1
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Victor NR, Costa‐Pereira R. Trophic allometry in a predator that carries corpses of its prey. Biotropica 2022. [DOI: 10.1111/btp.13148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Raul Costa‐Pereira
- Departamento de Biologia Animal, Instituto de Biologia Universidade Estadual de Campinas Campinas Brazil
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2
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Cruz LR, Pires MM. Body mass ratios determine dietary patterns and help predicting predator–prey interactions of Neotropical Carnivora. MAMMAL RES 2022. [DOI: 10.1007/s13364-022-00631-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Anderson KE, Fahimipour AK. Body size dependent dispersal influences stability in heterogeneous metacommunities. Sci Rep 2021; 11:17410. [PMID: 34465802 PMCID: PMC8408130 DOI: 10.1038/s41598-021-96629-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 08/12/2021] [Indexed: 11/25/2022] Open
Abstract
Body size affects key biological processes across the tree of life, with particular importance for food web dynamics and stability. Traits influencing movement capabilities depend strongly on body size, yet the effects of allometrically-structured dispersal on food web stability are less well understood than other demographic processes. Here we study the stability properties of spatially-arranged model food webs in which larger bodied species occupy higher trophic positions, while species’ body sizes also determine the rates at which they traverse spatial networks of heterogeneous habitat patches. Our analysis shows an apparent stabilizing effect of positive dispersal rate scaling with body size compared to negative scaling relationships or uniform dispersal. However, as the global coupling strength among patches increases, the benefits of positive body size-dispersal scaling disappear. A permutational analysis shows that breaking allometric dispersal hierarchies while preserving dispersal rate distributions rarely alters qualitative aspects of metacommunity stability. Taken together, these results suggest that the oft-predicted stabilizing effects of large mobile predators may, for some dimensions of ecological stability, be attributed to increased patch coupling per se, and not necessarily coupling by top trophic levels in particular.
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Affiliation(s)
- Kurt E Anderson
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, CA, USA.
| | - Ashkaan K Fahimipour
- Department of Computer Science, University of California, Davis, CA, USA.,Institute of Marine Sciences, University of California, Santa Cruz, CA, USA
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4
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Ma G, Bai C, Rudolf VHW, Ma C. Night warming alters mean warming effects on predator–prey interactions by modifying predator demographics and interaction strengths. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gang Ma
- Climate Change Biology Research Group State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing China
| | - Chun‐Ming Bai
- Climate Change Biology Research Group State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing China
| | | | - Chun‐Sen Ma
- Climate Change Biology Research Group State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing China
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5
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Henriques JF, Lacava M, Guzmán C, Gavín-Centol MP, Ruiz-Lupión D, De Mas E, Magalhães S, Moya-Laraño J. The sources of variation for individual prey-to-predator size ratios. Heredity (Edinb) 2021; 126:684-694. [PMID: 33452465 PMCID: PMC8115045 DOI: 10.1038/s41437-020-00395-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
The relative body size at which predators are willing to attack prey, a key trait for predator-prey interactions, is usually considered invariant. However, this ratio can vary widely among individuals or populations. Identifying the range and origin of such variation is key to understanding the strength and constraints on selection in both predators and prey. Still, these sources of variation remain largely unknown. We filled this gap by measuring the genetic, maternal and environmental variation of the maximum prey-to-predator size ratio (PPSRmax) in juveniles of the wolf spider Lycosa fasciiventris using a paternal half-sib split-brood design, in which each male was paired with two females and the offspring reared in two food environments: poor and rich. Each juvenile spider was then sequentially offered crickets of decreasing size and the maximum prey size killed was determined. We also measured body size and body condition of spiders upon emergence and just before the trial. We found low, but significant heritability (h2 = 0.069) and dominance and common environmental variance (d2 + 4c2 = 0.056). PPSRmax was also partially explained by body condition (during trial) but there was no effect of the rearing food environment. Finally, a maternal correlation between body size early in life and PPSRmax indicated that offspring born larger were less predisposed to feed on larger prey later in life. Therefore, PPSRmax, a central trait in ecosystems, can vary widely and this variation is due to different sources, with important consequences for changes in this trait in the short and long terms.
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Affiliation(s)
- Jorge F. Henriques
- grid.9983.b0000 0001 2181 4263cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal ,grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
| | - Mariángeles Lacava
- grid.11630.350000000121657640CENUR Noreste Sede Rivera, Universidad de la República, Ituzaingó, 667 Rivera Uruguay
| | - Celeste Guzmán
- grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
| | - Maria Pilar Gavín-Centol
- grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
| | - Dolores Ruiz-Lupión
- grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
| | - Eva De Mas
- grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
| | - Sara Magalhães
- grid.9983.b0000 0001 2181 4263cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Jordi Moya-Laraño
- grid.466639.80000 0004 0547 1725Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas, CSIC, Carretera de Sacramento s/n, 04120-La Cañada De San Urbano, Almeria, Spain
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6
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Moroti MDT, Soares PT, Pedrozo M, Provete DB, Santana DJ. The effects of morphology, phylogeny and prey availability on trophic resource partitioning in an anuran community. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2020.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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7
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DeLong JP. Detecting the Signature of Body Mass Evolution in the Broad-Scale Architecture of Food Webs. Am Nat 2020; 196:443-453. [PMID: 32970468 DOI: 10.1086/710350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractBody mass-based links between predator and prey are fundamental to the architecture of food webs. These links determine who eats whom across trophic levels and strongly influence the population abundance, flow of energy, and stability properties of natural communities. Body mass links scale up to create predator-prey mass relationships across species, but the origin of these relationships is unclear. Here I show that predator-prey mass relationships are consistent with the idea that body mass evolves to maximize a dependable supply of resource uptake. I used a global database of ~2,100 predator-prey links and a mechanistic optimization model to correctly predict the slope of the predator-prey mass scaling relationships across species generally and for nine taxonomic subsets. The model also predicted cross-group variation in the heights of the body mass relationships, providing an integrated explanation for mass relationships and their variation across taxa. The results suggest that natural selection on body mass at the local scale is detectable in ecological organization at the macro scale.
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8
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Murphy KJ, Pecl GT, Richards SA, Semmens JM, Revill AT, Suthers IM, Everett JD, Trebilco R, Blanchard JL. Functional traits explain trophic allometries of cephalopods. J Anim Ecol 2020; 89:2692-2703. [PMID: 32895913 DOI: 10.1111/1365-2656.13333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 08/13/2020] [Indexed: 11/29/2022]
Abstract
Individual body size strongly influences the trophic role of marine organisms and the structure and function of marine ecosystems. Quantifying trophic position-individual body size relationships (trophic allometries) underpins the development of size-structured ecosystem models to predict abundance and the transfer of energy through ecosystems. Trophic allometries are well studied for fishes but remain relatively unexplored for cephalopods. Cephalopods are important components of coastal, oceanic and deep-sea ecosystems, and they play a key role in the transfer of biomass from low trophic positions to higher predators. It is therefore important to resolve cephalopod trophic allometries to accurately represent them within size-structured ecosystem models. We assessed the trophic positions of cephalopods in an oceanic pelagic (0-500 m) community (sampled by trawling in a cold-core eddy in the western Tasman Sea), comprising 22 species from 12 families, using bulk tissue stable isotope analysis and amino acid compound-specific stable isotope analysis. We assessed whether ontogenetic trophic position shifts were evident at the species-level and tested for the best predictor of community-level trophic allometry among body size, taxonomy and functional grouping (informed by fin and mantle morphology). Individuals in this cephalopod community spanned two trophic positions and fell into three functional groups on an activity level gradient: low, medium and high. The relationship between trophic position and ontogeny varied among species, with the most marked differences evident between species from different functional groups. Activity-level-based functional group and individual body size are best explained by cephalopod trophic positions (marginal R2 = 0.43). Our results suggest that the morphological traits used to infer activity level, such as fin-to-mantle length ratio, fin musculature and mantle musculature are strong predictors of cephalopod trophic allometries. Contrary to established theory, not all cephalopods are voracious predators. Low activity level cephalopods have a distinct feeding mode, with low trophic positions and little-to-no ontogenetic increases. Given the important role of cephalopods in marine ecosystems, distinct feeding modes could have important consequences for energy pathways and ecosystem structure and function. These findings will facilitate trait-based and other model estimates of cephalopod abundance in the changing global ocean.
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Affiliation(s)
- Kieran J Murphy
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas, Australia
| | - Gretta T Pecl
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas, Australia
| | - Shane A Richards
- School of Natural Sciences, University of Tasmania, Hobart, Tas, Australia
| | - Jayson M Semmens
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas, Australia
| | | | - Iain M Suthers
- School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.,Sydney Institute of Marine Science, Mosman, NSW, Australia
| | - Jason D Everett
- School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.,Centre for Applications in Natural Resource Mathematics, The University of Queensland, St Lucia, Qld, Australia
| | - Rowan Trebilco
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas, Australia.,CSIRO Oceans and Atmosphere, Hobart, Tas, Australia
| | - Julia L Blanchard
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas, Australia
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9
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Costa-Pereira R, Araújo MS, Souza FL, Ingram T. Competition and resource breadth shape niche variation and overlap in multiple trophic dimensions. Proc Biol Sci 2020; 286:20190369. [PMID: 31039715 DOI: 10.1098/rspb.2019.0369] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Competition plays a central role in the maintenance of biodiversity. A backbone of classic niche theory is that local coexistence of competitors is favoured by the contraction or divergence of species' niches. However, this effect should depend on the diversity of resources available in the local environment, particularly when resources vary in multiple ecological dimensions. Here, we investigated how available resource breadth (i.e. prey diversity) and competition together shape multidimensional niche variation (between and within individuals) and interspecific niche overlap in 42 populations of congeneric tropical frog species. We modelled realized niches in two key trophic dimensions (prey size and carbon stable isotopes) and sampled available food resources to quantify two-dimensional resource breadth. We found a 14-fold variation in multidimensional population niche width across populations, most of which was accounted for by within-individual diet variation. This striking variation was predicted by an interaction whereby individual niche breadth increased with resource breadth and decreased with the number of congeneric competitors. These ecological gradients also interact to influence the degree of niche overlap between species, which surprisingly decreased with population total niche width, providing novel insights on how similar species can coexist in local communities. Together, our results emphasize that patterns of exploitation of resources in multiple dimensions are driven by both competitive interactions and extrinsic factors such as local resource breadth.
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Affiliation(s)
- Raul Costa-Pereira
- 1 Programa de Pós-Graduação em Ecologia e Biodiversidade, Universidade Estadual Paulista (UNESP) , Rio Claro , Brazil.,2 Instituto de Biociências, Universidade Estadual Paulista (UNESP) , Rio Claro , Brazil.,3 Department of Zoology, University of Otago , PO Box 56, Dunedin 9054 , New Zealand
| | - Márcio S Araújo
- 2 Instituto de Biociências, Universidade Estadual Paulista (UNESP) , Rio Claro , Brazil
| | - Franco L Souza
- 4 Instituto de Biociências, Universidade Federal de Mato Grosso do Sul , Campo Grande , Brazil
| | - Travis Ingram
- 3 Department of Zoology, University of Otago , PO Box 56, Dunedin 9054 , New Zealand
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10
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Dermond P, Melián CJ, Brodersen J. Size-dependent tradeoffs in seasonal freshwater environments facilitate differential salmonid migration. MOVEMENT ECOLOGY 2019; 7:40. [PMID: 31890216 PMCID: PMC6925424 DOI: 10.1186/s40462-019-0185-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/29/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Seasonal spatio-temporal variation in habitat quality and abiotic conditions leads to animals migrating between different environments around the world. Whereas mean population timing of migration is often fairly well understood, explanations for variation in migratory timing within populations are often lacking. Condition-dependent tradeoffs may be an understudied mechanism that can explain this differential migration. While fixed condition-specific thresholds have been identified in earlier work on ontogenetic niche shifts, they are rare in differential migration, suggesting that thresholds in such systems can shift based on temporally variable environmental conditions. METHODS We introduced a model based on size-specific tradeoffs between migration and growth in seasonal environments. We focused on optimal migratory timing for first-time migrants with no knowledge of an alternative habitat, which is a crucial stage in the life history of migratory salmonids. We predicted that optimal timing would occur when individuals move from their natal habitats based on a seasonally variable ratio of predation and growth. When the ratio becomes slightly more favorable in the alternative habitat, migratory movement can occur. As it keeps shifting throughout the season, the threshold for migration is variable, allowing smaller individuals to move at later dates. We compared our model predictions to empirical data on 3 years of migratory movement of more than 800 juvenile trout of varying size from natal to feeding habitat. RESULTS Both our model and empirical data showed that large individuals, which are assumed to have a lower predation risk in the migratory habitat, move earlier in the season than smaller individuals, whose predicted predation-to-growth ratio shifted to being favorable only later in the migratory season. Our model also predicted that the observed difference in migratory timing between large and small migrants occurred most often at low values of growth differential between the two habitats, suggesting that it was not merely high growth potential but rather the tradeoff between predation and growth that shaped differential migration patterns. CONCLUSIONS We showed the importance of considering condition-specific tradeoffs for understanding temporal population dynamics in spatially structured landscapes. Rather than assuming a fixed threshold, which appears to be absent based on previous work on salmonids, we showed that the body-size threshold for migration changed temporally throughout the season. This allowed increasingly smaller individuals to migrate when growth conditions peaked in the migratory habitat. Our model illuminates an understudied aspect of predation as part of a condition-dependent tradeoff that shapes migratory patterns, and our empirical data back patterns predicted by this model.
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Affiliation(s)
- Philip Dermond
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
- Institute of Ecology and Evolution, Aquatic Ecology, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
| | - Carlos J. Melián
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
- Institute of Ecology and Evolution, Aquatic Ecology, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
| | - Jakob Brodersen
- Department of Fish Ecology and Evolution, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Centre of Ecology, Evolution and Biogeochemistry, Seestrasse 79, CH-6047 Kastanienbaum, Switzerland
- Institute of Ecology and Evolution, Aquatic Ecology, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland
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11
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Hillaert J, Vandegehuchte ML, Hovestadt T, Bonte D. Habitat loss and fragmentation increase realized predator–prey body size ratios. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jasmijn Hillaert
- Department of Biology Terrestrial Ecology Unit Ghent University Ghent Belgium
| | | | - Thomas Hovestadt
- Department of Animal Ecology and Tropical Biology Biocenter University of Würzburg Würzburg Germany
| | - Dries Bonte
- Department of Biology Terrestrial Ecology Unit Ghent University Ghent Belgium
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12
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Preston DL, Falke LP, Henderson JS, Novak M. Food-web interaction strength distributions are conserved by greater variation between than within predator-prey pairs. Ecology 2019; 100:e02816. [PMID: 31287561 DOI: 10.1002/ecy.2816] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/10/2019] [Accepted: 06/10/2019] [Indexed: 12/25/2022]
Abstract
Species interactions in food webs are usually recognized as dynamic, varying across species, space, and time because of biotic and abiotic drivers. Yet food webs also show emergent properties that appear consistent, such as a skewed frequency distribution of interaction strengths (many weak, few strong). Reconciling these two properties requires an understanding of the variation in pairwise interaction strengths and its underlying mechanisms. We estimated stream sculpin feeding rates in three seasons at nine sites in Oregon to examine variation in trophic interaction strengths both across and within predator-prey pairs. Predator and prey densities, prey body mass, and abiotic factors were considered as putative drivers of within-pair variation over space and time. We hypothesized that consistently skewed interaction strength distributions could result if individual interaction strengths show relatively little variation, or alternatively, if interaction strengths vary but shift in ways that conserve their overall frequency distribution. Feeding rate distributions remained consistently and positively skewed across all sites and seasons. The mean coefficient of variation in feeding rates within each of 25 focal species pairs across surveys was less than half the mean coefficient of variation seen across species pairs within a survey. The rank order of feeding rates also remained conserved across streams, seasons and individual surveys. On average, feeding rates on each prey taxon nonetheless varied by a hundredfold, with some feeding rates showing more variation in space and others in time. In general, feeding rates increased with prey density and decreased with high stream flows and low water temperatures, although for nearly half of all species pairs, factors other than prey density explained the most variation. Our findings show that although individual interaction strengths exhibit considerable variation in space and time, they can nonetheless remain relatively consistent, and thus predictable, compared to the even larger variation that occurs across species pairs. These results highlight how the ecological scale of inference can strongly shape conclusions about interaction strength consistency and help reconcile how the skewed nature of interaction strength distributions can persist in highly dynamic food webs.
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Affiliation(s)
- Daniel L Preston
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Landon P Falke
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA
| | - Jeremy S Henderson
- Oregon Department of Fish and Wildlife, 305 North Canyon Boulevard, Canyon City, Oregon, 97820, USA
| | - Mark Novak
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, 97330, USA
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13
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Costa‐Pereira R, Toscano B, Souza FL, Ingram T, Araújo MS. Individual niche trajectories drive fitness variation. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13389] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Raul Costa‐Pereira
- Instituto de Biociências Universidade Estadual Paulista (UNESP) Rio Claro Brazil
- McMaster University Hamilton Ontario Canada
| | | | - Franco L. Souza
- Instituto de Biociências Universidade Federal de Mato Grosso do Sul Campo Grande Brazil
| | - Travis Ingram
- Department of Zoology University of Otago Dunedin New Zealand
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14
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Costa-Pereira R, Pruitt J. Behaviour, morphology and microhabitat use: what drives individual niche variation? Biol Lett 2019; 15:20190266. [PMID: 31164064 PMCID: PMC6597513 DOI: 10.1098/rsbl.2019.0266] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/14/2019] [Indexed: 01/21/2023] Open
Abstract
Generalist populations are often composed of individuals each specialized on only a subset of the resources exploited by the entire population. However, the traits underlying such niche variation remain underexplored. Classically, ecologists have focused on understanding why populations vary in their degree of intraspecific niche variation, with less attention paid to how individual-level traits lead to intraspecific differences in niches. We investigated how differences in behaviour, morphology and microhabitat affect niche variation between and within individuals in two species of spider Anelosimus studiosus and Theridion murarium. Our results convey that behaviour (i.e. individual aggressiveness) was a key driver of intraspecific trophic variation in both species. More aggressive individuals capture more prey, but particularly more Coleoptera, Hymenoptera and Diptera. These findings suggest that behavioural traits play a critical role in determining individuals' diet and that behaviour can be a powerful force in driving intraspecific niche variation.
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Affiliation(s)
- Raul Costa-Pereira
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, Ontario, Canada L8S 4L8
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15
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Predator traits determine food-web architecture across ecosystems. Nat Ecol Evol 2019; 3:919-927. [PMID: 31110252 DOI: 10.1038/s41559-019-0899-x] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 04/10/2019] [Indexed: 11/09/2022]
Abstract
Predator-prey interactions in natural ecosystems generate complex food webs that have a simple universal body-size architecture where predators are systematically larger than their prey. Food-web theory shows that the highest predator-prey body-mass ratios found in natural food webs may be especially important because they create weak interactions with slow dynamics that stabilize communities against perturbations and maintain ecosystem functioning. Identifying these vital interactions in real communities typically requires arduous identification of interactions in complex food webs. Here, we overcome this obstacle by developing predator-trait models to predict average body-mass ratios based on a database comprising 290 food webs from freshwater, marine and terrestrial ecosystems across all continents. We analysed how species traits constrain body-size architecture by changing the slope of the predator-prey body-mass scaling. Across ecosystems, we found high body-mass ratios for predator groups with specific trait combinations including (1) small vertebrates and (2) large swimming or flying predators. Including the metabolic and movement types of predators increased the accuracy of predicting which species are engaged in high body-mass ratio interactions. We demonstrate that species traits explain striking patterns in the body-size architecture of natural food webs that underpin the stability and functioning of ecosystems, paving the way for community-level management of the most complex natural ecosystems.
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16
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Guzman LM, Srivastava DS. Prey body mass and richness underlie the persistence of a top predator. Proc Biol Sci 2019; 286:20190622. [PMID: 31064301 DOI: 10.1098/rspb.2019.0622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Predators and prey often differ in body mass. The ratio of predator to prey body mass influences the predator's functional response (how consumption varies with prey density), and therefore, the strength and stability of the predator-prey interaction. The persistence of food chains is maximized when prey species are neither too big nor too small relative to their predator. Nonetheless, we do not know if (i) food web persistence requires that all predator-prey body mass ratios are intermediate, nor (ii) if this constraint depends on prey diversity. We experimentally quantified the functional response for a single predator consuming prey species of different body masses. We used the resultant allometric functional response to parametrize a food web model. We found that predator persistence was maximized when the minimum prey size in the community was intermediate, but as prey diversity increased, the minimum body size could take a broader range of values. This last result occurs because of Jensen's inequality: the average handling time for multiple prey of different sizes is higher than the handling time of the average sized prey. Our results demonstrate that prey diversity mediates how differences between predators and prey in body mass determine food web stability.
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Affiliation(s)
- Laura Melissa Guzman
- 1 Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada V6T1Z4.,2 Biodiversity Research Centre, University of British Columbia , Vancouver, British Columbia , Canada V6T1Z4
| | - Diane S Srivastava
- 1 Department of Zoology, University of British Columbia , Vancouver, British Columbia , Canada V6T1Z4.,2 Biodiversity Research Centre, University of British Columbia , Vancouver, British Columbia , Canada V6T1Z4
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