynamics. The analysis indicates that prey-dependent e and δ should be considered when structuring population models and that both prey and predator biomass also vary with prey abundance. Both of these impact the ability of the model to predict population dynamics and, therefore, should be included in theoretical model evaluations and assessment of ecosystem dynamics associated with biomass flux. PMID:25819465

  15. Predator prey interactions of Procambarus clarkii with aquatic macroinvertebrates in single and multiple prey systems

    NASA Astrophysics Data System (ADS)

    Correia, Alexandra Marçal; Bandeira, Nuno; Anastácio, Pedro Manuel

    2005-11-01

    Understanding the interspecific interactions of Procambarus clarkii with other aquatic macroinvertebrates will help to unveil the mechanisms and processes underlying biological invasiveness. The purpose of this study was to investigate predator-prey interactions of two ontogenic phases of P. clarkii with native and exotic species of aquatic macroinvertebrates at a single and multiple prey level. We performed laboratory experiments to determine the consumption and the behavioral responses of Chironomus riparius, Physa acuta and Corbicula fluminea to P. clarkii. The presence of P. clarkii significantly affected the abundance of C. riparius and P. acuta, but not of C. fluminea whether prey species were provided singly or simultaneously. The consumption of C. riparius by P. clarkii was higher than P. acuta for both crayfish sizes and situations (single/multiple prey systems) and C. fluminea was never consumed. Physa acuta was the only species that exhibited an anti-predator behavior to P. clarkii. Our results show that P. clarkii can have strong consumptive and trait effects on aquatic macroinvertebrate prey at a single and multiple prey level, resulting in differential impacts on different prey species. This study clarifies some aspects of the predator-prey interactions between P. clarkii and native as well as other exotic macroinvertebrate species that have invaded freshwater biocenosis worldwide.

  16. How the Magnitude of Prey Genetic Variation Alters Predator-Prey Eco-Evolutionary Dynamics.

    PubMed

    Cortez, Michael H

    2016-09-01

    Evolution can alter the stability and dynamics of ecological communities; for example, prey evolution can drive cyclic dynamics in predator-prey systems that are not possible in the absence of evolution. However, it is unclear how the magnitude of additive genetic variation in the evolving species mediates those effects. In this study, I explore how the magnitude of prey additive genetic variation determines what effects prey evolution has on the dynamics and stability of predator-prey systems. I use linear stability analysis to decompose the stability of a general eco-evolutionary predator-prey model into components representing the stabilities of the ecological and evolutionary subsystems as well as the interactions between those subsystems. My results show that with low genetic variation, the cyclic dynamics and stability of the system are determined by the ecological subsystem. With increased genetic variation, disruptive selection always destabilizes stable communities, stabilizing selection can stabilize or destabilize communities, and prey evolution can alter predator-prey phase lags. Stability changes occur approximately when the magnitude of genetic variation balances the (in)stabilities of the ecological and evolutionary subsystems. I discuss the connections between my stability results and prior results from the theory of adaptive dynamics. PMID:27501090

  17. Measuring the extent and effectiveness of protected areas as an indicator for meeting global biodiversity targets

    PubMed Central

    Chape, S; Harrison, J; Spalding, M; Lysenko, I

    2005-01-01

    There are now over 100 000 protected areas worldwide, covering over 12% of the Earth's land surface. These areas represent one of the most significant human resource use allocations on the planet. The importance of protected areas is reflected in their widely accepted role as an indicator for global targets and environmental assessments. However, measuring the number and extent of protected areas only provides a unidimensional indicator of political commitment to biodiversity conservation. Data on the geographic location and spatial extent of protected areas will not provide information on a key determinant for meeting global biodiversity targets: ‘effectiveness’ in conserving biodiversity. Although tools are being devised to assess management effectiveness, there is no globally accepted metric. Nevertheless, the numerical, spatial and geographic attributes of protected areas can be further enhanced by investigation of the biodiversity coverage of these protected areas, using species, habitats or biogeographic classifications. This paper reviews the current global extent of protected areas in terms of geopolitical and habitat coverage, and considers their value as a global indicator of conservation action or response. The paper discusses the role of the World Database on Protected Areas and collection and quality control issues, and identifies areas for improvement, including how conservation effectiveness indicators may be included in the database to improve the value of protected areas data as an indicator for meeting global biodiversity targets. PMID:15814356

  18. Flash visual evoked potentials in diurnal birds of prey.

    PubMed

    Dondi, Maurizio; Biaggi, Fabio; Di Ianni, Francesco; Dodi, Pier Luigi; Quintavalla, Fausto

    2016-01-01

    The objective of this pilot study was to evaluate the feasibility of Flash Visual Evoked Potentials (FVEPs) testing in birds of prey in a clinical setting and to describe the protocol and the baseline data for normal vision in this species. FVEP recordings were obtained from 6 normal adult birds of prey: n. 2 Harris's Hawks (Parabuteo unicinctus), n. 1 Lanner Falcon (Falco biarmicus), n. 2 Gyrfalcons (Falco rusticolus) and n. 1 Saker Falcon (Falco cherrug). Before carrying out VEP tests, all animals underwent neurologic and ophthalmic routine examination. Waveforms were analysed to identify reproducible peaks from random variation of baseline. At least three positive and negative peaks were highlighted in all tracks with elevated repeatability. Measurements consisted of the absolute and relative latencies of these peaks (P1, N1, P2, N2, P3, and N3) and their peak-to-peak amplitudes. Both the peak latency and wave morphology achieved from normal animals were similar to those obtained previously in other animal species. This test can be easily and safely performed in a clinical setting in birds of prey and could be useful for an objective assessment of visual function. PMID:27547536

  19. Flash visual evoked potentials in diurnal birds of prey

    PubMed Central

    Biaggi, Fabio; Di Ianni, Francesco; Dodi, Pier Luigi; Quintavalla, Fausto

    2016-01-01

    The objective of this pilot study was to evaluate the feasibility of Flash Visual Evoked Potentials (FVEPs) testing in birds of prey in a clinical setting and to describe the protocol and the baseline data for normal vision in this species. FVEP recordings were obtained from 6 normal adult birds of prey: n. 2 Harris’s Hawks (Parabuteo unicinctus), n. 1 Lanner Falcon (Falco biarmicus), n. 2 Gyrfalcons (Falco rusticolus) and n. 1 Saker Falcon (Falco cherrug). Before carrying out VEP tests, all animals underwent neurologic and ophthalmic routine examination. Waveforms were analysed to identify reproducible peaks from random variation of baseline. At least three positive and negative peaks were highlighted in all tracks with elevated repeatability. Measurements consisted of the absolute and relative latencies of these peaks (P1, N1, P2, N2, P3, and N3) and their peak-to-peak amplitudes. Both the peak latency and wave morphology achieved from normal animals were similar to those obtained previously in other animal species. This test can be easily and safely performed in a clinical setting in birds of prey and could be useful for an objective assessment of visual function. PMID:27547536

  20. Blue whale habitat and prey in the California Channel Islands

    NASA Astrophysics Data System (ADS)

    Fiedler, Paul C.; Reilly, Stephen B.; Hewitt, Roger P.; Demer, David; Philbrick, Valerie A.; Smith, Susan; Armstrong, Wesley; Croll, Donald A.; Tershy, Bernie R.; Mate, Bruce R.

    1998-08-01

    Whale Habitat and Prey Studies were conducted off southern California during August 1995 (WHAPS95) and July 1996 (WHAPS96) to (1) study the distribution and activities of blue whales and other large whales, (2) survey the distribution of prey organisms (krill), and (3) measure physical and biological habitat variables that influence the distribution of whales and prey. A total of 1307 cetacean sightings included 460 blue whale, 78 fin whale and 101 humpback whale sightings. Most blue whales were found in cold, well-mixed and productive water that had upwelled along the coast north of Point Conception and then advected south. They were aggregated in this water near San Miguel and Santa Rosa Islands, where they fed on dense, subsurface layers of euphausiids both on the shelf and extending off the shelf edge. Two species of euphausiids were consumed by blue whales, Thysanoessa spinifera and Euphausia pacifica, with evidence of preference for the former, a larger and more coastal species. These krill patches on the Channel Island feeding grounds are a resource exploited during summer-fall by the world's largest stock of blue whales.

  1. Selective Predation of a Stalking Predator on Ungulate Prey.

    PubMed

    Heurich, Marco; Zeis, Klara; Küchenhoff, Helmut; Müller, Jörg; Belotti, Elisa; Bufka, Luděk; Woelfing, Benno

    2016-01-01

    Prey selection is a key factor shaping animal populations and evolutionary dynamics. An optimal forager should target prey that offers the highest benefits in terms of energy content at the lowest costs. Predators are therefore expected to select for prey of optimal size. Stalking predators do not pursue their prey long, which may lead to a more random choice of prey individuals. Due to difficulties in assessing the composition of available prey populations, data on prey selection of stalking carnivores are still scarce. We show how the stalking predator Eurasian lynx (Lynx lynx) selects prey individuals based on species identity, age, sex and individual behaviour. To address the difficulties in assessing prey population structure, we confirm inferred selection patterns by using two independent data sets: (1) data of 387 documented kills of radio-collared lynx were compared to the prey population structure retrieved from systematic camera trapping using Manly's standardized selection ratio alpha and (2) data on 120 radio-collared roe deer were analysed using a Cox proportional hazards model. Among the larger red deer prey, lynx selected against adult males-the largest and potentially most dangerous prey individuals. In roe deer lynx preyed selectively on males and did not select for a specific age class. Activity during high risk periods reduced the risk of falling victim to a lynx attack. Our results suggest that the stalking predator lynx actively selects for size, while prey behaviour induces selection by encounter and stalking success rates. PMID:27548478

  2. Selective Predation of a Stalking Predator on Ungulate Prey

    PubMed Central

    Heurich, Marco; Zeis, Klara; Küchenhoff, Helmut; Müller, Jörg; Belotti, Elisa; Bufka, Luděk; Woelfing, Benno

    2016-01-01

    Prey selection is a key factor shaping animal populations and evolutionary dynamics. An optimal forager should target prey that offers the highest benefits in terms of energy content at the lowest costs. Predators are therefore expected to select for prey of optimal size. Stalking predators do not pursue their prey long, which may lead to a more random choice of prey individuals. Due to difficulties in assessing the composition of available prey populations, data on prey selection of stalking carnivores are still scarce. We show how the stalking predator Eurasian lynx (Lynx lynx) selects prey individuals based on species identity, age, sex and individual behaviour. To address the difficulties in assessing prey population structure, we confirm inferred selection patterns by using two independent data sets: (1) data of 387 documented kills of radio-collared lynx were compared to the prey population structure retrieved from systematic camera trapping using Manly’s standardized selection ratio alpha and (2) data on 120 radio-collared roe deer were analysed using a Cox proportional hazards model. Among the larger red deer prey, lynx selected against adult males—the largest and potentially most dangerous prey individuals. In roe deer lynx preyed selectively on males and did not select for a specific age class. Activity during high risk periods reduced the risk of falling victim to a lynx attack. Our results suggest that the stalking predator lynx actively selects for size, while prey behaviour induces selection by encounter and stalking success rates. PMID:27548478

  3. Effects of prey assemblage on mercury bioaccumulation in a piscivorous sport fish.

    PubMed

    Johnson, Brett M; Lepak, Jesse M; Wolff, Brian A

    2015-02-15

    Mercury (Hg) is a persistent global contaminant that biomagnifies, often reaching maximum levels in apex predators. Mercury contamination in piscivorous fish is a serious health risk for anglers and other fish consumers. We used data collected from a reservoir in Colorado to develop bioenergetics-based simulations of Hg bioaccumulation to estimate Hg concentrations in walleye (Sander vitreus), a popular sport fish. We evaluated how changes in the prey available to walleye might affect walleye Hg concentrations. Our simulations showed that such changes could result in almost a 10-fold range in walleye Hg concentration. Walleye consuming invertebrates had low growth, low growth efficiency, and high Hg concentrations. Conversely, when walleye diet contained only fish prey their growth and growth efficiency were higher and Hg concentrations were about 85% lower. These predictions were consistent with independent measurements in the study system observed under two different prey regimes in 2008 and 2013. Because prey assemblages in freshwaters can exhibit high natural and anthropogenic variability, understanding variation in predator Hg and providing accurate fish consumption advice to anglers and their families will require frequent monitoring of both predator and prey species. Further, manipulation of prey assemblages is a routine fishery management strategy that could be applied to reduce Hg contamination in piscivorous fishes. PMID:25460967

  4. Effects of predator hunger and food abundance on prey selection by Chaoborus larvae

    SciTech Connect

    Pastorok, R.A.

    1980-09-01

    Laboratory experiments on prey selection by Chaoborus larvae show that predator choice as well as differential encounter rates with prey determine the composition of the diet. As the larvae crop and midgut become filled with food during a feeding bout, the predator avoids eating some available Daphnia and specializes on Diaptomus. After 3 days of starvation at 15/sup 0/C, the gut system is empty and Chaoborus attacks prey indiscriminately. Then, daphnids are overrepresented in the diet because the predator encounters them more frequently than copepods of equal size. Daphnia swims about twice as fast as Diaptomus and encounters a stationary electric eye at twice the rate measured for copepods. The strike efficiency of larvae for encountered prey is the same for both species. Since feeding selectivity is inversely proportional to larval hunger state, prey selection varies with the abundance of prey and season. In general, larvae collected during autumn have lower feeding rates and are more selective than larvae collected during summer. When food increases, previously opportunistic larvae may become selective within a few hours; but satiated larvae take several days to relax their preferences under a lowered food regime.

  5. Breaking symmetry: the marine environment, prey size, and the evolution of asymmetry in cetacean skulls.

    PubMed

    MacLeod, C D; Reidenberg, J S; Weller, M; Santos, M B; Herman, J; Goold, J; Pierce, G J

    2007-06-01

    Skulls of odontocetes (toothed whales, including dolphins and porpoises) are typified by directional asymmetry, particularly in elements associated with the airway. Generally, it is assumed this asymmetry is related to biosonar production. However, skull asymmetry may actually be a by-product of selection pressure for an asymmetrically positioned larynx. The odontocete larynx traverses the pharynx and is held permanently in place by a ring of muscle. This allows prey swallowing while remaining underwater without risking water entering the lungs and causing injury or death. However, protrusion of the larynx through the pharynx causes a restriction around which prey must pass to reach the stomach. The larynx and associated hyoid apparatus has, therefore, been shifted to the left to provide a larger right piriform sinus (lateral pharyngeal food channel) for swallowing larger prey items. This asymmetry is reflected in the skull, particularly the dorsal openings of the nares. It is hypothesized that there is a relationship between prey size and skull asymmetry. This relationship was examined in 13 species of odontocete cetaceans from the northeast Atlantic, including four narrow-gaped genera (Mesoplodon, Ziphius, Hyperoodon, and Kogia) and eight wide-gaped genera (Phocoena, Delphinus, Stenella, Lagenorhynchus, Tursiops, Grampus, Globicephala, and Orcinus). Skulls were examined from 183 specimens to assess asymmetry of the anterior choanae. Stomach contents were examined from 294 specimens to assess prey size. Results show there is a significant positive relationship between maximum relative prey size consumed and average asymmetry relative to skull size in odontocete species (wide-gape species: R2 = 0.642, P = 0.006; narrow-gape species: R2 = 0.909, P = 0.031). This finding provides support for the hypothesis that the directional asymmetry found in odontocete skulls is related to an aquatic adaptation enabling swallowing large, whole prey while maintaining respiratory

  6. 50 CFR 648.81 - NE multispecies closed areas and measures to protect EFH.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false NE multispecies closed areas and measures to protect EFH. 648.81 Section 648.81 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the...

  7. 50 CFR 648.81 - NE multispecies closed areas and measures to protect EFH.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false NE multispecies closed areas and measures to protect EFH. 648.81 Section 648.81 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the...

  8. Leakage current measurement of protective equipment insulating materials used in electrical installations

    NASA Astrophysics Data System (ADS)

    Buică, G.; Dobra, R.; Păsculescu, D.; Tătar, A.

    2016-06-01

    This research describes the behaviour of equipment and safety devices during use in extreme environmental conditions, in order to establish the technical conditions and additional health and safety requirements during operation, to ensure the health and safety of users, regardless of conditions and working environment in which they are use. The studies have been conducted both on new equipment and means of protection used in electrical installations. There has been evaluated protective equipment made of insulating rubber, reinforced fiberglass or PVC. They have been followed the technical characteristics and protection against electric shock by measuring the leakage current of different insulating materials.

  9. Aerosol penetration measurements through protective clothing in small scale simulation tests

    SciTech Connect

    Bergman, W.; Garr, J.; Fearon, D.; Gerdner, P.

    1989-06-01

    We have developed a new laboratory apparatus and technique to measure the penetration of aerosols through protective clothing. The unique feature of this apparatus is a cylindrical fabric holder that incorporates the complex aerodynamics of flow around protective clothing. Because of this feature, the test results from small patch samples in this apparatus can be used to predict aerosol penetration in full scale clothing. This apparatus has the potential for large time and cost savings in new suit development and in evaluating protective clothing against biological agents and chemical aerosols. 2 refs., 8 figs.

  10. Predator functional response and prey survival: Direct and indirect interactions affecting a marked prey population

    USGS Publications Warehouse

    Miller, David A.; Grand, J.B.; Fondell, T.F.; Anthony, M.

    2006-01-01

    1. Predation plays an integral role in many community interactions, with the number of predators and the rate at which they consume prey (i.e. their functional response) determining interaction strengths. Owing to the difficulty of directly observing predation events, attempts to determine the functional response of predators in natural systems are limited. Determining the forms that predator functional responses take in complex systems is important in advancing understanding of community interactions. 2. Prey survival has a direct relationship to the functional response of their predators. We employed this relationship to estimate the functional response for bald eagle Haliaeetus leucocepalus predation of Canada goose Branta canadensis nests. We compared models that incorporated eagle abundance, nest abundance and alternative prey presence to determine the form of the functional response that best predicted intra-annual variation in survival of goose nests. 3. Eagle abundance, nest abundance and the availability of alternative prey were all related to predation rates of goose nests by eagles. There was a sigmoidal relationship between predation rate and prey abundance and prey switching occurred when alternative prey was present. In addition, predation by individual eagles increased as eagle abundance increased. 4. A complex set of interactions among the three species examined in this study determined survival rates of goose nests. Results show that eagle predation had both prey- and predator-dependent components with no support for ratio dependence. In addition, indirect interactions resulting from the availability of alternative prey had an important role in mediating the rate at which eagles depredated nests. As a result, much of the within-season variation in nest survival was due to changing availability of alternative prey consumed by eagles. 5. Empirical relationships drawn from ecological theory can be directly integrated into the estimation process to

  11. Predator-prey interactions, resource depression and patch revisitation

    USGS Publications Warehouse

    Erwin, R.M.

    1989-01-01

    Generalist predators may be confronted by different types of prey in different patches: sedentary and conspicuous, cryptic (with or without refugia), conspicuous and nonsocial, or conspicuous and social. I argue that, where encounter rates with prey are of most importance, patch revisitation should be a profitable tactic where prey have short 'recovery' times (conspicuous, nonsocial prey), or where anti-predator response (e.g. shoaling) may increase conspicuousness. Predictions are made for how temporal changes in prey encounter rates should affect revisit schedules and feeding rates for the 4 different prey types.

  12. Oxytocin tempers calculated greed but not impulsive defense in predator–prey contests

    PubMed Central

    Scholte, H. Steven; van Winden, Frans A. A. M.; Ridderinkhof, K. Richard

    2015-01-01

    Human cooperation and competition is modulated by oxytocin, a hypothalamic neuropeptide that functions as both hormone and neurotransmitter. Oxytocin’s functions can be captured in two explanatory yet largely contradictory frameworks: the fear-dampening (FD) hypothesis that oxytocin has anxiolytic effects and reduces fear-motivated action; and the social approach/avoidance (SAA) hypothesis that oxytocin increases cooperative approach and facilitates protection against aversive stimuli and threat. We tested derivations from both frameworks in a novel predator–prey contest game. Healthy males given oxytocin or placebo invested as predator to win their prey’s endowment, or as prey to protect their endowment against predation. Neural activity was registered using 3T-MRI. In prey, (fear-motivated) investments were fast and conditioned on the amygdala. Inconsistent with FD, oxytocin did not modulate neural and behavioral responding in prey. In predators, (greed-motivated) investments were slower, and conditioned on the superior frontal gyrus (SFG). Consistent with SAA, oxytocin reduced predator investment, time to decide and activation in SFG. Thus, whereas oxytocin does not incapacitate the impulsive ability to protect and defend oneself, it lowers the greedy and more calculated appetite for coming out ahead. PMID:25140047

  13. Does prey capture induce area-restricted search? A fine-scale study using GPS in a marine predator, the wandering albatross.

    PubMed

    Weimerskirch, Henri; Pinaud, David; Pawlowski, Frédéric; Bost, Charles-André

    2007-11-01

    In a patchy environment, predators are expected to increase turning rate and start an area-restricted search (ARS) when prey have been encountered, but few empirical data exist for large predators. By using GPS loggers with devices measuring prey capture, we studied how a marine predator adjusts foraging movements at various scales in relation to prey capture. Wandering albatrosses use two tactics, sit and wait and foraging in flight, the former tactic being three times less efficient than the latter. During flight foraging, birds caught large isolated prey and used ARS at scales varying from 5 to 90 km, with large-scale ARS being used only by young animals. Birds did not show strong responses to prey capture at a large scale, few ARS events occurred after prey capture, and birds did not have high rates of prey capture in ARS. Only at small scales did birds increase sinuosity after prey captures for a limited time period, and this occurred only after they had caught a large prey item within an ARS zone. When this species searches over a large scale, the most effective search rule was to follow a nearly straight path. ARS may be used to restrict search to a particular environment where prey capture is more predictable and profitable. PMID:17926295

  14. Testing the Prey-Trap Hypothesis at Two Wildlife Conservancies in Kenya.

    PubMed

    Dupuis-Desormeaux, Marc; Davidson, Zeke; Mwololo, Mary; Kisio, Edwin; Taylor, Sam; MacDonald, Suzanne E

    2015-01-01

    Protecting an endangered and highly poached species can conflict with providing an open and ecologically connected landscape for coexisting species. In Kenya, about half of the black rhino (Diceros bicornis) live in electrically fenced private conservancies. Purpose-built fence-gaps permit some landscape connectivity for elephant while restricting rhino from escaping. We monitored the usage patterns at these gaps by motion-triggered cameras and found high traffic volumes and predictable patterns of prey movement. The prey-trap hypothesis (PTH) proposes that predators exploit this predictable prey movement. We tested the PTH at two semi-porous reserves using two different methods: a spatial analysis and a temporal analysis. Using spatial analysis, we mapped the location of predation events with GPS and looked for concentration of kill sites near the gaps as well as conducting clustering and hot spot analysis to determine areas of statistically significant predation clustering. Using temporal analysis, we examined the time lapse between the passage of prey and predator and searched for evidence of active prey seeking and/or predator avoidance. We found no support for the PTH and conclude that the design of the fence-gaps is well suited to promoting connectivity in these types of conservancies. PMID:26489024

  15. Testing the Prey-Trap Hypothesis at Two Wildlife Conservancies in Kenya

    PubMed Central

    Dupuis-Desormeaux, Marc; Davidson, Zeke; Mwololo, Mary; Kisio, Edwin; Taylor, Sam; MacDonald, Suzanne E.

    2015-01-01

    Protecting an endangered and highly poached species can conflict with providing an open and ecologically connected landscape for coexisting species. In Kenya, about half of the black rhino (Diceros bicornis) live in electrically fenced private conservancies. Purpose-built fence-gaps permit some landscape connectivity for elephant while restricting rhino from escaping. We monitored the usage patterns at these gaps by motion-triggered cameras and found high traffic volumes and predictable patterns of prey movement. The prey-trap hypothesis (PTH) proposes that predators exploit this predictable prey movement. We tested the PTH at two semi-porous reserves using two different methods: a spatial analysis and a temporal analysis. Using spatial analysis, we mapped the location of predation events with GPS and looked for concentration of kill sites near the gaps as well as conducting clustering and hot spot analysis to determine areas of statistically significant predation clustering. Using temporal analysis, we examined the time lapse between the passage of prey and predator and searched for evidence of active prey seeking and/or predator avoidance. We found no support for the PTH and conclude that the design of the fence-gaps is well suited to promoting connectivity in these types of conservancies. PMID:26489024

  16. Effects of prey quality and predator body size on prey DNA detection success in a centipede predator.

    PubMed

    Eitzinger, B; Unger, E M; Traugott, M; Scheu, S

    2014-08-01

    Predator body size and prey quality are important factors driving prey choice and consumption rates. Both factors might affect prey detection success in PCR-based gut content analysis, potentially resulting in over- or underestimation of feeding rates. Experimental evidence, however, is scarce. We examined how body size and prey quality affect prey DNA detection success in centipede predators. Due to metabolic rates increasing with body size, we hypothesized that prey DNA detection intervals will be shorter in large predators than in smaller ones. Moreover, we hypothesized that prey detection intervals of high-quality prey, defined by low carbon-to-nitrogen ratio will be shorter than in low-quality prey due to faster assimilation. Small, medium and large individuals of centipedes Lithobius spp. (Lithobiidae, Chilopoda) were fed Collembola and allowed to digest prey for up to 168 h post-feeding. To test our second hypothesis, medium-sized lithobiids were fed with either Diptera or Lumbricidae. No significant differences in 50% prey DNA detection success time intervals for a 272-bp prey DNA fragment were found between the predator size groups, indicating that body size does not affect prey DNA detection success. Post-feeding detection intervals were significantly shorter in Lumbricidae and Diptera compared to Collembola prey, apparently supporting the second hypothesis. However, sensitivity of diagnostic PCR differed between prey types, and quantitative PCR revealed that concentration of targeted DNA varied significantly between prey types. This suggests that both DNA concentration and assay sensitivity need to be considered when assessing prey quality effects on prey DNA detection success. PMID:24383982

  17. Functional response of wolves preying on barren-ground caribou in a multiple-prey ecosystem

    USGS Publications Warehouse

    Dale, B.W.; Adams, Layne G.; Bowyer, R.T.

    1994-01-01

    1. We investigated the functional response of wolves (Canis lupus) to varying abundance of ungulate prey to test the hypothesis that switching from alternate prey to preferred prey results in regulation of a caribou (Rangifer tarandus) population at low densities. 2. We determined prey selection, kill rates, and prey abundance for four wolf packs during three 30-day periods in March 1989, March 1990, November 1990, and created a simple discrete model to evaluate the potential for the expected numerical and observed functional responses of wolves to regulate caribou populations. 3. We observed a quickly decelerating type II functional response that, in the absence of numerical response, implicates an anti-regulatory effect of wolf predation on barren-ground caribou dynamics. 4. There was little potential for regulation caused by the multiplicative effect of increasing functional and numerical responses because of presence of alternative prey. This resulted in high wolf:caribou ratios at low prey densities which precluded the effects of an increasing functional response. 5. Inversely density-dependent predation by other predators, such as bears, reduces the potential for predators to regulate caribou populations at low densities, and small reductions in predation by one predator may have disproportionately large effects on the total predation rate.

  18. Immune protection factors of chemical sunscreens measured in the local contact hypersensitivity model in humans.

    PubMed

    Wolf, Peter; Hoffmann, Christine; Quehenberger, Franz; Grinschgl, Stephan; Kerl, Helmut

    2003-11-01

    We conducted a randomized trial designed to calculate human in vivo immune protection factors of two sunscreen preparations in a model of ultraviolet-induced local suppression of the induction of contact hypersensitivity to 2,4-dinitrochlorobenzene. Seventy-five male subjects were exposed in a multistage study to multiples of their individual minimal erythema dose of solar-simulated ultraviolet radiation with or without protection by an ultraviolet B sunscreen (sun protection factor 5.2) or a broad-spectrum ultraviolet A + B sunscreen (sun protection factor 6.2). After 24 h subjects were sensitized with 50 microL of 0.0625% 2,4-dinitrochlorobenzene on a nonirradiated or ultraviolet-irradiated field on the buttock that was unprotected or protected by sunscreen. Three weeks after sensitization the subjects were challenged with varying concentrations of 2,4-dinitrochlorobenzene on their upper inner arm, and the contact hypersensitivity response was determined at 48 and 72 h based on a semiquantitative clinical score, contact hypersensitivity lesion diameters, and dermal skin edema measurement by 20 MHz ultrasound. The 50% immunosuppressive dose ranged from 0.63 to 0.79 minimal erythema dose, depending on the endpoint parameter. Both sunscreens offered significant immunoprotection (p = 0.014-0.002) and their immune protection factor ranged from 4.5 to 5.8 (ultraviolet B sunscreen) and from 7.7 to 11 (ultraviolet A + B sunscreen). The immune protection factor of the ultraviolet B sunscreen was similar to the sun protection factor (5.2), whereas the sunscreen with broad-spectrum ultraviolet A + B protection exhibited better immunoprotective capacity than predicted from the sun protection factor. PMID:14708610

  19. Protecting tripartite entanglement in non-Markovian environments via quantum partially collapsing measurements

    NASA Astrophysics Data System (ADS)

    Ding, Zhi-Yong; He, Juan; Ye, Liu

    2016-08-01

    In this paper, the dynamics of tripartite entanglement via π -tangle in independent non-Markovian environments is investigated. The results indicate that the π -tangle vanishes periodically as decoherence time increases with a damping of its revival amplitude due to the memory of the non-Markovian environments. In addition, we present a scheme to protect entanglement of W state from non-Markovian environments by means of the quantum partially collapsing measurements. It is worth mentioning that our scheme is a successful protection for the tripartite quantum system and the effect is better for the larger measurement strength, while the stronger decoherence suppression induces smaller success probability.

  20. Protecting a quantum state from environmental noise by an incompatible finite-time measurement

    SciTech Connect

    Brasil, Carlos Alexandre; Castro, L. A. de; Napolitano, R. d. J.

    2011-08-15

    We show that measurements of finite duration performed on an open two-state system can protect the initial state from a phase-noisy environment, provided the measured observable does not commute with the perturbing interaction. When the measured observable commutes with the environmental interaction, the finite-duration measurement accelerates the rate of decoherence induced by the phase noise. For the description of the measurement of an observable that is incompatible with the interaction between system and environment, we have found an approximate analytical expression, valid at zero temperature and weak coupling with the measuring device. We have tested the validity of the analytical predictions against an exact numerical approach, based on the superoperator-splitting method, that confirms the protection of the initial state of the system. When the coupling between the system and the measuring apparatus increases beyond the range of validity of the analytical approximation, the initial state is still protected by the finite-time measurement, according with the exact numerical calculations.

  1. Prey escaping wolves, Canis lupus, despite close proximity

    USGS Publications Warehouse

    Nelson, M.E.; Mech, L.D.

    1993-01-01

    We describe attacks by wolf (Canis lupus) packs in Minnesota on a white-tailed deer (Odocoileus virginianus) and a moose (Alces alces) in which wolves were within contact distance of the prey but in which the prey escaped.

  2. A single predator charging a herd of prey: effects of self volume and predator–prey decision-making

    NASA Astrophysics Data System (ADS)

    Schwarzl, Maria; Godec, Aljaz; Oshanin, Gleb; Metzler, Ralf

    2016-06-01

    We study the degree of success of a single predator hunting a herd of prey on a two-dimensional square lattice landscape. We explicitly consider the self volume of the prey restraining their dynamics on the lattice. The movement of both predator and prey is chosen to include an intelligent, decision making step based on their respective sighting ranges, the radius in which they can detect the other species (prey cannot recognise each other besides the self volume interaction): after spotting each other the motion of prey and predator turns from a nearest neighbour random walk into directed escape or chase, respectively. We consider a large range of prey densities and sighting ranges and compute the mean first passage time for a predator to catch a prey as well as characterise the effective dynamics of the hunted prey. We find that the prey's sighting range dominates their life expectancy and the predator profits more from a bad eyesight of the prey than from his own good eye sight. We characterise the dynamics in terms of the mean distance between the predator and the nearest prey. It turns out that effectively the dynamics of this distance coordinate can be captured in terms of a simple Ornstein–Uhlenbeck picture. Reducing the many-body problem to a simple two-body problem by imagining predator and nearest prey to be connected by an effective Hookean bond, all features of the model such as prey density and sighting ranges merge into the effective binding constant.

  3. National measures under the chemical weapons convention to protect confidential business information and compensate for its loss

    SciTech Connect

    Tanzman, E.A.; Kellman, B.

    1995-07-01

    This report contains a discussion presented at the Regional Seminar on the National Authority and the Chemical Weapons Convention. Measures to protect confidential business information and compensation for information which has not been sufficiently protected is discussed.

  4. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density

    PubMed Central

    Hazen, Elliott Lee; Friedlaender, Ari Seth; Goldbogen, Jeremy Arthur

    2015-01-01

    Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency. PMID:26601290

  5. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density.

    PubMed

    Hazen, Elliott Lee; Friedlaender, Ari Seth; Goldbogen, Jeremy Arthur

    2015-10-01

    Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency. PMID:26601290

  6. Ethopharmacological evaluation of the rat exposure test: a prey-predator interaction test.

    PubMed

    Campos, Kelciane Ferreira Caetano; Amaral, Vanessa Cristiane Santana; Rico, Javier Leonardo; Miguel, Tarciso Tadeu; Nunes-de-Souza, Ricardo Luiz

    2013-03-01

    The rat exposure test (RET) is a prey (mouse)-predator (rat) situation that activates brain defensive areas and elicits hormonal and defensive behavior in the mouse. Here, we investigated possible correlations between the spatiotemporal [time spent in protected (home chamber and tunnel) and unprotected (surface) compartments and frequency of entries into the three compartments] and ethological [e.g., duration of protected and unprotected stretched-attend postures (SAP), duration of contact with the rat's compartment] measures (Experiment 1). Secondly, we investigated the effects of systemic treatment with pro- or anti-aversive drugs on the behavior that emerged from the factor analysis (Experiment 2). The effects of chronic (21 days) imipramine and fluoxetine on defensive behavior were also investigated (Experiment 3). Exp. 1 revealed that the time in the protected compartment, protected SAP and rat contacts loaded on factor 1 (defensive behavior), while the total entries and unprotected SAP loaded on factor 2 (locomotor activity). Exp. 2 showed that alprazolam (but not diazepam) selectively changed the defensive factor. Caffeine produced a mild proaversive-like effect, whereas yohimbine only decreased locomotor activity (total entries). Fluoxetine (but not imipramine) produced a weak proaversive-like effect. 5-HT(1A)/5-HT(2) receptor ligands did not change any behavioral measure. In Exp. 3, chronic fluoxetine (but not imipramine) attenuated the defensive behavior factor without changing locomotion. Given that the defensive factor was sensitive to drugs known to attenuate (alprazolam and chronic fluoxetine) and induce (caffeine) panic attack, we suggest the RET as a useful test to assess the effects of panicolytic and panicogenic drugs. PMID:23195112

  7. Diet, prey delivery rates, and prey biomass of Northern Goshawks in East-Central Arizona

    USGS Publications Warehouse

    Rogers, A.S.; DeStefano, S.; Ingraldi, M.F.

    2006-01-01

    Recent concern over persistence of Northern Goshawk (Accipiter gentilis) populations in Arizona has stemmed from two long-term demography studies that report substantial yearly fluctuations in productivity and evidence of a declining population. Although many factors could be involved in changes in productivity and population declines, availability of food is one such factor. As part of a demography study on the Sitgreaves portion of the Apache-Sitgreaves National Forest in Arizona, we used remote cameras to assess diets of goshawks. Northern Goshawks preyed upon 22 species during two nesting seasons. Adult pairs tended to specialize on particular species of prey. Prey delivery rates decreased throughout the nesting season with a corresponding increase in biomass in the latter stages of the nestling and fledgling periods. Adults appeared to take larger prey as nestlings increased in age.

  8. Investigation of Stinson Beach Park storm damage and evaluation of alternative shore protection measures

    SciTech Connect

    Ecker, R.M.; Whelan, G.

    1984-07-01

    An investigation was made of storm damage during the winter of 1982-83 to the National Park Service's Stinson Beach Park. The investigation included an assessment of the storm damage, evaluation of physical processes contributing to the damage, subsequent beach recovery, and the feasibility of implementing shoreline protection measure to reduce future risk. During the winter of 1982-83, the beach was almost completely denuded of sand, wave overwash damaged the foredune, vegetation on the foredune was destroyed, and backshore flooding occurred. Two structures and a parking lot were endangered as the shoreline receded. Subsequent recovery of the park beach was rapid. By January 1982 sand had moved back onshore and a beach berm was beginning to reform. The foredune and dune vegetation received the only permanent damage. Four shoreline protection alternatives were evaluated. These include no action, dune development/enhancement, construction of a rock riprap revetment, and offshore installation of artificial seaweed. The first costs (estimated costs, excluding maintenance) range from about $90,000 to $475,000. The least-cost protection measure is riprap revetment, which protects the two structures and parking lot endangered during the 1982-83 winter storms. Construction of a foredune along the entire park beach is the highest cost protection measure. If no shore protection action measures are implemented, wave overwash of the foredune can be expected to occur on the average of every 2 to 3 years, and beach degradation, similar to that during the 1982-83 winter, can be expected to occur on the average of every 10 to 12 years. 12 references, 19 figures, 18 tables.

  9. 78 FR 55765 - Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... (78 FR 45573) a request for public comment on NUREG/CR-7135, ``Compensatory and Alternative Regulatory... COMMISSION Compensatory and Alternative Regulatory Measures for Nuclear Power Plant Fire Protection (CARMEN-FIRE) AGENCY: Nuclear Regulatory Commission. ACTION: Draft NUREG/CR, reopening of comment...

  10. 43 CFR 3272.12 - What environmental protection measures must I include in my utilization plan?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What environmental protection measures must I include in my utilization plan? 3272.12 Section 3272.12 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE...

  11. Testing the Measurement Properties of Risk Assessment Instruments in Child Protective Services.

    ERIC Educational Resources Information Center

    Fanshel, David; And Others

    1994-01-01

    This study examined 72 children at risk of abuse and the relevant adults, to identify variables predictive of child abuse risk. The measures used (New York Child Protective Services Review Document, Magura-Moses Child Well-Being Scales, and Beck and Jones List of Problems and Conditions) each had predictive value for case decision making.…

  12. Alterations in prey capture and induction of metallothioneins in grass shrimp fed cadmium-contaminated prey

    SciTech Connect

    Wallace, W.G.; Hoexum Brouwer, T.M.; Brouwer, M.; Lopez, G.R.

    2000-04-01

    The aquatic oligochaete Limnodrilus hoffmeisteri from a Cd-contaminated cove on the Hudson River, Foundry Cove, New York, USA, has evolved Cd resistance. Past studies have focused on how the mode of detoxification of Cd by these Cd-resistant worms influences Cd trophic transfer to the grass shrimp Palaemonetes pugio. In the present study, the authors investigate reductions in prey capture in grass shrimp fed Cd-contaminated prey. They also investigate the induction of metal-binding proteins, metallothioneins, in these Cd-exposed shrimp. Grass shrimp were fed field-exposed Cd-contaminated Foundry Cove oligochaetes or laboratory-exposed Cd-contaminated Artemia salina. Following these exposures, the ability of Cd- dosed and control shrimp to capture live A. salina was compared. Results show that shrimp fed laboratory-exposed Cd-contaminated A. salina for 2 weeks exhibit significant reductions in their ability to successfully capture prey (live A. salina). Reductions in prey capture were also apparent, though not as dramatic in shrimp fed for 1 week on field-exposed Cd-contained Foundry Cove oligochaetes. Shrimp were further investigated for their subcellular distribution of Cd to examine if alterations in prey capture could be linked to saturation of Cd-metallothionein. Cd-dosed shrimp produced a low molecular weight CD-binding metallothionein protein in a dose- and time-dependent manner. Most importantly, successful prey capture decreased with increased Cd body burdens and increased Cd concentration bound to high molecular weight proteins.

  13. A predator-prey model with diseases in both prey and predator

    NASA Astrophysics Data System (ADS)

    Gao, Xubin; Pan, Qiuhui; He, Mingfeng; Kang, Yibin

    2013-12-01

    In this paper, we present and analyze a predator-prey model, in which both predator and prey can be infected. Each of the predator and prey is divided into two categories, susceptible and infected. The epidemics cannot be transmitted between prey and predator by predation. The predation ability of susceptible predators is stronger than infected ones. Likewise, it is more difficult to catch a susceptible prey than an infected one. And the diseases cannot be hereditary in both of the predator and prey populations. Based on the assumptions above, we find that there are six equilibrium points in this model. Using the base reproduction number, we discuss the stability of the equilibrium points qualitatively. Then both of the local and global stabilities of the equilibrium points are analyzed quantitatively by mathematical methods. We provide numerical results to discuss some interesting biological cases that our model exhibits. Lastly, we discuss how the infectious rates affect the stability, and how the other parameters work in the five possible cases within this model.

  14. Insect prey characteristics affecting regional variation in chimpanzee tool use.

    PubMed

    Sanz, Crickette M; Deblauwe, Isra; Tagg, Nikki; Morgan, David B

    2014-06-01

    It is an ongoing interdisciplinary pursuit to identify the factors shaping the emergence and maintenance of tool technology. Field studies of several primate taxa have shown that tool using behaviors vary within and between populations. While similarity in tools over spatial and temporal scales may be the product of socially learned skills, it may also reflect adoption of convergent strategies that are tailored to specific prey features. Much has been claimed about regional variation in chimpanzee tool use, with little attention to the ecological circumstances that may have shaped such differences. This study examines chimpanzee tool use in termite gathering to evaluate the extent to which the behavior of insect prey may dictate chimpanzee technology. More specifically, we conducted a systematic comparison of chimpanzee tool use and termite prey between the Goualougo Triangle in the Republic of Congo and the La Belgique research site in southeast Cameroon. Apes at both of these sites are known to use tool sets to gather several species of termites. We collected insect specimens and measured the characteristics of their nests. Associated chimpanzee tool assemblages were documented at both sites and video recordings were conducted in the Goualougo Triangle. Although Macrotermitinae assemblages were identical, we found differences in the tools used to gather these termites. Based on measurements of the chimpanzee tools and termite nests at each site, we concluded that some characteristics of chimpanzee tools were directly related to termite nest structure. While there is a certain degree of uniformity within approaches to particular tool tasks across the species range, some aspects of regional variation in hominoid technology are likely adaptations to subtle environmental differences between populations or groups. Such microecological differences between sites do not negate the possibility of cultural transmission, as social learning may be required to transmit

  15. Arthropod prey for riparian associated birds in headwater forests of the Oregon Coast Range

    USGS Publications Warehouse

    Hagar, Joan C.; Li, Judith; Sobota, Janel; Jenkins, Stephanie

    2012-01-01

    Headwater riparian areas occupy a large proportion of the land base in Pacific Northwest forests, and thus are ecologically and economically important. Although a primary goal of management along small headwater streams is the protection of aquatic resources, streamside habitat also is important for many terrestrial wildlife species. However, mechanisms underlying the riparian associations of some terrestrial species have not been well studied, particularly for headwater drainages. We investigated the diets of and food availability for four bird species associated with riparian habitats in montane coastal forests of western Oregon, USA. We examined variation in the availability of arthropod prey as a function of distance from stream. Specifically, we tested the hypotheses that (1) emergent aquatic insects were a food source for insectivorous birds in headwater riparian areas, and (2) the abundances of aquatic and terrestrial arthropod prey did not differ between streamside and upland areas during the bird breeding season. We found that although adult aquatic insects were available for consumption throughout the study period, they represented a relatively small proportion of available prey abundance and biomass and were present in only 1% of the diet samples from only one of the four riparian-associated bird species. Nonetheless, arthropod prey, comprised primarily of insects of terrestrial origin, was more abundant in streamside than upland samples. We conclude that food resources for birds in headwater riparian areas are primarily associated with terrestrial vegetation, and that bird distributions along the gradient from streamside to upland may be related to variation in arthropod prey availability. Because distinct vegetation may distinguish riparian from upland habitats for riparian-associated birds and their terrestrial arthropod prey, we suggest that understory communities be considered when defining management zones for riparian habitat.

  16. Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences.

    PubMed

    Kojima, Yosuke; Mori, Akira

    2015-01-01

    Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. PMID:25392472

  17. Active foraging for toxic prey during gestation in a snake with maternal provisioning of sequestered chemical defences

    PubMed Central

    Kojima, Yosuke; Mori, Akira

    2015-01-01

    Many animals sequester dietary defensive compounds and incorporate them into the offspring, which protects the young against predation. One possible but poorly investigated question is whether females of such species actively prey upon toxic diets. The snake Rhabdophis tigrinus sequesters defensive steroids from toads consumed as prey; it also feeds on other amphibians. Females produce chemically armed offspring in direct proportion to their own level of toad-derived toxins by provisioning the toxins to their eggs. Our field observations of movements and stomach contents of radio-tracked R. tigrinus showed that gravid snakes preyed upon toads by actively foraging in the habitat of toads, even though toads were a scarce resource and toad-searching may incur potential costs. Our Y-maze experiments demonstrated that gravid females were more likely to trail the chemical cues of toads than were males or non-gravid females. These results showed behavioural switching in females and active foraging for scarce, toxic prey during gestation. Because exploitation of toads by gravid females results in their offspring being more richly endowed with prey-derived toxins, active foraging for toxic prey is expected to be an adaptive antipredator trait, which may enhance chemical defence in offspring. PMID:25392472

  18. Body size matters for aposematic prey during predator aversion learning.

    PubMed

    Smith, Karen E; Halpin, Christina G; Rowe, Candy

    2014-11-01

    Aposematic prey advertise their toxicity to predators using conspicuous warning signals, which predators learn to use to reduce their intake of toxic prey. Like other types of prey, aposematic prey often differ in body size, both within and between species. Increasing body size can increase signal size, which make larger aposematic prey more detectable but also gives them a more effective and salient deterrent. However, increasing body size also increases the nutritional value of prey, and larger aposematic prey may make a more profitable meal to predators that are trading off the costs of eating toxins with the benefits of ingesting nutrients. We tested if body size, independent of signal size, affected predation of toxic prey as predators learn to reduce their attacks on them. European starlings (Sturnus vulgaris) learned to discriminate between defended (quinine-injected) and undefended (water-injected) mealworm prey (Tenebrio molitor) using visual signals. During this process, we found that birds attacked and ate more defended prey the larger they were. Body size does affect the probability that toxic prey are attacked and eaten, which has implications for the evolutionary dynamics of aposematism and mimicry (where species share the same warning pattern). PMID:25256160

  19. Intense or Spatially Heterogeneous Predation Can Select against Prey Dispersal

    PubMed Central

    Barraquand, Frederic; Murrell, David J.

    2012-01-01

    Dispersal theory generally predicts kin competition, inbreeding, and temporal variation in habitat quality should select for dispersal, whereas spatial variation in habitat quality should select against dispersal. The effect of predation on the evolution of dispersal is currently not well-known: because predation can be variable in both space and time, it is not clear whether or when predation will promote dispersal within prey. Moreover, the evolution of prey dispersal affects strongly the encounter rate of predator and prey individuals, which greatly determines the ecological dynamics, and in turn changes the selection pressures for prey dispersal, in an eco-evolutionary feedback loop. When taken all together the effect of predation on prey dispersal is rather difficult to predict. We analyze a spatially explicit, individual-based predator-prey model and its mathematical approximation to investigate the evolution of prey dispersal. Competition and predation depend on local, rather than landscape-scale densities, and the spatial pattern of predation corresponds well to that of predators using restricted home ranges (e.g. central-place foragers). Analyses show the balance between the level of competition and predation pressure an individual is expected to experience determines whether prey should disperse or stay close to their parents and siblings, and more predation selects for less prey dispersal. Predators with smaller home ranges also select for less prey dispersal; more prey dispersal is favoured if predators have large home ranges, are very mobile, and/or are evenly distributed across the landscape. PMID:22247764

  20. Modelled three-dimensional suction accuracy predicts prey capture success in three species of centrarchid fishes

    PubMed Central

    Kane, Emily A.; Higham, Timothy E.

    2014-01-01

    Prey capture is critical for survival, and differences in correctly positioning and timing a strike (accuracy) are likely related to variation in capture success. However, an ability to quantify accuracy under natural conditions, particularly for fishes, is lacking. We developed a predictive model of suction hydrodynamics and applied it to natural behaviours using three-dimensional kinematics of three centrarchid fishes capturing evasive and non-evasive prey. A spheroid ingested volume of water (IVW) with dimensions predicted by peak gape and ram speed was verified with known hydrodynamics for two species. Differences in capture success occurred primarily with evasive prey (64–96% success). Micropterus salmoides had the greatest ram and gape when capturing evasive prey, resulting in the largest and most elongate IVW. Accuracy predicted capture success, although other factors may also be important. The lower accuracy previously observed in M. salmoides was not replicated, but this is likely due to more natural conditions in our study. Additionally, we discuss the role of modulation and integrated behaviours in shaping the IVW and determining accuracy. With our model, accuracy is a more accessible performance measure for suction-feeding fishes, which can be used to explore macroevolutionary patterns of prey capture evolution. PMID:24718455

  1. Morphology does not predict performance: jaw curvature and prey crushing in durophagous stingrays.

    PubMed

    Kolmann, Matthew A; Crofts, Stephanie B; Dean, Mason N; Summers, Adam P; Lovejoy, Nathan R

    2015-12-01

    All stingrays in the family Myliobatidae are durophagous, consuming bivalves and gastropods, as well as decapod crustaceans. Durophagous rays have rigid jaws, flat teeth that interlock to form pavement-like tooth plates, and large muscles that generate bite forces capable of fracturing stiff biological composites (e.g. mollusk shell). The relative proportion of different prey types in the diet of durophagous rays varies between genera, with some stingray species specializing on particular mollusk taxa, while others are generalists. The tooth plate module provides a curved occlusal surface on which prey is crushed, and this curvature differs significantly among myliobatids. We measured the effect of jaw curvature on prey-crushing success in durophagous stingrays. We milled aluminum replica jaws rendered from computed tomography scans, and crushed live mollusks, three-dimensionally printed gastropod shells, and ceramic tubes with these fabricated jaws. Our analysis of prey items indicate that gastropods were consistently more difficult to crush than bivalves (i.e. were stiffer), but that mussels require the greatest work-to-fracture. We found that replica shells can provide an important proxy for investigations of failure mechanics. We also found little difference in crushing performance between jaw shapes, suggesting that disparate jaws are equally suited for processing different types of shelled prey. Thus, durophagous stingrays exhibit a many-to-one mapping of jaw morphology to mollusk crushing performance. PMID:26567348

  2. Coevolution of venom function and venom resistance in a rattlesnake predator and its squirrel prey.

    PubMed

    Holding, Matthew L; Biardi, James E; Gibbs, H Lisle

    2016-04-27

    Measuring local adaptation can provide insights into how coevolution occurs between predators and prey. Specifically, theory predicts that local adaptation in functionally matched traits of predators and prey will not be detected when coevolution is governed by escalating arms races, whereas it will be present when coevolution occurs through an alternate mechanism of phenotype matching. Here, we analyse local adaptation in venom activity and prey resistance across 12 populations of Northern Pacific rattlesnakes and California ground squirrels, an interaction that has often been described as an arms race. Assays of venom function and squirrel resistance show substantial geographical variation (influenced by site elevation) in both venom metalloproteinase activity and resistance factor effectiveness. We demonstrate local adaptation in the effectiveness of rattlesnake venom to overcoming present squirrel resistance, suggesting that phenotype matching plays a role in the coevolution of these molecular traits. Further, the predator was the locally adapted antagonist in this interaction, arguing that rattlesnakes are evolutionarily ahead of their squirrel prey. Phenotype matching needs to be considered as an important mechanism influencing coevolution between venomous animals and resistant prey. PMID:27122552

  3. Thermal acclimation of interactions: differential responses to temperature change alter predator–prey relationship

    PubMed Central

    Grigaltchik, Veronica S.; Ward, Ashley J. W.; Seebacher, Frank

    2012-01-01

    Different species respond differently to environmental change so that species interactions cannot be predicted from single-species performance curves. We tested the hypothesis that interspecific difference in the capacity for thermal acclimation modulates predator–prey interactions. Acclimation of locomotor performance in a predator (Australian bass, Macquaria novemaculeata) was qualitatively different to that of its prey (eastern mosquitofish, Gambusia holbrooki). Warm (25°C) acclimated bass made more attacks than cold (15°C) acclimated fish regardless of acute test temperatures (10–30°C), and greater frequency of attacks was associated with increased prey capture success. However, the number of attacks declined at the highest test temperature (30°C). Interestingly, escape speeds of mosquitofish during predation trials were greater than burst speeds measured in a swimming arena, whereas attack speeds of bass were lower than burst speeds. As a result, escape speeds of mosquitofish were greater at warm temperatures (25°C and 30°C) than attack speeds of bass. The decline in the number of attacks and the increase in escape speed of prey means that predation pressure decreases at high temperatures. We show that differential thermal responses affect species interactions even at temperatures that are within thermal tolerance ranges. This thermal sensitivity of predator–prey interactions can be a mechanism by which global warming affects ecological communities. PMID:22859598

  4. Estimating mercury exposure of piscivorous birds and sport fish using prey fish monitoring

    USGS Publications Warehouse

    Ackerman, Joshua T.; Hartman, C. Alex; Eagles-Smith, Collin A.; Herzog, Mark P.; Davis, Jay; Ichikawa, Gary; Bonnema, Autumn

    2015-01-01

    Methylmercury is a global pollutant of aquatic ecosystems, and monitoring programs need tools to predict mercury exposure of wildlife. We developed equations to estimate methylmercury exposure of piscivorous birds and sport fish using mercury concentrations in prey fish. We collected original data on western grebes (Aechmophorus occidentalis) and Clark’s grebes (Aechmophorus clarkii) and summarized the published literature to generate predictive equations specific to grebes and a general equation for piscivorous birds. We measured mercury concentrations in 354 grebes (blood averaged 1.06 ± 0.08 μg/g ww), 101 grebe eggs, 230 sport fish (predominantly largemouth bass and rainbow trout), and 505 prey fish (14 species) at 25 lakes throughout California. Mercury concentrations in grebe blood, grebe eggs, and sport fish were strongly related to mercury concentrations in prey fish among lakes. Each 1.0 μg/g dw (∼0.24 μg/g ww) increase in prey fish resulted in an increase in mercury concentrations of 103% in grebe blood, 92% in grebe eggs, and 116% in sport fish. We also found strong correlations between mercury concentrations in grebes and sport fish among lakes. Our results indicate that prey fish monitoring can be used to estimate mercury exposure of piscivorous birds and sport fish when wildlife cannot be directly sampled.

  5. Estimating Mercury Exposure of Piscivorous Birds and Sport Fish Using Prey Fish Monitoring.

    PubMed

    Ackerman, Joshua T; Hartman, C Alex; Eagles-Smith, Collin A; Herzog, Mark P; Davis, Jay; Ichikawa, Gary; Bonnema, Autumn

    2015-11-17

    Methylmercury is a global pollutant of aquatic ecosystems, and monitoring programs need tools to predict mercury exposure of wildlife. We developed equations to estimate methylmercury exposure of piscivorous birds and sport fish using mercury concentrations in prey fish. We collected original data on western grebes (Aechmophorus occidentalis) and Clark's grebes (Aechmophorus clarkii) and summarized the published literature to generate predictive equations specific to grebes and a general equation for piscivorous birds. We measured mercury concentrations in 354 grebes (blood averaged 1.06 ± 0.08 μg/g ww), 101 grebe eggs, 230 sport fish (predominantly largemouth bass and rainbow trout), and 505 prey fish (14 species) at 25 lakes throughout California. Mercury concentrations in grebe blood, grebe eggs, and sport fish were strongly related to mercury concentrations in prey fish among lakes. Each 1.0 μg/g dw (∼0.24 μg/g ww) increase in prey fish resulted in an increase in mercury concentrations of 103% in grebe blood, 92% in grebe eggs, and 116% in sport fish. We also found strong correlations between mercury concentrations in grebes and sport fish among lakes. Our results indicate that prey fish monitoring can be used to estimate mercury exposure of piscivorous birds and sport fish when wildlife cannot be directly sampled. PMID:26449260

  6. Influence of prey type on nickel and thallium assimilation, subcellular distribution and effects in juvenile fathead minnows (Pimephales promelas).

    PubMed

    Lapointe, Dominique; Gentès, Sophie; Ponton, Dominic E; Hare, Landis; Couture, Patrice

    2009-11-15

    Because fish take up metals from prey, it is important to measure factors controlling metal transfer between these trophic levels so as to explain metal bioaccumulation and effects in fish. To achieve this, we exposed two types of invertebrates, an oligochaete (Tubifex tubifex) and a crustacean (Daphnia magna), to environmentally relevant concentrations of two important contaminants, nickel (Ni) and thallium (Tl), and fed these prey to juvenile fathead minnows (Pimephales promelas). We then measured the assimilation efficiency (AE), subcellular distribution and effects of these metals in fish. Fish assimilated dietary Tl more efficiently from D. magna than from T. tubifex, and more efficiently than Ni, regardless of prey type. However, the proportion of metal bound to prey subcellular fractions that are likely to be trophically available (TAM) had no significant influence on the efficiency with which fish assimilated Ni or Tl. In fish, the majority of their Ni and Tl was bound to subcellular fractions that are purportedly detoxified, and prey type had a significant influence on the proportion of detoxified Ni and Tl in fish. We measured higher activities of cytochrome C oxidase and glutathione S-transferase in fish fed D. magna compared to fish fed T. tubifex, regardless of the presence or absence of Ni or Tl in prey. However, we measured decreased activities of glutathione S-transferase and nucleoside diphosphate kinase in fish fed Tl-contaminated D. magna compared to fish from the three other treatment levels. PMID:20028068

  7. Mechanical performance of spider orb webs is tuned for high-speed prey.

    PubMed

    Sensenig, Andrew T; Kelly, Sean P; Lorentz, Kimberly A; Lesher, Brittany; Blackledge, Todd A

    2013-09-15

    Spiders in the Orbiculariae spin orb webs that dissipate the mechanical energy of their flying prey, bringing the insects to rest and retaining them long enough for the spider to attack and subdue their meals. Small prey are easily stopped by webs but provide little energetic gain. While larger prey offer substantial nourishment, they are also challenging to capture and can damage the web if they escape. We therefore hypothesized that spider orb webs exhibit properties that improve their probability of stopping larger insects while minimizing damage when the mechanical energy of those prey exceeds the web's capacity. Large insects are typically both heavier and faster flying than smaller prey, but speed plays a disproportionate role in determining total kinetic energy, so we predicted that orb webs may dissipate energy more effectively under faster impacts, independent of kinetic energy per se. We used high-speed video to visualize the impact of wooden pellets fired into orb webs to simulate prey strikes and tested how capture probability varied as a function of pellet size and speed. Capture probability was virtually nil above speeds of ~3 m s(-1). However, successful captures do not directly measure the maximum possible energy dissipation by orb webs because these events include lower-energy impacts that may not significantly challenge orb web performance. Therefore, we also compared the total kinetic energy removed from projectiles that escaped orb webs by breaking through the silk, asking whether more energy was removed at faster speeds. Over a range of speeds relevant to insect flight, the amount of energy absorbed by orb webs increases with the speed of prey (i.e. the rates at which webs are stretched). Orb webs therefore respond to faster - and hence higher kinetic energy - prey with better performance, suggesting adaptation to capture larger and faster flying insect prey. This speed-dependent toughness of a complex structure suggests the utility of the

  8. Net trophic transfer efficiency of PCBs to Lake Michigan coho salmon from their prey

    USGS Publications Warehouse

    Madenjian, Charles P.; Elliott, Robert F.; Schmidt, Larry J.; DeSorcie, Timothy J.; Hesselberg, Robert J.; Quintal, Richard T.; Begnoche, Linda J.; Bouchard, Patrick M.; Holey, Mark E.

    1998-01-01

    Most of the polychlorinated biphenyl (PCB) body burden accumulated by coho salmon (Oncorhynchus kisutch) from the Laurentian Great Lakes is from their food. We used diet information, PCB determinations in both coho salmon and their prey, and bioenergetics modeling to estimate the efficiency with which Lake Michigan coho salmon retain PCBs from their food. Our estimate was the most reliable estimate to date because (a) the coho salmon and prey fish sampled during our study were sampled in spring, summer, and fall from various locations throughout the lake, (b) detailed measurements were made on the PCB concentrations of both coho salmon and prey fish over wide ranges in fish size, and (c) coho salmon diet was analyzed in detail from April through November over a wide range of salmon size from numerous locations throughout the lake. We estimated that coho salmon from Lake Michigan retain 50% of the PCBs that are contained within their food.

  9. Infomechanical specializations for prey capture in knifefish

    NASA Astrophysics Data System (ADS)

    Maciver, Malcolm; Patankar, Neelesh; Curet, Oscar; Shirgaonkar, Anup

    2007-11-01

    How does an animal's mechanics and its information acquisition system work together to solve crucial behavioral tasks? We examine this question for the black ghost weakly electric knifefish (Apteronotus albifrons), which is a leading model system for the study of sensory processing in vertebrates. These animals hunt at night by detecting perturbations of a self-generated electric field caused by prey. While the fish searches for prey, it pitches at 30 . Fully resolved Navier-Stokes simulations of their swimming, which occurs through undulations of a long ribbon-like fin along the bottom edge of the body, indicates that this configuration enables maximal thrust while minimizing pitch moment. However, pitching the body also increases drag. Our analysis of the sensory volume for detection of prey shows this volume to be similar to a cylinder around the body. Thus, pitching the body enables a greater swept volume of scanned fluid. Examining the mechanical and information acquisition demands on the animal in this task gives insight into how these sometimes conflicting demands are resolved.

  10. Increased predation of nutrient-enriched aposematic prey.

    PubMed

    Halpin, Christina G; Skelhorn, John; Rowe, Candy

    2014-04-22

    Avian predators readily learn to associate the warning coloration of aposematic prey with the toxic effects of ingesting them, but they do not necessarily exclude aposematic prey from their diets. By eating aposematic prey 'educated' predators are thought to be trading-off the benefits of gaining nutrients with the costs of eating toxins. However, while we know that the toxin content of aposematic prey affects the foraging decisions made by avian predators, the extent to which the nutritional content of toxic prey affects predators' decisions to eat them remains to be tested. Here, we show that European starlings (Sturnus vulgaris) increase their intake of a toxic prey type when the nutritional content is artificially increased, and decrease their intake when nutritional enrichment is ceased. This clearly demonstrates that birds can detect the nutritional content of toxic prey by post-ingestive feedback, and use this information in their foraging decisions, raising new perspectives on the evolution of prey defences. Nutritional differences between individuals could result in equally toxic prey being unequally predated, and might explain why some species undergo ontogenetic shifts in defence strategies. Furthermore, the nutritional value of prey will likely have a significant impact on the evolutionary dynamics of mimicry systems. PMID:24598424