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Hale KRS, Curlis JD, Auteri GG, Bishop S, French RLK, Jones LE, Mills KL, Scholtens BG, Simons M, Thompson C, Tourville J, Valdovinos FS. A highly resolved network reveals the role of terrestrial herbivory in structuring aboveground food webs. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230180. [PMID: 39034695 PMCID: PMC11293847 DOI: 10.1098/rstb.2023.0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/23/2024] [Accepted: 05/05/2024] [Indexed: 07/23/2024] Open
Abstract
Comparative studies suggest remarkable similarities among food webs across habitats, including systematic changes in their structure with diversity and complexity (scale-dependence). However, historic aboveground terrestrial food webs (ATFWs) have coarsely grouped plants and insects such that these webs are generally small, and herbivory is disproportionately under-represented compared to vertebrate predator-prey interactions. Furthermore, terrestrial herbivory is thought to be structured by unique processes compared to size-structured feeding in other systems. Here, we present the richest ATFW to date, including approximately 580 000 feeding links among approximately 3800 taxonomic species, sourced from approximately 27 000 expert-vetted interaction records annotated as feeding upon one of six different resource types: leaves, flowers, seeds, wood, prey and carrion. By comparison to historical ATFWs and null ecological hypotheses, we show that our temperate forest web displays a potentially unique structure characterized by two properties: (i) a large fraction of carnivory interactions dominated by a small number of hyper-generalist, opportunistic bird and bat predators; and (ii) a smaller fraction of herbivory interactions dominated by a hyper-rich community of insects with variably sized but highly specific diets. We attribute our findings to the large-scale, even resolution of vertebrate, insect and plant guilds in our food web.This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.
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Affiliation(s)
- Kayla R. S. Hale
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - John David Curlis
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Giorgia G. Auteri
- Department of Biology, Missouri State University, Springfield, MO, USA
| | - Sasha Bishop
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Rowan L. K. French
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Lance E. Jones
- Department of Plant Biology, University of Illinois at Urbana-Champaign, UrbanaIL, USA
| | - Kirby L. Mills
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
| | | | - Meagan Simons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Cody Thompson
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
- Museum of Zoology, University of Michigan, Ann Arbor, MI, USA
| | - Jordon Tourville
- Department of Environmental Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY, USA
- Research Department, Appalachian Mountain Club, Boston, MA, USA
| | - Fernanda S. Valdovinos
- Department of Environmental Science and Policy, University of California, Davis, CA, USA
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2
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The role of evolutionary modes for trait-based cascades in mutualistic networks. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2022.109983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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3
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Lewinsohn TM, Almeida Neto M, Almeida A, Prado PI, Jorge LR. From insect-plant interactions to ecological networks. BIOTA NEOTROPICA 2022. [DOI: 10.1590/1676-0611-bn-2022-1399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abstract Since its inception, biodiversity has largely been understood as species diversity and assessed as such. Interactions among species or functional groups are gradually becoming part of an expanded concept of biodiversity. As a case study of the development of a research program in biodiversity, we summarize our multi-decade studies on interactions of Asteraceae and flowerhead-feeding insects in Brazil. Initially, host species were treated as independent replicates in order to assess the local and turnover components of their herbivore diversity. Research then expanded into sampling entire interactive communities of host plants and their associated herbivores in different localities and regions, enabling new research lines to be pursued. Interaction diversity could be assessed and factored into spatial and among-host components, suggesting a new field of interaction geography. Second, host specialization, a key component of interaction diversity, was reframed considering simultaneously relatedness and local availability of plant hosts. Third, with the influence of complex network theory, community-wide species interactions were probed for topological patterns. Having identified the modular structure of these plant-herbivore systems, later we demonstrated that they fit a compound hierarchical topology, in which interactions are nested within large-scale modules. In a brief survey of research funded by Fapesp, especially within the Biota-Fapesp program, we highlight several lines of internationally recognized research on interaction diversity, notably on plant-frugivore and plant-pollinator interactions, together with new theoretical models. The interplay of field studies with new theoretical and analytical approaches has established interaction diversity as an essential component for monitoring, conserving and restoring biodiversity in its broader sense.
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Pedraza F, Bascompte J. The joint role of coevolutionary selection and network structure in shaping trait matching in mutualisms. Proc Biol Sci 2021; 288:20211291. [PMID: 34403630 DOI: 10.1098/rspb.2021.1291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Coevolution can sculpt remarkable trait similarity between mutualistic partners. Yet, it remains unclear which network topologies and selection regimes enhance trait matching. To address this, we simulate coevolution in topologically distinct networks under a gradient of mutualistic selection strength. We describe three main insights. First, trait matching is jointly influenced by the strength of mutualistic selection and the structural properties of the network where coevolution is unfolding. Second, the strength of mutualistic selection determines the network descriptors better correlated with higher trait matching. While network modularity enhances trait matching when coevolution is weak, network connectance does so when coevolution is strong. Third, the structural properties of networks outrank those of modules or species in determining the degree of trait matching. Our findings suggest networks can both enhance or constrain trait matching, depending on the strength of mutualistic selection.
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Affiliation(s)
- Fernando Pedraza
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse, 190, Zurich CH-8057, Switzerland
| | - Jordi Bascompte
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse, 190, Zurich CH-8057, Switzerland
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Yeakel JD, Pires MM, de Aguiar MAM, O'Donnell JL, Guimarães PR, Gravel D, Gross T. Diverse interactions and ecosystem engineering can stabilize community assembly. Nat Commun 2020; 11:3307. [PMID: 32620766 PMCID: PMC7335095 DOI: 10.1038/s41467-020-17164-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 06/11/2020] [Indexed: 12/02/2022] Open
Abstract
The complexity of an ecological community can be distilled into a network, where diverse interactions connect species in a web of dependencies. Species interact directly with each other and indirectly through environmental effects, however to our knowledge the role of these ecosystem engineers has not been considered in ecological network models. Here we explore the dynamics of ecosystem assembly, where species colonization and extinction depends on the constraints imposed by trophic, service, and engineering dependencies. We show that our assembly model reproduces many key features of ecological systems, such as the role of generalists during assembly, realistic maximum trophic levels, and increased nestedness with mutualistic interactions. We find that ecosystem engineering has large and nonlinear effects on extinction rates. While small numbers of engineers reduce stability by increasing primary extinctions, larger numbers of engineers increase stability by reducing primary extinctions and extinction cascade magnitude. Our results suggest that ecological engineers may enhance community diversity while increasing persistence by facilitating colonization and limiting competitive exclusion.
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Affiliation(s)
- Justin D Yeakel
- University of California Merced, 5200 Lake Road, Merced, CA, 95343, USA.
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM, 87501, USA.
| | - Mathias M Pires
- Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz-Barão Geraldo, Campinas, São Paulo, 13083-970, Brazil
| | - Marcus A M de Aguiar
- Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz-Barão Geraldo, Campinas, São Paulo, 13083-970, Brazil
| | | | - Paulo R Guimarães
- Universidade de São Paulo, Cidade Universitária, São Paulo-State of São Paulo, São Paulo, Brazil
| | - Dominique Gravel
- Universitè de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, QC, J1K 2R1, Canada
| | - Thilo Gross
- University of California, Davis, CA, 95616, USA
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstrasse 231, 26129, Oldenburg, Germany
- University of Oldenburg, ICBM, 26129, Oldenburg, Germany
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6
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de Andreazzi CS, Astegiano J, Guimarães PR. Coevolution by different functional mechanisms modulates the structure and dynamics of antagonistic and mutualistic networks. OIKOS 2019. [DOI: 10.1111/oik.06737] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cecilia Siliansky de Andreazzi
- Depto de Ecologia, Univ. de São Paulo (USP), Rua do Matão, 321 – Trav. 14 Cid. Universitária São Paulo CEP 05508‐090 Brazil
- Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Instituto Oswaldo Cruz, FIOCRUZ Rio de Janeiro Brazil
| | - Julia Astegiano
- Depto de Ecologia, Univ. de São Paulo (USP), Rua do Matão, 321 – Trav. 14 Cid. Universitária São Paulo CEP 05508‐090 Brazil
- Grupo de Interacciones Ecológicas y Conservación, Instituto Multidisciplinario de Biología Vegetal (IMBIV), Facultad de Ciencias Exactas, Físicas y Naturales, Univ. Nacional de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas Córdoba Argentina
| | - Paulo R. Guimarães
- Depto de Ecologia, Univ. de São Paulo (USP), Rua do Matão, 321 – Trav. 14 Cid. Universitária São Paulo CEP 05508‐090 Brazil
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7
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Maia KP, Rasmussen C, Olesen JM, Guimarães PR. Does the sociality of pollinators shape the organisation of pollination networks? OIKOS 2019. [DOI: 10.1111/oik.05387] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kate P. Maia
- Inst. de Biociências, Univ. de São Paulo, Rua do Matão, 321 – Trav. 14 Cid. Universitária Sao Paulo São Paulo 05508‐090 Brazil
- School of Biological Sciences, Univ. of Bristol Bristol UK
| | | | | | - Paulo R. Guimarães
- Inst. de Biociências, Univ. de São Paulo, Rua do Matão, 321 – Trav. 14 Cid. Universitária Sao Paulo São Paulo 05508‐090 Brazil
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8
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Cirtwill AR, Roslin T, Rasmussen C, Olesen JM, Stouffer DB. Between-year changes in community composition shape species’ roles in an Arctic plant-pollinator network. OIKOS 2018. [DOI: 10.1111/oik.05074] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Alyssa R. Cirtwill
- Centre for Integrative Ecology, School of Biological Sciences; Univ. of Canterbury; Christchurch New Zealand
- Dept of Physics, Chemistry and Biology (IFM); Linköping Univ.; SE-581 83 Linköping Sweden
| | - Tomas Roslin
- Dept of Ecology; Swedish Univ. of Agricultural Sciences; Uppsala Sweden
- Dept of Agricultural Sciences; University of Helsinki; Helsinki Finland
| | | | | | - Daniel B. Stouffer
- Centre for Integrative Ecology, School of Biological Sciences; Univ. of Canterbury; Christchurch New Zealand
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10
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Ponisio LC, M'Gonigle LK. Coevolution leaves a weak signal on ecological networks. Ecosphere 2017. [DOI: 10.1002/ecs2.1798] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Lauren C. Ponisio
- Department of Environmental Science, Policy, and Management University of California, Berkeley 130 Mulford Hall Berkeley California 94720 USA
- Berkeley Institute for Data Science (BIDS) University of California, Berkeley 190 Doe Library Berkeley California 94720 USA
- Department of Entomology University of California, Riverside 417 Entomology Building Riverside California 92521 USA
| | - Leithen K. M'Gonigle
- Department of Environmental Science, Policy, and Management University of California, Berkeley 130 Mulford Hall Berkeley California 94720 USA
- Department of Biological Science Florida State University Tallahassee Florida 32306 USA
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11
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Lemos-Costa P, Pires MM, Araújo MS, de Aguiar MAM, Guimarães PR. Network analyses support the role of prey preferences in shaping resource use patterns within five animal populations. OIKOS 2016. [DOI: 10.1111/oik.03006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Paula Lemos-Costa
- Programa de Pós-graduação em Ecologia, Inst. de Biocências; Univ. de São Paulo; São Paulo Brasil
- Depto de Física da Matéria Condensada, Inst. de Física “Gleb Wataghin”; Univ. Estadual de Campinas; Campinas Brasil
| | - Mathias M. Pires
- Programa de Pós-graduação em Ecologia, Inst. de Biocências; Univ. de São Paulo; São Paulo Brasil
- Depto de Ecologia, Inst. de Biociências; Univ. de São Paulo; São Paulo Brasil
| | - Márcio S. Araújo
- Depto de Ecologia; Univ. Estadual “Julio de Mesquita Filho”; Rio Claro Brasil
| | - Marcus A. M. de Aguiar
- Depto de Física da Matéria Condensada, Inst. de Física “Gleb Wataghin”; Univ. Estadual de Campinas; Campinas Brasil
| | - Paulo R. Guimarães
- Depto de Ecologia, Inst. de Biociências; Univ. de São Paulo; São Paulo Brasil
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12
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Pires MM, Cantor M, Guimarães PR, de Aguiar MAM, Dos Reis SF, Coltri PP. The network organization of protein interactions in the spliceosome is reproduced by the simple rules of food-web models. Sci Rep 2015; 5:14865. [PMID: 26443080 PMCID: PMC4595644 DOI: 10.1038/srep14865] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 09/09/2015] [Indexed: 12/02/2022] Open
Abstract
The network structure of biological systems provides information on the underlying processes shaping their organization and dynamics. Here we examined the structure of the network depicting protein interactions within the spliceosome, the macromolecular complex responsible for splicing in eukaryotic cells. We show the interactions of less connected spliceosome proteins are nested subsets of the connections of the highly connected proteins. At the same time, the network has a modular structure with groups of proteins sharing similar interaction patterns. We then investigated the role of affinity and specificity in shaping the spliceosome network by adapting a probabilistic model originally designed to reproduce food webs. This food-web model was as successful in reproducing the structure of protein interactions as it is in reproducing interactions among species. The good performance of the model suggests affinity and specificity, partially determined by protein size and the timing of association to the complex, may be determining network structure. Moreover, because network models allow building ensembles of realistic networks while encompassing uncertainty they can be useful to examine the dynamics and vulnerability of intracelullar processes. Unraveling the mechanisms organizing the spliceosome interactions is important to characterize the role of individual proteins on splicing catalysis and regulation.
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Affiliation(s)
- Mathias M Pires
- Departamento de Ecologia, Instituto de Biociências, 05508-090, Universidade de São Paulo, São Paulo, Brazil
| | - Maurício Cantor
- Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada
| | - Paulo R Guimarães
- Departamento de Ecologia, Instituto de Biociências, 05508-090, Universidade de São Paulo, São Paulo, Brazil
| | - Marcus A M de Aguiar
- Departamento de Física da Matéria Condensada, Instituto de Física 'Gleb Wataghin', 13083-859, Universidade Estadual de Campinas, Campinas, Brazil
| | - Sérgio F Dos Reis
- Departamento de Biologia Animal, Instituto de Biologia, 13083-970, Universidade Estadual de Campinas, Campinas, Brazil
| | - Patricia P Coltri
- Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, 05508-000, Universidade de São Paulo, São Paulo, Brazil
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13
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Rohr RP, Bascompte J. Components of Phylogenetic Signal in Antagonistic and Mutualistic Networks. Am Nat 2014; 184:556-64. [DOI: 10.1086/678234] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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14
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Takemoto K, Yoshitake I. Limited influence of oxygen on the evolution of chemical diversity in metabolic networks. Metabolites 2013; 3:979-92. [PMID: 24958261 PMCID: PMC3937826 DOI: 10.3390/metabo3040979] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 12/04/2022] Open
Abstract
Oxygen is thought to promote species and biomolecule diversity. Previous studies have suggested that oxygen expands metabolic networks by acquiring metabolites with different chemical properties (higher hydrophobicity, for example). However, such conclusions are typically based on biased evaluation, and are therefore non-conclusive. Thus, we re-investigated the effect of oxygen on metabolic evolution using a phylogenetic comparative method and metadata analysis to reduce the bias as much as possible. Notably, we found no difference in metabolic network expansion between aerobes and anaerobes when evaluating phylogenetic relationships. Furthermore, we showed that previous studies have overestimated or underestimated the degrees of differences in the chemical properties (e.g., hydrophobicity) between oxic and anoxic metabolites in metabolic networks of unicellular organisms; however, such overestimation was not observed when considering the metabolic networks of multicellular organisms. These findings indicate that the contribution of oxygen to increased chemical diversity in metabolic networks is lower than previously thought; rather, phylogenetic signals and cell-cell communication result in increased chemical diversity. However, this conclusion does not contradict the effect of oxygen on metabolic evolution; instead, it provides a deeper understanding of how oxygen contributes to metabolic evolution despite several limitations in data analysis methods.
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Affiliation(s)
- Kazuhiro Takemoto
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502, Japan.
| | - Ikumi Yoshitake
- Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502, Japan
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15
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Lin Y, Sutherland WJ. Color and degree of interspecific synchrony of environmental noise affect the variability of complex ecological networks. Ecol Modell 2013. [DOI: 10.1016/j.ecolmodel.2013.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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16
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Maeng SE, Lee JW, Lee DS. Impact of compatibility on the organization of mutualistic networks. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:022804. [PMID: 24032880 DOI: 10.1103/physreve.88.022804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 07/05/2013] [Indexed: 06/02/2023]
Abstract
Distinct relationships such as activation, inhibition, cooperation, and competition are not established independently but in a correlated manner in complex systems. Thus the patterns of one type of interaction may reflect the impacts of other classes of interactions, but its quantitative understanding remains to be done. Referring to the plant-pollinator mutualistic networks, here we propose and investigate the structural features of a model bipartite network, in which the mutualistic relationship between two different types of nodes is established under the influence of the compatibility among the nodes of the same type. Interestingly, we find that the degree distributions obtained for extremely broad compatibility distributions are similar to those for a constant compatibility, both of which deviate from those for the Gaussian compatibility distributions. We present the analytic arguments to explain this finding. Also the dependence of the topological similarity of two nodes on their compatibility is illustrated. We discuss the application of our findings to complex systems.
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Affiliation(s)
- Seong Eun Maeng
- Department of Physics, Inha University, Incheon 402-751, Korea
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17
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Holland JN, Wang Y, Sun S, DeAngelis DL. Consumer–resource dynamics of indirect interactions in a mutualism–parasitism food web module. THEOR ECOL-NETH 2013. [DOI: 10.1007/s12080-013-0181-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Background Networks of single interaction types, such as plant-pollinator mutualisms, are biodiversity’s “building blocks”. Yet, the structure of mutualistic and antagonistic networks differs, leaving no unified modeling framework across biodiversity’s component pieces. Methods/Principal Findings We use a one-dimensional “niche model” to predict antagonistic and mutualistic species interactions, finding that accuracy decreases with the size of the network. We show that properties of the modeled network structure closely approximate empirical properties even where individual interactions are poorly predicted. Further, some aspects of the structure of the niche space were consistently different between network classes. Conclusions/Significance These novel results reveal fundamental differences between the ability to predict ecologically important features of the overall structure of a network and the ability to predict pair-wise species interactions.
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Affiliation(s)
- Lucas N Joppa
- Computational Ecology and Environmental Sciences, Microsoft Research, Cambridge, United Kingdom.
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19
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Saavedra S, Malmgren RD, Switanek N, Uzzi B. Foraging under conditions of short-term exploitative competition: the case of stock traders. Proc Biol Sci 2013; 280:20122901. [PMID: 23363635 DOI: 10.1098/rspb.2012.2901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Theory purports that animal foraging choices evolve to maximize returns, such as net energy intake. Empirical research in both human and non-human animals reveals that individuals often attend to the foraging choices of their competitors while making their own foraging choices. Owing to the complications of gathering field data or constructing experiments, however, broad facts relating theoretically optimal and empirically realized foraging choices are only now emerging. Here, we analyse foraging choices of a cohort of professional day traders who must choose between trading the same stock multiple times in a row--patch exploitation--or switching to a different stock--patch exploration--with potentially higher returns. We measure the difference between a trader's resource intake and the competitors' expected intake within a short period of time--a difference we call short-term comparative returns. We find that traders' choices can be explained by foraging heuristics that maximize their daily short-term comparative returns. However, we find no one-best relationship between different trading choices and net income intake. This suggests that traders' choices can be short-term win oriented and, paradoxically, maybe maladaptive for absolute market returns.
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Affiliation(s)
- Serguei Saavedra
- Integrative Ecology Group, Estación Biológica de Doñana (EBD-CSIC), Américo Vespucio s/n, 41092 Sevilla, Spain.
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20
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Pires MM, Guimarães PR. Interaction intimacy organizes networks of antagonistic interactions in different ways. J R Soc Interface 2012; 10:20120649. [PMID: 23015523 DOI: 10.1098/rsif.2012.0649] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Interaction intimacy, the degree of biological integration between interacting individuals, shapes the ecology and evolution of species interactions. A major question in ecology is whether interaction intimacy also shapes the way interactions are organized within communities. We combined analyses of network structure and food web models to test the role of interaction intimacy in determining patterns of antagonistic interactions, such as host-parasite, predator-prey and plant-herbivore interactions. Networks describing interactions with low intimacy were more connected, more nested and less modular than high-intimacy networks. Moreover, the performance of the models differed across networks with different levels of intimacy. All models reproduced well low-intimacy networks, whereas the more elaborate models were also capable of reproducing networks depicting interactions with higher levels of intimacy. Our results indicate the key role of interaction intimacy in organizing antagonisms, suggesting that greater interaction intimacy might be associated with greater complexity in the assembly rules shaping ecological networks.
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Affiliation(s)
- Mathias M Pires
- Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
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21
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Yeakel JD, Guimarães PR, Novak M, Fox-Dobbs K, Koch PL. Probabilistic patterns of interaction: the effects of link-strength variability on food web structure. J R Soc Interface 2012; 9:3219-28. [PMID: 22832361 DOI: 10.1098/rsif.2012.0481] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Patterns of species interactions affect the dynamics of food webs. An important component of species interactions that is rarely considered with respect to food webs is the strengths of interactions, which may affect both structure and dynamics. In natural systems, these strengths are variable, and can be quantified as probability distributions. We examined how variation in strengths of interactions can be described hierarchically, and how this variation impacts the structure of species interactions in predator-prey networks, both of which are important components of ecological food webs. The stable isotope ratios of predator and prey species may be particularly useful for quantifying this variability, and we show how these data can be used to build probabilistic predator-prey networks. Moreover, the distribution of variation in strengths among interactions can be estimated from a limited number of observations. This distribution informs network structure, especially the key role of dietary specialization, which may be useful for predicting structural properties in systems that are difficult to observe. Finally, using three mammalian predator-prey networks (two African and one Canadian) quantified from stable isotope data, we show that exclusion of link-strength variability results in biased estimates of nestedness and modularity within food webs, whereas the inclusion of body size constraints only marginally increases the predictive accuracy of the isotope-based network. We find that modularity is the consequence of strong link-strengths in both African systems, while nestedness is not significantly present in any of the three predator-prey networks.
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Affiliation(s)
- Justin D Yeakel
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
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