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Ekanayake-Weber MS, O'Connor-Coates CJ, Koenig A. Steep Hierarchies without Skew? Modeling How Ecology and Decision-Making Shape Despotism of Relationships. Am Nat 2024; 203:189-203. [PMID: 38306279 DOI: 10.1086/727702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
AbstractAnimals can form dominance relationships that vary from highly unequal, or despotic, to egalitarian, and this variation likely impacts the fitness of individuals. How and why these differences in relationships and fitness exist among groups, populations, and species has been the subject of much debate. Here, we investigated the influence of two major factors: (1) spatial resource distribution and (2) the presence or absence of winner-loser effects. To determine the effects of these factors, we built an agent-based model that represented 10 agents directly competing over food resources on a simple landscape. By varying the food distribution and using either asymmetry of strength or experience, we contrasted four scenarios from which we recorded attack decisions, fight outcomes, and individual energy intake to calculate dominance hierarchy steepness and energetic skew. Surprisingly, resource distribution and winner-loser effects did not have the predicted effects on hierarchy steepness. However, skew in energy intake arose when resources were distributed heterogeneously, despite hierarchy steepness frequently being higher in the homogeneous resource scenarios. Thus, this study confirms some decades-old predictions about feeding competition but also casts doubt on the ability to infer energetic consequences from observations of agonistic interactions.
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Scott R, Resetarits WJ. Spatially explicit habitat selection: Testing contagion and the ideal free distribution with Culex mosquitoes. Am Nat 2022; 200:675-690. [DOI: 10.1086/721009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Walters K, Reynolds J, Ydenberg R. Ideal free eagles: Bald Eagle (Haliaeetus leucocephalus) distribution in relation to Pacific salmon (Oncorhynchus spp.) availability on four spawning rivers. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The movement of individuals according to the availability of resources has a fundamental effect on animal distributions. In the Pacific Northwest, Bald Eagles (Haliaeetus leucocephalus (Linnaeus, 1766)) rely heavily on scavenging opportunities during the non-breeding period, and their distribution and movements are thought to be strongly influenced by the availability of post-spawning Pacific salmon (genus Oncorhynchus Suckley, 1861) carcasses. We surveyed the abundance of eagles and salmon on four adjacent rivers on Vancouver Island, British Columbia, Canada, during the 2017 fall spawning season. Salmon began to arrive in late September, peaked in abundance in mid-November, and were absent after early December. The seasonal progression of Bald Eagle abundance matched that of salmon carcass availability. The slope of proportional eagle–salmon relationship was significantly positive, though lower than the 1:1 match predicted by Ideal Free Distribution theory. The numerical response of Bald Eagles to salmon abundance was elevated on one of the rivers, potentially due to physical features such as sandbars and mudflats that increased the availability of carcasses and provided access points for eagles.
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Affiliation(s)
- K.E. Walters
- Centre for Wildlife Ecology, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - J.D. Reynolds
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - R.C. Ydenberg
- Centre for Wildlife Ecology, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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Scharf I, Reshef MH, Avidov B, Ovadia O. Evidence for competition and cannibalism in wormlions. Sci Rep 2021; 11:12733. [PMID: 34140585 PMCID: PMC8211784 DOI: 10.1038/s41598-021-92154-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 06/07/2021] [Indexed: 02/05/2023] Open
Abstract
Trap-building predators, such as web-building spiders and pit-building antlions, construct traps to capture their prey. These predators compete over sites that either enable the construction of suitable traps, are prey rich, or simply satisfy their abiotic requirements. We examined the effect of intraspecific competition over suitable space in pit-building wormlions. As expected, the ability of wormlions to select their favorable microhabitats-shaded or deep sand over lit or shallow sand-decreased with increasing density. Favorable microhabitats were populated more frequently by large than by small individuals and the density of individuals in the favorable microhabitat decreased with their increase in body mass. The advantage of large individuals in populating favorable microhabitats is nevertheless not absolute: both size categories constructed smaller pits when competing over a limited space compared to those constructed in isolation. The outcome of competition also depends on the type of habitat: deep sand is more important for large wormlions than small ones, while shade is similarly important for both size classes. Finally, in contrast to previous reports, cannibalism is shown here to be possible in wormlions. Its prevalence however is much lower compared to that documented in other trap-building predators. Our findings show that the advantage of large individuals over small ones should not be taken for granted, as it can depend on the environmental context. We present suggestions for the relative lack of competitive advantage of large wormlion individuals compared to other trap-building predators, which may stem from the absence of obvious weaponry, such as sharp mandibles.
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Affiliation(s)
- Inon Scharf
- grid.12136.370000 0004 1937 0546School of Zoology, Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | - May Hershkovitz Reshef
- grid.12136.370000 0004 1937 0546School of Zoology, Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Bar Avidov
- grid.12136.370000 0004 1937 0546School of Zoology, Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ofer Ovadia
- grid.7489.20000 0004 1937 0511Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Wyatt GAK, Kiers ET, Gardner A, West SA. A BIOLOGICAL MARKET ANALYSIS OF THE PLANT-MYCORRHIZAL SYMBIOSIS. Evolution 2014; 68:2603-18. [DOI: 10.1111/evo.12466] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 05/27/2014] [Indexed: 12/21/2022]
Affiliation(s)
| | - E. Toby Kiers
- Institute of Ecological Sciences; Faculty of Earth and Life Sciences; Vrije Universiteit; De Boelelaan 1085, 1081 HV Amsterdam The Netherlands
| | - Andy Gardner
- School of Biology; University of St Andrews; Dyers Brae, St Andrews KY16 9 United Kingdom
| | - Stuart A. West
- Department of Zoology; University of Oxford; Oxford OX1 3PS United Kingdom
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Tan L, Sosa F, Talbot E, Berg D, Eversz D, Hackenberg TD. Effects of predictability and competition on group and individual choice in a free-ranging foraging environment. J Exp Anal Behav 2014; 101:288-302. [PMID: 24500764 DOI: 10.1002/jeab.76] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 01/07/2014] [Indexed: 11/06/2022]
Abstract
The present study examined the social foraging of rats in an open arena. The relative quantity of food varied across two food sources, or "patches." Five food quantity ratios (1:1, 1:2, 1:8, 8:1, 2:1) were presented in a series of 30-min sessions. Ratios varied randomly across 6-min components within sessions (Phase 1), or in a consistent order across sessions (Phase 2). Group and individual preferences were well described by the ideal free distribution and the generalized matching law, respectively, with evidence of undermatching at both group and individual levels. Sensitivity of individual and collective behavior to the relative quantities of food was higher in Phase 2 than in Phase 1. Competitiveness rankings, assessed before and after experimental sessions by delivering food in rapid succession from a single feeder, was positively related to sensitivity values in Phase 1, but less consistently so in Phase 2. This study illustrates a promising experimental method for investigating foraging in a social context.
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Hugie DM, Grand TC. Movement between patches, unequal competitors and the ideal free distribution. Evol Ecol 2013. [DOI: 10.1023/a:1006527305773] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Kennedy M, Gray RD. Agonistic Interactions and the Distribution of Foraging Organisms: Individual Costs and Social Information. Ethology 2010. [DOI: 10.1111/j.1439-0310.1994.tb00891.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Andersen IL, Nævdal E, Bøe KE, Bakken M. The significance of theories in behavioural ecology for solving problems in applied ethology—Possibilities and limitations. Appl Anim Behav Sci 2006. [DOI: 10.1016/j.applanim.2005.11.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Critchfield TS, Atteberry T. Temporal discounting predicts individual competitive success in a human analogue of group foraging. Behav Processes 2003; 64:315-331. [PMID: 14580701 DOI: 10.1016/s0376-6357(03)00129-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Twenty groups of college undergraduates (N=9-12) participated in a discrete-trials analogue of group foraging in which points, exchangeable for course credit, were the resource to be acquired. Group matching of foragers to patch resource availability was well described by the generalized Ideal Free Distribution, with undermatching (imperfect sensitivity to resource differentials) the norm. Individuals differed on several measures of competitive success, and a measure of temporal discounting (TD) accounted for a significant proportion of the variance in these measures. Tendencies in switch patterns and visit durations differed for the most-impulsive and least-impulsive individuals in a fashion that was consistent with a TD interpretation. When competitive weights, defined in terms of TD scores, were substituted for counts of individuals in the generalized Ideal Free Distribution, group-matching slopes more closely approximated perfect sensitivity than in standard analyses. This was true for groups incorporating all impulsive individuals, all non-impulsive individuals, or a broad range of TD scores. The results suggest that well-understood individual psychological processes are associated with competitive ability in group choice.
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Affiliation(s)
- Thomas S. Critchfield
- Department of Psychology, Illinois State University, Box 4620, 61790-4620, Normal, IL, USA
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Cresswell W, Smith RD, Ruxton GD. Absolute foraging rate and susceptibility to interference competition in blackbirds varies with patch conditions. J Anim Ecol 2001. [DOI: 10.1046/j.1365-2656.2001.00487.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Cresswell W, Smith RD, Ruxton GD. Absolute foraging rate and susceptibility to interference competition in blackbirds varies with patch conditions. J Anim Ecol 2001. [DOI: 10.1111/j.1365-2656.2001.00487.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Humphries S, Ruxton GD, Metcalfe NB. Patch choice and risk: relative competitive ability is context dependent. Anim Behav 1999; 58:1131-1138. [PMID: 10564617 DOI: 10.1006/anbe.1999.1247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The relative abilities of individual cichlids, Tilapia zillii to obtain food under scramble competition was highly repeatable between trials using a single input source, regardless of whether the input was constant or variable. However, when given a choice between two patches differing only in their temporal variability in input about an identical mean, an individual's rank based on intake in one patch was uncorrelated with either its intake in the other patch or its intake in the single-patch trials. In the two-patch trials, certain individuals both spent more time in food patches and visited patches more often than others, and overall the fish spent more time in the constant rate patch than the variable patch, leading to more items being consumed from the constant rate patch. We discuss possible causes and consequences of this dependence of relative competitive ability on the context of the foraging situation. Copyright 1999 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- S Humphries
- Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow
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Rowcliffe JM, Sutherland WJ, Watkinson AR. The functional and aggregative responses of a herbivore: underlying mechanisms and the spatial implications for plant depletion. J Anim Ecol 1999. [DOI: 10.1046/j.1365-2656.1999.00335.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Cresswell W. Relative competitive ability changes with competitor density: evidence from feeding blackbirds. Anim Behav 1998; 56:1367-1373. [PMID: 9933532 DOI: 10.1006/anbe.1998.0902] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
How individual competitive ability varies with competitor density in systems where interference competition occurs has been studied in few systems, despite its importance in determining the fundamental predictions of influential phenotype-limited ideal free distribution models. I measured individual variation in competitive ability in wild wintering blackbirds, Turdus merula. Variation in feeding rate of single birds, and the decline in their feeding rate in the presence of competitors, were measured in experimental patches. Individuals varied significantly both in their feeding rate when alone and in the decline in that feeding rate in the presence of competitors. Individuals that had high absolute feeding rates did not tend to have smaller declines in feeding rate in the presence of competitors. The relative ranking among birds in their feeding rate was strongly dependent on competitor density. This result has important implications for the expected distributions of competitors between patches. (c) 1998 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- W Cresswell
- Institute of Biological and Life Sciences, University of Glasgow
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Affiliation(s)
- David J. D. Earn
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Rufus A. Johnstone
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
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Hakoyama H, Iguchi K. The information of food distribution realizes an ideal free distribution: Support of perceptual limitation. J ETHOL 1997. [DOI: 10.1007/bf02769391] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Foraging site selection by juvenile coho salmon: ideal free distributions of unequal competitors. Anim Behav 1997. [DOI: 10.1006/anbe.1996.0287] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Tregenza T, Shaw JJ, Thompson DJ. An experimental investigation of a new ideal free distribution model. Evol Ecol 1996. [DOI: 10.1007/bf01239345] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ideal free distribution and natal dispersal in female roe deer. Oecologia 1995; 103:302-308. [PMID: 28306823 DOI: 10.1007/bf00328618] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/1995] [Accepted: 03/29/1995] [Indexed: 10/26/2022]
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Heard SB. Imperfect oviposition decisions by the pitcher plant mosquito (Wyeomyia smithii). Evol Ecol 1994. [DOI: 10.1007/bf01238254] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Male distribution and interactions at female oviposition sites as factors affecting mating success in the flyDryomyza anilis (Dryomyzidae). Evol Ecol 1993. [DOI: 10.1007/bf01239384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sutherland W, Parker G. The relationship between continuous input and interference models of ideal free distributions with unequal competitors. Anim Behav 1992. [DOI: 10.1016/0003-3472(92)90040-g] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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