1
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Redpath SHA, Marks NJ, Menzies FD, O'Hagan MJH, Wilson RP, Smith S, Magowan EA, McClune DW, Collins SF, McCormick CM, Scantlebury DM. Impact of test, vaccinate or remove protocol on home ranges and nightly movements of badgers a medium density population. Sci Rep 2023; 13:2592. [PMID: 36788237 PMCID: PMC9929337 DOI: 10.1038/s41598-023-28620-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/20/2023] [Indexed: 02/16/2023] Open
Abstract
In the British Isles, the European badger (Meles meles) is thought to be the primary wildlife reservoir of bovine tuberculosis (bTB), an endemic disease in cattle. Test, vaccinate or remove ('TVR') of bTB test-positive badgers, has been suggested to be a potentially useful protocol to reduce bTB incidence in cattle. However, the practice of removing or culling badgers is controversial both for ethical reasons and because there is no consistent observed effect on bTB levels in cattle. While removing badgers reduces population density, it may also result in disruption of their social behaviour, increase their ranging, and lead to greater intra- and inter-species bTB transmission. This effect has been recorded in high badger density areas, such as in southwest England. However, little is known about how TVR affects the behaviour and movement of badgers within a medium density population, such as those that occur in Northern Ireland (NI), which the current study aimed to examine. During 2014-2017, badger ranging behaviours were examined prior to and during a TVR protocol in NI. Nightly distances travelled by 38 individuals were determined using Global Positioning System (GPS) measurements of animal tracks and GPS-enhanced dead-reckoned tracks. The latter was calculated using GPS, tri-axial accelerometer and tri-axial magnetometer data loggers attached to animals. Home range and core home range size were measured using 95% and 50% autocorrelated kernel density estimates, respectively, based on location fixes. TVR was not associated with measured increases in either distances travelled per night (mean = 3.31 ± 2.64 km) or home range size (95% mean = 1.56 ± 0.62 km2, 50% mean = 0.39 ± 0.62 km2) over the four years of study. However, following trapping, mean distances travelled per night increased by up to 44% eight days post capture. Findings differ from those observed in higher density badger populations in England, in which badger ranging increased following culling. Whilst we did not assess behaviours of individual badgers, possible reasons why no differences in home range size were observed include higher inherent 'social fluidity' in Irish populations whereby movements are less restricted by habitat saturation and/or that the numbers removed did not reach a threshold that might induce increases in ranging behaviour. Nevertheless, short-term behavioural disruption from trapping was observed, which led to significant increases in the movements of individual animals within their home range. Whether or not TVR may alter badger behaviours remains to be seen, but it would be better to utilise solutions such as oral vaccination of badgers and/or cattle as well as increased biosecurity to limit bTB transmission, which may be less likely to cause interference and thereby reduce the likelihood of bTB transmission.
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Affiliation(s)
- Sophie H A Redpath
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, BT4 3SD, Northern Ireland
| | - Nikki J Marks
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland
| | - Fraser D Menzies
- Department of Agriculture, Environment and Rural Affairs, Veterinary Epidemiology Unit, Belfast, BT4 3SB, Northern Ireland
| | - Maria J H O'Hagan
- Department of Agriculture, Environment and Rural Affairs, Veterinary Epidemiology Unit, Belfast, BT4 3SB, Northern Ireland
| | - Rory P Wilson
- Department of Biological Sciences, Swansea University, Singleton Park, Swansea, SA2 8PP, Wales
| | - Sinéad Smith
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland
| | - Elizabeth A Magowan
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland
| | - David W McClune
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland
| | - Shane F Collins
- Department of Agriculture, Environment and Rural Affairs, Veterinary Epidemiology Unit, Belfast, BT4 3SB, Northern Ireland
| | - Carl M McCormick
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Belfast, BT4 3SD, Northern Ireland
| | - D Michael Scantlebury
- School of Biological Sciences, Queens' University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, Northern Ireland.
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2
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Fokidis HB, Brock T, Newman C, Macdonald DW, Buesching CD. Assessing chronic stress in wild mammals using claw-derived cortisol: a validation using European badgers ( Meles meles). CONSERVATION PHYSIOLOGY 2023; 11:coad024. [PMID: 37179707 PMCID: PMC10171820 DOI: 10.1093/conphys/coad024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 01/26/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Measuring stress experienced by wild mammals is increasingly important in the context of human-induced rapid environmental change and initiatives to mitigate human-wildlife conflicts. Glucocorticoids (GC), such as cortisol, mediate responses by promoting physiological adjustments during environmental perturbations. Measuring cortisol is a popular technique; however, this often reveals only recent short-term stress such as that incurred by restraining the animal to sample blood, corrupting the veracity of this approach. Here we present a protocol using claw cortisol, compared with hair cortisol, as a long-term stress bio-indicator, which circumvents this constraint, where claw tissue archives the individual's GC concentration over preceding weeks. We then correlate our findings against detailed knowledge of European badger life history stressors. Based on a solid-phase extraction method, we assessed how claw cortisol concentrations related to season and badger sex, age and body-condition using a combination of generalized linear mixed models (GLMM) (n = 668 samples from 273 unique individuals) followed by finer scale mixed models for repeated measures (MMRM) (n = 152 re-captured individuals). Claw and hair cortisol assays achieved high accuracy, precision and repeatability, with similar sensitivity. The top GLMM model for claw cortisol included age, sex, season and the sex*season interaction. Overall, claw cortisol levels were significantly higher among males than females, but strongly influenced by season, where females had higher levels than males in autumn. The top fine scale MMRM model included sex, age and body condition, with claw cortisol significantly higher in males, older and thinner individuals. Hair cortisol was more variable than claw; nevertheless, there was a positive correlation after removing 34 outliers. We discuss strong support for these stress-related claw cortisol patterns from previous studies of badger biology. Given the potential of this technique, we conclude that it has broad application in conservation biology.
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Affiliation(s)
- H Bobby Fokidis
- Corresponding author: Department of Biology, Rollins College, Winter Park, Florida, USA.
| | - Taylor Brock
- Department of Biology, Rollins College, 1000 Holt Avenue, Winter Park, Florida, 32789-4499, USA
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - Christina D Buesching
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan campus, 3187 University Way, Kelowna, British Columbia, V1V1V7, Canada
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3
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van Lieshout SHJ, Badás EP, Bright Ross JG, Bretman A, Newman C, Buesching CD, Burke T, Macdonald DW, Dugdale HL. Early-life seasonal, weather and social effects on telomere length in a wild mammal. Mol Ecol 2022; 31:5993-6007. [PMID: 34101279 DOI: 10.1111/mec.16014] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/03/2021] [Indexed: 01/31/2023]
Abstract
Early-life environmental conditions can provide a source of individual variation in life-history strategies and senescence patterns. Conditions experienced in early life can be quantified by measuring telomere length, which can act as a biomarker of survival probability in some species. Here, we investigate whether seasonal changes, weather conditions and group size are associated with early-life and/or early-adulthood telomere length in a wild population of European badgers (Meles meles). We found substantial intra-annual changes in telomere length during the first 3 years of life, where within-individual effects showed shorter telomere lengths in the winter following the first spring and a trend for longer telomere lengths in the second spring compared to the first winter. In terms of weather conditions, cubs born in warmer, wetter springs with low rainfall variability had longer early-life (3-12 months old) telomeres. Additionally, cubs born in groups with more cubs had marginally longer early-life telomeres, providing no evidence of resource constraint from cub competition. We also found that the positive association between early-life telomere length and cub survival probability remained when social and weather variables were included. Finally, after sexual maturity, in early adulthood (i.e., 12-36 months) we found no significant association between same-sex adult group size and telomere length (i.e., no effect of intrasexual competition). Overall, we show that controlling for seasonal effects, which are linked to food availability, is important in telomere length analyses, and that variation in telomere length in badgers reflects early-life conditions and also predicts first year cub survival.
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Affiliation(s)
- Sil H J van Lieshout
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,NERC Environmental Omics Visitor Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Elisa P Badás
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Julius G Bright Ross
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Amanda Bretman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Christina D Buesching
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK.,Department of Biology, The University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
| | - Terry Burke
- NERC Environmental Omics Visitor Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Hannah L Dugdale
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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4
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Theodorou C, Velisavljevic V, Dyo V, Nonyelu F. Visual SLAM algorithms and their application for AR, mapping, localization and wayfinding. ARRAY 2022. [DOI: 10.1016/j.array.2022.100222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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5
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Noonan MJ, Martinez‐Garcia R, Davis GH, Crofoot MC, Kays R, Hirsch BT, Caillaud D, Payne E, Sih A, Sinn DL, Spiegel O, Fagan WF, Fleming CH, Calabrese JM. Estimating encounter location distributions from animal tracking data. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13597] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Michael J. Noonan
- Department of Biology, The Irving K. Barber Faculty of Science The University of British Columbia Kelowna BC Canada
- Smithsonian Conservation Biology InstituteNational Zoological Park Front Royal VA USA
| | - Ricardo Martinez‐Garcia
- ICTP South American Institute for Fundamental Research & Instituto de Fisica Teorica – UNESP Sao Paulo Brazil
| | - Grace H. Davis
- Department of Anthropology University of California Davis CA USA
- Smithsonian Tropical Research Institute Panama City Panama
- Department for the Ecology of Animal Societies Max Planck Institute of Animal Behavior Konstanz Germany
- Department of Biology University of Konstanz Konstanz Germany
- Centre for the Advanced Study of Collective Behaviour University of Konstanz Konstanz Germany
| | - Margaret C. Crofoot
- Department of Anthropology University of California Davis CA USA
- Smithsonian Tropical Research Institute Panama City Panama
- Department for the Ecology of Animal Societies Max Planck Institute of Animal Behavior Konstanz Germany
- Department of Biology University of Konstanz Konstanz Germany
- Centre for the Advanced Study of Collective Behaviour University of Konstanz Konstanz Germany
| | - Roland Kays
- North Carolina Museum of Natural Sciences and North Carolina State University Raleigh NC USA
| | - Ben T. Hirsch
- Smithsonian Tropical Research Institute Panama City Panama
- College of Science and Engineering James Cook University Townsville Qld Australia
| | - Damien Caillaud
- Department of Anthropology University of California Davis CA USA
| | - Eric Payne
- Department of Environmental Science and Policy University of California Davis Davis CA USA
| | - Andrew Sih
- Department of Environmental Science and Policy University of California Davis Davis CA USA
| | - David L. Sinn
- Department of Environmental Science and Policy University of California Davis Davis CA USA
| | - Orr Spiegel
- School of Zoology Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - William F. Fagan
- Department of Biology University of Maryland College Park MD USA
| | - Christen H. Fleming
- Smithsonian Conservation Biology InstituteNational Zoological Park Front Royal VA USA
- Department of Biology University of Maryland College Park MD USA
| | - Justin M. Calabrese
- Smithsonian Conservation Biology InstituteNational Zoological Park Front Royal VA USA
- Department of Biology University of Maryland College Park MD USA
- Center for Advanced Systems Understanding (CASUS) Görlitz Germany
- Helmholtz‐Zentrum Dresden Rossendorf (HZDR) Dresden Germany
- Department of Ecological Modelling Helmholtz Centre for Environmental Research (UFZ) Leipzig Germany
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6
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Mbizah MM, Farine DR, Valeix M, Hunt JE, Macdonald DW, Loveridge AJ. Effect of ecological factors on fine-scale patterns of social structure in African lions. J Anim Ecol 2020; 89:2665-2676. [PMID: 32895921 DOI: 10.1111/1365-2656.13334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/07/2020] [Indexed: 01/21/2023]
Abstract
Environmental variations can influence the extent to which individuals interact with other individuals by changing the value of grouping. It is well known that many species can form and disband groups, often in response to the distribution and abundance of resources. While previous studies showed that resources influence the broad-scale structure of animal groups, knowledge gaps remain on whether they affect fine-scale patterns of association among individuals within groups. We quantify association patterns in African lions while simultaneously monitoring the abundance and distribution of prey. We test how social and ecological factors, including individual trait (age, sex, reproductive state) similarity and prey availability (prey abundance, dispersion, herd size and body size) affect within-pride social structure in African lions. We found that individual decisions about associates depended on resource availability with individuals associating equally across all members of the pride when prey herds were scarce, aggregated or large bodied, and associating more exclusively (in subgroups of preferred associates) when prey herds were abundant, dispersed or small bodied. Individuals within lion prides seemed to be buffering against changes in prey availability by modulating their strength and density of connections with conspecifics when prides split into subgroups. The strength and density of connections among individuals within subgroups was greater when prey herds were large and lower when prey herds were dispersed or are large bodied. Our findings suggest that individual lions are making social decisions at both the subgroup level and the pride level, with decisions representing putatively fitness-enhancing strategies. Individuals were typically shifting between having few strong connections and having many weaker connections depending on prevailing ecological conditions, with prey abundance, dispersion and body size having the greatest impact on decisions about splitting into subgroups. The maintenance of connections within prides and subgroups in the face of ecological change suggests that the fission-fusion nature of lion prides might be essential for the long-term maintenance of social connections even when short-term conditions do not allow them. More broadly, our study reveals how fission-fusion dynamics and ecological factors can simultaneously have an effect on animals across multiple levels of sociality.
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Affiliation(s)
- Moreangels M Mbizah
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - Damien R Farine
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.,Department of Biology, University of Konstanz, Konstanz, Germany.,Edward Grey Institute, Department of Zoology, University of Oxford, Oxford, UK
| | - Marion Valeix
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK.,Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, CNRS, Université de Lyon, Université Lyon 1, Villeurbanne, France.,LTSER France, Zone Atelier "Hwange", CNRS HERD (Hwange Environmental Research Development) Program, Dete, Zimbabwe
| | - Jane E Hunt
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
| | - Andrew J Loveridge
- Wildlife Conservation Research Unit (WildCRU), Department of Zoology, Recanati-Kaplan Centre, University of Oxford, Oxford, Oxford, UK
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7
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Extra Territorial Excursions by European badgers are not limited by age, sex or season. Sci Rep 2020; 10:9665. [PMID: 32541685 PMCID: PMC7296015 DOI: 10.1038/s41598-020-66809-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 05/27/2020] [Indexed: 11/09/2022] Open
Abstract
European badgers (Meles meles) in medium and high density populations show strong territorial behaviour. Territories in these populations are contiguous, well-marked and often unchanging over many years. However, badgers do not always stay within their territorial boundaries. In our medium-density population, most individual badgers made extra-territorial excursions (ETEs) throughout the year. ETEs were most frequent between April and September and least frequent in December and January (the period of winter lethargy). Male badgers made longer and more frequent ETEs than females (especially between January and March, and in autumn). Breeding females made longer and more frequent ETEs than non-breeding females in November. While these peaks correspond with the main mating seasons, mating activity does not explain ETEs throughout the year. The shorter, but more frequent, ETEs in summer months may serve a monitoring purpose, rather than simply providing additional mating opportunities with badgers from outside the 'home' social group. We found that young badgers did not make regular ETEs until the summer of their second year. If badgers could be vaccinated as cubs, this would reduce any potential risk of TB spread during ETEs.
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8
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Lieshout SHJ, Bretman A, Newman C, Buesching CD, Macdonald DW, Dugdale HL. Individual variation in early‐life telomere length and survival in a wild mammal. Mol Ecol 2019; 28:4152-4165. [DOI: 10.1111/mec.15212] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 07/12/2019] [Accepted: 07/23/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Sil H. J. Lieshout
- School of Biology Faculty of Biological Sciences University of Leeds Leeds UK
- NERC Biomolecular Analysis Facility Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| | - Amanda Bretman
- School of Biology Faculty of Biological Sciences University of Leeds Leeds UK
| | - Chris Newman
- Wildlife Conservation Research Unit Department of Zoology University of Oxford Abingdon UK
| | - Christina D. Buesching
- Wildlife Conservation Research Unit Department of Zoology University of Oxford Abingdon UK
| | - David W. Macdonald
- Wildlife Conservation Research Unit Department of Zoology University of Oxford Abingdon UK
| | - Hannah L. Dugdale
- School of Biology Faculty of Biological Sciences University of Leeds Leeds UK
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9
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Smith JE, Gamboa DA, Spencer JM, Travenick SJ, Ortiz CA, Hunter RD, Sih A. Split between two worlds: automated sensing reveals links between above- and belowground social networks in a free-living mammal. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0249. [PMID: 29967307 DOI: 10.1098/rstb.2017.0249] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2018] [Indexed: 11/12/2022] Open
Abstract
Many animals socialize in two or more major ecological contexts. In nature, these contexts often involve one situation in which space is more constrained (e.g. shared refuges, sleeping cliffs, nests, dens or burrows) and another situation in which animal movements are relatively free (e.g. in open spaces lacking architectural constraints). Although it is widely recognized that an individual's characteristics may shape its social life, the extent to which architecture constrains social decisions within and between habitats remains poorly understood. Here we developed a novel, automated-monitoring system to study the effects of personality, life-history stage and sex on the social network structure of a facultatively social mammal, the California ground squirrel (Otospermophilus beecheyi) in two distinct contexts: aboveground where space is relatively open and belowground where it is relatively constrained by burrow architecture. Aboveground networks reflected affiliative social interactions whereas belowground networks reflected burrow associations. Network structure in one context (belowground), along with preferential juvenile-adult associations, predicted structure in a second context (aboveground). Network positions of individuals were generally consistent across years (within contexts) and between ecological contexts (within years), suggesting that individual personalities and behavioural syndromes, respectively, contribute to the social network structure of these free-living mammals. Direct ties (strength) tended to be stronger in belowground networks whereas more indirect paths (betweenness centrality) flowed through individuals in aboveground networks. Belowground, females fostered significantly more indirect paths than did males. Our findings have important potential implications for disease and information transmission, offering new insights into the multiple factors contributing to social structures across ecological contexts.This article is part of the theme issue 'Interdisciplinary approaches for uncovering the impacts of architecture on collective behaviour'.
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Affiliation(s)
- Jennifer E Smith
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Denisse A Gamboa
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Julia M Spencer
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Sarah J Travenick
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Chelsea A Ortiz
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Riana D Hunter
- Biology Department, Mills College, 5000 MacArthur Blvd., Oakland, CA, 94631, USA
| | - Andy Sih
- Department of Environmental Science and Policy, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
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10
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Taff CC, Zimmer C, Vitousek MN. Achromatic plumage brightness predicts stress resilience and social interactions in tree swallows (Tachycineta bicolor). Behav Ecol 2019. [DOI: 10.1093/beheco/arz010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Theory suggests that signal honesty may be maintained by differential costs for high and low quality individuals. For signals that mediate social interactions, costs can arise from the way that a signal changes the subsequent social environment via receiver responses. These receiver-dependent costs may be linked with individual quality through variation in resilience to environmental and social stress. Here, we imposed stressful conditions on female tree swallows (Tachycineta bicolor) by attaching groups of feathers during incubation to decrease flight efficiency and maneuverability. We simultaneously monitored social interactions using an RFID network that allowed us to track the identity of every individual that visited each nest for the entire season. Before treatments, plumage coloration was correlated with baseline and stress-induced corticosterone. Relative to controls, experimentally challenged females were more likely to abandon their nest during incubation. Overall, females with brighter white breasts were less likely to abandon, but this pattern was only significant under stressful conditions. In addition to being more resilient, brighter females received more unique visitors at their nest-box and tended to make more visits to other active nests. In contrast, dorsal coloration did not reliably predict abandonment or social interactions. Taken together, our results suggest that females differ in their resilience to stress and that these differences are signaled by plumage brightness, which is in turn correlated with the frequency of social interactions. While we do not document direct costs of social interaction, our results are consistent with models of signal honesty based on receiver-dependent costs.
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Affiliation(s)
- Conor C Taff
- Corson Hall, Cornell University, Ithaca, NY
- Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | | | - Maren N Vitousek
- Corson Hall, Cornell University, Ithaca, NY
- Lab of Ornithology, Cornell University, Ithaca, NY, USA
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11
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Munir B, Dyo V. On the Impact of Mobility on Battery-Less RF Energy Harvesting System Performance. SENSORS (BASEL, SWITZERLAND) 2018; 18:E3597. [PMID: 30360501 PMCID: PMC6263956 DOI: 10.3390/s18113597] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 11/29/2022]
Abstract
The future of Internet of Things (IoT) envisions billions of sensors integrated with the physical environment. At the same time, recharging and replacing batteries on this infrastructure could result not only in high maintenance costs, but also large amounts of toxic waste due to the need to dispose of old batteries. Recently, battery-free sensor platforms have been developed that use supercapacitors as energy storage, promising maintenance-free and perpetual sensor operation. While prior work focused on supercapacitor characterization, modelling and supercapacitor-aware scheduling, the impact of mobility on capacitor charging and overall sensor application performance has been largely ignored. We show that supercapacitor size is critical for mobile system performance and that selecting an optimal value is not trivial: small capacitors charge quickly and enable the node to operate in low energy environments, but cannot support intensive tasks such as communication or reprogramming; increasing the capacitor size, on the other hand, enables the support for energy-intensive tasks, but may prevent the node from booting at all if the node navigates in a low energy area. The paper investigates this problem and proposes a hybrid storage solution that uses an adaptive learning algorithm to predict the amount of available ambient energy and dynamically switch between two capacitors depending on the environment. The evaluation based on extensive simulations and prototype measurements showed up to 40% and 80% improvement compared to a fixed-capacitor approach in terms of the amount of harvested energy and sensor coverage.
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Affiliation(s)
- Bilal Munir
- Department of Computer Science and Technology, University of Bedfordshire, Luton LU1 3JU, UK.
| | - Vladimir Dyo
- Department of Computer Science and Technology, University of Bedfordshire, Luton LU1 3JU, UK.
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