1
|
Palaoro AV, García-Hernández S, Buzatto BA, Machado G. Function predicts the allometry of contest-related traits, but not sexual or male dimorphism in the amazonian tusked harvestman. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10152-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
2
|
Gamble MM, Calsbeek RG. A potential role for restricted intertactical heritability in preventing intralocus conflict. Evol Appl 2021; 14:2576-2590. [PMID: 34815740 PMCID: PMC8591329 DOI: 10.1111/eva.13292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 11/29/2022] Open
Abstract
Intralocus sexual conflict, which arises when the same trait has different fitness optima in males and females, reduces population growth rates. Recently, evolutionary biologists have recognized that intralocus conflict can occur between morphs or reproductive tactics within a sex and that intralocus tactical conflict might constrain tactical dimorphism and population growth rates just as intralocus sexual conflict constrains sexual dimorphism and population growth rates. However, research has only recently focused on sexual and tactical intralocus conflict simultaneously, and there is no formal theory connecting the two. We present a graphical model of how tactical and sexual conflict over the same trait could constrain both sexual and tactical dimorphisms. We then use Coho salmon (Oncorhynchus kisutch), an important species currently protected under the Endangered Species Act, to investigate the possibility of simultaneous sexual and tactical conflict. Larger Coho males gain access to females through fighting while smaller males are favored through sneaking tactics, and female reproductive success is positively correlated with length. We tested for antagonistic selection on length at maturity among sexes and tactics and then used parent-offspring regression to calculate sex- and tactic-specific heritabilities to determine whether and where intralocus conflict exists. Selection on length varied in intensity and form among tactics and years. Length was heritable between dams and daughters (h 2 ± 95% CI = 0.361 ± 0.252) and between fighter males and their fighter sons (0.867 ± 0.312), but no other heritabilities differed significantly from zero. The lack of intertactical heritabilities in this system, combined with similar selection on length among tactics, suggests the absence of intralocus conflict between sexes and among tactics, allowing for the evolution of sexual and tactical dimorphisms. Our results suggest that Coho salmon populations are unlikely to be constrained by intralocus conflict or artificial selection on male tactic.
Collapse
Affiliation(s)
- Madilyn M. Gamble
- Graduate Program in Ecology, Evolution, Ecosystems, and SocietyDartmouth CollegeHanoverNHUSA
| | - Ryan G. Calsbeek
- Graduate Program in Ecology, Evolution, Ecosystems, and SocietyDartmouth CollegeHanoverNHUSA
| |
Collapse
|
3
|
Evidence for genetic integration of mating behavior and morphology in a behaviorally plastic alternative reproductive tactic. Evol Ecol 2021. [DOI: 10.1007/s10682-021-10129-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
4
|
Liotta MN, Abbott JK, Morris MR, Rios‐Cardenas O. Antagonistic selection on body size and sword length in a wild population of the swordtail fish, Xiphophorus multilineatus: Potential for intralocus tactical conflict. Ecol Evol 2021; 11:3941-3955. [PMID: 33976786 PMCID: PMC8093718 DOI: 10.1002/ece3.7288] [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: 12/15/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 11/06/2022] Open
Abstract
Alternative reproductive tactics (ARTs) have provided valuable insights into how sexual selection and life history trade-offs can lead to variation within a sex. However, the possibility that tactics may constrain evolution through intralocus tactical conflict (IATC) is rarely considered. In addition, when IATC has been considered, the focus has often been on the genetic correlations between the ARTs, while evidence that the ARTs have different optima for associated traits and that at least one of the tactics is not at its optimum is often missing. Here, we investigate selection on three traits associated with the ARTs in the swordtail fish Xiphophorus multilineatus; body size, body shape, and the sexually selected trait for which these fishes were named, sword length (elongation of the caudal fin). All three traits are tactically dimorphic, with courter males being larger, deeper bodied and having longer swords, and the sneaker males being smaller, more fusiform and having shorter swords. Using measures of reproductive success in a wild population we calculated selection differentials, as well as linear and quadratic gradients. We demonstrated that the tactics have different optima and at least one of the tactics is not at its optimum for body size and sword length. Our results provide the first evidence of selection in the wild on the sword, an iconic trait for sexual selection. In addition, given the high probability that these traits are genetically correlated to some extent between the two tactics, our study suggests that IATC is constraining both body size and the sword from reaching their phenotypic optima. We discuss the importance of considering the role of IATC in the evolution of tactical dimorphism, how this conflict can be present despite tactical dimorphism, and how it is important to consider this conflict when explaining not only variation within a species but differences across species as well.
Collapse
Affiliation(s)
- Melissa N. Liotta
- Department of Biological SciencesThe Ohio Center for Ecological and Evolutionary StudiesOhio UniversityAthensOHUSA
| | | | - Molly R. Morris
- Department of Biological SciencesThe Ohio Center for Ecological and Evolutionary StudiesOhio UniversityAthensOHUSA
| | | |
Collapse
|
5
|
Moore MN, Sforzini S, Viarengo A, Barranger A, Aminot Y, Readman JW, Khlobystov AN, Arlt VM, Banni M, Jha AN. Antagonistic cytoprotective effects of C 60 fullerene nanoparticles in simultaneous exposure to benzo[a]pyrene in a molluscan animal model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 755:142355. [PMID: 33022458 DOI: 10.1016/j.scitotenv.2020.142355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The hypothesis that C60 fullerene nanoparticles (C60) exert an antagonistic interactive effect on the toxicity of benzo[a]pyrene (BaP) has been supported by this investigation. Mussels were exposed to BaP (5, 50 & 100μg/L) and C60 (C60-1mg/L) separately and in combination. Both BaP and C60 were shown to co-localize in the secondary lysosomes of the hepatopancreatic digestive cells in the digestive gland where they reduced lysosomal membrane stability (LMS) or increased membrane permeability, while BaP also induced increased lysosomal lipid and lipofuscin, indicative of oxidative cell injury and autophagic dysfunction. Combinations of BaP and C60 showed antagonistic effects for lysosomal stability, mTORC1 (mechanistic target of rapamycin complex 1) inhibition and intralysosomal lipid (5 & 50μg/L BaP). The biomarker data (i.e., LMS, lysosomal lipidosis and lipofuscin accumulation; lysosomal/cell volume and dephosphorylation of mTORC1) were further analysed using multivariate statistics. Principal component and cluster analysis clearly indicated that BaP on its own was more injurious than in combination with C60. Use of a network model that integrated the biomarker data for the cell pathophysiological processes, indicated that there were significant antagonistic interactions in network complexity (% connectance) at all BaP concentrations for the combined treatments. Loss of lysosomal membrane stability probably causes the release of intralysosomal iron and hydrolases into the cytosol, where iron can generate harmful reactive oxygen species (ROS). It was inferred that this adverse oxidative reaction induced by BaP was ameliorated in the combination treatments by the ROS scavenging property of intralysosomal C60, thus limiting the injury to the lysosomal membrane; and reducing the oxidative damage in the cytosol and to the nuclear DNA. The ROS scavenging by C60, in combination with enhanced autophagic turnover of damaged cell constituents, appeared to have a cytoprotective effect against the toxic reaction to BaP in the combined treatments.
Collapse
Affiliation(s)
- Michael N Moore
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK; European Centre for Environment & Human Health (ECEHH), University of Exeter Medical School, Knowledge Spa, Royal Cornwall Hospital, Cornwall TR1 3LJ, UK; Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3HD, UK.
| | - Susanna Sforzini
- Institute for the Study of Anthropic Impacts and Sustainability in Marine Environment - IAS, National Research Council - CNR, Via de Marini, 6, 16149 Genova, GE, Italy
| | - Aldo Viarengo
- Institute for the Study of Anthropic Impacts and Sustainability in Marine Environment - IAS, National Research Council - CNR, Via de Marini, 6, 16149 Genova, GE, Italy
| | - Audrey Barranger
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK
| | - Yann Aminot
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK
| | - James W Readman
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK; Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3HD, UK
| | - Andrei N Khlobystov
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK; Nanoscale and Microscale Research Centre, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, King's College London, MRC-PHE Centre for Environmental & Health, London SE1 9NH, UK; Toxicology Department, GAB Consulting GmbH, 69126 Heidelberg, Germany
| | - Mohamed Banni
- Laboratory of Biochemistry and Environmental Toxicology, ISA, Chott-Mariem, Sousse, Tunisia
| | - Awadhesh N Jha
- School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK
| |
Collapse
|
6
|
Berson JD, Zuk M, Simmons LW. Natural and sexual selection on cuticular hydrocarbons: a quantitative genetic analysis. Proc Biol Sci 2020; 286:20190677. [PMID: 31064302 DOI: 10.1098/rspb.2019.0677] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
While the reproductive benefits of sexual displays have been widely studied, we have relatively limited evidence of the fitness costs associated with most display traits. Insect cuticular hydrocarbon (CHC) profiles are sexually selected traits that also protect against desiccation. These two functions are thought to oppose each other, with investment in particular compounds believed to increase attractiveness at the expense of compounds that protect against water loss. We investigated this potential trade-off in a quantitative genetic framework using the Australian field cricket, Teleogryllus oceanicus. Several compounds were significantly genetically correlated with either attractiveness or desiccation resistance. Of these compounds, one was negatively genetically correlated with attractiveness but positively genetically correlated with desiccation resistance. Furthermore, scoring each individual's overall CHC profile for its level of attractiveness and desiccation resistance indicated a negative genetic correlation between these multivariate phenotypes. Together, our results provide evidence for a genetic trade-off between sexually and naturally selected functions of the CHC profile. We suggest that the production of an attractive CHC profile may be costly for males, but highlight the need for further work to support this finding experimentally. Genetic covariation between the CHC profile and attractiveness suggests that females can gain attractive sons through female choice.
Collapse
Affiliation(s)
- Jacob D Berson
- 1 Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia , Crawley, Western Australia 6009 , Australia
| | - Marlene Zuk
- 2 Department of Ecology, Evolution and Behavior, and Minnesota Center for Philosophy of Science, University of Minnesota , Twin Cities, St Paul, MN 55108 , USA
| | - Leigh W Simmons
- 1 Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia , Crawley, Western Australia 6009 , Australia
| |
Collapse
|
7
|
Kerman K, Roggero A, Piccini I, Rolando A, Palestrini C. Dung beetle distress signals may be correlated with sex and male morph: a case study on Copris lunaris (Coleoptera: Scarabaeidae, Coprini). BIOACOUSTICS 2020. [DOI: 10.1080/09524622.2019.1710255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kaan Kerman
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Angela Roggero
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Irene Piccini
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Antonio Rolando
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Claudia Palestrini
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| |
Collapse
|
8
|
Male Horn Lack of Allometry May be Tied to Food Relocation Behaviour in Lifting Dung Beetles (Coleoptera, Scarabaeidae, Eucraniini). INSECTS 2019; 10:insects10100359. [PMID: 31635392 PMCID: PMC6835258 DOI: 10.3390/insects10100359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/12/2019] [Accepted: 10/17/2019] [Indexed: 11/17/2022]
Abstract
The small dung beetle tribe Eucraniini includes extremely specialized species that have been defined as "lifters" according to their food relocation behaviour. They are characterized by the presence of well-developed expansions on the head and pronotum, which can be included in the large and varied group of horns, whose presence is usually related to complex reproductive tactics. In this study, two closely related species, Anomiopsoides cavifrons and A. heteroclyta, were examined employing traditional and geometric morphometrics to test whether the Eucraniini has polymorphic males that might exhibit different reproductive tactics, as in the sister tribe Phanaeini, for which a male trimorphism was demonstrated. If also present in Eucraniini polyphenism could be considered a plesiomorphy common to the two clades. The inter- and intraspecific shape variation and object symmetry of the head and the scaling relationships between body size and traits were evaluated. Marked interspecific and small intraspecific differences in shape variation, high symmetry, and similar isometric growth patterns were shown in both species. The hypothesis of male polymorphism in Anomiopsoides was thus rejected. Instead, the results supported the alternative hypothesis that Eucraniini lacks male polymorphism, perhaps due to functional constraints affecting the shape of the structures involved in their peculiar food relocating behaviour.
Collapse
|
9
|
Abbott J, Rios‐Cardenas O, Morris MR. Insights from intralocus tactical conflict: adaptive states, interactions with ecology and population divergence. OIKOS 2019. [DOI: 10.1111/oik.06264] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Jessica Abbott
- Section for Evolutionary Ecology, Dept of Biology, Univ. Of Lund Sölvegatan 37 SE‐223 62 Lund Swede
| | | | | |
Collapse
|
10
|
Buzatto BA, Kotiaho JS, Assis LAF, Simmons LW. A link between heritable parasite resistance and mate choice in dung beetles. Behav Ecol 2019. [DOI: 10.1093/beheco/arz089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AbstractParasites play a central role in the adaptiveness of sexual reproduction. Sexual selection theory suggests a role for parasite resistance in the context of mate choice, but the evidence is mixed. The parasite-mediated sexual selection (PMSS) hypothesis derives a number of predictions, among which that resistance to parasites is heritable, and that female choice favors parasite resistance genes in males. Here, we tested the PMSS hypothesis using the dung beetle Onthophagus taurus, a species that can be heavily parasitized by Macrocheles merdarius mites, which are known to affect adult survival. We investigated the heritability of resistance to M. merdarius, as well as whether female O. taurus impose a mating bias against males susceptible to mite infestation. Female choice for parasite resistance is difficult to disentangle from the possibility that females are simply choosing less parasitized males due to naturally selected benefits of avoiding contracting those parasites. This is especially likely for ectoparasites, such as mites. We tackled this problem by performing a mate choice trial first, and then measuring a male’s resistance to mite infestation. Resistance to mite infestation exhibited significant levels of additive genetic variance. Although we found no relationship between mating success and parasite resistance, males with greater resistance to infestation mated for longer. If females control copula duration, given that short copulations often result in mating failure, female choice could act on parasite resistance.
Collapse
Affiliation(s)
- Bruno A Buzatto
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, WA, Australia
- Department of Biological Sciences (E8C 209), Macquarie University, Sydney, NSW, Australia
| | - Janne S Kotiaho
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- School of Resource Wisdom, University of Jyväskylä, Jyväskylä, Finland
| | - Larissa A F Assis
- Departamento de Ecologia, Instituto de Biociências, Rua do Matão, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, WA, Australia
| |
Collapse
|
11
|
Liotta MN, Abbott JK, Rios-Cardenas O, Morris MR. Tactical dimorphism: the interplay between body shape and mating behaviour in the swordtail Xiphophorus multilineatus (Cyprinodontiformes: Poeciliidae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz053] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Melissa N Liotta
- Department of Biological Sciences, The Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH, USA
| | | | - Oscar Rios-Cardenas
- Instituto de Ecología A.C., Red de Biología Evolutiva, Xalapa, Veracruz, México
| | - Molly R Morris
- Department of Biological Sciences, The Ohio Center for Ecological and Evolutionary Studies, Ohio University, Athens, OH, USA
| |
Collapse
|
12
|
Moore MN, Wedderburn RJ, Clarke KR, McFadzen IRB, Lowe DM, Readman JW. Emergent synergistic lysosomal toxicity of chemical mixtures in molluscan blood cells (hemocytes). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 235:1006-1014. [PMID: 29751396 DOI: 10.1016/j.envpol.2018.01.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/05/2018] [Accepted: 01/07/2018] [Indexed: 05/24/2023]
Abstract
The problem of effective assessment of risk posed by complex mixtures of toxic chemicals in the environment is a major challenge for government regulators and industry. The biological effect of the individual contaminants, where these are known, can be measured; but the problem lies in relating toxicity to the multiple constituents of contaminant cocktails. The objective of this study was to test the hypothesis that diverse contaminant mixtures may cause a greater toxicity than the sum of their individual parts, due to synergistic interactions between contaminants with different intracellular targets. Lysosomal membrane stability in hemocytes from marine mussels was used for in vitro toxicity tests; and was coupled with analysis using the isobole method and a linear additive statistical model. The findings from both methods have shown significant emergent synergistic interactions between environmentally relevant chemicals (i.e., polycyclic aromatic hydrocarbons, pesticides, biocides and a surfactant) when exposed to isolated hemocytes as a mixture of 3 & 7 constituents. The results support the complexity-based hypothesis that emergent toxicity occurs with increasing contaminant diversity, and raises questions about the validity of estimating toxicity of contaminant mixtures based on the additive toxicity of single components. Further experimentation is required to investigate the potential for interactive effects in mixtures with more constituents (e.g., 50-100) at more environmentally realistic concentrations in order to test other regions of the model, namely, very low concentrations and high diversity. Estimated toxicant diversity coupled with tests for lysosomal damage may provide a potential tool for determining the toxicity of estuarine sediments, dredge spoil or contaminated soil.
Collapse
Affiliation(s)
- M N Moore
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK; University of Exeter Medical School, European Centre for Environment & Human Health (ECEHH), Truro, TR1 3HD, UK; University of Plymouth, School of Biological and Marine Sciences, Drake Circus, Plymouth, PL4 8AA, UK.
| | - R J Wedderburn
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK
| | - K R Clarke
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK
| | - I R B McFadzen
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK; University of Plymouth, School of Biological and Marine Sciences, Drake Circus, Plymouth, PL4 8AA, UK
| | - D M Lowe
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK
| | - J W Readman
- Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK; University of Plymouth, School of Geography, Earth and Environmental Sciences, Drake Circus, Plymouth, PL4 8AA, UK
| |
Collapse
|
13
|
Pike KN, Tomkins JL, Buzatto BA. Mixed evidence for the erosion of intertactical genetic correlations through intralocus tactical conflict. J Evol Biol 2017; 30:1195-1204. [PMID: 28430382 DOI: 10.1111/jeb.13093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 03/17/2017] [Accepted: 04/13/2017] [Indexed: 10/19/2022]
Abstract
Alternative reproductive tactics, whereby members of the same sex use different tactics to secure matings, are often associated with conditional intrasexual dimorphisms. Given the different selective pressures on males adopting each mating tactic, intrasexual dimorphism is more likely to arise if phenotypes are genetically uncoupled and free to evolve towards their phenotypic optima. However, in this context, genetic correlations between male morphs could result in intralocus tactical conflict (ITC). We investigated the genetic architecture of male dimorphism in bulb mites (Rhizoglyphus echinopus) and earwigs (Forficula auricularia). We used half-sibling breeding designs to assess the heritability and intra/intersexual genetic correlations of dimorphic and monomorphic traits in each species. We found two contrasting patterns; F. auricularia exhibited low intrasexual genetic correlations for the dimorphic trait, suggesting that the ITC is moving towards a resolution. Meanwhile, R. echinopus exhibited high and significant intrasexual genetic correlations for most traits, suggesting that morphs in the bulb mite may be limited in evolving to their optima. This also shows that intrasexual dimorphisms can evolve despite strong genetic constraints, contrary to current predictions. We discuss the implications of this genetic constraint and emphasize the potential importance of ITC for our understanding of intrasexual dimorphisms.
Collapse
Affiliation(s)
- K N Pike
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
| | - J L Tomkins
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
| | - B A Buzatto
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
| |
Collapse
|
14
|
Weir LK, Kindsvater HK, Young KA, Reynolds JD. Sneaker Males Affect Fighter Male Body Size and Sexual Size Dimorphism in Salmon. Am Nat 2016; 188:264-71. [PMID: 27420790 DOI: 10.1086/687253] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Large male body size is typically favored by directional sexual selection through competition for mates. However, alternative male life-history phenotypes, such as "sneakers," should decrease the strength of sexual selection acting on body size of large "fighter" males. We tested this prediction with salmon species; in southern populations, where sneakers are common, fighter males should be smaller than in northern populations, where sneakers are rare, leading to geographical clines in sexual size dimorphism (SSD). Consistent with our prediction, fighter male body size and SSD (fighter male∶female size) increase with latitude in species with sneaker males (Atlantic salmon Salmo salar and masu salmon Oncorhynchus masou) but not in species without sneakers (chum salmon Oncorhynchus keta and pink salmon Oncorhynchus gorbuscha). This is the first evidence that sneaker males affect SSD across populations and species, and it suggests that alternative male mating strategies may shape the evolution of body size.
Collapse
|