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Cox CL, Logan ML, Nicholson DJ, Chung AK, Rosso AA, McMillan WO, Cox RM. Species-Specific Expression of Growth-Regulatory Genes in 2 Anoles with Divergent Patterns of Sexual Size Dimorphism. Integr Org Biol 2022; 4:obac025. [PMID: 35958165 PMCID: PMC9362763 DOI: 10.1093/iob/obac025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 05/20/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
Synopsis
Sexual size dimorphism is widespread in nature and often develops through sexual divergence in growth trajectories. In vertebrates, the growth hormone/insulin-like growth factor (GH/IGF) network is an important regulator of growth, and components of this network are often regulated in sex-specific fashion during the development of sexual size dimorphism. However, expression of the GH/IGF network is not well characterized outside of mammalian model systems, and the extent to which species differences in sexual size dimorphism are related to differences in GH/IGF network expression is unclear. To begin bridging this gap, we compared GH/IGF network expression in liver and muscle from 2 lizard congeners, one with extreme male-biased sexual size dimorphism (brown anole, Anolis sagrei), and one that is sexually monomorphic in size (slender anole, A. apletophallus). Specifically, we tested whether GH/IGF network expression in adult slender anoles resembles the highly sex-biased expression observed in adult brown anoles or the relatively unbiased expression observed in juvenile brown anoles. We found that adults of the 2 species differed significantly in the strength of sex-biased expression for several key upstream genes in the GH/IGF network, including insulin-like growth factors 1 and 2. However, species differences in sex-biased expression were minor when comparing adult slender anoles to juvenile brown anoles. Moreover, the multivariate expression of the entire GH/IGF network (as represented by the first two principal components describing network expression) was sex-biased for the liver and muscle of adult brown anoles, but not for either tissue in juvenile brown anoles or adult slender anoles. Our work suggests that species differences in sex-biased expression of genes in the GH/IGF network (particularly in the liver) may contribute to the evolution of species differences in sexual size dimorphism.
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Affiliation(s)
- Christian L Cox
- Florida International University , 11200 SW 8th St, Miami, FL 33199 , USA
- Smithsonian Tropical Research Institute , Amador Causeway, Panama City , Panama
- Georgia Southern University , 1332 Southern Dr, Statesboro, GA 30458 , USA
| | - Michael L Logan
- Smithsonian Tropical Research Institute , Amador Causeway, Panama City , Panama
- University of Nevada Reno , 1664 N Virginia St, Reno, NV 89557 , USA
| | - Daniel J Nicholson
- Smithsonian Tropical Research Institute , Amador Causeway, Panama City , Panama
- Queen Mary University , Mile End Rd, Bethnal Green, London E1 4NS , UK
- University of Texas-Arlington , 701 S Nedderman Dr. Arlington, TX 76019 , USA
| | - Albert K Chung
- Smithsonian Tropical Research Institute , Amador Causeway, Panama City , Panama
- Georgia Southern University , 1332 Southern Dr, Statesboro, GA 30458 , USA
- University of Texas-Arlington , 701 S Nedderman Dr. Arlington, TX 76019 , USA
- Princeton University , Princeton, NJ 08544 , USA
| | - Adam A Rosso
- Georgia Southern University , 1332 Southern Dr, Statesboro, GA 30458 , USA
| | - W Owen McMillan
- Smithsonian Tropical Research Institute , Amador Causeway, Panama City , Panama
| | - Robert M Cox
- University of Virginia , Charlottesville, VA 22904 , USA
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2
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Anderson AP, Jones AG. The relationship between sexual dimorphism and androgen response element proliferation in primate genomes. Evolution 2022; 76:1331-1346. [PMID: 35420699 PMCID: PMC9321733 DOI: 10.1111/evo.14483] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 03/04/2022] [Accepted: 03/13/2022] [Indexed: 01/22/2023]
Abstract
In the males of many vertebrate species, sexual selection has led to the evolution of sexually dimorphic traits, which often are developmentally controlled by androgen signaling involving androgen response elements (AREs). Evolutionary changes in the number and genomic locations of AREs can modify patterns of receptor regulation and potentially alter gene expression. Here, we use recently sequenced primate genomes to evaluate the hypothesis that the strength of sexual selection is related to the genome-wide number of AREs in a diversifying lineage. In humans, we find a higher incidence of AREs near male-biased genes and androgen-responsive genes when compared to randomly selected genes from the genome. In a set of primates, we find that gains or losses of AREs proximal to genes are correlated with changes in male expression levels and the degree of sex-biased expression of those genes. In a larger set of primates, we find that increases in indicators of sexual selection are correlated with genome-wide ARE counts. Our results suggest that the responsiveness of the genome to androgens in humans and their close relatives has been shaped by sexual selection that arises from competition among males for mating access to females.
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Affiliation(s)
| | - Adam G. Jones
- Department of BiologyUniversity of IdahoMoscowIdaho83844
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3
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Selection on Sperm Count, but Not on Sperm Morphology or Velocity, in a Wild Population of Anolis Lizards. Cells 2021; 10:cells10092369. [PMID: 34572018 PMCID: PMC8464841 DOI: 10.3390/cells10092369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/04/2021] [Accepted: 09/06/2021] [Indexed: 12/25/2022] Open
Abstract
Sperm competition is a widespread phenomenon that shapes male reproductive success. Ejaculates present many potential targets for postcopulatory selection (e.g., sperm morphology, count, and velocity), which are often highly correlated and potentially subject to complex multivariate selection. Although multivariate selection on ejaculate traits has been observed in laboratory experiments, it is unclear whether selection is similarly complex in wild populations, where individuals mate frequently over longer periods of time. We measured univariate and multivariate selection on sperm morphology, sperm count, and sperm velocity in a wild population of brown anole lizards (Anolis sagrei). We conducted a mark-recapture study with genetic parentage assignment to estimate individual reproductive success. We found significant negative directional selection and negative quadratic selection on sperm count, but we did not detect directional or quadratic selection on any other sperm traits, nor did we detect correlational selection on any trait combinations. Our results may reflect pressure on males to produce many small ejaculates and mate frequently over a six-month reproductive season. This study is the first to measure multivariate selection on sperm traits in a wild population and provides an interesting contrast to experimental studies of external fertilizers, which have found complex multivariate selection on sperm phenotypes.
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4
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Janicke T, Fromonteil S. Sexual selection and sexual size dimorphism in animals. Biol Lett 2021; 17:20210251. [PMID: 34520680 PMCID: PMC8440037 DOI: 10.1098/rsbl.2021.0251] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/23/2021] [Indexed: 11/12/2022] Open
Abstract
Sexual selection is often considered as a critical evolutionary force promoting sexual size dimorphism (SSD) in animals. However, empirical evidence for a positive relationship between sexual selection on males and male-biased SSD received mixed support depending on the studied taxonomic group and on the method used to quantify sexual selection. Here, we present a meta-analytic approach accounting for phylogenetic non-independence to test how standardized metrics of the opportunity and strength of pre-copulatory sexual selection relate to SSD across a broad range of animal taxa comprising up to 95 effect sizes from 59 species. We found that SSD based on length measurements was correlated with the sex difference in the opportunity for sexual selection but showed a weak and statistically non-significant relationship with the sex difference in the Bateman gradient. These findings suggest that pre-copulatory sexual selection plays a limited role for the evolution of SSD in a broad phylogenetic context.
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Affiliation(s)
- Tim Janicke
- Centre d’Écologie Fonctionnelle et Évolutive, UMR 5175 CNRS, Université de Montpellier, École Pratique des Hautes Études, Montpellier, France
- Applied Zoology, Technical University Dresden, Zellescher Weg 20b, Dresden 01062, Germany
| | - Salomé Fromonteil
- Centre d’Écologie Fonctionnelle et Évolutive, UMR 5175 CNRS, Université de Montpellier, École Pratique des Hautes Études, Montpellier, France
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5
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De Nardo AN, Roy J, Sbilordo SH, Lüpold S. Condition-dependent interaction between mating success and competitive fertilization success in Drosophila melanogaster. Evolution 2021; 75:2014-2026. [PMID: 33834478 DOI: 10.1111/evo.14228] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/06/2021] [Accepted: 03/13/2021] [Indexed: 12/12/2022]
Abstract
Dietary restriction during development can affect adult body size and condition. In many species, larger (high-condition) males gain higher mating success through male-male competition and female choice, and female condition can affect the extent of both female mate choice and male investment in courtship or ejaculates. However, few studies have examined the joint effects and interplay of male and female condition during both the pre- and the postcopulatory phases of sexual selection. We therefore manipulated the larval diet of male and female Drosophila melanogaster to study how body size variation in both sexes biases competitive outcomes at different reproductive stages, from mating to paternity. We did not find a difference in mate preference or mating latency between females of different conditions, nor any interaction between male and female conditions. However, large males were more successful in gaining matings, but only when in direct competition, whereas mating latencies were shorter for low-condition males in noncompetitive settings. Small males also transferred more sperm to nonvirgin females, displaced a larger proportion of resident sperm, and achieved higher paternity shares per mating than large males. In agreement with existing theory, we suggest that small males might partially compensate for their low mating success by strategically investing in larger sperm numbers and potentially other, unmeasured ejaculate traits, when they do have a mating opportunity.
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Affiliation(s)
- Alessio N De Nardo
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Jeannine Roy
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Sonja H Sbilordo
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
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6
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Cox CL, Logan ML. Using Integrative Biology to Infer Adaptation from Comparisons of Two (or a Few) Species. Physiol Biochem Zool 2021; 94:162-170. [PMID: 33821779 DOI: 10.1086/714018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractPhylogenetic comparative methods represent a major advance in integrative and comparative biology and have allowed researchers to rigorously test for adaptation in a macroevolutionary framework. However, phylogenetic comparative methods require trait data for many species, which is impractical for certain taxonomic groups and trait types. We propose that the philosophical principle of severity can be implemented in an integrative framework to generate strong inference of adaptation in studies that compare only a few populations or species. This approach requires (1) ensuring that the study system contains species that are relatively closely related; (2) formulating a specific, clear, overarching hypothesis that can be subjected to integrative testing across levels of biological organization (e.g., ecology, behavior, morphology, physiology, and genetics); (3) collecting data that avoid statistical underdetermination and thus allow severe tests of hypotheses; and (4) systematically refining and refuting alternative hypotheses. Although difficult to collect for more than a few species, detailed, integrative data can be used to differentiate among several potential agents of selection. In this way, integrative studies of small numbers of closely related species can complement and even improve on broadscale phylogenetic comparative studies by revealing the specific drivers of adaptation.
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7
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Friesen CR, Mason RT, Uhrig EJ. Postcopulatory sexual selection as a driver of sex- and population-specific kidney mass in garter snakes? Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Abstract
In lizards and snakes, the kidneys produce seminal fluid in addition to having osmoregulatory functions. Therefore, in response to polyandry, kidney mass should be under selection regimes such as those influencing testes. Male red-sided garter snakes deposit a kidney-derived copulatory plug that functions in sperm competition. We first tested for intersexual differences in kidney mass and allometry in one population and found that males had kidneys twice as heavy as those of females, consistent with stronger selection on male kidney mass. Previous studies have shown that male size enhances mating success in one-on-one competition prevalent in small mating aggregations. We then examined the relationship between body size, kidney mass and testes mass in two populations with low (LD) and high (HD) mating aggregation densities. Males from the HD population had heavier testes and heavier kidneys compared with males from the LD population; HD males were also smaller in body size. Our results suggest that the strength of sexual selection, and possibly the balance between pre- and postcopulatory selection, varies in response to population size or density. However, more replication is needed to confirm the generality of these results within red-sided garter snakes and other squamate reptiles.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Robert T Mason
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Emily J Uhrig
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
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8
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Measuring Pre- and Post-Copulatory Sexual Selection and Their Interaction in Socially Monogamous Species with Extra-Pair Paternity. Cells 2021; 10:cells10030620. [PMID: 33799610 PMCID: PMC7999480 DOI: 10.3390/cells10030620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 01/08/2023] Open
Abstract
When females copulate with multiple males, pre- and post-copulatory sexual selection may interact synergistically or in opposition. Studying this interaction in wild populations is complex and potentially biased, because copulation and fertilization success are often inferred from offspring parentage rather than being directly measured. Here, I simulated 15 species of socially monogamous birds with varying levels of extra-pair paternity, where I could independently cause a male secondary sexual trait to improve copulation success, and a sperm trait to improve fertilization success. By varying the degree of correlation between the male and sperm traits, I show that several common statistical approaches, including univariate selection gradients and paired t-tests comparing extra-pair males to the within-pair males they cuckolded, can give highly biased results for sperm traits. These tests should therefore be avoided for sperm traits in socially monogamous species with extra-pair paternity, unless the sperm trait is known to be uncorrelated with male trait(s) impacting copulation success. In contrast, multivariate selection analysis and a regression of the proportion of extra-pair brood(s) sired on the sperm trait of the extra-pair male (including only broods where the male sired ≥1 extra-pair offspring) were unbiased, and appear likely to be unbiased under a broad range of conditions for this mating system. In addition, I investigated whether the occurrence of pre-copulatory selection impacted the strength of post-copulatory selection, and vice versa. I found no evidence of an interaction under the conditions simulated, where the male trait impacted only copulation success and the sperm trait impacted only fertilization success. Instead, direct selection on each trait was independent of whether the other trait was under selection. Although pre- and post-copulatory selection strength was independent, selection on the two traits was positively correlated across species because selection on both traits increased with the frequency of extra-pair copulations in these socially monogamous species.
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9
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Rosso AA, Nicholson DJ, Logan ML, Chung AK, Curlis JD, Degon ZM, Knell RJ, Garner TWJ, McMillan WO, Cox CL. Sex-biased parasitism and expression of a sexual signal. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Given that sexual signals are often expressed more highly in one sex than the other, they can impose a sex-specific cost of reproduction through parasitism. The two primary paradigms regarding the relationship of parasites to sexual signals are the good genes hypothesis and the immunocompetence handicap hypothesis; however, there are other ecological, morphological and energetic factors that might influence parasite infections in a sex-specific fashion. We tested the relationship between expression of a sexual signal (the dewlap) and ecological, morphological and energetic factors mediating ectoparasite (mite) load between male and female Panamanian slender anoles (Anolis apletophallus). We found that males were more highly parasitized than females because of the preponderance of ectoparasites on the larger dewlap of males. Indeed, ectoparasite infection increased with both body size and dewlap size in males but not in females, and parasite infection was related to energy storage in a sex-specific fashion for the fat bodies, liver and gonads. Our work and previous work on testosterone in anoles suggests that this pattern did not arise solely from immunosuppression by testosterone, but that mites prefer the dewlap as an attachment site. Thus, the expression of this sexual signal could incur a fitness cost that might structure life-history trade-offs.
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Affiliation(s)
- Adam A Rosso
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - Daniel J Nicholson
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Michael L Logan
- Department of Biology, University of Nevada-Reno, Reno, NV, USA
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Albert K Chung
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
- Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | - John David Curlis
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Zachariah M Degon
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
| | - Robert J Knell
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | | | - W Owen McMillan
- Department of Biology, University of Nevada-Reno, Reno, NV, USA
| | - Christian L Cox
- Department of Biology, Georgia Southern University, Statesboro, GA, USA
- Institute of Environment and Department of Biological Sciences, Florida International University, Miami, FL, USA
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10
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Glaudas X, Rice SE, Clark RW, Alexander GJ. The intensity of sexual selection, body size and reproductive success in a mating system with male–male combat: is bigger better? OIKOS 2020. [DOI: 10.1111/oik.07223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xavier Glaudas
- School of Animal, Plant and Environmental Sciences, Univ. of the Witwatersrand Johannesburg PO Wits 2050 South Africa
| | - Stephen E. Rice
- Dept of Biology, San Diego State Univ. San Diego CA USA
- Dept of Natural Sciences, Fairmont State Univ. Fairmont WV USA
| | | | - Graham J. Alexander
- School of Animal, Plant and Environmental Sciences, Univ. of the Witwatersrand Johannesburg PO Wits 2050 South Africa
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11
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Durrant KL, Reader T, Symonds MRE. Pre- and post-copulatory traits working in concert: sexual dichromatism in passerines is associated with sperm morphology. Biol Lett 2020; 16:20190568. [PMID: 31937213 DOI: 10.1098/rsbl.2019.0568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Passerine birds produce costly traits under intense sexual selection, including elaborate sexually dichromatic plumage and sperm morphologies, to compete for fertilizations. Plumage and sperm traits vary markedly among species, but it is unknown if this reflects a trade-off between pre- and post-copulatory investment under strong sexual selection producing negative trait covariance, or variation in the strength of sexual selection among species producing positive covariance. Using phylogenetic regression, we analysed datasets describing plumage and sperm morphological traits for 278 passerine species. We found a significant positive relationship between sperm midpiece length and male plumage elaboration and sexual dichromatism. We did not find a relationship between plumage elaboration and testes mass. Our results do not support a trade-off between plumage and sperm traits, but may be indicative of variance among species in the strength of sexual selection to produce both brightly coloured plumage and costly sperm traits.
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Affiliation(s)
- Kate L Durrant
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Tom Reader
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Matthew R E Symonds
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
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12
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Meniri M, Gohon F, Gning O, Glauser G, Vallat A, Fasel NJ, Helfenstein F. Experimental manipulation of reproductive tactics in Seba's short-tailed bats: consequences on sperm quality and oxidative status. Curr Zool 2019; 65:609-616. [PMID: 31857807 PMCID: PMC6911846 DOI: 10.1093/cz/zoz011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/14/2019] [Indexed: 12/25/2022] Open
Abstract
To reproduce, males have to fertilize the female's eggs, sometimes in competition with ejaculates of other males. In species where males display alternative reproductive tactics, whereby territorial males secure mating and non-territorial males have to sneak copulations, the latter might be expected to invest relatively more resources towards sperm quality compared with the territorial males. Sperm cells are especially vulnerable to oxidative stress, which reduces male fertility. Therefore, antioxidant resources are expected to modulate sperm quality, and might be allocated differently between reproductive tactics. To test the link between reproductive tactics, redox profile and sperm quality, we experimentally induced changes in the reproductive tactics of 39 captive males Seba's short-tailed bats Carollia perspicillata. We monitored the blood and ejaculate oxidative balance, and the sperm quality before, 7 days and 21 days after the manipulation of reproductive tactic. Although ejaculates' oxidative damage was negatively related to sperm velocity, males exhibited similar blood and ejaculates redox profiles and similar sperm quality, regardless of their reproductive tactic. Possibly, these results arise as a consequence of some constraints having been lifted during the experiment. Our results also suggest that, in Seba's short-tailed bats, the expression of alternative reproductive tactics is not subjected to strong oxidative constraints. Furthermore, our results could reflect an absence of trade-off between pre- and post-copulatory traits in harem males, as they could be selected to invest both in female attraction and sperm quality, as a consequence of their inability to fully monopolize females.
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Affiliation(s)
- Magali Meniri
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Florence Gohon
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Ophélie Gning
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
| | - Gaétan Glauser
- Neuchatel Platform of Analytical Chemistry, University of Neuchâtel, Switzerland
| | - Armelle Vallat
- Neuchatel Platform of Analytical Chemistry, University of Neuchâtel, Switzerland
| | | | - Fabrice Helfenstein
- Laboratory of Evolutionary Ecophysiology, Institute of Biology, University of Neuchâtel, Switzerland
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13
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Friesen CR, Shine R. At the invasion front, male cane toads (Rhinella marina) have smaller testes. Biol Lett 2019; 15:20190339. [PMID: 31337295 DOI: 10.1098/rsbl.2019.0339] [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: 01/05/2023] Open
Abstract
As a colonizing species expands its range, individuals at the invasion front experience different evolutionary pressures than do those at the range-core. For example, low densities at the edge of the range mean that males should rarely experience intense sperm competition from rivals; and investment into reproduction may trade-off with adaptations for more rapid dispersal. Both of these processes are predicted to favour a reduction in testis size at the invasion front. To explore effects of invasion stage in Australian cane toads (Rhinella marina), we collected and dissected 214 adult males from three regions: one in the species' range-core (northeastern Australia), and two from invasion fronts (one in northwestern Australia and one in southeastern Australia). Despite the brief duration of separation between toads in these areas (approx. 85 years), testis masses averaged greater than 30% higher (as a proportion of body mass) in range-core males than in conspecifics sampled from either vanguard of the invasion. Previous work has documented low reproductive frequencies in female cane toads at the invasion front also, consistent with the hypothesis that evolutionary and ecological pressures unleashed by an invasion can favour relatively low resource allocation to reproduction in both sexes.
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Affiliation(s)
- Christopher R Friesen
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.,School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.,Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
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14
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Friesen CR, de Graaf SP, Olsson M. The relationship of body condition, superoxide dismutase, and superoxide with sperm performance. Behav Ecol 2019. [DOI: 10.1093/beheco/arz086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract
Sperm competition theory predicts a negative correlation between somatic investment and traits that aid in pre- and postcopulatory sexual selection. Sperm performance is critical for postcopulatory success but sperm are susceptible to damage by free radicals such as superoxide radicals generated during mitochondrial respiration (mtSOx). Males can ameliorate damage to spermatozoa by investing in the production of antioxidants, like superoxide dismutase (SOD), which may act as a mechanistic link to pre- and postcopulatory trade-offs. Some male Australian, color-polymorphic painted dragon lizards (Ctenophorus pictus) possess a yellow throat patch (bib) that females prefer over nonbibbed males and are also more likely to win male–male contests indicating that males with bibs may be better at monopolizing females. We tested whether the sperm performance in nonbibbed males was superior to that of bibbed males. We show that overall sperm performance was not different between the bib-morphs, however, higher mtSOx levels were negatively correlated with sperm performance in bibbed males, but not of nonbibbed males. Blood cell mtSOx levels are negatively correlated with SOD activity in the plasma in all males early in the breeding season but SOD was lower in bibbed males. Nonbibbed males maintain a positive correlation between body condition and SOD activity over time while bibbed males do not. Together, these data suggest physiological associations between body condition, SOD activity, and sperm performance are linked to the expression of a yellow gular patch, which may be related to intrinsic differences in the metabolism of bibbed versus nonbibbed males.
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Affiliation(s)
- Christopher R Friesen
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Ross St. Camperdown, NSW Australia, Australia
| | - Simon P de Graaf
- Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Ross St. Camperdown, NSW Australia, Australia
| | - Mats Olsson
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Department of Biological & Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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15
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Lüpold S, Simmons LW, Grueter CC. Sexual ornaments but not weapons trade off against testes size in primates. Proc Biol Sci 2019; 286:20182542. [PMID: 30966988 PMCID: PMC6501695 DOI: 10.1098/rspb.2018.2542] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 03/18/2019] [Indexed: 12/27/2022] Open
Abstract
Males must partition their limited reproductive investments between traits that promote access to females (sexual ornaments and weapons) and traits that enhance fertilization success, such as testes and ejaculates. Recent studies show that if the most weaponized males can monopolize access to females through contest competition, thereby reducing the risk of sperm competition, they tend to invest less in sperm production. However, how males invest in sexual ornaments relative to sperm production remains less clear. If male ornaments serve as badges of status, with high-ranking males attaining near-exclusive access to females, similar to monopolizing females through combat, their expression should also covary negatively with investment in post-mating traits. In a comparative study across primates, which exhibit considerable diversification in sexual ornamentation, male weaponry and testes size, we found relative testes size to decrease with sexual ornaments but increase with canine size. These contrasting evolutionary trajectories might be driven by differential selection, functional constraints or temporal patterns of metabolic investment between the different types of sexual traits. Importantly, however, our results indicate that the theory of relative investments between weapons and testes in the context of monopolizing females can extend to male ornaments.
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Affiliation(s)
- Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Cyril C. Grueter
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, Western Australia 6009, Australia
- School of Human Sciences (M309), The University of Western Australia, Crawley, Western Australia 6009, Australia
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16
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Nguyen K, Stahlschmidt Z. When to fight? Disentangling temperature and circadian effects on aggression and agonistic contests. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2018.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Supriya K, Price TD, Rowe M. Resource variation generates positive correlations between pre- and postcopulatory sexual traits. Behav Ecol 2018. [DOI: 10.1093/beheco/ary170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- K Supriya
- Committee on Evolutionary Biology, University of Chicago, Chicago, USA
| | - Trevor D Price
- Department of Ecology and Evolution, University of Chicago, Chicago, USA
| | - Melissah Rowe
- Natural History Museum, University of Oslo, Blindern, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Blindern, Oslo, Norway
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18
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Taylor Q, Cox CL. Evidence of predation risk increases with body size in a diminutive snake. J Zool (1987) 2018. [DOI: 10.1111/jzo.12627] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Q. Taylor
- Department of Biology Georgia Southern University Statesboro GA USA
| | - C. L. Cox
- Department of Biology Georgia Southern University Statesboro GA USA
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19
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Moss JB, Gerber GP, Schwirian A, Jackson AC, Welch ME. Evidence for dominant males but not choosy females in an insular rock iguana. Behav Ecol 2018. [DOI: 10.1093/beheco/ary131] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jeanette B Moss
- Biological Sciences Department, Mississippi State University, Mississippi State, MS, USA
| | - Glenn P Gerber
- Institute for Conservation Research, San Diego Zoo Global, Escondido, CA, USA
| | - Aumbriel Schwirian
- Biological Sciences Department, Mississippi State University, Mississippi State, MS, USA
| | - Anna C Jackson
- Biological Sciences Department, Mississippi State University, Mississippi State, MS, USA
| | - Mark E Welch
- Biological Sciences Department, Mississippi State University, Mississippi State, MS, USA
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20
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Kahrl AF, Ivanov BM, Valero KCW, Johnson MA. Ecomorphological Variation in Three Species of Cybotoid Anoles. HERPETOLOGICA 2018. [DOI: 10.1655/herpetologica-d-17-00040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ariel F. Kahrl
- Zoologiska Institutionen: Etologi, Stockholm University, Stockholm, SE-10691, Sweden
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21
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Simmons LW, Lüpold S, Fitzpatrick JL. Evolutionary Trade-Off between Secondary Sexual Traits and Ejaculates. Trends Ecol Evol 2017; 32:964-976. [PMID: 29050795 DOI: 10.1016/j.tree.2017.09.011] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/21/2017] [Accepted: 09/22/2017] [Indexed: 12/29/2022]
Abstract
Recent theoretical models predict that the evolutionary diversification of the weapons and ornaments of pre-mating sexual selection should be influenced by trade-offs with male expenditure on ejaculates. However, the patterns of association between secondary sexual traits and ejaculate expenditure are frequently inconsistent in their support of this prediction. We show why consideration of additional life-history, ecological, and mating-system variables is crucial for the interpretation of associations between secondary sexual traits and ejaculate production. Incorporation of these 'missing variables' provides evidence that interactions between pre- and post-mating sexual selection can underlie broad patterns of diversification in male weapons and ornaments. We call for more experimental and genetic approaches to uncover trade-offs, as well as for studies that consider the costs of mate-searching.
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Affiliation(s)
- Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - John L Fitzpatrick
- Department of Zoology and Ethology, Stockholm University, Svante Arrhenius väg 18B, SE-10691 Stockholm, Sweden
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22
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McDiarmid CS, Friesen CR, Ballen C, Olsson M. Sexual coloration and sperm performance in the Australian painted dragon lizard,
Ctenophorus pictus. J Evol Biol 2017; 30:1303-1312. [DOI: 10.1111/jeb.13092] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/12/2017] [Indexed: 12/16/2022]
Affiliation(s)
- C. S. McDiarmid
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - C. R. Friesen
- School of Life and Environmental Sciences University of Sydney Sydney NSW Australia
| | - C. Ballen
- College of Biological Sciences University of Minnesota Minneapolis MN USA
| | - M. Olsson
- Department of Biological and Environmental Sciences Göteborg University Göteborg Sweden
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23
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Lüpold S, Jin L, Liao WB. Population density and structure drive differential investment in pre- and postmating sexual traits in frogs. Evolution 2017; 71:1686-1699. [PMID: 28394412 DOI: 10.1111/evo.13246] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/25/2017] [Indexed: 01/01/2023]
Abstract
Sexual selection theory predicts a trade-off between premating (ornaments and armaments) and postmating (testes and ejaculates) sexual traits, assuming that growing and maintaining these traits is costly and that total reproductive investments are limited. The number of males in competition, the reproductive gains from investing in premating sexual traits, and the level of sperm competition are all predicted to influence how males allocate their finite resources to these traits. Yet, empirical examination of these predictions is currently scarce. Here, we studied relative expenditure on pre- and postmating sexual traits among frog species varying in their population density, operational sex ratio, and the number of competing males for each clutch of eggs. We found that the intensifying struggle to monopolize fertilizations as more and more males clasp the same female to fertilize her eggs shifts male reproductive investment toward sperm production and away from male weaponry. This shift, which is mediated by population density and the associated level of male-male competition, likely also explains the trade-off between pre- and postmating sexual traits in our much broader sample of anuran species. Our results highlight the power of such a multilevel approach in resolving the evolution of traits and allocation trade-offs.
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Affiliation(s)
- Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies, University of Zurich-Irchel, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Long Jin
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, P. R. China
| | - Wen Bo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, P. R. China
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