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Moffett ER, Fryxell DC, Benavente JN, Kinnison MT, Palkovacs EP, Symons CC, Simon KS. The effect of pregnancy on metabolic scaling and population energy demand in the viviparous fish Gambusia affinis. Integr Comp Biol 2022; 62:icac099. [PMID: 35767874 DOI: 10.1093/icb/icac099] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Metabolism is a fundamental attribute of all organisms that influences how species affect and are affected by their natural environment. Differences between sexes in ectothermic species may substantially alter metabolic scaling patterns, particularly in viviparous or live-bearing species where females must support their basal metabolic costs and that of their embryos. Indeed, if pregnancy is associated with marked increases in metabolic demand and alters scaling patterns between sexes, this could in turn interact with natural sex ratio variation in nature to affect population-level energy demand. Here, we aimed to understand how sex and pregnancy influence metabolic scaling and how differences between sexes affect energy demand in Gambusia affinis (Western mosquitofish). Using the same method, we measured routine metabolic rate in the field on reproductively active fish and in the laboratory on virgin fish. Our data suggest that changes in energy expenditure related to pregnancy may lead to steeper scaling coefficients in females (b = 0.750) compared to males (b = 0.595). In contrast, virgin females and males had similar scaling coefficients, suggesting negligible sex differences in metabolic costs in reproductively inactive fish. Further, our data suggest that incorporating sex differences in allometric scaling may alter population-level energy demand by as much as 20-28%, with the most pronounced changes apparent in male-biased populations due to the lower scaling coefficient of males. Overall, our data suggest that differences in energy investment in reproduction between sexes driven by pregnancy may alter allometric scaling and population-level energy demand.
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Affiliation(s)
- Emma R Moffett
- Ecology and Evolutionary Biology, University of California, Irvine, USA
| | - David C Fryxell
- School of Environment, The University of Auckland, New Zealand
- Ecology and Evolutionary Biology, The University of California, Santa Cruz, USA
| | - J N Benavente
- School of Environment, The University of Auckland, New Zealand
| | - M T Kinnison
- School of Biology and Ecology,The University of Maine, USA
| | - E P Palkovacs
- Ecology and Evolutionary Biology, The University of California, Santa Cruz, USA
| | - C C Symons
- Ecology and Evolutionary Biology, University of California, Irvine, USA
| | - K S Simon
- School of Environment, The University of Auckland, New Zealand
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Moffett ER, Fryxell DC, Lee F, Palkovacs EP, Simon KS. Consumer trait responses track change in resource supply along replicated thermal gradients. Proc Biol Sci 2021; 288:20212144. [PMID: 34847762 PMCID: PMC8634111 DOI: 10.1098/rspb.2021.2144] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/04/2021] [Indexed: 12/03/2022] Open
Abstract
Rising temperatures may alter consumer diets through increased metabolic demand and altered resource availability. However, current theories assessing dietary shifts with warming do not account for a change in resource availability. It is unknown whether consumers will increase consumption rates or consume different resources to meet increased energy requirements and whether the dietary change will lead to associated variation in morphology and nutrient utilization. Here, we used populations of Gambusia affinis across parallel thermal gradients in New Zealand (NZ) and California (CA) to understand the influence of temperature on diets, morphology and stoichiometric phenotypes. Our results show that with increasing temperature in NZ, mosquitofish consumed more plant material, whereas in CA mosquitofish shifted towards increased consumption of invertebrate prey. In both regions, populations with plant-based diets had fuller guts, longer relative gut lengths, better-orientated mouths and reduced body elemental %C and N/P. Together, our results show multiple pathways by which consumers may alter their feeding patterns with rising temperatures, and they suggest that warming-induced changes to resource availability may be the principal determinant of which pathway is taken.
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Affiliation(s)
- E. R. Moffett
- School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - D. C. Fryxell
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA
| | - F. Lee
- School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - E. P. Palkovacs
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA
| | - K. S. Simon
- School of Environment, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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Tank JL, Martí E, Riis T, Schiller D, Reisinger AJ, Dodds WK, Whiles MR, Ashkenas LR, Bowden WB, Collins SM, Crenshaw CL, Crowl TA, Griffiths NA, Grimm NB, Hamilton SK, Johnson SL, McDowell WH, Norman BM, Rosi EJ, Simon KS, Thomas SA, Webster JR. Partitioning assimilatory nitrogen uptake in streams: an analysis of stable isotope tracer additions across continents. ECOL MONOGR 2017. [DOI: 10.1002/ecm.1280] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J. L. Tank
- Department of Biological Sciences University of Notre Dame Notre Dame Indiana 46656 USA
| | - E. Martí
- Integrative Freshwater Ecology Group Centre d'Estudis Avançats de Blanes (CEAB‐CSIC) 17300 Blanes Catalonia Spain
| | - T. Riis
- Department of Bioscience Aarhus University Ole Worms Alle 1 8000 Aarhus C Denmark
| | - D. Schiller
- Faculty of Science and Technology University of the Basque Country 48080 Bilbao Spain
| | - A. J. Reisinger
- Cary Institute of Ecosystem Studies Millbrook New York 12545 USA
| | - W. K. Dodds
- Division of Biology Kansas State University 106 Ackert Hall Manhattan Kansas 66506 USA
| | - M. R. Whiles
- Department of Zoology and Center for Ecology Southern Illinois University Carbondale Illinois 62901 USA
| | - L. R. Ashkenas
- Department of Fisheries & Wildlife Oregon State University Corvallis Oregon 97331 USA
| | - W. B. Bowden
- Rubenstein School of Environment and Natural Resources University of Vermont 303D Aiken Center Burlington Vermont 05405 USA
| | - S. M. Collins
- Center for Limnology University of Wisconsin Madison Wisconsin 53706 USA
| | - C. L. Crenshaw
- Department of Biology University of New Mexico Albuquerque New Mexico 87131 USA
| | - T. A. Crowl
- Department of Biology Southeast Environmental Research Center Florida International University Miami Florida 33199 USA
| | - N. A. Griffiths
- Climate Change Science Institute and Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA
| | - N. B. Grimm
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
| | - S. K. Hamilton
- W. K. Kellogg Biological Station Michigan State University Hickory Corners Michigan 49060 USA
| | - S. L. Johnson
- Pacific Northwest Research Station USDA Forest Service 3200 SW Jefferson Way Corvallis Oregon 97331 USA
| | - W. H. McDowell
- Natural Resources and the Environment University of New Hampshire Durham New Hampshire 03824 USA
| | - B. M. Norman
- Department of Microbiology and Molecular Genetics Michigan State University East Lansing Michigan 48824 USA
| | - E. J. Rosi
- Cary Institute of Ecosystem Studies Millbrook New York 12545 USA
| | - K. S. Simon
- School of Environment University of Auckland P.O. Box 92019 Auckland 1142 New Zealand
| | - S. A. Thomas
- School of Natural Resources University of Nebraska 403 Hardin Hall Lincoln Nebraska 68583 USA
| | - J. R. Webster
- Department of Biological Sciences Virginia Tech 1405 Perry Street Blacksburg Virginia 24601 USA
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Dodds WK, Collins SM, Hamilton SK, Tank JL, Johnson S, Webster JR, Simon KS, Whiles MR, Rantala HM, McDowell WH, Peterson SD, Riis T, Crenshaw CL, Thomas SA, Kristensen PB, Cheever BM, Flecker AS, Griffiths NA, Crowl T, Rosi-Marshall EJ, El-Sabaawi R, Martí E. You are not always what we think you eat: selective assimilation across multiple whole-stream isotopic tracer studies. Ecology 2014. [DOI: 10.1890/13-2276.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Acidification is a widespread phenomenon that damages aquatic systems, and it has been the focus of intensive management efforts. While most management has focused on community structure as an endpoint, ecosystem function is also sensitive to acidification and important in stream health. We examined how a key ecosystem function in streams, leaf breakdown, varied along a gradient of pH resulting from acid deposition, natural conditions, and liming. We also measured how invertebrate and microbial assemblage structure and microbial function were related to altered leaf breakdown rates. Leaf breakdown rates declined more than threefold along a gradient of stream acidity from pH 6.8 to 4.9. The diversity of leaf-shredding invertebrates, bacteria, and fungi showed little response to variation in pH. The abundance of one acid-sensitive caddisfly, Lepidostoma, declined with acidification, and Lepidostoma abundance explained 37% of the variation in leaf breakdown rates among sites. Microbial respiration was suppressed along the acidity gradient, although the pattern was weaker than that for breakdown rate. In short-term laboratory incubations, microbes at acidic and circumneutral sites demonstrated adaptation to ambient pH. The activity of microbial extracellular enzymes was strongly influenced by pH. In particular, the pattern of activity of phosphatase indicated increasing P limitation of microbes with increasing acidification. Our results show that leaf breakdown is a sensitive tool for examining the response of stream function to acidification and also for defining the mechanisms that drive functional response. Future management efforts should focus on key taxa that are particularly sensitive and effective at shredding leaves and also the role of shifting acidity in mediating the availability of phosphorus to microbial films that are important for stream function.
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Affiliation(s)
- K S Simon
- School of Biology and Ecology, University of Maine, Orono, Maine 04469-5722, USA.
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Simon KS, Townsend CR, Biggs BJF, Bowden WB, Frew RD. Habitat-Specific Nitrogen Dynamics in New Zealand Streams Containing Native or Invasive Fish. Ecosystems 2004. [DOI: 10.1007/s10021-004-0024-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Affiliation(s)
- K. S. Simon
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA
| | - E. F. Benfield
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 USA
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