1
|
Johnson ES. Standardized Approach to Life History Data Collection in Poeciliid Fishes. Ecol Evol 2025; 15:e70735. [PMID: 39975705 PMCID: PMC11836904 DOI: 10.1002/ece3.70735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Revised: 11/27/2024] [Accepted: 12/03/2024] [Indexed: 02/21/2025] Open
Abstract
Livebearing fishes in the family Poeciliidae have been essential to testing life history theory. These species are remarkable because males internally inseminate females, and females give birth to free-swimming young, making these fishes amenable to investigating the evolution of a variety of life history traits, including the timing and nature of maternal reproductive investment, timing of maturity, strategies for maternal provisioning of embryos, and several other classic life history traits. However, researchers vary in the methods that they use to measure these traits, making it difficult to compare findings across studies. Here, I present a standardized approach to studying life history traits in livebearing fishes. I describe methods for preserving samples in the field, for collecting data on a standard set of life history traits, and for processing data in ways that will allow comparisons among studies. I highlight different options in preservation techniques and in data collection that are dependent on the specific questions being addressed. Finally, I argue for a standard approach moving forward to make it possible to complete large-scale comparative studies to reveal how life history traits have evolved in this important model system.
Collapse
Affiliation(s)
- Erik S. Johnson
- Department of BiologyUniversity of MissouriSt. LouisMissouriUSA
- Whitney R. Harris World Ecology CenterSt. LouisMissouriUSA
| |
Collapse
|
2
|
Travis J, Trexler JC. Phenotypic plasticity in the sailfin molly III: Geographic variation in reaction norms of growth and maturation to temperature and salinity. Ecol Evol 2024; 14:e11482. [PMID: 38826157 PMCID: PMC11140554 DOI: 10.1002/ece3.11482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 06/04/2024] Open
Abstract
Phenotypic plasticity, the ability of a single genotype to produce different phenotypes under different environmental conditions, plays a profound role in several areas of evolutionary biology. One important role is as an adaptation to a variable environment. While plasticity is extremely well documented in response to many environmental factors, there is controversy over how much of that plasticity is adaptive. Evidence is also mixed over how often conspecific populations display qualitative differences in the nature of plasticity. We present data on the reaction norms of growth and maturation to variation in temperature and salinity in male and female sailfin mollies (Poecilia latipinna) from three locally adjacent populations from South Carolina (SC). We compare these reaction norms to those previously reported in locally adjacent populations from north Florida (NF). In general, patterns of plasticity in fish from SC were similar to those in fish from NF. The magnitude of plasticity differed; fish from SC displayed less plasticity than fish from NF. This was because SC fish grew faster and matured earlier at the lower temperatures and salinities compared to NF fish. This is a countergradient pattern of variation, in which SC fish grew faster and matured earlier in conditions that would otherwise slow growth and delay maturity. Among fish from both regions, males were much less plastic than females, especially for length at maturity. While there was no detectable heterogeneity among populations from NF, males from one of the SC populations, which is furthest from the other two, displayed a qualitatively different response in age at maturity to temperature variation than did males from the other two SC populations. The pattern of population variation in plasticity within and among regions suggests that gene flow, which diminishes with distance in sailfin mollies, plays a critical role in constraining divergence in norms of reaction.
Collapse
Affiliation(s)
- Joseph Travis
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| | - Joel C. Trexler
- Department of Biological ScienceFlorida State UniversityTallahasseeFloridaUSA
| |
Collapse
|
3
|
Travis J, Bassar RD, Coulson T, Lopez-Sepulcre A, Reznick D. Population Regulation and Density-Dependent Demography in the Trinidadian Guppy. Am Nat 2023; 202:413-432. [PMID: 37792920 DOI: 10.1086/725796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
AbstractClassic theory for density-dependent selection for delayed maturation requires that a population be regulated through some combination of adult fecundity and/or juvenile survival. We tested whether those demographic conditions were met in four experimental populations of Trinidadian guppies in which delayed maturation of males evolved when the densities of those populations became high. We used monthly mark-recapture data to examine population dynamics and demography in these populations. Three of the four populations displayed clear evidence of regulation. In all four populations, monthly adult survival rates were independent of biomass density or actually increased with increased biomass density. Juvenile recruitment, which is a combination of adult fecundity and juvenile survival, decreased as biomass density increased in all four populations. Demography showed marked seasonality, with greater survival and higher recruitment in the dry season than the wet season. Population regulation via juvenile recruitment supports the hypothesis that density-dependent selection was responsible for the evolution of delayed maturity in males. This body of work represents one of the few complete tests of density-dependent selection theory.
Collapse
|
4
|
Blake A, Marshall DJ. Copepod life history evolution under high- and low-food regimes. Evol Appl 2023; 16:1274-1283. [PMID: 37492146 PMCID: PMC10363812 DOI: 10.1111/eva.13563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/04/2023] [Accepted: 05/09/2023] [Indexed: 07/27/2023] Open
Abstract
Copepods play a critical role in the carbon cycle of the planet - they mediate the sequestration of carbon into the deep ocean and are the trophic link between phytoplankton and marine food webs. Global change stressors that decrease copepod productivity create the potential for catastrophic positive feedback loops. Accordingly, a growing list of studies examine the evolutionary capacity of copepods to adapt to the two primary stressors associated with global change: warmer temperatures and lower pH. But the evolutionary capacity of copepods to adapt to changing food regimes, the third major stressor associated with global change, remains unknown. We used experimental evolution to explore how a 10-fold difference in food availability affects life history evolution in the copepod, Tisbe sp. over 2 years, and spanning 30+ generations. Different food regimes evoked evolutionary responses across the entire copepod life history: we observed evolution in body size, size-fecundity relationships and offspring investment strategies. Our results suggest that changes to food regimes reshape life histories and that cryptic evolution in traits such as body size is likely. We demonstrate that evolution in response to changes in ocean productivity will alter consumer life histories and may distort trophic links in marine foodchains. Evolution in response to changing phytoplankton productivity may alter the efficacy of the global carbon pump in ways that have not been anticipated until now.
Collapse
Affiliation(s)
- Alexander Blake
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
| | | |
Collapse
|
5
|
Potter T, Arendt J, Bassar RD, Watson B, Bentzen P, Travis J, Reznick DN. Female preference for rare males is maintained by indirect selection in Trinidadian guppies. Science 2023; 380:309-312. [PMID: 37079663 DOI: 10.1126/science.ade5671] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
When females prefer mates with rare phenotypes, sexual selection can maintain rather than deplete genetic variation. However, there is no consensus on why this widespread and frequently observed preference might evolve and persist. We examine the fitness consequences of female preference for rare male color patterns in a natural population of Trinidadian guppies, using a pedigree that spans 10 generations. We demonstrate (i) a rare male reproductive advantage, (ii) that females that mate with rare males gain an indirect fitness advantage through the mating success of their sons, and (iii) the fitness benefit that females accrue through their "sexy sons" evaporates for their grandsons as their phenotype becomes common. Counter to prevailing theory, we show that female preference can be maintained through indirect selection.
Collapse
Affiliation(s)
- Tomos Potter
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Jeff Arendt
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, California, USA
| | - Ronald D Bassar
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Beth Watson
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Paul Bentzen
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Joseph Travis
- Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - David N Reznick
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, California, USA
| |
Collapse
|
6
|
van der Zee MJ, Whiting JR, Paris JR, Bassar RD, Travis J, Weigel D, Reznick DN, Fraser BA. Rapid genomic convergent evolution in experimental populations of Trinidadian guppies ( Poecilia reticulata). Evol Lett 2022; 6:149-161. [PMID: 35386829 PMCID: PMC8966473 DOI: 10.1002/evl3.272] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 12/08/2021] [Accepted: 12/14/2021] [Indexed: 01/14/2023] Open
Abstract
Although rapid phenotypic evolution has been documented often, the genomic basis of rapid adaptation to natural environments is largely unknown in multicellular organisms. Population genomic studies of experimental populations of Trinidadian guppies (Poecilia reticulata) provide a unique opportunity to study this phenomenon. Guppy populations that were transplanted from high-predation (HP) to low-predation (LP) environments have been shown to evolve toward the phenotypes of naturally colonized LP populations in as few as eight generations. These changes persist in common garden experiments, indicating that they have a genetic basis. Here, we report results of whole genome variation in four experimental populations colonizing LP sites along with the corresponding HP source population. We examined genome-wide patterns of genetic variation to estimate past demography and used a combination of genome scans, forward simulations, and a novel analysis of allele frequency change vectors to uncover the signature of selection. We detected clear signals of population growth and bottlenecks at the genome-wide level that matched the known history of population numbers. We found a region on chromosome 15 under strong selection in three of the four populations and with our multivariate approach revealing subtle parallel changes in allele frequency in all four populations across this region. Investigating patterns of genome-wide selection in this uniquely replicated experiment offers remarkable insight into the mechanisms underlying rapid adaptation, providing a basis for comparison with other species and populations experiencing rapidly changing environments.
Collapse
Affiliation(s)
| | | | | | - Ron D. Bassar
- Department of BiologyWilliams CollegeWilliamstownMassachusetts01267
| | - Joseph Travis
- Department of Biological ScienceFlorida State UniversityTallahasseeFlorida32306
| | - Detlef Weigel
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingen72076Germany
| | - David N. Reznick
- Department of BiologyUniversity of California, RiversideRiversideCalifornia92521
| | | |
Collapse
|
7
|
Felmy A, Reznick DN, Travis J, Potter T, Coulson T. Life histories as mosaics: plastic and genetic components differ among traits that underpin life-history strategies. Evolution 2022; 76:585-604. [PMID: 35084046 PMCID: PMC9303950 DOI: 10.1111/evo.14440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 12/23/2021] [Accepted: 01/05/2022] [Indexed: 11/29/2022]
Abstract
Life‐history phenotypes emerge from clusters of traits that are the product of genes and phenotypic plasticity. If the impact of the environment differs substantially between traits, then life histories might not evolve as a cohesive whole. We quantified the sensitivity of components of the life history to food availability, a key environmental difference in the habitat occupied by contrasting ecotypes, for 36 traits in fast‐ and slow‐reproducing Trinidadian guppies. Our dataset included six putatively independent origins of the slow‐reproducing, derived ecotype. Traits varied substantially in plastic and genetic control. Twelve traits were influenced only by food availability (body lengths, body weights), five only by genetic differentiation (interbirth intervals, offspring sizes), 10 by both (litter sizes, reproductive timing), and nine by neither (fat contents, reproductive allotment). Ecotype‐by‐food interactions were negligible. The response to low food was aligned with the genetic difference between high‐ and low‐food environments, suggesting that plasticity was adaptive. The heterogeneity among traits in environmental sensitivity and genetic differentiation reveals that the components of the life history may not evolve in concert. Ecotypes may instead represent mosaics of trait groups that differ in their rate of evolution.
Collapse
Affiliation(s)
- Anja Felmy
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, United Kingdom
| | - David N Reznick
- Department of Evolution, Ecology and Organismal Biology, University of California, Riverside, California, 922521, USA
| | - Joseph Travis
- Department of Biological Science, Florida State University, Tallahassee, Florida, 32306, USA
| | - Tomos Potter
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, United Kingdom
| | - Tim Coulson
- Department of Zoology, University of Oxford, Oxford, OX1 3SZ, United Kingdom
| |
Collapse
|
8
|
Coulson T, Potter T, Felmy A. Predicting evolution over multiple generations in deteriorating environments using evolutionarily explicit Integral Projection Models. Evol Appl 2021; 14:2490-2501. [PMID: 34745339 PMCID: PMC8549625 DOI: 10.1111/eva.13272] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/20/2021] [Accepted: 06/25/2021] [Indexed: 11/27/2022] Open
Abstract
Human impacts on the natural world often generate environmental trends that can have detrimental effects on distributions of phenotypic traits. We do not have a good understanding of how deteriorating environments might impact evolutionary trajectories across multiple generations, even though effects of environmental trends are often significant in the statistical quantitative genetic analyses of phenotypic trait data that are used to estimate additive genetic (co)variances. These environmental trends capture reaction norms, where the same (average) genotype expresses different phenotypic trait values in different environments. Not incorporated into the predictive models typically parameterised from statistical analyses to predict evolution, such as the breeder's equation. We describe how these environmental effects can be incorporated into multi-generational, evolutionarily explicit, structured population models before exploring how these effects can influence evolutionary dynamics. The paper is primarily a description of the modelling approach, but we also show how incorporation into models of the types of environmental trends that human activity has generated can have considerable impacts on the evolutionary dynamics that are predicted.
Collapse
Affiliation(s)
- Tim Coulson
- Department of ZoologyUniversity of OxfordOxfordUK
| | - Tomos Potter
- Department of ZoologyUniversity of OxfordOxfordUK
| | - Anja Felmy
- Department of ZoologyUniversity of OxfordOxfordUK
| |
Collapse
|
9
|
Potter T, Reznick DN, Coulson T. Substantial intraspecific variation in energy budgets: Biology or artefact? Funct Ecol 2021. [DOI: 10.1111/1365-2435.13847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tomos Potter
- Department of Zoology University of Oxford Oxford UK
| | - David N. Reznick
- Department of Evolution, Ecology and Organismal Biology University of California Riverside CA USA
| | - Tim Coulson
- Department of Zoology University of Oxford Oxford UK
| |
Collapse
|