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von Schmalensee L, Caillault P, Gunnarsdóttir KH, Gotthard K, Lehmann P. Seasonal specialization drives divergent population dynamics in two closely related butterflies. Nat Commun 2023; 14:3663. [PMID: 37339960 DOI: 10.1038/s41467-023-39359-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 06/07/2023] [Indexed: 06/22/2023] Open
Abstract
Seasons impose different selection pressures on organisms through contrasting environmental conditions. How such seasonal evolutionary conflict is resolved in organisms whose lives span across seasons remains underexplored. Through field experiments, laboratory work, and citizen science data analyses, we investigate this question using two closely related butterflies (Pieris rapae and P. napi). Superficially, the two butterflies appear highly ecologically similar. Yet, the citizen science data reveal that their fitness is partitioned differently across seasons. Pieris rapae have higher population growth during the summer season but lower overwintering success than do P. napi. We show that these differences correspond to the physiology and behavior of the butterflies. Pieris rapae outperform P. napi at high temperatures in several growth season traits, reflected in microclimate choice by ovipositing wild females. Instead, P. rapae have higher winter mortality than do P. napi. We conclude that the difference in population dynamics between the two butterflies is driven by seasonal specialization, manifested as strategies that maximize gains during growth seasons and minimize harm during adverse seasons, respectively.
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Affiliation(s)
- Loke von Schmalensee
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden.
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Pauline Caillault
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
| | | | - Karl Gotthard
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Philipp Lehmann
- Department of Zoology, Stockholm University, SE-106 91, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-106 91, Stockholm, Sweden
- Department of Animal Physiology, Zoological Institute and Museum, University of Greifswald, 1D-17489, Greifswald, Germany
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2
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Lackey ACR, Murray AC, Mirza NA, Powell THQ. The role of sexual isolation during rapid ecological divergence: Evidence for a new dimension of isolation in Rhagoletis pomonella. J Evol Biol 2023. [PMID: 37173822 DOI: 10.1111/jeb.14179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 03/05/2023] [Accepted: 03/23/2023] [Indexed: 05/15/2023]
Abstract
The pace of divergence and likelihood of speciation often depends on how and when different types of reproductive barriers evolve. Questions remain about how reproductive isolation evolves after initial divergence. We tested for the presence of sexual isolation (reduced mating between populations due to divergent mating preferences and traits) in Rhagoletis pomonella flies, a model system for incipient ecological speciation. We measured the strength of sexual isolation between two very recently diverged (~170 generations) sympatric populations, adapted to different host fruits (hawthorn and apple). We found that flies from both populations were more likely to mate within than between populations. Thus, sexual isolation may play an important role in reducing gene flow allowed by early-acting ecological barriers. We also tested how warmer temperatures predicted under climate change could alter sexual isolation and found that sexual isolation was markedly asymmetric under warmer temperatures - apple males and hawthorn females mated randomly while apple females and hawthorn males mated more within populations than between. Our findings provide a window into the early speciation process and the role of sexual isolation after initial ecological divergence, in addition to examining how environmental conditions could shape the likelihood of further divergence.
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Affiliation(s)
- Alycia C R Lackey
- University of Louisville, Louisville, Kentucky, USA
- Binghamton University, Binghamton, New York, USA
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3
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Feder JL, Nosil P. Beyond dichotomies in species and speciation. Natl Sci Rev 2023; 9:nwad018. [PMID: 36778105 PMCID: PMC9905644 DOI: 10.1093/nsr/nwad018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2023] [Indexed: 01/19/2023] Open
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4
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McCulloch GA, Waters JM. Rapid adaptation in a fast-changing world: Emerging insights from insect genomics. GLOBAL CHANGE BIOLOGY 2023; 29:943-954. [PMID: 36333958 PMCID: PMC10100130 DOI: 10.1111/gcb.16512] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 10/07/2022] [Indexed: 05/31/2023]
Abstract
Many researchers have questioned the ability of biota to adapt to rapid anthropogenic environmental shifts. Here, we synthesize emerging genomic evidence for rapid insect evolution in response to human pressure. These new data reveal diverse genomic mechanisms (single locus, polygenic, structural shifts; introgression) underpinning rapid adaptive responses to a variety of anthropogenic selective pressures. While the effects of some human impacts (e.g. pollution; pesticides) have been previously documented, here we highlight startling new evidence for rapid evolutionary responses to additional anthropogenic processes such as deforestation. These recent findings indicate that diverse insect assemblages can indeed respond dynamically to major anthropogenic evolutionary challenges. Our synthesis also emphasizes the critical roles of genomic architecture, standing variation and gene flow in maintaining future adaptive potential. Broadly, it is clear that genomic approaches are essential for predicting, monitoring and responding to ongoing anthropogenic biodiversity shifts in a fast-changing world.
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Ward AKG, Bagley RK, Egan SP, Hood GR, Ott JR, Prior KM, Sheikh SI, Weinersmith KL, Zhang L, Zhang YM, Forbes AA. Speciation in Nearctic oak gall wasps is frequently correlated with changes in host plant, host organ, or both. Evolution 2022; 76:1849-1867. [PMID: 35819249 PMCID: PMC9541853 DOI: 10.1111/evo.14562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 01/22/2023]
Abstract
Quantifying the frequency of shifts to new host plants within diverse clades of specialist herbivorous insects is critically important to understand whether and how host shifts contribute to the origin of species. Oak gall wasps (Hymenoptera: Cynipidae: Cynipini) comprise a tribe of ∼1000 species of phytophagous insects that induce gall formation on various organs of trees in the family Fagacae-primarily the oaks (genus Quercus; ∼435 sp.). The association of oak gall wasps with oaks is ancient (∼50 my), and most oak species are galled by one or more gall wasp species. Despite the diversity of both gall wasp species and their plant associations, previous phylogenetic work has not identified the strong signal of host plant shifting among oak gall wasps that has been found in other phytophagous insect systems. However, most emphasis has been on the Western Palearctic and not the Nearctic where both oaks and oak gall wasps are considerably more species rich. We collected 86 species of Nearctic oak gall wasps from most of the major clades of Nearctic oaks and sequenced >1000 Ultraconserved Elements (UCEs) and flanking sequences to infer wasp phylogenies. We assessed the relationships of Nearctic gall wasps to one another and, by leveraging previously published UCE data, to the Palearctic fauna. We then used phylogenies to infer historical patterns of shifts among host tree species and tree organs. Our results indicate that oak gall wasps have moved between the Palearctic and Nearctic at least four times, that some Palearctic wasp clades have their proximate origin in the Nearctic, and that gall wasps have shifted within and between oak tree sections, subsections, and organs considerably more often than previous data have suggested. Given that host shifts have been demonstrated to drive reproductive isolation between host-associated populations in other phytophagous insects, our analyses of Nearctic gall wasps suggest that host shifts are key drivers of speciation in this clade, especially in hotspots of oak diversity. Although formal assessment of this hypothesis requires further study, two putatively oligophagous gall wasp species in our dataset show signals of host-associated genetic differentiation unconfounded by geographic distance, suggestive of barriers to gene flow associated with the use of alternative host plants.
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Affiliation(s)
| | - Robin K. Bagley
- Department of BiologyUniversity of IowaIowa CityIowa52245,Department of Evolution, Ecology, and Organismal BiologyThe Ohio State UniversityLimaOhio45804
| | - Scott P. Egan
- Department of BioSciencesRice UniversityHoustonTexas77005
| | - Glen Ray Hood
- Department of BioSciencesRice UniversityHoustonTexas77005,Department of Biological ScienceWayne State UniversityDetroitMichigan48202
| | - James R. Ott
- Department of BiologyTexas State UniversitySan MarcosTexas78666
| | - Kirsten M. Prior
- Department of Biological SciencesBinghamton UniversityBinghamtonNew York13902
| | - Sofia I. Sheikh
- Department of BiologyUniversity of IowaIowa CityIowa52245,Department of Ecology and EvolutionUniversity of ChicagoChicagoIllinois60637
| | | | - Linyi Zhang
- Department of BioSciencesRice UniversityHoustonTexas77005,Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONM5S 3B2Canada
| | - Y. Miles Zhang
- Systematic Entomology Laboratory, USDA‐ARSc/o National Museum of Natural HistoryWashingtonD.C.20560
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6
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Rosser N, Seixas F, Mallet J. Sympatric speciation by allochrony? Mol Ecol 2022; 31:3975-3978. [PMID: 35789010 DOI: 10.1111/mec.16599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/28/2022] [Indexed: 11/30/2022]
Abstract
Sympatric speciation was once thought most improbable, but careful study of some systems, particularly the apple maggot (Rhagoletis pomonella) and related Rhagoletis species, has led to its reinstatement as a likely mode of speciation in some cases. Different species and host races in this clade of flies often have highly specialized host preference, and along with frequent evolutionary shifts to different fruit species between sister taxa, there is a likely effect of the timing of adult emergence that follows host fruiting phenology. This is known as “allochronic” isolation (from the Greek meaning “different timing”). This overview covers recent discoveries by Inskeep et al. (Molecular Ecology, 2021) showing how allochrony is a major factor in preventing gene flow between a pair of sister species of Rhagoletis on different host fruits. Although the authors do not claim to prove sympatric speciation, it does seem very likely, and the work clearly underscores how readily host shifts via allochrony can aid sympatric speciation.
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Affiliation(s)
- Neil Rosser
- Dept. of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, CAMBRIDGE, MA, USA
| | - Fernando Seixas
- Dept. of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, CAMBRIDGE, MA, USA
| | - James Mallet
- Dept. of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, CAMBRIDGE, MA, USA
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Carscadden KA, Doak DF, Emery NC. Climate Variation Influences Flowering Time Overlap in a Pair of Hybridizing Montane Plants. WEST N AM NATURALIST 2022. [DOI: 10.3398/064.082.0112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Kelly A. Carscadden
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St., Boulder, CO 80309
| | - Daniel F. Doak
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St., Boulder, CO 80309
| | - Nancy C. Emery
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 1900 Pleasant St., Boulder, CO 80309
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8
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The Build-Up of Population Genetic Divergence along the Speciation Continuum during a Recent Adaptive Radiation of Rhagoletis Flies. Genes (Basel) 2022; 13:genes13020275. [PMID: 35205320 PMCID: PMC8872456 DOI: 10.3390/genes13020275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 02/05/2023] Open
Abstract
New species form through the evolution of genetic barriers to gene flow between previously interbreeding populations. The understanding of how speciation proceeds is hampered by our inability to follow cases of incipient speciation through time. Comparative approaches examining different diverging taxa may offer limited inferences, unless they fulfill criteria that make the comparisons relevant. Here, we test for those criteria in a recent adaptive radiation of the Rhagoletis pomonella species group (RPSG) hypothesized to have diverged in sympatry via adaptation to different host fruits. We use a large-scale population genetic survey of 1568 flies across 33 populations to: (1) detect on-going hybridization, (2) determine whether the RPSG is derived from the same proximate ancestor, and (3) examine patterns of clustering and differentiation among sympatric populations. We find that divergence of each in-group RPSG taxon is occurring under current gene flow, that the derived members are nested within the large pool of genetic variation present in hawthorn-infesting populations of R. pomonella, and that sympatric population pairs differ markedly in their degree of genotypic clustering and differentiation across loci. We conclude that the RPSG provides a particularly robust opportunity to make direct comparisons to test hypotheses about how ecological speciation proceeds despite on-going gene flow.
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Bruzzese DJ, Schuler H, Wolfe TM, Glover MM, Mastroni JV, Doellman MM, Tait C, Yee WL, Rull J, Aluja M, Hood GR, Goughnour RB, Stauffer C, Nosil P, Feder JL. Testing the potential contribution of Wolbachia to speciation when cytoplasmic incompatibility becomes associated with host-related reproductive isolation. Mol Ecol 2021; 31:2935-2950. [PMID: 34455644 PMCID: PMC9290789 DOI: 10.1111/mec.16157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 08/18/2021] [Accepted: 08/25/2021] [Indexed: 01/04/2023]
Abstract
Endosymbiont‐induced cytoplasmic incompatibility (CI) may play an important role in arthropod speciation. However, whether CI consistently becomes associated or coupled with other host‐related forms of reproductive isolation (RI) to impede the transfer of endosymbionts between hybridizing populations and further the divergence process remains an open question. Here, we show that varying degrees of pre‐ and postmating RI exist among allopatric populations of two interbreeding cherry‐infesting tephritid fruit flies (Rhagoletis cingulata and R. indifferens) across North America. These flies display allochronic and sexual isolation among populations, as well as unidirectional reductions in egg hatch in hybrid crosses involving southwestern USA males. All populations are infected by a Wolbachia strain, wCin2, whereas a second strain, wCin3, only co‐infects flies from the southwest USA and Mexico. Strain wCin3 is associated with a unique mitochondrial DNA haplotype and unidirectional postmating RI, implicating the strain as the cause of CI. When coupled with nonendosymbiont RI barriers, we estimate the strength of CI associated with wCin3 would not prevent the strain from introgressing from infected southwestern to uninfected populations elsewhere in the USA if populations were to come into secondary contact and hybridize. In contrast, cytoplasmic–nuclear coupling may impede the transfer of wCin3 if Mexican and USA populations were to come into contact. We discuss our results in the context of the general paucity of examples demonstrating stable Wolbachia hybrid zones and whether the spread of Wolbachia among taxa can be constrained in natural hybrid zones long enough for the endosymbiont to participate in speciation.
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Affiliation(s)
- Daniel J Bruzzese
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Hannes Schuler
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bozen-Bolzano, Italy.,Competence Centre for Plant Health, Free University of Bozen-Bolzano, Bozen-Bolzano, Italy
| | - Thomas M Wolfe
- Department of Forest and Soil Sciences, Boku, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mary M Glover
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Joseph V Mastroni
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Meredith M Doellman
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Cheyenne Tait
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Wee L Yee
- United States Department of Agriculture, Temperate Tree Fruit & Vegetable Research Unit, Agricultural Research Service, Wapato, WA, USA
| | - Juan Rull
- Instituto de Ecología A.C., Xalapa, México.,LIEMEN-División Control Biológico de Plagas, PROIMI Biotecnología-CONICET, Tucumán, Argentina
| | | | - Glen Ray Hood
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | | | - Christian Stauffer
- Department of Forest and Soil Sciences, Boku, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Patrik Nosil
- CEFE, University Montpellier, CNRS, EPHE, IRD, University Paul Valéry Montpellier 3, Montpellier, France.,Department of Biology, Utah State University, UT, USA
| | - Jeffery L Feder
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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Inskeep KA, Doellman MM, Powell THQ, Berlocher SH, Seifert NR, Hood GR, Ragland GJ, Meyers PJ, Feder JL. Divergent diapause life history timing drives both allochronic speciation and reticulate hybridization in an adaptive radiation of Rhagoletis flies. Mol Ecol 2021; 31:4031-4049. [PMID: 33786930 DOI: 10.1111/mec.15908] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 03/01/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022]
Abstract
Divergent adaptation to new ecological opportunities can be an important factor initiating speciation. However, as niches are filled during adaptive radiations, trait divergence driving reproductive isolation between sister taxa may also result in trait convergence with more distantly related taxa, increasing the potential for reticulated gene flow across the radiation. Here, we demonstrate such a scenario in a recent adaptive radiation of Rhagoletis fruit flies, specialized on different host plants. Throughout this radiation, shifts to novel hosts are associated with changes in diapause life history timing, which act as "magic traits" generating allochronic reproductive isolation and facilitating speciation-with-gene-flow. Evidence from laboratory rearing experiments measuring adult emergence timing and genome-wide DNA-sequencing surveys supported allochronic speciation between summer-fruiting Vaccinium spp.-infesting Rhagoletis mendax and its hypothesized and undescribed sister taxon infesting autumn-fruiting sparkleberries. The sparkleberry fly and R. mendax were shown to be genetically discrete sister taxa, exhibiting no detectable gene flow and allochronically isolated by a 2-month average difference in emergence time corresponding to host availability. At sympatric sites across the southern USA, the later fruiting phenology of sparkleberries overlaps with that of flowering dogwood, the host of another more distantly related and undescribed Rhagoletis taxon. Laboratory emergence data confirmed broadly overlapping life history timing and genomic evidence supported on-going gene flow between sparkleberry and flowering dogwood flies. Thus, divergent phenological adaptation can drive the initiation of reproductive isolation, while also enhancing genetic exchange across broader adaptive radiations, potentially serving as a source of novel genotypic variation and accentuating further diversification.
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Affiliation(s)
- Katherine A Inskeep
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Meredith M Doellman
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Thomas H Q Powell
- Department of Biological Sciences, Binghamton University (State University of New York), Binghamton, NY, USA
| | - Stewart H Berlocher
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicholas R Seifert
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Glen R Hood
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA
| | - Gregory J Ragland
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, USA
| | - Peter J Meyers
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Jeffrey L Feder
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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