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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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Oke KB, Cunningham CJ, Westley PAH, Baskett ML, Carlson SM, Clark J, Hendry AP, Karatayev VA, Kendall NW, Kibele J, Kindsvater HK, Kobayashi KM, Lewis B, Munch S, Reynolds JD, Vick GK, Palkovacs EP. Recent declines in salmon body size impact ecosystems and fisheries. Nat Commun 2020; 11:4155. [PMID: 32814776 PMCID: PMC7438488 DOI: 10.1038/s41467-020-17726-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 07/15/2020] [Indexed: 11/21/2022] Open
Abstract
Declines in animal body sizes are widely reported and likely impact ecological interactions and ecosystem services. For harvested species subject to multiple stressors, limited understanding of the causes and consequences of size declines impedes prediction, prevention, and mitigation. We highlight widespread declines in Pacific salmon size based on 60 years of measurements from 12.5 million fish across Alaska, the last largely pristine North American salmon-producing region. Declines in salmon size, primarily resulting from shifting age structure, are associated with climate and competition at sea. Compared to salmon maturing before 1990, the reduced size of adult salmon after 2010 has potentially resulted in substantial losses to ecosystems and people; for Chinook salmon we estimated average per-fish reductions in egg production (-16%), nutrient transport (-28%), fisheries value (-21%), and meals for rural people (-26%). Downsizing of organisms is a global concern, and current trends may pose substantial risks for nature and people.
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Affiliation(s)
- K B Oke
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA.
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, AK, 99801, USA.
| | - C J Cunningham
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, AK, 99801, USA
- Fisheries, Aquatic Science & Technology Laboratory, Alaska Pacific University, Anchorage, AK, 99508, USA
| | - P A H Westley
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
| | - M L Baskett
- Department of Environmental Science and Policy, University of California, Davis, CA, 95616, USA
| | - S M Carlson
- Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - J Clark
- National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, CA, 93101, USA
| | - A P Hendry
- Department of Biology and Redpath Museum, McGill University, Montreal, QC, H3A 2K6, Canada
| | - V A Karatayev
- Department of Environmental Science and Policy, University of California, Davis, CA, 95616, USA
| | - N W Kendall
- Washington Department of Fish and Wildlife, Olympia, WA, 98501, USA
| | - J Kibele
- National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, CA, 93101, USA
| | - H K Kindsvater
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - K M Kobayashi
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - B Lewis
- Division of Commercial Fisheries, Alaska Department of Fish and Game, Anchorage, AK, 99518, USA
| | - S Munch
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
- National Marine Fisheries Service, Fisheries Ecology Division, Southwest Fisheries Science Center, Santa Cruz, CA, 95060, USA
| | - J D Reynolds
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - G K Vick
- GKV & Sons, Contracting to Tanana Chiefs Conference, Fairbanks, AK, 99709, USA
| | - E P Palkovacs
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA.
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Russell AL, Ranivo J, Palkovacs EP, Goodman SM, Yoder AD. Working at the interface of phylogenetics and population genetics: a biogeographical analysis of Triaenops spp. (Chiroptera: Hipposideridae). Mol Ecol 2007; 16:839-51. [PMID: 17284215 DOI: 10.1111/j.1365-294x.2007.03192.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New applications of genetic data to questions of historical biogeography have revolutionized our understanding of how organisms have come to occupy their present distributions. Phylogenetic methods in combination with divergence time estimation can reveal biogeographical centres of origin, differentiate between hypotheses of vicariance and dispersal, and reveal the directionality of dispersal events. Despite their power, however, phylogenetic methods can sometimes yield patterns that are compatible with multiple, equally well-supported biogeographical hypotheses. In such cases, additional approaches must be integrated to differentiate among conflicting dispersal hypotheses. Here, we use a synthetic approach that draws upon the analytical strengths of coalescent and population genetic methods to augment phylogenetic analyses in order to assess the biogeographical history of Madagascar's Triaenops bats (Chiroptera: Hipposideridae). Phylogenetic analyses of mitochondrial DNA sequence data for Malagasy and east African Triaenops reveal a pattern that equally supports two competing hypotheses. While the phylogeny cannot determine whether Africa or Madagascar was the centre of origin for the species investigated, it serves as the essential backbone for the application of coalescent and population genetic methods. From the application of these methods, we conclude that a hypothesis of two independent but unidirectional dispersal events from Africa to Madagascar is best supported by the data.
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Affiliation(s)
- A L Russell
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA.
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