1
|
Garlovsky MD, Whittington E, Albrecht T, Arenas-Castro H, Castillo DM, Keais GL, Larson EL, Moyle LC, Plakke M, Reifová R, Snook RR, Ålund M, Weber AAT. Synthesis and Scope of the Role of Postmating Prezygotic Isolation in Speciation. Cold Spring Harb Perspect Biol 2024; 16:a041429. [PMID: 38151330 PMCID: PMC11444258 DOI: 10.1101/cshperspect.a041429] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
How barriers to gene flow arise and are maintained are key questions in evolutionary biology. Speciation research has mainly focused on barriers that occur either before mating or after zygote formation. In comparison, postmating prezygotic (PMPZ) isolation-a barrier that acts after gamete release but before zygote formation-is less frequently investigated but may hold a unique role in generating biodiversity. Here we discuss the distinctive features of PMPZ isolation, including the primary drivers and molecular mechanisms underpinning PMPZ isolation. We then present the first comprehensive survey of PMPZ isolation research, revealing that it is a widespread form of prezygotic isolation across eukaryotes. The survey also exposes obstacles in studying PMPZ isolation, in part attributable to the challenges involved in directly measuring PMPZ isolation and uncovering its causal mechanisms. Finally, we identify outstanding knowledge gaps and provide recommendations for improving future research on PMPZ isolation. This will allow us to better understand the nature of this often-neglected reproductive barrier and its contribution to speciation.
Collapse
Affiliation(s)
- Martin D Garlovsky
- Applied Zoology, Faculty of Biology, Technische Universität Dresden, Dresden 01062, Germany
| | | | - Tomas Albrecht
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno 60365, Czech Republic
- Department of Zoology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
| | - Henry Arenas-Castro
- School of Biological Sciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Dean M Castillo
- Department of Biological Sciences, Miami University, Hamilton, Ohio 45011, USA
| | - Graeme L Keais
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, Colorado 80208, USA
| | - Leonie C Moyle
- Department of Biology, Indiana University Bloomington, Indiana 47405, USA
| | - Melissa Plakke
- Division of Science, Mathematics, and Technology, Governors State University, University Park, Illinois 60484, USA
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague 128 00, Czech Republic
| | - Rhonda R Snook
- Department of Zoology, Stockholm University, Stockholm 109 61, Sweden
| | - Murielle Ålund
- Department of Ecology and Genetics, Animal Ecology, Uppsala University, Uppsala 75236, Sweden
| | - Alexandra A-T Weber
- Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Dübendorf 8600, Zürich, Switzerland
| |
Collapse
|
2
|
Feller AF, Burgin G, Lewis N, Prabhu R, Hopkins R. Mismatch between pollen and pistil size causes asymmetric mechanical reproductive isolation across Phlox species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593106. [PMID: 38766021 PMCID: PMC11100701 DOI: 10.1101/2024.05.08.593106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
In flowering plants, pollen-pistil interactions can serve as an important barrier to reproduction between species. As the last barrier to reproduction before fertilization, interactions between these reproductive organs are both complex and important for determining a suitable mate. Here, we test whether differences in style length generate a post-mating prezygotic mechanical barrier between five species of perennial Phlox wildflowers with geographically overlapping distributions. We perform controlled pairwise reciprocal crosses between three species with long styles and two species with short styles to assess crossing success (seed set). We find that heterospecific seed set is broadly reduced compared to conspecific cross success and reveal a striking asymmetry in heterospecific crosses between species with different style lengths. To determine the mechanism underlying this asymmetric reproductive isolating barrier we assess pollen tube growth in vitro and in vivo. We demonstrate that pollen tubes of short-styled species do not grow long enough to reach the ovaries of long-styled species. We find that short-styled species also have smaller pollen and that both within and between species pollen diameter is highly correlated with pollen tube length. Our results support the hypothesis that the small pollen of short-styled species lacks resources to grow pollen tubes long enough to access the ovaries of the long-styled species, resulting in an asymmetrical, mechanical barrier to reproduction. Such mechanisms, combined with additional pollen-pistil incompatibilities, may be particularly important for closely related species in geographic proximity that share pollinators.
Collapse
Affiliation(s)
- Anna F. Feller
- Department of Organismic and Evolutionary Biology & Arnold Arboretum, Harvard University, Cambridge, MA 02138, USA
| | - Grace Burgin
- Department of Organismic and Evolutionary Biology & Arnold Arboretum, Harvard University, Cambridge, MA 02138, USA
| | - Nia Lewis
- Department of Organismic and Evolutionary Biology & Arnold Arboretum, Harvard University, Cambridge, MA 02138, USA
| | - Rohan Prabhu
- Department of Organismic and Evolutionary Biology & Arnold Arboretum, Harvard University, Cambridge, MA 02138, USA
- Northeastern University, Boston, MA 02115, USA
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology & Arnold Arboretum, Harvard University, Cambridge, MA 02138, USA
| |
Collapse
|
3
|
Yukilevich R, Aoki F, Egan S, Zhang L. Coevolutionary Interactions between Sexual and Habitat Isolation during Reinforcement. Cold Spring Harb Perspect Biol 2024; 16:a041431. [PMID: 38316551 PMCID: PMC11065176 DOI: 10.1101/cshperspect.a041431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Speciation often involves the evolution of multiple genetic-based barriers to gene flow (i.e., "coupling"). However, barriers may exhibit a diversity of evolutionary interactions during speciation. These dynamics are important in reinforcement, where selection may favor different prezygotic isolating barriers to avoid maladaptive hybridization. Here we study the interaction between evolution of sexual and habitat isolation. We first review the empirical literature where both barriers were explicitly considered, and then develop a population genetic model of reinforcement. Most studies of both sexual and habitat isolation were found in phytophagous insect systems. In 76% of these studies, both barriers coevolved; the remaining cases either showed only habitat isolation (21%) or only sexual isolation (3%). Our two-allele genetic mechanism model of each barrier also found that these often coevolved, but habitat isolation was generally more effective during reinforcement. Depending on the fitness of hybrids (e.g., Dobzhansky-Muller incompatibilities) and initial migration rate, these barriers could either facilitate, curtail, or have no effect on each other. This indicates that basic parameters will alter the underlying evolutionary dynamics, and thus the nature of "speciation coupling" will be highly variable in natural systems. Finally, we studied initially asymmetrical migration rates and found that populations with higher initial emigration evolved stronger habitat isolation, while populations that initially received more immigrants exhibited stronger sexual isolation. These results are in line with observations in some empirical studies, but more data is needed to test their generality.
Collapse
Affiliation(s)
- Roman Yukilevich
- Department of Biology, Union College, Integrated Science and Engineering Complex, Schenectady, New York 12308, USA
| | - Fumio Aoki
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York 11794, USA
| | - Scott Egan
- Department of Biosciences, Rice University, Houston, Texas 77005, USA
| | - Linyi Zhang
- Department of Biological Sciences, George Washington University, Washington, D.C. 20052, USA
| |
Collapse
|
4
|
Singh P, Ballmer DN, Laubscher M, Schärer L. Successful mating and hybridisation in two closely related flatworm species despite significant differences in reproductive morphology and behaviour. Sci Rep 2020; 10:12830. [PMID: 32732887 PMCID: PMC7393371 DOI: 10.1038/s41598-020-69767-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Reproductive traits are some of the fastest diverging characters and can serve as reproductive barriers. The free-living flatworm Macrostomum lignano, and its congener M. janickei are closely related, but differ substantially in their male intromittent organ (stylet) morphology. Here, we examine whether these morphological differences are accompanied by differences in behavioural traits, and whether these could represent barriers to successful mating and hybridization between the two species. Our data shows that the two species differ in many aspects of their mating behaviour. Despite these differences, the species mate readily with each other in heterospecific pairings. Although both species have similar fecundity in conspecific pairings, the heterospecific pairings revealed clear postmating barriers, as few heterospecific pairings produced F1 hybrids. These hybrids had a stylet morphology that was intermediate between that of the parental species, and they were fertile. Finally, using a mate choice experiment, we show that the nearly two-fold higher mating rate of M. lignano caused it to mate more with conspecifics, leading to assortative mating, while M. janickei ended up mating more with heterospecifics. Thus, while the two species can hybridize, the mating rate differences could possibly lead to higher fitness costs for M. janickei compared to M. lignano.
Collapse
Affiliation(s)
- Pragya Singh
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.
| | - Daniel N Ballmer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland.,Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Max Laubscher
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| | - Lukas Schärer
- Department of Environmental Sciences, Zoological Institute, University of Basel, Vesalgasse 1, 4051, Basel, Switzerland
| |
Collapse
|
5
|
Larson EL, Brassil MM, Maslan J, Juárez D, Lilagan F, Tipton H, Schweitzer A, Skillman J, Monsen-Collar KJ, Peterson MA. The effects of heterospecific mating frequency on the strength of cryptic reproductive barriers. J Evol Biol 2019; 32:900-912. [PMID: 31162735 DOI: 10.1111/jeb.13495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/22/2019] [Accepted: 05/28/2019] [Indexed: 01/02/2023]
Abstract
Heterospecific mating frequency is critical to hybrid zone dynamics and can directly impact the strength of reproductive barriers and patterns of introgression. The effectiveness of post-mating prezygotic (PMPZ) reproductive barriers, which include reduced fecundity via heterospecific matings and conspecific sperm precedence, may depend on the number, identity and order of mates. Studies of PMPZ barriers suggest that they may be important in many systems, but whether these barriers are effective at realistic heterospecific mating frequencies has not been tested. Here, we evaluate the strength of cryptic reproductive isolation in two leaf beetles (Chrysochus auratus and C. cobaltinus) in the context of a range of heterospecific mating frequencies observed in natural populations. We found both species benefited from multiple matings, but the benefits were greater in C. cobaltinus and extended to heterospecific matings. We found that PMPZ barriers greatly limited hybrid production by C. auratus females with moderate heterospecific mating frequencies, but that their effectiveness diminished at higher heterospecific mating frequencies. In contrast, there was no evidence for PMPZ barriers in C. cobaltinus females at any heterospecific mating frequency. We show that integrating realistic estimates of cryptic isolation with information on relative abundance and heterospecific mating frequency in the field substantially improves our understanding of the strong directional bias in F1 production previously documented in the Chrysochus hybrid zone. Our results demonstrate that heterospecific mating frequency is critical to understanding the impact of cryptic post-copulatory barriers on hybrid zone structure and dynamics, and that future studies of such barriers should incorporate field-relevant heterospecific mating frequencies.
Collapse
Affiliation(s)
- Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, Colorado, USA.,Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Margaret M Brassil
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Jonathan Maslan
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Danielle Juárez
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Flordeliza Lilagan
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Hallie Tipton
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Andrew Schweitzer
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | - Joe Skillman
- Biology Department, Western Washington University, Bellingham, Washington, USA
| | | | - Merrill A Peterson
- Biology Department, Western Washington University, Bellingham, Washington, USA
| |
Collapse
|
6
|
Garlovsky MD, Snook RR. Persistent postmating, prezygotic reproductive isolation between populations. Ecol Evol 2018; 8:9062-9073. [PMID: 30271566 PMCID: PMC6157668 DOI: 10.1002/ece3.4441] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/23/2018] [Accepted: 07/09/2018] [Indexed: 12/23/2022] Open
Abstract
Studying reproductive barriers between populations of the same species is critical to understand how speciation may proceed. Growing evidence suggests postmating, prezygotic (PMPZ) reproductive barriers play an important role in the evolution of early taxonomic divergence. However, the contribution of PMPZ isolation to speciation is typically studied between species in which barriers that maintain isolation may not be those that contributed to reduced gene flow between populations. Moreover, in internally fertilizing animals, PMPZ isolation is related to male ejaculate-female reproductive tract incompatibilities but few studies have examined how mating history of the sexes can affect the strength of PMPZ isolation and the extent to which PMPZ isolation is repeatable or restricted to particular interacting genotypes. We addressed these outstanding questions using multiple populations of Drosophila montana. We show a recurrent pattern of PMPZ isolation, with flies from one population exhibiting reproductive incompatibility in crosses with all three other populations, while those three populations were fully fertile with each other. Reproductive incompatibility is due to lack of fertilization and is asymmetrical, affecting female fitness more than males. There was no effect of male or female mating history on reproductive incompatibility, indicating that PMPZ isolation persists between populations. We found no evidence of variability in fertilization outcomes attributable to different female × male genotype interactions, and in combination with our other results, suggests that PMPZ isolation is not driven by idiosyncratic genotype × genotype interactions. Our results show PMPZ isolation as a strong, consistent barrier to gene flow early during speciation and suggest several targets of selection known to affect ejaculate-female reproductive tract interactions within species that may cause this PMPZ isolation.
Collapse
Affiliation(s)
| | - Rhonda R. Snook
- Department of Animal and Plant SciencesUniversity of SheffieldSheffieldUK
- Department of ZoologyStockholm UniversityStockholmSweden
| |
Collapse
|