1
|
Dorsey OC, Rosenthal GG. A taste for the familiar: explaining the inbreeding paradox. Trends Ecol Evol 2023; 38:132-142. [PMID: 36241551 DOI: 10.1016/j.tree.2022.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 09/04/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022]
Abstract
The negative consequences of inbreeding have led animal biologists to assume that mate choice is generally biased against relatives. However, inbreeding avoidance is highly variable and by no means the rule across animal taxa. Even when inbreeding is costly, there are numerous examples of animals failing to avoid inbreeding or even preferring to mate with close kin. We argue that selective and mechanistic constraints interact to limit the evolution of inbreeding avoidance, notably when there is a risk of mating with heterospecifics and losing fitness through hybridization. Further, balancing inbreeding avoidance with conspecific mate preference may drive the evolution of multivariate sexual communication. Studying different social and sexual decisions within the same species can illuminate trade-offs among mate-choice mechanisms.
Collapse
Affiliation(s)
- Owen C Dorsey
- Program in Ecology and Evolutionary Biology and Department of Biology, Texas A&M University, TX, USA; Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico.
| | - Gil G Rosenthal
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", Calnali, Hidalgo, Mexico; Department of Biology, University of Padua, Padua, Italy
| |
Collapse
|
2
|
Secci-Petretto G, Englmaier GK, Weiss SJ, Antonov A, Persat H, Denys GPJ, Schenekar T, Romanov VI, Taylor EB, Froufe E. Evaluating a species phylogeny using ddRAD SNPs: Cyto-nuclear discordance and introgression in the salmonid genus Thymallus (Salmonidae). Mol Phylogenet Evol 2023; 178:107654. [PMID: 36336233 DOI: 10.1016/j.ympev.2022.107654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/05/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
Abstract
Hybridization and introgression are very common among freshwater fishes due to the dynamic nature of hydrological landscapes. Cyclic patterns of allopatry and secondary contact provide numerous opportunities for interspecific gene flow, which can lead to discordant paths of evolution for mitochondrial and nuclear genomes. Here, we used double digest restriction-site associated DNA sequencing (ddRADseq) to obtain a genome-wide single nucleotide polymorphism (SNP) dataset comprehensive for allThymallus (Salmonidae)species to infer phylogenetic relationships and evaluate potential recent and historical gene flow among species. The newly obtained nuclear phylogeny was largely concordant with a previously published mitogenome-based topology but revealed a few cyto-nuclear discordances. These incongruencies primarily involved the placement of internal nodes rather than the resolution of species, except for one European species where anthropogenic stock transfers are thought to be responsible for the observed pattern. The analysis of four contact zones where multiple species are found revealed a few cases of mitochondrial capture and limited signals of nuclear introgression. Interestingly, the mechanisms restricting interspecific gene flow might be distinct; while in zones of secondary contact, small-scale physical habitat separation appeared as a limiting factor, biologically based reinforcement mechanisms are presumed to be operative in areas where species presumably evolved in sympatry. Signals of historical introgression were largely congruent with the routes of species dispersal previously inferred from mitogenome data. Overall, the ddRADseq dataset provided a robust phylogenetic reconstruction of the genus Thymallus including new insights into historical hybridization and introgression, opening up new questions concerning their evolutionary history.
Collapse
Affiliation(s)
- Giulia Secci-Petretto
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Department of Biology, Faculty of Sciences, U. Porto - University of Porto, Portugal
| | - Gernot K Englmaier
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | - Steven J Weiss
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria.
| | - Alexander Antonov
- Institute of Water and Ecological Problems, Far East Branch, Russian Academy of Sciences, ul. Kim Yu Chena 65, Khabarovsk, 680063 Russia
| | - Henri Persat
- Société Française d'Ichthyologie, Muséum National d'Histoire Naturelle Paris, France, 57 rue Cuvier CP26, 75005 Paris, France
| | - Gael P J Denys
- Unité Patrimoine Naturel - Centre d'expertise et de données (2006 OFB - CNRS - MNHN), Muséum national d'Histoire naturelle, 36 rue Geoffroy Saint-Hilaire CP 41, 75005 Paris, France; Biologie des organismes et écosystèmes aquatiques (BOREA 8067), MNHN, CNRS, IRD, SU, UCN, UA, 57 rue Cuvier CP26, 75005 Paris, France
| | - Tamara Schenekar
- University of Graz, Institute of Biology, Universitätsplatz 2, 8010 Graz, Austria
| | | | - Eric B Taylor
- Department of Zoology, Biodiversity Research Centre and Beaty Biodiversity Museum, University of British Columbia, 6270 University Blvd, Vancouver, BC V6T 1Z, Canada
| | - Elsa Froufe
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal.
| |
Collapse
|
3
|
Nishimura T, Terada K, Xia T, Takami Y. Relationships between reproductive character displacement in genital morphology and the population-level cost of interspecific mating: implications for the Templeton effect. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
Natural selection against maladaptive interspecific reproductive interactions may cause greater divergence in mating traits between sympatric populations than between allopatric populations in a pair of species, known as reproductive character displacement (RCD) which is evidence for the lock-and-key hypothesis of genital evolution. However, the relative importance of various processes contributing to RCD in genital morphology (e.g. reinforcement, reproductive interference, and population filtering or the Templeton effect) is not clear. Here, we examined hypotheses for RCD in genital morphology, with a special focus on the Templeton effect (which predicts that only highly differentiated populations can exist in sympatry). We examined population-level fitness costs in interspecific mating between Carabus maiyasanus and Carabus iwawakianus with RCD in genital morphology. A mating experiment using populations with various degrees of RCD in genital morphology showed no evidence for consistently lower interspecific mating costs in C. maiyasanus populations in contact with displacement in genital morphology than in remote populations, contrary to the predictions of the Templeton effect. Alternatively, interspecific mating costs varied among populations. Observed relationships between the sizes of genital parts concerning isolation and interspecific mating costs across populations suggested that population-level fitness costs do not necessarily decrease during the process leading to RCD. Our results provide insight into ecological and evolutionary processes during secondary contact in closely related species.
Collapse
Affiliation(s)
- Taira Nishimura
- Graduate School of Human Development and Environment, Kobe University , Tsurukabuto 3-11, Nada, Kobe 657-8501 , Japan
| | - Karen Terada
- Graduate School of Human Development and Environment, Kobe University , Tsurukabuto 3-11, Nada, Kobe 657-8501 , Japan
| | - Tian Xia
- Graduate School of Human Development and Environment, Kobe University , Tsurukabuto 3-11, Nada, Kobe 657-8501 , Japan
| | - Yasuoki Takami
- Graduate School of Human Development and Environment, Kobe University , Tsurukabuto 3-11, Nada, Kobe 657-8501 , Japan
| |
Collapse
|
4
|
Non-parallel morphological divergence following colonization of a new host plant. Evol Ecol 2022. [DOI: 10.1007/s10682-022-10189-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractAdaptation to new ecological niches is known to spur population diversification and may lead to speciation if gene flow is ceased. While adaptation to the same ecological niche is expected to be parallel, it is more difficult to predict whether selection against maladaptive hybridization in secondary sympatry results in parallel divergence also in traits that are not directly related to the ecological niches. Such parallelisms in response to selection for reproductive isolation can be identified through estimating parallelism in reproductive character displacement across different zones of secondary contact. Here, we use a host shift in the phytophagous peacock fly Tephritis conura, with both host races represented in two geographically separate areas East and West of the Baltic Sea to investigate convergence in morphological adaptations. We asked (i) if there are consistent morphological adaptations to a host plant shift and (ii) if the response to secondary sympatry with the alternate host race is parallel across contact zones. We found surprisingly low and variable, albeit significant, divergence between host races. Only one trait, the length of the female ovipositor, which serves an important function in the interaction with the hosts, was consistently different between host races. Instead, co-existence with the other host race significantly affected the degree of morphological divergence, but the divergence was largely driven by different traits in different contact zones. Thus, local stochastic fixation or reinforcement could generate trait divergence, and additional evidence is needed to conclude whether divergence is locally adaptive.
Collapse
|
5
|
Thompson KA, Schluter D. Heterosis counteracts hybrid breakdown to forestall speciation by parallel natural selection. Proc Biol Sci 2022; 289:20220422. [PMID: 35506223 PMCID: PMC9065978 DOI: 10.1098/rspb.2022.0422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In contrast to ecological speciation, where reproductive isolation evolves as a consequence of divergent natural selection, speciation by parallel natural selection has been less thoroughly studied. To test whether parallel evolution drives speciation, we leveraged the repeated evolution of benthic and limnetic ecotypes of threespine stickleback fish and estimated fitness for pure crosses and within-ecotype hybrids in semi-natural ponds and in laboratory aquaria. In ponds, we detected hybrid breakdown in both ecotypes but this was counterbalanced by heterosis and the strength of post-zygotic isolation was nil. In aquaria, we detected heterosis in limnetic crosses and breakdown in benthic crosses, which is suggestive of process- and ecotype-specific environment-dependence. In ponds, heterosis and breakdown were three times greater in limnetic crosses than in benthic crosses, contrasting the prediction that the fitness consequences of hybridization should be greater in crosses among more derived ecotypes. Consistent with a primary role for stochastic processes, patterns differed among crosses between populations from different lakes. Yet, the observation of qualitatively similar patterns of heterosis and hybrid breakdown for both ecotypes when averaging the lake pairs indicates that the outcome of hybridization is repeatable in a general sense.
Collapse
Affiliation(s)
- Ken A. Thompson
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dolph Schluter
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
6
|
Reproductive character displacement allows two sexually deceptive orchids to coexist and attract the same specific pollinator. Evol Ecol 2022. [DOI: 10.1007/s10682-021-10149-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AbstractAn increased divergence in characters between species in secondary contact can be shaped by selection against competition for a common resource (ecological character displacement, ECD) or against maladapted hybridization (reproductive character displacement, RCD). These selective pressures can act between incipient species (reinforcement) or well-separated species that already completed the speciation process, but that can still hybridize and produce maladapted hybrids. Here, we investigated two well-separated sexually deceptive orchid species that, unusually, share their specific pollinator. Sympatric individuals of these species are more divergent than allopatric ones in floral characters involved in a mechanical isolating barrier, a pattern suggestive of RCD. To experimentally test this scenario, we built an artificial sympatric population with allopatric individuals. We measured flower characters, genotyped the offspring in natural and artificial sympatry and estimated fertility of hybrids. Different from naturally sympatric individuals, allopatric individuals in artificial sympatry hybridized widely. Hybrids showed lower pollination success and seed viability than parentals. Character displacement did not affect plant pollination success. These findings suggest that RCD evolved between these species to avoid hybridization and that selection on reinforcement may be very strong even in plants with highly specialized pollination.
Collapse
|
7
|
Thompson KA, Peichel CL, Rennison DJ, McGee MD, Albert AYK, Vines TH, Greenwood AK, Wark AR, Brandvain Y, Schumer M, Schluter D. Analysis of ancestry heterozygosity suggests that hybrid incompatibilities in threespine stickleback are environment dependent. PLoS Biol 2022; 20:e3001469. [PMID: 35007278 PMCID: PMC8746713 DOI: 10.1371/journal.pbio.3001469] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 11/04/2021] [Indexed: 12/25/2022] Open
Abstract
Hybrid incompatibilities occur when interactions between opposite ancestry alleles at different loci reduce the fitness of hybrids. Most work on incompatibilities has focused on those that are "intrinsic," meaning they affect viability and sterility in the laboratory. Theory predicts that ecological selection can also underlie hybrid incompatibilities, but tests of this hypothesis using sequence data are scarce. In this article, we compiled genetic data for F2 hybrid crosses between divergent populations of threespine stickleback fish (Gasterosteus aculeatus L.) that were born and raised in either the field (seminatural experimental ponds) or the laboratory (aquaria). Because selection against incompatibilities results in elevated ancestry heterozygosity, we tested the prediction that ancestry heterozygosity will be higher in pond-raised fish compared to those raised in aquaria. We found that ancestry heterozygosity was elevated by approximately 3% in crosses raised in ponds compared to those raised in aquaria. Additional analyses support a phenotypic basis for incompatibility and suggest that environment-specific single-locus heterozygote advantage is not the cause of selection on ancestry heterozygosity. Our study provides evidence that, in stickleback, a coarse-albeit indirect-signal of environment-dependent hybrid incompatibility is reliably detectable and suggests that extrinsic incompatibilities can evolve before intrinsic incompatibilities.
Collapse
Affiliation(s)
- Ken A. Thompson
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, Canada
| | - Catherine L. Peichel
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - Diana J. Rennison
- Division of Biological Sciences, University of California San Diego, San Diego, California, United States of America
| | - Matthew D. McGee
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | | | - Timothy H. Vines
- DataSeer Research Data Services, Vancouver, British Columbia, Canada
| | | | - Abigail R. Wark
- Harvard Medical School, Cambridge, Massachusetts, United States of America
| | - Yaniv Brandvain
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California, United States of America
- Howard Hughes Medical Institute, Maryland, United States of America
| | - Dolph Schluter
- Department of Zoology & Biodiversity Research Centre, University of British Columbia, Canada
| |
Collapse
|
8
|
Nishimura T, Nagata N, Terada K, Xia T, Kubota K, Sota T, Takami Y. Reproductive character displacement in genital morphology in Ohomopterus ground beetles. Am Nat 2021; 199:E76-E90. [DOI: 10.1086/717864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
9
|
Hudson CM, Lucek K, Marques DA, Alexander TJ, Moosmann M, Spaak P, Seehausen O, Matthews B. Threespine Stickleback in Lake Constance: The Ecology and Genomic Substrate of a Recent Invasion. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.611672] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Invasive species can be powerful models for studying contemporary evolution in natural environments. As invading organisms often encounter new habitats during colonization, they will experience novel selection pressures. Threespine stickleback (Gasterosteus aculeatus complex) have recently colonized large parts of Switzerland and are invasive in Lake Constance. Introduced to several watersheds roughly 150 years ago, they spread across the Swiss Plateau (400–800 m a.s.l.), bringing three divergent hitherto allopatric lineages into secondary contact. As stickleback have colonized a variety of different habitat types during this recent range expansion, the Swiss system is a useful model for studying contemporary evolution with and without secondary contact. For example, in the Lake Constance region there has been rapid phenotypic and genetic divergence between a lake population and some stream populations. There is considerable phenotypic variation within the lake population, with individuals foraging in and occupying littoral, offshore pelagic, and profundal waters, the latter of which is a very unusual habitat for stickleback. Furthermore, adults from the lake population can reach up to three times the size of adults from the surrounding stream populations, and are large by comparison to populations globally. Here, we review the historical origins of the threespine stickleback in Switzerland, and the ecomorphological variation and genomic basis of its invasion in Lake Constance. We also outline the potential ecological impacts of this invasion, and highlight the interest for contemporary evolution studies.
Collapse
|
10
|
Härer A, Bolnick DI, Rennison DJ. The genomic signature of ecological divergence along the benthic-limnetic axis in allopatric and sympatric threespine stickleback. Mol Ecol 2020; 30:451-463. [PMID: 33222348 DOI: 10.1111/mec.15746] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/21/2020] [Accepted: 11/09/2020] [Indexed: 12/23/2022]
Abstract
The repeated occurrence of similar phenotypes in independent lineages (i.e., parallel evolution) in response to similar ecological conditions can provide compelling insights into the process of adaptive evolution. An intriguing question is to what extent repeated phenotypic changes are underlain by repeated changes at the genomic level and whether patterns of genomic divergence differ with the geographic context in which populations evolve. Here, we combined genomic, morphological and ecological data sets to investigate the genomic signatures of divergence across populations of threespine stickleback (Gasterosteus aculeatus) that adapted to contrasting ecological niches (benthic or limnetic) in either sympatry or allopatry. We found that genome-wide differentiation (FST ) was an order of magnitude higher and substantially more repeatable for sympatric benthic and limnetic specialists compared to allopatric populations with similar levels of ecological divergence. We identified genomic regions consistently differentiated between sympatric ecotypes that were also differentiated between or associated with benthic vs. limnetic niche in allopatric populations. These candidate regions were enriched on three chromosomes known to be involved in the benthic-limnetic divergence of threespine stickleback. Some candidate regions overlapped with QTL for body shape and trophic traits such as gill raker number, traits that strongly differ between benthic and limnetic ecotypes. In summary, our study shows that magnitude and repeatability of genomic signatures of ecological divergence in threespine stickleback highly depend on the geographic context. The identified candidate regions provide starting points to identify functionally important genes for the adaptation to benthic and limnetic niches.
Collapse
Affiliation(s)
- Andreas Härer
- Division of Biological Sciences, Section of Ecology, Behavior, & Evolution, University of California San Diego, La Jolla, CA, USA
| | - Daniel I Bolnick
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Diana J Rennison
- Division of Biological Sciences, Section of Ecology, Behavior, & Evolution, University of California San Diego, La Jolla, CA, USA
| |
Collapse
|
11
|
St John ME, Fuller RC. Asymmetric reinforcement in Lucania killifish: assessing reproductive isolation when both sexes choose. Curr Zool 2020; 67:215-224. [PMID: 33854539 PMCID: PMC8026148 DOI: 10.1093/cz/zoaa049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/25/2020] [Indexed: 11/21/2022] Open
Abstract
Reinforcement can occur when maladaptive hybridization in sympatry favors the evolution of conspecific preferences and target traits that promote behavioral isolation (BI). In many systems, enhanced BI is due to increased female preference for conspecifics. In others, BI is driven by male preference, and in other systems both sexes exert preferences. Some of these patterns can be attributed to classic sex-specific costs and benefits of preference. Alternatively, sex differences in conspecific preference can emerge due to asymmetric postzygotic isolation (e.g., hybrid offspring from female A × male B have lower fitness than hybrid offspring from female B × male A), which can lead to asymmetric BI (e.g., female A and male B are less likely to mate than female B and male A). Understanding reinforcement requires understanding how conspecific preferences evolve in sympatry. Yet, estimating conspecific preferences can be difficult when both sexes are choosy. In this study, we use Lucania killifish to test the hypothesis that patterns of reinforcement are driven by asymmetric postzygotic isolation between species. If true, we predicted that sympatric female Lucania goodei and sympatric male L. parva should have lower levels of BI compared with their sympatric counterparts, as they produce hybrid offspring with the highest fitness. To address the problem of measuring BI when both sexes are choosy, we inferred the contribution to BI of each partner using assays where one sex in the mating pair comes from an allopatric population with potentially low preference, whereas the other comes from a sympatric population with high preference. For one hybrid cross direction, we found that both female L. parva and male L. goodei have high contributions to BI in sympatry. In the other hybrid cross direction, we found that only female L. goodei contribute to BI. Sympatric male L. parva readily engaged in hybrid spawnings with allopatric L. goodei females. These results indicate that both asymmetric postzygotic isolation and the traditional sex-specific costs to preference likely affect the nature of selection on conspecific preferences and target traits.
Collapse
Affiliation(s)
- Michelle E St John
- School of Integrative Biology, University of Illinois Urbana-Champaign, Champaign, IL 61820, USA
| | - Rebecca C Fuller
- School of Integrative Biology, University of Illinois Urbana-Champaign, Champaign, IL 61820, USA
| |
Collapse
|
12
|
Coughlan JM, Matute DR. The importance of intrinsic postzygotic barriers throughout the speciation process. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190533. [PMID: 32654642 DOI: 10.1098/rstb.2019.0533] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Intrinsic postzygotic barriers can play an important and multifaceted role in speciation, but their contribution is often thought to be reserved to the final stages of the speciation process. Here, we review how intrinsic postzygotic barriers can contribute to speciation, and how this role may change through time. We outline three major contributions of intrinsic postzygotic barriers to speciation. (i) reduction of gene flow: intrinsic postzygotic barriers can effectively reduce gene exchange between sympatric species pairs. We discuss the factors that influence how effective incompatibilities are in limiting gene flow. (ii) early onset of species boundaries via rapid evolution: intrinsic postzygotic barriers can evolve between recently diverged populations or incipient species, thereby influencing speciation relatively early in the process. We discuss why the early origination of incompatibilities is expected under some biological models, and detail how other (and often less obvious) incompatibilities may also serve as important barriers early on in speciation. (iii) reinforcement: intrinsic postzygotic barriers can promote the evolution of subsequent reproductive isolation through processes such as reinforcement, even between relatively recently diverged species pairs. We incorporate classic and recent empirical and theoretical work to explore these three facets of intrinsic postzygotic barriers, and provide our thoughts on recent challenges and areas in the field in which progress can be made. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
Collapse
Affiliation(s)
- Jenn M Coughlan
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
| | - Daniel R Matute
- Department of Biology, University of North Carolina, 120 South Road, Coker Hall, Chapel Hill, NC 27599, USA
| |
Collapse
|
13
|
Moran PA, Hunt J, Mitchell C, Ritchie MG, Bailey NW. Sexual selection and population divergence III: Interspecific and intraspecific variation in mating signals. J Evol Biol 2020; 33:990-1005. [PMID: 32281707 DOI: 10.1111/jeb.13631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022]
Abstract
A major challenge for studying the role of sexual selection in divergence and speciation is understanding the relative influence of different sexually selected signals on those processes in both intra- and interspecific contexts. Different signals may be more or less susceptible to co-option for species identification depending on the balance of sexual and ecological selection acting upon them. To examine this, we tested three predictions to explain geographic variation in long- versus short-range sexual signals across a 3,500 + km transect of two related Australian field cricket species (Teleogryllus spp.): (a) selection for species recognition, (b) environmental adaptation and (c) stochastic divergence. We measured male calling song and male and female cuticular hydrocarbons (CHCs) in offspring derived from wild populations, reared under common garden conditions. Song clearly differentiated the species, and no hybrids were observed suggesting that hybridization is rare or absent. Spatial variation in song was not predicted by geography, genetics or climatic factors in either species. In contrast, CHC divergence was strongly associated with an environmental gradient supporting the idea that the climatic environment selects more directly upon these chemical signals. In light of recently advocated models of diversification via ecological selection on secondary sexual traits, the different environmental associations we found for song and CHCs suggest that the impact of ecological selection on population divergence, and how that influences speciation, might be different for acoustic versus chemical signals.
Collapse
Affiliation(s)
- Peter A Moran
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
| | - John Hunt
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Christopher Mitchell
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Michael G Ritchie
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
| | - Nathan W Bailey
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
| |
Collapse
|
14
|
Lehto WR, Tinghitella RM. Predator‐induced maternal and paternal effects independently alter sexual selection. Evolution 2020; 74:404-418. [DOI: 10.1111/evo.13906] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 11/27/2019] [Accepted: 12/01/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Whitley R. Lehto
- Department of Biological Sciences University of Denver Denver Colorado 80210
- Current Address: College of Natural Science Michigan State University East Lansing Michigan 48823
| | | |
Collapse
|
15
|
Chin TA, Cáceres CE, Cristescu ME. The evolution of reproductive isolation in Daphnia. BMC Evol Biol 2019; 19:216. [PMID: 31775606 PMCID: PMC6880586 DOI: 10.1186/s12862-019-1542-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 11/15/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The process by which populations evolve to become new species involves the emergence of various reproductive isolating barriers (RIB). Despite major advancements in understanding this complex process, very little is known about the order in which RIBs evolve or their relative contribution to the total restriction of gene flow during various stages of speciation. This is mainly due to the difficulties of studying reproductive isolation during the early stages of species formation. This study examines ecological and non-ecological RIB within and between Daphnia pulex and Daphnia pulicaria, two recently diverged species that inhabit distinct habitats and exhibit an unusual level of intraspecific genetic subdivision. RESULTS We find that while ecological prezygotic barriers are close to completion, none of the non-ecological barriers can restrict gene flow between D. pulex and D. pulicaria completely when acting alone. Surprisingly, we also identified high levels of postzygotic reproductive isolation in 'conspecific' interpopulation crosses of D. pulex. CONCLUSIONS While the ecological prezygotic barriers are prevalent during the mature stages of speciation, non-ecological barriers likely dominated the early stages of speciation. This finding indicates the importance of studying the very early stages of speciation and suggests the contribution of postzygotic isolation in initiating the process of speciation.
Collapse
Affiliation(s)
- Tiffany A Chin
- Department of Biology, McGill University, 1205 ave Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada.
| | - Carla E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Melania E Cristescu
- Department of Biology, McGill University, 1205 ave Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
| |
Collapse
|
16
|
Albrecht T, Opletalová K, Reif J, Janoušek V, Piálek L, Cramer ERA, Johnsen A, Reifová R. Sperm divergence in a passerine contact zone: Indication of reinforcement at the gametic level. Evolution 2019; 73:202-213. [DOI: 10.1111/evo.13677] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 12/19/2018] [Indexed: 12/23/2022]
Affiliation(s)
- Tomáš Albrecht
- Faculty of Science, Department of ZoologyCharles University in Prague Praha 2 , CZ‐12844 Czech Republic
- Institute of Vertebrate Biology, v.v.i.The Czech Academy of Sciences Brno CZ‐60365 Czech Republic
| | - Kamila Opletalová
- Faculty of Science, Department of ZoologyCharles University in Prague Praha 2 , CZ‐12844 Czech Republic
| | - Jiří Reif
- Faculty of Science, Institute for Environmental StudiesCharles University in Prague Praha 2 CZ‐12100 Czech Republic
| | - Václav Janoušek
- Faculty of Science, Department of ZoologyCharles University in Prague Praha 2 , CZ‐12844 Czech Republic
| | - Lubomír Piálek
- Faculty of Science, Department of ZoologyUniversity of South Bohemia České Budějovice CZ‐370 05 Czech Republic
| | | | - Arild Johnsen
- Natural History MuseumUniversity of Oslo 0318 Oslo Norway
| | - Radka Reifová
- Faculty of Science, Department of ZoologyCharles University in Prague Praha 2 , CZ‐12844 Czech Republic
| |
Collapse
|
17
|
St. John ME, Fuller RC. The effects of experimental design on mating preferences and reproductive isolation in killifish. Behav Ecol 2018. [DOI: 10.1093/beheco/ary150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Michelle E St. John
- School of Integrative Biology, University of Illinois Urbana – Champaign, Champaign, IL, USA
| | - Rebecca C Fuller
- School of Integrative Biology, University of Illinois Urbana – Champaign, Champaign, IL, USA
| |
Collapse
|
18
|
Quantification of Reproductive Isolating Barriers Between Two Naturally Hybridizing Killifish Species. Evol Biol 2018. [DOI: 10.1007/s11692-018-9460-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
19
|
Suni SS, Hopkins R. The relationship between postmating reproductive isolation and reinforcement in Phlox. Evolution 2018; 72:1387-1398. [PMID: 29774945 DOI: 10.1111/evo.13507] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 04/09/2018] [Accepted: 04/14/2018] [Indexed: 02/06/2023]
Abstract
The process of speciation involves the accumulation of reproductive isolation (RI) between diverging lineages. Selection can favor increased RI via the process of reinforcement, whereby costs to hybridization impose selection for increased prezygotic RI. Reinforcement results in phenotypic divergence within at least one taxon, as a result of costly hybridization between sympatric taxa. The strength of selection driving reinforcement is determined by the cost of hybridization and the frequency of hybridization. We investigated the cost of hybridization by quantifying postmating RI barriers among Phlox species that comprise one of the best-studied cases of reinforcement. We determined if the strength of RI differs among lineages that have and have not undergone reinforcement, how much variability there is within species in RI, and whether RI is associated with phylogenetic relatedness. We found high RI for the species that underwent phenotypic divergence due to reinforcement; however, RI was also high between other species pairs. We found extensive variability in RI among individuals within species, and no evidence that the strength of RI was associated with phylogenetic relatedness. We suggest that phenotypic divergence due to reinforcement is associated with the frequency of hybridization and introgression, and not the cost of hybridization in this clade.
Collapse
Affiliation(s)
- Sevan S Suni
- The Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA 02131
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA
- Present Address: The University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117
| | - Robin Hopkins
- The Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA 02131
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA
| |
Collapse
|
20
|
Garner AG, Goulet BE, Farnitano MC, Molina-Henao YF, Hopkins R. Genomic Signatures of Reinforcement. Genes (Basel) 2018; 9:E191. [PMID: 29614048 PMCID: PMC5924533 DOI: 10.3390/genes9040191] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 12/21/2022] Open
Abstract
Reinforcement is the process by which selection against hybridization increases reproductive isolation between taxa. Much research has focused on demonstrating the existence of reinforcement, yet relatively little is known about the genetic basis of reinforcement or the evolutionary conditions under which reinforcement can occur. Inspired by reinforcement's characteristic phenotypic pattern of reproductive trait divergence in sympatry but not in allopatry, we discuss whether reinforcement also leaves a distinct genomic pattern. First, we describe three patterns of genetic variation we expect as a consequence of reinforcement. Then, we discuss a set of alternative processes and complicating factors that may make the identification of reinforcement at the genomic level difficult. Finally, we consider how genomic analyses can be leveraged to inform if and to what extent reinforcement evolved in the face of gene flow between sympatric lineages and between allopatric and sympatric populations of the same lineage. Our major goals are to understand if genome scans for particular patterns of genetic variation could identify reinforcement, isolate the genetic basis of reinforcement, or infer the conditions under which reinforcement evolved.
Collapse
Affiliation(s)
- Austin G Garner
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 021382, USA.
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA.
| | - Benjamin E Goulet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 021382, USA.
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA.
| | - Matthew C Farnitano
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 021382, USA.
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA.
| | - Y Franchesco Molina-Henao
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 021382, USA.
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA.
- Department of Biology, Universidad del Valle, Cali 760032, Colombia.
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 021382, USA.
- The Arnold Arboretum, Harvard University, Boston, MA 02131, USA.
| |
Collapse
|
21
|
Fishman L, Wyatt R. POLLINATOR-MEDIATED COMPETITION, REPRODUCTIVE CHARACTER DISPLACEMENT, AND THE EVOLUTION OF SELFING IN ARENARIA UNIFLORA (CARYOPHYLLACEAE). Evolution 2017; 53:1723-1733. [PMID: 28565464 DOI: 10.1111/j.1558-5646.1999.tb04557.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/1998] [Accepted: 07/07/1999] [Indexed: 11/26/2022]
Abstract
Ecological factors that reduce the effectiveness of cross-pollination are likely to play a role in the frequent evolution of routine self-fertilization in flowering plants. However, we lack empirical evidence linking the reproductive assurance value of selfing in poor pollination environments to evolutionary shifts in mating system. Here, we investigated the adaptive significance of prior selfing in the polymorphic annual plant Arenaria uniflora (Caryophyllaceae), in which selfer populations occur only in areas of range overlap with congener A. glabra. To examine the hypothesis that secondary contact between the two species contributed to the evolution and maintenance of selfing, we used field competition experiments and controlled hand-pollinations to measure the female fitness consequences of pollinator-mediated interspecific interactions. Uniformly high fruit set by selfers in the naturally pollinated field arrays confirmed the reproductive assurance value of selfing, whereas substantial reductions in outcrosser fruit set (15%) and total seed production (20-35%) in the presence of A. glabra demonstrated that pollinator-mediated interactions can provide strong selection for self-pollination. Heterospecific pollen transfer, rather than competition for pollinator service, appears to be the primary mechanism of pollinator-mediated competition in Arenaria. Premating barriers to hybridization between outcrossers and A. glabra are extremely weak. The production of a few inviable hybrid seeds after heterospecific pollination and intermediate seed set after mixed pollinations indicates that A. glabra pollen can usurp A. uniflora ovules. Thus, any visit to A. uniflora by shared pollinators carries a potential female fitness cost. Moreover, patterns of fruit set and seed set in the competition arrays relative to controls were consistent with the receipt of mixed pollen loads, rather than a lack of pollinator visits. Competition through pollen transfer favors preemptive self-pollination and may be responsible for the evolution of a highly reduced floral morphology in A. uniflora selfers as well as their current geographical distribution.
Collapse
Affiliation(s)
- Lila Fishman
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, 08544
| | - Robert Wyatt
- Highlands Biological Station, P.O. Box 580, Highlands, North Carolina, 28741
| |
Collapse
|
22
|
Rohde K, Hau Y, Kranz N, Weinberger J, Elle O, Hochkirch A. Climatic effects on population declines of a rare wetland species and the role of spatial and temporal isolation as barriers to hybridization. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Katja Rohde
- Department of Biogeography Trier University D‐54286 Trier Germany
| | - Yvonne Hau
- Department of Biogeography Trier University D‐54286 Trier Germany
| | - Nicole Kranz
- Department of Biogeography Trier University D‐54286 Trier Germany
| | | | - Ortwin Elle
- Department of Biogeography Trier University D‐54286 Trier Germany
| | - Axel Hochkirch
- Department of Biogeography Trier University D‐54286 Trier Germany
| |
Collapse
|
23
|
Roth-Monzón AJ, Scott LE, Camargo AA, Clark EI, Schott EE, Johnson JB. Sympatry Predicts Spot Pigmentation Patterns and Female Association Behavior in the Livebearing Fish Poeciliopsis baenschi. PLoS One 2017; 12:e0170326. [PMID: 28107407 PMCID: PMC5249170 DOI: 10.1371/journal.pone.0170326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 01/03/2017] [Indexed: 12/03/2022] Open
Abstract
In this study, we explored the possibility that differences in pigmentation patterns among populations of the fish Poeciliopsis baenschi were associated with the presence or absence of the closely related species P. turneri. If reproductive character displacement is responsible, spotting patterns in these two species should diverge in sympatry, but not allopatry. We predicted that female P. baenschi from sympatric sites should show a preference for associating with conspecifics vs. heterospecific males, but females from allopatric sites should show no such preferences. To evaluate these predictions, we compared spotting patterns and female association behaviors in populations of P. baenschi from Central Mexico. We found that both of our predictions were supported. Poeciliopsis baenschi that co-occured with P. turneri had spotting patterns significantly different than their counterparts from allopatric sites. Using a simultaneous choice test of video presentations of males, we also found that female P. baenschi from populations that co-occured with P. turneri spent significantly more time with males of their own species than with P. turneri males. In contrast, females from allopatric populations of P. baenschi showed no differences in the amount of time they spent with either conspecific or heterospecific males. Together, our results are consistent with the hypothesis that reproductive character displacement may be responsible for behavioral and spotting pattern differences in these populations of P. baenschi.
Collapse
Affiliation(s)
- Andrea J Roth-Monzón
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America
| | - Laura E Scott
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America
| | - Ashley A Camargo
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America
| | - Eliza I Clark
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America
| | - Eric E Schott
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America
| | - Jerald B Johnson
- Evolutionary Ecology Laboratories, Department of Biology, Brigham Young University, Provo, Utah, United States of America.,Monte L. Bean Life Science Museum, Brigham Young University, Provo, Utah, United States of America
| |
Collapse
|
24
|
Davis JS, Castillo DM, Moyle LC. Remating responses are consistent with male postcopulatory manipulation but not reinforcement in D. pseudoobscura. Ecol Evol 2017; 7:507-515. [PMID: 28116047 PMCID: PMC5243186 DOI: 10.1002/ece3.2628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 11/05/2022] Open
Abstract
Reinforcement occurs when hybridization between closely related lineages produces low-fitness offspring, prompting selection for elevated reproductive isolation specifically in areas of sympatry. Both premating and postmating prezygotic behaviors have been shown to be the target of reinforcing selection, but it remains unclear whether remating behaviors experience reinforcement, although they can also influence offspring identity and limit formation of hybrids. Here, we evaluated evidence for reinforcing selection on remating behaviors in Drosophila pseudoobscura, by comparing remating traits in females from populations historically allopatric and sympatric with Drosophila persimilis. We found that the propensity to remate was not higher in sympatric females, compared to allopatric females, regardless of whether the first mated male was heterospecific or conspecific. Moreover, remating behavior did not contribute to interspecific reproductive isolation among any population; that is, females showed no higher propensity to remate following a heterospecific first mating than following a conspecific first mating. Instead, we found that females are less likely to remate after initial matings with unfamiliar males, regardless of species identity. This is consistent with one scenario of postmating sexual conflict in which females are poorly defended against postcopulatory manipulation by males with whom they have not coevolved. Our results are generally inconsistent with reinforcement on remating traits and suggest that this behavior might be more strongly shaped by the consequences of local antagonistic male-female interactions than interactions with heterospecifics.
Collapse
|
25
|
Lackey ACR, Boughman JW. Evolution of reproductive isolation in stickleback fish. Evolution 2016; 71:357-372. [PMID: 27901265 DOI: 10.1111/evo.13114] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 10/15/2016] [Accepted: 10/24/2016] [Indexed: 12/21/2022]
Abstract
To understand how new species form and what causes their collapse, we examined how reproductive isolation evolves during the speciation process, considering species pairs with little to extensive divergence, including a recently collapsed pair. We estimated many reproductive barriers in each of five sets of stickleback fish species pairs using our own data and decades of previous work. We found that the types of barriers important early in the speciation process differ from those important late. Two premating barriers-habitat and sexual isolation-evolve early in divergence and remain two of the strongest barriers throughout speciation. Premating isolation evolves before postmating isolation, and extrinsic isolation is far stronger than intrinsic. Completing speciation, however, may require postmating intrinsic incompatibilities. Reverse speciation in one species pair was characterized by significant loss of sexual isolation. We present estimates of barrier strengths before and after collapse of a species pair; such detail regarding the loss of isolation has never before been documented. Additionally, despite significant asymmetries in individual barriers, which can limit speciation, total isolation was essentially symmetric between species. Our study provides important insight into the order of barrier evolution and the relative importance of isolating barriers during speciation and tests fundamental predictions of ecological speciation.
Collapse
Affiliation(s)
- Alycia C R Lackey
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan.,Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan.,Department of Biological Sciences, Watershed Studies Institute, Murray State University, 2112 Biology Building, Murray, State University, Murray, Kentucky, 42071
| | - Janette W Boughman
- Department of Integrative Biology, Michigan State University, East Lansing, Michigan.,Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, East Lansing, Michigan.,BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan
| |
Collapse
|
26
|
Greenway R, Drexler S, Arias‐Rodriguez L, Tobler M. Adaptive, but not condition‐dependent, body shape differences contribute to assortative mating preferences during ecological speciation. Evolution 2016; 70:2809-2822. [DOI: 10.1111/evo.13087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 02/05/2023]
Affiliation(s)
- Ryan Greenway
- Division of Biology Kansas State University Manhattan Kansas 66506
| | - Shannon Drexler
- Department of Biology University of Wisconsin‐Platteville 1 University Plaza Platteville Wisconsin 53818
| | - Lenin Arias‐Rodriguez
- División Académica de Ciencias Biológicas Universidad Juárez Autónoma de Tabasco Villahermosa Tabasco México
| | - Michael Tobler
- Division of Biology Kansas State University Manhattan Kansas 66506
| |
Collapse
|
27
|
Ostevik KL, Andrew RL, Otto SP, Rieseberg LH. Multiple reproductive barriers separate recently diverged sunflower ecotypes. Evolution 2016; 70:2322-2335. [PMID: 27479368 DOI: 10.1111/evo.13027] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 06/12/2016] [Accepted: 06/27/2016] [Indexed: 01/17/2023]
Abstract
Measuring reproductive barriers between groups of organisms is an effective way to determine the traits and mechanisms that impede gene flow. However, to understand the ecological and evolutionary factors that drive speciation, it is important to distinguish between the barriers that arise early in the speciation process and those that arise after speciation is largely complete. In this article, we comprehensively test for reproductive isolation between recently diverged (<10,000 years bp) dune and nondune ecotypes of the prairie sunflower, Helianthus petiolaris. We find reproductive barriers acting at multiple stages of hybridization, including premating, postmating-prezygotic, and postzygotic barriers, despite the recent divergence. Barriers include extrinsic selection against immigrants and hybrids, a shift in pollinator assemblage, and postpollination assortative mating. Together, these data suggest that multiple barriers can be important for reducing gene flow in the earliest stages of speciation.
Collapse
Affiliation(s)
- Katherine L Ostevik
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Rose L Andrew
- School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia
| | - Sarah P Otto
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Loren H Rieseberg
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Biology, Indiana University, Bloomington, Indiana
| |
Collapse
|
28
|
Pfennig KS. Reinforcement as an initiator of population divergence and speciation. Curr Zool 2016; 62:145-154. [PMID: 29491902 PMCID: PMC5804236 DOI: 10.1093/cz/zow033] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 12/29/2015] [Indexed: 02/02/2023] Open
Abstract
When hybridization results in reduced fitness, natural selection is expected to favor the evolution of traits that minimize the likelihood of hybridizing in the first place. This process, termed reinforcement (or, more generally, reproductive character displacement), thereby contributes to the evolution of enhanced reproductive isolation between hybridizing groups. By enhancing reproductive isolation in this way, reinforcement plays an important role in the final stages of speciation. However, reinforcement can also contribute to the early stages of speciation. Specifically, because selection to avoid hybridization occurs only in sympatric populations, the unfolding of reinforcement can lead to the evolution of traits in sympatric populations that reduce reproduction between conspecifics in sympatry versus those in allopatry. Thus, reinforcement between species can lead to reproductive isolation—and possibly speciation—between populations in sympatry versus those in allopatry or among different sympatric populations. Here, I describe how this process can occur, the conditions under which it is most likely to occur, and the empirical data needed to evaluate the hypothesis that reinforcement can initiate speciation.
Collapse
Affiliation(s)
- Karin S Pfennig
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA
| |
Collapse
|
29
|
Bacquet PMB, Brattström O, Wang HL, Allen CE, Löfstedt C, Brakefield PM, Nieberding CM. Selection on male sex pheromone composition contributes to butterfly reproductive isolation. Proc Biol Sci 2015; 282:20142734. [PMID: 25740889 DOI: 10.1098/rspb.2014.2734] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Selection can facilitate diversification by inducing character displacement in mate choice traits that reduce the probability of maladaptive mating between lineages. Although reproductive character displacement (RCD) has been demonstrated in two-taxa case studies, the frequency of this process in nature is still debated. Moreover, studies have focused primarily on visual and acoustic traits, despite the fact that chemical communication is probably the most common means of species recognition. Here, we showed in a large, mostly sympatric, butterfly genus, a strong pattern of recurrent RCD for predicted male sex pheromone composition, but not for visual mate choice traits. Our results suggest that RCD is not anecdotal, and that selection for divergence in male sex pheromone composition contributed to reproductive isolation within the Bicyclus genus. We propose that selection may target olfactory mate choice traits as a more common sensory modality to ensure reproductive isolation among diverging lineages than previously envisaged.
Collapse
Affiliation(s)
- P M B Bacquet
- Evolutionary Ecology and Genetics Group, Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| | - O Brattström
- Department of Zoology, University Museum of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - H-L Wang
- Department of Biology, Pheromone Group, Lund University, SE-223 62 Lund, Sweden
| | - C E Allen
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - C Löfstedt
- Department of Biology, Pheromone Group, Lund University, SE-223 62 Lund, Sweden
| | - P M Brakefield
- Department of Zoology, University Museum of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - C M Nieberding
- Evolutionary Ecology and Genetics Group, Biodiversity Research Centre, Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 4-5, 1348 Louvain-la-Neuve, Belgium
| |
Collapse
|
30
|
Rohde K, Hau Y, Weyer J, Hochkirch A. Wide prevalence of hybridization in two sympatric grasshopper species may be shaped by their relative abundances. BMC Evol Biol 2015; 15:191. [PMID: 26376739 PMCID: PMC4573947 DOI: 10.1186/s12862-015-0460-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/19/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Hybridization between species is of conservation concern as it might threaten the genetic integrity of species. Anthropogenic factors can alter hybridization dynamics by introducing new potentially hybridizing species or by diminishing barriers to hybridization. This may even affect sympatric species pairs through environmental change, which so far has received little attention. We studied hybridization prevalence and the underlying behavioral mechanisms in two sympatric grasshopper species, a rare specialist (Chorthippus montanus) and a common generalist (Chorthippus parallelus). We conducted a mate choice experiment with constant intraspecific density and varying heterospecific density, i.e. varying relative frequency of both species. RESULTS Mate choice was frequency-dependent in both species with a higher risk of cross-mating with increasing heterospecific frequency, while conspecific mating increased linearly with increasing conspecific density. This illustrates that reproductive barriers could be altered by environmental change, if the relative frequency of species pairs is affected. Moreover, we performed a microsatellite analysis to detect hybridization in twelve syntopic populations (and four allotopic populations). Hybrids were detected in nearly all syntopic populations with hybridization rates reaching up to 8.9 %. Genetic diversity increased for both species when hybrids were included in the data set, but only in the common species a positive correlation between hybridization rate and genetic diversity was detected. CONCLUSION Our study illustrates that the relative frequency of the two species strongly determines the effectiveness of reproductive barriers and that even the more choosy species (Ch. montanus) may face a higher risk of hybridization if population size decreases and its relative frequency becomes low compared to its sister species. The asymmetric mate preferences of both species may lead to quasi-unidirectional gene flow caused by unidirectional backcrossing. This might explain why genetic diversity increased only in the common species, but not in the rare one. Altogether, the hybridization rate was much higher than expected for a widely sympatric species pair.
Collapse
Affiliation(s)
- Katja Rohde
- Department of Biogeography, Trier University, D-54286, Trier, Germany.
| | - Yvonne Hau
- Department of Biogeography, Trier University, D-54286, Trier, Germany.
| | - Jessica Weyer
- Department of Biogeography, Trier University, D-54286, Trier, Germany.
| | - Axel Hochkirch
- Department of Biogeography, Trier University, D-54286, Trier, Germany.
| |
Collapse
|
31
|
Smadja CM, Loire E, Caminade P, Thoma M, Latour Y, Roux C, Thoss M, Penn DJ, Ganem G, Boursot P. Seeking signatures of reinforcement at the genetic level: a hitchhiking mapping and candidate gene approach in the house mouse. Mol Ecol 2015; 24:4222-4237. [PMID: 26132782 DOI: 10.1111/mec.13301] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 12/11/2022]
Abstract
Reinforcement is the process by which prezygotic isolation is strengthened as a response to selection against hybridization. Most empirical support for reinforcement comes from the observation of its possible phenotypic signature: an accentuated degree of prezygotic isolation in the hybrid zone as compared to allopatry. Here, we implemented a novel approach to this question by seeking for the signature of reinforcement at the genetic level. In the house mouse, selection against hybrids and enhanced olfactory-based assortative mate preferences are observed in a hybrid zone between the two European subspecies Mus musculus musculus and M. m. domesticus, suggesting a possible recent reinforcement event. To test for the genetic signature of reinforcing selection and identify genes involved in sexual isolation, we adopted a hitchhiking mapping approach targeting genomic regions containing candidate genes for assortative mating in mice. We densely scanned these genomic regions in hybrid zone and allopatric samples using a large number of fast evolving microsatellite loci that allow the detection of recent selection events. We found a handful of loci showing the expected pattern of significant reduction in variability in populations close to the hybrid zone, showing assortative odour preference in mate choice experiments as compared to populations further away and displaying no such preference. These loci lie close to genes that we pinpoint as testable candidates for further investigation.
Collapse
Affiliation(s)
- Carole M Smadja
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Etienne Loire
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Pierre Caminade
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Marios Thoma
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Yasmin Latour
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Camille Roux
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Michaela Thoss
- University of Veterinary Medicine Vienna, Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, Vienna, Austria
| | - Dustin J Penn
- University of Veterinary Medicine Vienna, Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, Vienna, Austria
| | - Guila Ganem
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| | - Pierre Boursot
- Institut des Sciences de l'Evolution UMR 5554 (Centre National de la Recherche Scientifique CNRS, Institut pour la Recherche et le Développement IRD, Université de Montpellier), cc065 Université de Montpellier, Campus Triolet, 34095 Montpellier, France
| |
Collapse
|
32
|
Kozak GM, Boughman JW. Predator experience overrides learned aversion to heterospecifics in stickleback species pairs. Proc Biol Sci 2015; 282:20143066. [PMID: 25808887 PMCID: PMC4389616 DOI: 10.1098/rspb.2014.3066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 02/25/2015] [Indexed: 02/03/2023] Open
Abstract
Predation risk can alter female mating decisions because the costs of mate searching and selecting attractive mates increase when predators are present. In response to predators, females have been found to plastically adjust mate preference within species, but little is known about how predators alter sexual isolation and hybridization among species. We tested the effects of predator exposure on sexual isolation between benthic and limnetic threespine sticklebacks (Gasterosteus spp.). Female discrimination against heterospecific mates was measured before and after females experienced a simulated attack by a trout predator or a control exposure to a harmless object. In the absence of predators, females showed increased aversion to heterospecifics over time. We found that predator exposure made females less discriminating and precluded this learned aversion to heterospecifics. Benthic and limnetic males differ in coloration, and predator exposure also affected sexual isolation by weakening female preferences for colourful males. Predator effects on sexual selection were also tested but predators had few effects on female choosiness among conspecific mates. Our results suggest that predation risk may disrupt the cognitive processes associated with mate choice and lead to fluctuations in the strength of sexual isolation between species.
Collapse
Affiliation(s)
- Genevieve M Kozak
- Department of Zoology, University of Wisconsin, Madison, WI 53706, USA
| | - Janette W Boughman
- Department of Zoology, Michigan State University, East Lansing, MI 48824, USA BEACON, Michigan State University, East Lansing, MI 48824, USA Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
33
|
Hoarau G, Coyer JA, Giesbers MCWG, Jueterbock A, Olsen JL. Pre-zygotic isolation in the macroalgal genus Fucus from four contact zones spanning 100-10 000 years: a tale of reinforcement? ROYAL SOCIETY OPEN SCIENCE 2015; 2:140538. [PMID: 26064608 PMCID: PMC4448814 DOI: 10.1098/rsos.140538] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 01/13/2015] [Indexed: 06/04/2023]
Abstract
Hybrid zones provide an ideal natural experiment to study the selective forces driving evolution of reproductive barriers and speciation. If hybrid offspring are less fit than the parental species, pre-zygotic isolating barriers can evolve and strengthen in response to selection against the hybrids (reinforcement). Four contact zones between the intertidal macroalgae Fucus serratus (Fs) and Fucus distichus (Fd), characterized by varying times of sympatry and order of species introduction provide an opportunity to investigate reinforcement. We examined patterns of hybridization and reproductive isolation between Fs and Fd in: (i) northern Norway (consisting of two natural sites, 10 000 years old), (ii) the Kattegat near Denmark (Fd introduced, nineteenth century) and (iii) Iceland (Fs introduced, nineteenth century). Using 10 microsatellites and chloroplast DNA, we showed that hybridization and introgression decreased with increasing duration of sympatry. The two younger contact zones revealed 13 and 24% hybrids and several F 1 individuals, in contrast to the older contact zone with 2-3% hybrids and an absence of F 1s. Cross-fertilization experiments revealed that the reduction in hybridization in the oldest zone is consistent with increased gametic incompatibility.
Collapse
Affiliation(s)
- G. Hoarau
- Faculty of Aquaculture and Biosciences, University of Nordland, Bodø 8049, Norway
| | - J. A. Coyer
- Shoals Marine Laboratory, Cornell University, 400 Little Harbor Road, Portsmouth, NH, USA
| | - M. C. W. G. Giesbers
- Marine Benthic Ecology and Evolution Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
| | - A. Jueterbock
- Faculty of Aquaculture and Biosciences, University of Nordland, Bodø 8049, Norway
| | - J. L. Olsen
- Marine Benthic Ecology and Evolution Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Nijenborgh 7, Groningen 9747 AG, The Netherlands
| |
Collapse
|
34
|
Matute DR. Noisy neighbors can hamper the evolution of reproductive isolation by reinforcing selection. Am Nat 2015; 185:253-69. [PMID: 25616143 DOI: 10.1086/679504] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Reinforcement is the process by which selection against hybridization leads to an increase in reproductive isolation. The influence of reinforcing selection can be detected when sympatric individuals (those from areas of secondary contact) show a higher degree of prezygotic isolation than allopatric individuals (those from areas outside each other's range). In areas of secondary contact with Drosophila santomea, Drosophila yakuba females show reinforcement of gametic isolation but not behavioral isolation, despite the fact that both behavioral and gametic isolation evolve in D. yakuba in experimental sympatry. Using behavioral assays and experimental evolution, I studied how both gametic and behavioral isolation are affected by biotic factors that the two species encounter in their natural environment. I show that if D. yakuba females are in environments where D. yakuba, D. santomea, and males from other species coexist, these females cannot fully discern between conspecific and heterospecific males. In such complex environments, gametic but not behavioral isolation evolves. The presence of nonhybridizing species can constrain the effect of reinforcement on behavioral isolation.
Collapse
Affiliation(s)
- Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599
| |
Collapse
|
35
|
Taugbøl A, Junge C, Quinn TP, Herland A, Vøllestad LA. Genetic and morphometric divergence in threespine stickleback in the Chignik catchment, Alaska. Ecol Evol 2013; 4:144-56. [PMID: 24558570 PMCID: PMC3925378 DOI: 10.1002/ece3.918] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 11/11/2013] [Accepted: 11/24/2013] [Indexed: 11/18/2022] Open
Abstract
Divergent selection pressures induced by different environmental conditions typically lead to variation in life history, behavior, and morphology. When populations are locally adapted to their current environment, selection may limit movement into novel sites, leading to neutral and adaptive genetic divergence in allopatric populations. Subsequently, divergence can be reinforced by development of pre-or postzygotic barriers to gene flow. The threespine stickleback, Gasterosteus aculeatus, is a primarily marine fish that has invaded freshwater repeatedly in postglacial times. After invasion, the established freshwater populations typically show rapid diversification of several traits as they become reproductively isolated from their ancestral marine population. In this study, we examine the genetic and morphometric differentiation between sticklebacks living in an open system comprising a brackish water lagoon, two freshwater lakes, and connecting rivers. By applying a set of microsatellite markers, we disentangled the genetic relationship of the individuals across the diverse environments and identified two genetic populations: one associated with brackish and the other with the freshwater environments. The “brackish” sticklebacks were larger and had a different body shape than those in freshwater. However, we found evidence for upstream migration from the brackish lagoon into the freshwater environments, as fish that were genetically and morphometrically similar to the lagoon fish were found in all freshwater sampling sites. Regardless, few F1-hybrids were identified, and it therefore appears that some pre-and/or postzygotic barriers to gene flow rather than geographic distance are causing the divergence in this system.
Collapse
Affiliation(s)
- Annette Taugbøl
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of Biosciences, University of Oslo P.O.Box 1066, Blindern, NO-0316, Norway
| | - Claudia Junge
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of Biosciences, University of Oslo P.O.Box 1066, Blindern, NO-0316, Norway
| | - Thomas P Quinn
- School of Aquatic and Fishery Sciences, University of Washington Box 355020, Seattle, Washington, 98195-5020
| | - Anders Herland
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of Biosciences, University of Oslo P.O.Box 1066, Blindern, NO-0316, Norway
| | - Leif Asbjørn Vøllestad
- Centre for Ecological and Evolutionary Synthesis (CEES)Department of Biosciences, University of Oslo P.O.Box 1066, Blindern, NO-0316, Norway
| |
Collapse
|
36
|
Shurtliff QR, Murphy PJ, Yeiter JD, Matocq MD. Experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (Neotoma) hybrid zone. BMC Evol Biol 2013; 13:220. [PMID: 24093823 PMCID: PMC3853547 DOI: 10.1186/1471-2148-13-220] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 09/25/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Female mate preferences may be under strong selection in zones of contact between closely related species because of greater variation in available mates and the potential costs of hybridization. We studied female mate preferences experimentally in a zone of secondary contact between Desert and Bryant's Woodrat (Neotoma lepida and N. bryanti) in the southern foothills of the Sierra Nevada of California. We tested female preference for conspecific versus heterospecific males in paired choice trials in which females could interact freely with males, but males could not interact directly with each other. We compared preferences of females from both allopatric and sympatric sites. RESULTS We did not find evidence of the process of reinforcement as assortative preferences were not stronger in sympatry than in allopatry. Mate preferences, however, were asymmetric, with N. lepida females mating preferentially with conspecifics and N. bryanti females showing no preference by species. Sympatric females were less likely to mate than allopatric females, due in part to an increase in aggressive interactions. However, even in the absence of aggression, courtship led to mating less often in sympatric females, suggesting they were choosier or had lower sexual motivation than allopatric females. CONCLUSIONS Patterns of mate choice in this woodrat system appear to be strongly impacted by body size and aggressive behavior. In particular, females of the smaller-bodied species rarely interact with the relatively large heterospecific males. In contrast females of the larger-bodied species accept the relatively small heterospecific males. For sympatric animals, rates of aggression were markedly higher than for allopatric animals and reduced affiliative and reproductive behavior in our trials. Sympatric animals are larger and more aggressive, traits that are likely under strong ecological selection across the sharp resource gradient that characterizes the contact zone. However, our results suggest that these traits that are likely favored in competitive interactions between the species also impact reproductive interactions. Combined with our previous findings of post-zygotic isolation in this system, this study suggests that multiple isolating mechanisms contribute to the rate of genetic exchange between these species when they come into contact, and that these mechanisms are the result of selection on traits that are important in a range of ecological and reproductive interactions.
Collapse
Affiliation(s)
- Quinn R Shurtliff
- Wildlife Conservation Society, North America Program, Idaho Falls, ID 83402, USA
| | - Peter J Murphy
- Department of Natural Resources and Environmental Science, Mailstop 0186, University of Nevada Reno, Reno, NV 89557, USA
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV 89557, USA
| | - Jaclyn D Yeiter
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
| | - Marjorie D Matocq
- Department of Natural Resources and Environmental Science, Mailstop 0186, University of Nevada Reno, Reno, NV 89557, USA
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV 89557, USA
| |
Collapse
|
37
|
Zinck L, Lima SQ. Mate choice in Mus musculus is relative and dependent on the estrous state. PLoS One 2013; 8:e66064. [PMID: 23762466 PMCID: PMC3677927 DOI: 10.1371/journal.pone.0066064] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/03/2013] [Indexed: 11/20/2022] Open
Abstract
Mate choice is a critical behavioral decision process with profound impact on evolution. However, the mechanistic basis of mate choice is poorly understood. In this study we focused on assortative mate choice, which is known to contribute to the reproductive isolation of the two European subspecies of house mouse, Mus musculus musculus and Mus musculus domesticus. To understand the decision process, we developed both full mating and limited-contact paradigms and tested musculus females' preference for musculus versus domesticus males, mimicking the natural musculus/domesticus contact zone. As hypothesized, when allowed to mate we found that sexually receptive musculus females exhibited a robust preference to mate with musculus males. In contrast, when non-receptive, females did not exhibit a preference and rather alternated between males in response to male mount attempts. Moreover in a no-choice condition, females mated readily with males from both subspecies. Finally, when no physical contact was allowed, and therefore male's behavior could not influence female's behavior, female's preference for its own subspecies was maintained independently of the estrous state. Together, our results suggest that the assortative preference is relative and based on a comparison of the options available rather than on an absolute preference. The results of the limited-contact experiments highlight the interplay between female's internal state and the nature of the interaction with prospective mates in the full mating conditions. With these experiments we believe we established an assortative mate preference assay that is appropriate for the investigation of its underlying substrates.
Collapse
Affiliation(s)
- Léa Zinck
- Champalimaud Neuroscience Program, Champalimaud Centre for the Unknown, Lisbon, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Susana Q. Lima
- Champalimaud Neuroscience Program, Champalimaud Centre for the Unknown, Lisbon, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| |
Collapse
|
38
|
Head ML, Kozak GM, Boughman JW. Female mate preferences for male body size and shape promote sexual isolation in threespine sticklebacks. Ecol Evol 2013; 3:2183-96. [PMID: 23919161 PMCID: PMC3728956 DOI: 10.1002/ece3.631] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 12/22/2022] Open
Abstract
Female mate preferences for ecologically relevant traits may enhance natural selection, leading to rapid divergence. They may also forge a link between mate choice within species and sexual isolation between species. Here, we examine female mate preference for two ecologically important traits: body size and body shape. We measured female preferences within and between species of benthic, limnetic, and anadromous threespine sticklebacks (Gasterosteus aculeatus species complex). We found that mate preferences differed between species and between contexts (i.e., within vs. between species). Within species, anadromous females preferred males that were deep bodied for their size, benthic females preferred larger males (as measured by centroid size), and limnetic females preferred males that were more limnetic shaped. In heterospecific mating trials between benthics and limnetics, limnetic females continued to prefer males that were more limnetic like in shape when presented with benthic males. Benthic females showed no preferences for size when presented with limnetic males. These results show that females use ecologically relevant traits to select mates in all three species and that female preference has diverged between species. These results suggest that sexual selection may act in concert with natural selection on stickleback size and shape. Further, our results suggest that female preferences may track adaptation to local environments and contribute to sexual isolation between benthic and limnetic sticklebacks.
Collapse
Affiliation(s)
- Megan L Head
- Centre for Ecology and Conservation, School of Biosciences, University of Exeter Cornwall Campus, Penryn, TR10 9EZ, UK
| | | | | |
Collapse
|
39
|
Kozak GM, Head ML, Lackey ACR, Boughman JW. Sequential mate choice and sexual isolation in threespine stickleback species. J Evol Biol 2012. [DOI: 10.1111/jeb.12034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- G. M. Kozak
- Department of Zoology; University of Wisconsin; Madison WI USA
| | - M. L. Head
- Centre for Ecology and Conservation; School of Biosciences; University of Exeter; Penryn UK
| | - A. C. R. Lackey
- Department of Zoology, BEACON, Ecology, Evolutionary Biology & Behavior Program; Michigan State University; East Lansing MI USA
| | - J. W. Boughman
- Department of Zoology, BEACON, Ecology, Evolutionary Biology & Behavior Program; Michigan State University; East Lansing MI USA
| |
Collapse
|
40
|
Hollander J, Smadja CM, Butlin RK, Reid DG. Genital divergence in sympatric sister snails. J Evol Biol 2012; 26:210-5. [DOI: 10.1111/jeb.12029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/24/2012] [Accepted: 09/24/2012] [Indexed: 11/30/2022]
Affiliation(s)
- J. Hollander
- Department of Biology, Aquatic Ecology; Lund University; Lund Sweden
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - C. M. Smadja
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
- Centre National de la Recherche Scientifique (CNRS); Institut des Sciences de l'Evolution UMR 5554; Montpellier France
| | - R. K. Butlin
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield UK
| | - D. G. Reid
- Department of Life Sciences; Natural History Museum; London UK
| |
Collapse
|
41
|
Nosil P, Gompert Z, Farkas TE, Comeault AA, Feder JL, Buerkle CA, Parchman TL. Genomic consequences of multiple speciation processes in a stick insect. Proc Biol Sci 2012; 279:5058-65. [PMID: 22696527 PMCID: PMC3497229 DOI: 10.1098/rspb.2012.0813] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Diverse geographical modes and mechanisms of speciation are known, and individual speciation genes have now been identified. Despite this progress, genome-wide outcomes of different evolutionary processes during speciation are less understood. Here, we integrate ecological and spatial information, mating trials, transplantation data and analysis of 86 130 single nucleotide polymorphisms (SNPs) in eight populations (28 pairwise comparisons) of Timema cristinae stick insects to test the effects of different factors on genomic divergence in a system undergoing ecological speciation. We find patterns consistent with effects of numerous factors, including geographical distance, gene flow, divergence in host plant use and climate, and selection against maladaptive hybridization (i.e. reinforcement). For example, the number of highly differentiated ‘outlier loci’, allele-frequency clines and the overall distribution of genomic differentiation were recognizably affected by these factors. Although host use has strong effects on phenotypic divergence and reproductive isolation, its effects on genomic divergence were subtler and other factors had pronounced effects. The results demonstrate how genomic data can provide new insights into speciation and how genomic divergence can be complex, yet predictable. Future work could adopt experimental, mapping and functional approaches to directly test which genetic regions are affected by selection and determine their physical location in the genome.
Collapse
Affiliation(s)
- Patrik Nosil
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80303, USA.
| | | | | | | | | | | | | |
Collapse
|
42
|
McKinnon JS, Hamele N, Frey N, Chou J, McAleavey L, Greene J, Paulson W. Male choice in the stream-anadromous stickleback complex. PLoS One 2012; 7:e37951. [PMID: 22701589 PMCID: PMC3372497 DOI: 10.1371/journal.pone.0037951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 04/30/2012] [Indexed: 12/04/2022] Open
Abstract
Studies of mating preferences and pre-mating reproductive isolation have often focused on females, but the potential importance of male preferences is increasingly appreciated. We investigated male behavior in the context of reproductive isolation between divergent anadromous and stream-resident populations of threespine stickleback, Gasterosteus aculeatus, using size-manipulated females of both ecotypes. Specifically, we asked if male courtship preferences are present, and if they are based on relative body size, non-size aspects of ecotype, or other traits. Because male behaviors were correlated with each other, we conducted a principal components analysis on the correlations and ran subsequent analyses on the principal components. The two male ecotypes differed in overall behavioral frequencies, with stream-resident males exhibiting consistently more vigorous and positive courtship than anadromous males, and an otherwise aggressive behavior playing a more positive role in anadromous than stream-resident courtship. We observed more vigorous courtship toward smaller females by (relatively small) stream-resident males and the reverse pattern for (relatively large) anadromous males. Thus size-assortative male courtship preferences may contribute to reproductive isolation in this system, although preferences are far from absolute. We found little indication of males responding preferentially to females of their own ecotype independent of body size.
Collapse
Affiliation(s)
- Jeffrey S McKinnon
- Department of Biology, East Carolina University, Greenville, North Carolina, United States of America.
| | | | | | | | | | | | | |
Collapse
|
43
|
Furin CG, von Hippel FA, Bell MA. Partial reproductive isolation of a recently derived resident-freshwater population of threespine stickleback (Gasterosteus aculeatus) from its putative anadromous ancestor. Evolution 2012; 66:3277-86. [PMID: 23025615 DOI: 10.1111/j.1558-5646.2012.01672.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We used no-choice mating trials to test for assortative mating between a newly derived resident-freshwater population (8-22 generations since founding) of threespine stickleback (Gasterosteus aculeatus) in Loberg Lake, Alaska and its putative anadromous ancestor as well as a morphologically convergent but distantly related resident-freshwater population. Partial reproductive isolation has evolved between the Loberg Lake population and its ancestor within a remarkably short time period. However, Loberg stickleback readily mate with morphologically similar, but distantly related resident-freshwater stickleback. Partial premating isolation is asymmetrical; anadromous females and smaller resident-freshwater males from Loberg Lake readily mate, but the anadromous males and smaller Loberg females do not. Our results indicate that premating isolation can begin to evolve in allopatry within a few generations after isolation as a correlated effect of evolution of reduced body size.
Collapse
Affiliation(s)
- Christoff G Furin
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska 99508, USA.
| | | | | |
Collapse
|
44
|
Hohenlohe PA, Bassham S, Currey M, Cresko WA. Extensive linkage disequilibrium and parallel adaptive divergence across threespine stickleback genomes. Philos Trans R Soc Lond B Biol Sci 2012; 367:395-408. [PMID: 22201169 DOI: 10.1098/rstb.2011.0245] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Population genomic studies are beginning to provide a more comprehensive view of dynamic genome-scale processes in evolution. Patterns of genomic architecture, such as genomic islands of increased divergence, may be important for adaptive population differentiation and speciation. We used next-generation sequencing data to examine the patterns of local and long-distance linkage disequilibrium (LD) across oceanic and freshwater populations of threespine stickleback, a useful model for studies of evolution and speciation. We looked for associations between LD and signatures of divergent selection, and assessed the role of recombination rate variation in generating LD patterns. As predicted under the traditional biogeographic model of unidirectional gene flow from ancestral oceanic to derived freshwater stickleback populations, we found extensive local and long-distance LD in fresh water. Surprisingly, oceanic populations showed similar patterns of elevated LD, notably between large genomic regions previously implicated in adaptation to fresh water. These results support an alternative biogeographic model for the stickleback radiation, one of a metapopulation with appreciable bi-directional gene flow combined with strong divergent selection between oceanic and freshwater populations. As predicted by theory, these processes can maintain LD within and among genomic islands of divergence. These findings suggest that the genomic architecture in oceanic stickleback populations may provide a mechanism for the rapid re-assembly and evolution of multi-locus genotypes in newly colonized freshwater habitats, and may help explain genetic mapping of parallel phenotypic variation to similar loci across independent freshwater populations.
Collapse
Affiliation(s)
- Paul A Hohenlohe
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403-5289, USA
| | | | | | | |
Collapse
|
45
|
Myers EM, Frankino WA. Time in a bottle: the evolutionary fate of species discrimination in sibling Drosophila species. PLoS One 2012; 7:e31759. [PMID: 22384069 PMCID: PMC3288057 DOI: 10.1371/journal.pone.0031759] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 01/18/2012] [Indexed: 11/19/2022] Open
Abstract
Disadvantageous hybridization favors the evolution of prezygotic isolating behaviors, generating a geographic pattern of interspecific mate discrimination where members of different species drawn from sympatric populations exhibit stronger preference for members of their own species than do individuals drawn from allopatric populations. Geographic shifts in species' boundaries can relax local selection against hybridization; under such scenarios the fate of enhanced species preference is unknown. Lineages established from populations in the region of sympatry that have been maintained as single-species laboratory cultures represent cases where allopatry has been produced experimentally. Using such cultures dating from the 1950s, we assess how Drosophila pseudoobscura and D. persimilis mate preferences respond to relaxed natural selection against hybridization. We found that the propensity to hybridize generally declines with increasing time in experimental allopatry, suggesting that maintaining enhanced preference for conspecifics may be costly. However, our data also suggest a strong role for drift in determining mating preferences once secondary allopatry has been established. Finally, we discuss the interplay between populations in establishing the presence or absence of patterns consistent with reinforcement.
Collapse
Affiliation(s)
- Erin M Myers
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America.
| | | |
Collapse
|
46
|
Reifová R, Reif J, Antczak M, Nachman MW. Ecological character displacement in the face of gene flow: evidence from two species of nightingales. BMC Evol Biol 2011; 11:138. [PMID: 21609448 PMCID: PMC3121626 DOI: 10.1186/1471-2148-11-138] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 05/24/2011] [Indexed: 11/18/2022] Open
Abstract
Background Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (L. luscinia). Results We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry. Conclusions Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation.
Collapse
Affiliation(s)
- Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
| | | | | | | |
Collapse
|
47
|
Genes versus phenotypes in the study of speciation. Genetica 2011; 139:649-61. [PMID: 21442403 DOI: 10.1007/s10709-011-9562-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Accepted: 02/28/2011] [Indexed: 10/18/2022]
Abstract
Despite persistent debate on the nature of species, the widespread adoption of Mayr's biological species concept has led to a heavy emphasis on the importance of reproductive isolation to the speciation process. Equating the origin of species with the evolution of reproductive isolation has become common practice in the study of speciation, coincident with an increasing focus on elucidating the specific genetic changes (i.e.-speciation genes) underlying intrinsic reproductive barriers between species. In contrast, some have recognized that reproductive isolation is usually a signature effect rather than a primary cause of speciation. Here we describe a research paradigm that shifts emphasis from effects to causes in order to resolve this apparent contradiction and galvanize the study of speciation. We identify major elements necessary for a balanced and comprehensive investigation of the origin of species and place the study of so-called "speciation genes" into its appropriate context. We emphasize the importance of characterizing diverging phenotypes, identifying relevant evolutionary forces acting on those phenotypes and their role in the causal origins of reduced gene flow between incipient species, and the nature of the genetic and phenotypic boundaries that results from such processes. This approach has the potential to unify the field of speciation research, by allowing us to make better "historical" predictions about the fate of diverging populations regardless of taxon.
Collapse
|
48
|
Nydam ML, Harrison RG. Reproductive protein evolution in two cryptic species of marine chordate. BMC Evol Biol 2011; 11:18. [PMID: 21247489 PMCID: PMC3036616 DOI: 10.1186/1471-2148-11-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 01/19/2011] [Indexed: 12/11/2022] Open
Abstract
Background Reproductive character displacement (RCD) is a common and taxonomically widespread pattern. In marine broadcast spawning organisms, behavioral and mechanical isolation are absent and prezygotic barriers between species often operate only during the fertilization process. Such barriers are usually a consequence of differences in the way in which sperm and egg proteins interact, so RCD can be manifest as faster evolution of these proteins between species in sympatry than allopatry. Rapid evolution of these proteins often appears to be a consequence of positive (directional) selection. Here, we identify a set of candidate gamete recognition proteins (GRPs) in the ascidian Ciona intestinalis and showed that these GRPs evolve more rapidly than control proteins (those not involved in gamete recognition). Choosing a subset of these gamete recognition proteins that show evidence of positive selection (CIPRO37.40.1, CIPRO60.5.1, CIPRO100.7.1), we then directly test the RCD hypothesis by comparing divergence (omega) and polymorphism (McDonald-Kreitman, Tajima's D, Fu and Li's D and F, Fay and Wu's H) statistics in sympatric and allopatric populations of two distinct forms of C. intestinalis (Types A and B) between which there are strong post-zygotic barriers. Results Candidate gamete recognition proteins from two lineages of C. intestinalis (Type A and B) are evolving more rapidly than control proteins, consistent with patterns seen in insects and mammals. However, ω (dN/dS) is not significantly different between the sympatric and allopatric populations, and none of the polymorphism statistics show significant differences between sympatric and allopatric populations. Conclusions Enhanced prezygotic isolation in sympatry has become a well-known feature of gamete recognition proteins in marine broadcast spawners. But in most cases the evolutionary process or processes responsible for this pattern have not been identified. Although gamete recognition proteins in C. intestinalis do appear to evolve more rapidly, on average, than proteins with other functions, rates of evolution are not different in allopatric and sympatric populations of the two reproductively isolated forms. That sympatry is probably human-mediated, and therefore recent, may explain the absence of RCD.
Collapse
Affiliation(s)
- Marie L Nydam
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853, USA.
| | | |
Collapse
|
49
|
Matute DR. Reinforcement can overcome gene flow during speciation in Drosophila. Curr Biol 2010; 20:2229-33. [PMID: 21129972 PMCID: PMC3019097 DOI: 10.1016/j.cub.2010.11.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/28/2010] [Accepted: 11/04/2010] [Indexed: 11/15/2022]
Abstract
Reinforcement, the strengthening of prezygotic reproductive isolation by natural selection in response to maladaptive hybridization [1-3], is one of the few processes in which natural selection directly favors the evolution of species as discrete groups (e.g., [4-7]). The evolution of reproductive barriers via reinforcement is expected to evolve in regions where the ranges of two species overlap and hybridize as an evolutionary solution to avoiding the costs of maladaptive hybridization [2,3,8]. The role of reinforcement in speciation has, however, been highly controversial because population-genetic theory suggests that the process is severely impeded by both hybridization [8-11] and migration of individuals from outside the contact zone [12,13]. To determine whether reinforcement could strengthen the reproductive barriers between two sister species of Drosophila in the face of these impediments, I initiated experimental populations of these two species that allowed different degrees of hybridization, as well as migration from outside populations. Surprisingly, even in the face of gene flow, reinforcement could promote the evolution of reproductive isolation within only five generations. As theory predicts, high levels of hybridization (and/or strong selection against hybrids) and migration impeded this evolution. These results suggest that reinforcement can help complete the process of speciation.
Collapse
Affiliation(s)
- Daniel R Matute
- Department of Ecology and Evolution, The University of Chicago, 1101 East 57 Street, Chicago, IL 60637, USA.
| |
Collapse
|
50
|
Schwartz AK, Weese DJ, Bentzen P, Kinnison MT, Hendry AP. Both geography and ecology contribute to mating isolation in guppies. PLoS One 2010; 5:e15659. [PMID: 21179541 PMCID: PMC3002288 DOI: 10.1371/journal.pone.0015659] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 11/19/2010] [Indexed: 11/24/2022] Open
Abstract
Local adaptation to different environments can promote mating isolation--either as an incidental by-product of trait divergence, or as a result of selection to avoid maladaptive mating. Numerous recent empirical examples point to the common influence of divergent natural selection on speciation based largely on evidence of strong pre-mating isolation between populations from different habitat types. Accumulating evidence for natural selection's influence on speciation is therefore no longer a challenge. The difficulty, rather, is in determining the mechanisms involved in the progress of adaptive divergence to speciation once barriers to gene flow are already present. Here, we present results of both laboratory and field experiments with Trinidadian guppies (Poecilia reticulata) from different environments, who do not show complete reproductive isolation despite adaptive divergence. We investigate patterns of mating isolation between populations that do and do not exchange migrants and show evidence for both by-product and reinforcement mechanisms depending on female ecology. Specifically, low-predation females discriminate against all high-predation males thus implying a by-product mechanism, whereas high-predation females only discriminate against low-predation males from further upstream in the same river, implying selection to avoid maladaptive mating. Our study thus confirms that mechanisms of adaptive speciation are not necessarily mutually exclusive and uncovers the complex ecology-geography interactions that underlie the evolution of mating isolation in nature.
Collapse
Affiliation(s)
- Amy K Schwartz
- Redpath Museum and Department of Biology, McGill University, Montreal, Canada.
| | | | | | | | | |
Collapse
|