物種分布的交界帶就像一個天然的演化實驗室。從生態的觀點來看，此處提供了研究物種間互動的機會，包括：資源區分、種間競爭、訊息辨識與傳遞等等；另一方面，近緣種之間的分化時常伴隨遺傳交流，小尺度的交界帶也提供了檢測遺傳滲入方向與程度的機會。日本樹蛙(B. japonica)與太田樹蛙(B. otai)是溪樹蛙屬(Buergeria)中的姊妹物種，兩者使用的棲位相似，但分布地區有所差異：日本樹蛙分布於台灣西北部，太田樹蛙則分布於東部及西南部，在台灣東部的宜蘭和西部的嘉義各形成一個交界帶。兩者總共使用三種長鳴叫作為求偶訊息：共同使用的第一型叫聲(Type 1a和Type 1b)與太田樹蛙使用的獨特叫聲(Type 2)。在這個研究中，我們欲探討鳴叫聲辨識是否具有阻隔遺傳交流的效果。我們在最靠近交界帶的地方選取四個族群進行回播實驗，檢視兩物種的雄性個體對於三種聲音的反應，結果顯示兩種溪樹蛙皆對同種叫聲的反應較強，對異種訊息的反應程度低，呈現對稱的反應結果，雄性對分歧訊號的辨別能力暗示了物種之間能夠辨識彼此訊號的能力。遺傳交流以限制酶點位標定法(RAD-seq)取得的大量序列檢測，在親緣關係樹以及STRUCTURE歸群檢測中沒有發現近期的遺傳交流事件，但透過G-PhoCS則檢測出東西部交界帶均發生由日本樹蛙滲入太田樹蛙的歷史事件。遺傳與行為的檢測結果一致，暗示了兩個物種之間的訊號辨識能力能夠阻隔近期的遺傳交流。

Contact zones between sibling species are nature laboratories for evolutionary and ecological studies. In the genetic view, contact zones provide a good place to exam the genetic integrity of species. In the ecological view, the competition, communication and interaction between species were well studied in acoustic-communicated species such as frogs, birds, and some insects. The signal discrimination between two species is crucial to communication and species recognition, which may affect species fitness directly (female choice) or indirectly (male discrimination). Buergeria japonica and B. otai are sister species which use similar niche and communication signals. In Taiwan, they distribute in different drainages, forming two narrow contact zones in eastern (Yilan) and western (Jiayi) Taiwan. The acoustic signals they use include sharing long call (Type 1a of B. japonica and Type 1b of B. otai) and a unique long call (Type 2) of B. otai. In this study, I aim to test whether the divergence of acoustic signal plays a role on the barrier of gene flow. I conducted playback experiment to males both species to exam their response toward conspecific and heterospecific signals. The result shows symmetric result that both species response more to conspecific long call, implying their correct species recognition. In the test of gene flow, I obtained genome-wide SNPs by using RAD-seq. The assignment test showed no recent gene flow between two species, although ancient introgressions from B. japonica to B. otai in both contact zones were detected. The consistent results between genetic and behavioral experiments suggest that the discrimination of acoustic signal functions as a barrier of recent gene flow.

Andolfatto, P., D. Davison, D. Erezyilmaz, T. T. Hu, J. Mast, T. Sunayama-morita, and D. L. Stern. 2011. Multiplexed shotgun genotyping for rapid and efficient genetic mapping. Genome research 21:610–617.
Bastiaans, E., M. J. Bastiaans, G. Morinaga, J. G. Castañeda Gaytán, J. C. Marshall, B. Bane, F. Méndez De La Cruz, and B. Sinervo. 2014. Female preference for sympatric vs. allopatric male throat color morphs in the mesquite lizard (Sceloporus grammicus) species complex. PLoS ONE 9:44–48.
Beaulieu, M., and K. W. Sockman. 2012. One meadow for two sparrows: Resource partitioning in a high elevation habitat. Oecologia 170:529–540.
Boul, K. E., W. Chris Funk, C. R. Darst, D. C. Cannatella, and M. J. Ryan. 2007. Sexual selection drives speciation in an Amazonian frog. Proceedings of the Royal Society B: Biological Sciences 274:399–406.
Buxton, V. L., M. P. Ward, and J. H. Sperry. 2015. Use of chorus sounds for location of breeding habitat in 2 species of anuran amphibians. Behavioral Ecology 26:1111–1118.
Camargo, A., M. Morando, L. J. Avila, and J. W. Sites. 2012. Species delimitation with ABC and other coalescent-based methods : a test of accuracy with simulations and an empirical example with lizards of the Liolaemus darwinii complex (squamata: lilolaemidae). Evolution 66:2834–2849.
Chang, Y.-C., C.-M. Hung, M.-H .Chang, and S.-H. Li. 2017. Asymmetrical introgression between two sister tree frog species Kurixalus eiffingeri and K. berylliniris. Page Congress of Animal Behavior and Ecology.
Chhatre, V. E. 2012. StrAuto : A Python Program User Guide. Genetics.
Colbeck, G. J., T. S. Sillett, and M. S. Webster. 2010. Asymmetric discrimination of geographical variation in song in a migratory passerine. Animal Behaviour 80:311–318.
Curé, C., N. Mathevon, R. Mundry, and T. Aubin. 2012. Acoustic cues used for species recognition can differ between sexes and sibling species : evidence in shearwaters. Animal Behaviour 84:239–250.
Darriba, D., G. L. Taboada, R. Doallo, and D. Posada. 2012. JModelTest 2: More models, new heuristics and parallel computing. Nature Methods 9:772.
Dingle, C., J. W. Poelstra, W. Halfwerk, D. M. Brinkhuizen, and H. Slabbekoorn. 2010. Asymmetric response patterns to subspecies-specific song differences in allopatry and parapatry in the gray-breasted wood-wren. Evolution 64:3537–3548.
Earl, D. A., and B. M. VonHoldt. 2012. Structure Harvester. http://taylor0.biology.ucla.edu/structureHarvester/.
Eaton, D. A. R. 2014. PyRAD: Assembly of de novo RADseq loci for phylogenetic analyses. Bioinformatics 30:1844–1849.
Emerson, K. J., C. R. Merz, J. M. Catchen, P. A. Hohenlohe, W. A. Cresko, W. E. Bradshaw, and C. M. Holzapfel. 2010. Resolving postglacial phylogeography using high-throughput sequencing. Proceedings of the National Academy of Sciences of the United States of America 107:16196–16200.
Excoffier, L. and H. E. L. Lischer. 2010. Arlequin suite ver 3.5: a new series of programs to perform population genetics analyses under Linux and Windows. Molecular Ecology Resources 10: 564-567.
Freedman, A. H., I. Gronau, R. M. Schweizer, D. Ortega-Del Vecchyo, E. Han, P. M. Silva, M. Galaverni, Z. Fan, P. Marx, B. Lorente-Galdos, H. Beale, O. Ramirez, F. Hormozdiari, C. Alkan, C. Vilà, K. Squire, E. Geffen, J. Kusak, A. R. Boyko, H. G. Parker, C. Lee, V. Tadigotla, A. Siepel, C. D. Bustamante, T. T. Harkins, S. F. Nelson, E. A. Ostrander, T.M arques-Bonet, R. K. ayne, and J. Novembre. 2014. Genome sequencing highlights the dynamic early history of dogs. PLoS Genetics 10.
Gerhardt, H. C., and F. Huber. 2002. Acoustic communication in insects and anurans. The University of Chicago Press, Chicago.
Goodenough, J. E., B. McGuire, E. Jakob, and R. A. Wallace. 2009. Perspectives on Animal Behavior. Third edition. Wiley.
Gottscho, A. D., D. A. Wood, A. G. Vandergast, J. Lemos-Espinal, J. Gatesy, and T. W. Reeder. 2017. Lineage diversification of fringe-toed lizards (Phrynosomatidae: Uma notata complex) in the Colorado Desert: delimiting species in the presence of gene flow. Molecular Phylogenetics and Evolution 106:103–117.
Gronau, I., M. J. Hubisz, B. Gulko, C. G. Danko, and A. Siepel. 2011. Bayesian inference of ancient human demography from individual genome sequences. Nature Genetics 43:1031–1034.
Guerra, M. A., and S. R. Ron. 2008. Mate choice and courtship signal differentiation promotes speciation in an Amazonian frog. Behavioral Ecology 19:1128–1135.
Guindon, S., J.-F. Dufayard, V. Lefort, M. Anisimova, W. Hordijk, and O. Gascuel. 2010. New Algorithms and mehtods to estimate maximum-likelihood phylogenies: asessing the performance of PhyML 2.0. Systematic Biology 59:307–321.
Henry, C. S., and M. M. Wells. 2010. Acoustic niche partitioning in two cryptic sibling species of Chrysoperla green lacewings that must duet before mating. Animal Behaviour 80:991–1003.
Hey, J. 2006. Recent advances in assessing gene flow between diverging populations and species. Current Opinion in Genetics and Development 16:592–596.
Hey, J. 2010. Isolation with migration models for more than two populations. Molecular Biology and Evolution 27:905–920.
Höbel, G., and H. C. Gerhardt. 2003. Reproductive character displacement in the acoustic communication system of green tree frogs (Hyla cinerea). Evolution 57:894–904.
Hubisz, M. J., D. Falush, M. Stephens, and J. K. Pritchard. 2009. Inferring weak population structure with the assistance of sample group information. Molecular Ecology Resources 9:1322–1332.
Irwin, D. E. 2000. Song variation in an avian ring species. Evolution 54:998–1010.
Jacobs, C. H. C. M. 2009. Character displacement: ecological and reproductive responses to a common evolutionary problem. The quarterly review of biology 84:253–276.
Jakobsson, M., and N. A. Rosenberg. 2009. CLUster matching and permutation program. Bioinformatics:1801–1806.
Jang, Y. 2011. Male responses to conspecific advertisement signals in the field cricket Gryllus rubens (Orthoptera: Gryllidae). PLoS ONE 6:1–8.
Jeanmougin, F., J. D. Thompson, M. Gouy, D. G. Higgins, and T. J. Gibson. 1998. Multiple sequence alignment with Clustal X. Trends in Biochemical Sciences 23:403–405.
Jeffries, D. L., G. H. Copp, L. Lawson Handley, K. H. Olsén, C. D. Sayer, and B. Hänfling. 2016. Comparing RADseq and microsatellites to infer complex phylogeographic patterns, an empirical perspective in the Crucian carp, Carassius carassius, L. Molecular Ecology:2997–3018.
Kaneshiro, K. Y., and C. R. B. Boake. 1987. Sexual selection and speciation: Issues raised by Hawaiian Drosophila. Trends in Ecology and Evolution 2:207–212.
Kirschel, A. N. G., D. T. Blumstein, and T. B. Smith. 2009. Character displacement of song and morphology in African tinkerbirds. Proceedings of the National Academy of Sciences of the United States of America 106:8256–8261.
Komaki, S., T. Igawa, M. Nozawa, S.-M. Lin, S. umi, and M. Sumida. 2014. Development and characterization of 14 microsatellite markers for Buergeria japonica (Amphibia, Anura, Rhacophoridae). Genes & genetic systems 89:35–9.
Kuchta, S. R. 2007. Contact zones and species limits: hybridization between lineages of the California newt, Taricha torosa, in the Southern Sierra Nevada. Herpetologica 63:332–350.
Larkin, M. A., G. Blackshields, N. P. Brown, R. Chenna, P. A. Mcgettigan, H. McWilliam, F. Valentin, I. M. Wallace, A. Wilm, R. Lopez, J. D. Thompson, T. J. Gibson, and D. G. Higgins. 2007. Clustal W and Clustal X version 2.0. Bioinformatics 23:2947–2948.
Lin, Y.-P., H.-Y. Tseng, and S.-M. Lin. 2013. Inter- and intra-island differentiation: a case from Japanese tree frog (Buergeria japonica) in Taiwan and the Ryukyus. Page Congress of Animal Behavior and Ecology.
Martin, P. R., and T. E. Martin. 2001. Behavioral interactions between coexisting species: song playback experiments with wood warblers. Ecology 82:207–218.
Martin, S. H., K. K. Dasmahapatra, N. J. Nadeau, C. Slazar, J. R. Walters, F. Simpson, M. Blaxter, A. Manica, J. Mallet, and C. D. Jiggins. 2013. Genome-wide evidence for speciation with gene flow in Heliconius butterflies. Genome research 23:1817–1828.
Masta, S. E., and W. P. Maddison. 2002. Sexual selection driving diversification in jumping spiders. Proceedings of the National Academy of Sciences 99:4442–4447.
Megía-Palma, R., J. Martínez, and S. Merino. 2016. A structural colour ornament correlates positively with parasite load and body condition in an insular lizard species. The Science of Nature 103:52.
Minder, A. M., and A. Widmer. 2008. A population genomic analysis of species boundaries: neutral processes, adaptive divergence and introgression between two hybridizing plant species. Molecular Ecology 17:1552–1563.
Moreno-Gómez, F. N., L. D. Bacigalupe, A. A. Silva-Escobar, and M. Soto-Gamboa. 2015. Female and male phonotactic responses and the potential effect of sexual selection on the advertisement calls of a frog. Animal Behaviour 104:79–86.
Narum, S. R., C. A. Buerkle, J. W. Davey, M. R. Miller, and P. A. Hohenlohe. 2013. Genotyping-by-sequencing in ecological and conservation genomics. Molecular Ecology 22:2841–2847.
Nosil, P. 2008. Speciation with gene flow could be common. Molecular ecology 17:2006–2008.
Okuzaki, Y., Y. Takami, and T. Sota. 2010. Resource partitioning or reproductive isolation: the ecological role of body size differences among closely related species in sympatry. Journal of Animal Ecology 79:383–392.
Pante, E., J. Abdelkrim, A. Viricel, D. Gey, S. Grance, M. Boisselier, and S. Samadi. 2015. Use of RAD sequencing for delimiting species. Heredity 114:450–459.
Pargana, J. M., R. Márquez, R .Reques, M. J. Sánchez-Herraiz, M. Tejedo, and E. G. Crespo. 2003. The mating call of Pelodytes ibericus (Anura, Pelodytidae). Herpetological Journal 13:199–204.
Peig, J., and A. J. Green. 2009. New perspectives for estimating body condition from mass/length data: The scaled mass index as an alternative method. Oikos 118:1883–1891.
Petit, R. J., and L. Excoffier. 2009. Gene flow and species delimitation. Trends in Ecology and Evolution 24:386–393.
Pfennig, D. W., and K. S.Pfennig. 2012. Development and evolution of character displacement. Annals of the New York Academy of Sciences 1256:89–107.
Pröhl, H., S. Hagemann, J. Karsch, and G.Höbel. 2007. Geographic variation in male sexual signals in strawberry poison frogs (Dendrobates pumilio). Ethology 113:825–837.
de Queiroz, K. 1998. The general lineage concept of species, species crteria, and the process of speciation: A conceptual unification and terminological recommendations. Page 57-75 in Endless Forms: Species and Speciation (D.J. Howard, and S. H. Berlocher, eds). Oxford University Press, New York.
Qvarnström, A., N. Vallin, and A. Rudh. 2012. The role of male contest competition over mates in speciation. Current Zoology 58:493–509.
Rambaut, A., and A. Drummond. 2014. FigTree v1.4.2. http://tree.bio.ed.ac.uk/software/figtree/.
Rambaut, A., M. Suchard, and A. Drummond. 2013. Tracer v1.6. http://tree.bio.ed.ac.uk/software/tracer/.
Rheindt, F. E., and S.V. Edwards. 2011. Genetic introgression : an integral but neglected component of speciation in birds. The Auk 128(4):620–632.
Richards-Zawacki, C. L., and M. E. Cummings. 2011. Intraspecific reproductive character displacement in a polymorphic poison dart frog, Dendrobates pumilio. Evolution 65:259–267.
Rieseberg, L. H. 2009. Evolution: replacing genes and traits through hybridization. Current Biology 19:119–122.
Rognes, T., T. Flouri, B. Nichols, C. Quince, and F. Mahé. 2016. VSEARCH: a versatile open source tool for metagenomics. PeerJ 4:e2584.
Ronquist, F., M. Teslenko, P. Van Der Mark, D. L. Ayres, A. Darling, S. Höhna, B. Larget, L. Liu, M. A. Suchard, and J. P. Huelsenbeck. 2012. Mrbayes 3.2: efficient bayesian phylogenetic inference and model choice across a large model space. Systematic Biology 61:539–542.
Rubin, B. E. R., R. H. Ree, and C. S. Moreau. 2012. Inferring phylogenies from RAD sequence data. PLoS ONE 7:1–12.
Sánchez-Herráiz, M., L. J. Barbadillo, M. J. anchez-Herraiz, A. Machordom, and B. Sanchez. 2000. A new species of pelodytid frog from the Iberian Peninsula. Herpetologica 56:105–118.
Schaefer, H. M., and G. D. Ruxton. 2015. Signal diversity, sexual selection, and speciation. Annual Review of Ecology, Evolution, and Systematics 46:573–592.
Slagsvold, T., S. Dale, and G.-P. Sætre. 1994. Dawn singing in the great tit (Parus major): mate attraction, mate guarding, or territorial deffence? Behaviour 131:115–138.
Stamatakis, A. 2014. RAxML version 8: A tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics 30:1312–1313.
Stewart, K. A., J. D. Austin, K. R. Zamudio, and S. C. Lougheed. 2015. Contact zone dynamics during early stages of speciation in a chorus frog (Pseudacris crucifer). Heredity 116:1–9.
Streicher, J. W., T. J. Devitt, C. S. Goldberg, J. H. Malone, H. Blackmon, and M. K. Fujita. 2014. Diversification and asymmetrical gene flow across time and space: lineage sorting and hybridization in polytypic barking frogs. Molecular Ecology 23:3273–3291.
Tamura, K., G. Stecher, D. Peterson, A. Filipski, and S. Kumar. 2013. MEGA6: molecular evolutionary genetics analysis version 6.0. Molecular Biology and Evolution 30:2725–2729.
Trépanier, T. L., and R. W. Murphy. 2001. The Coachella Valley fringe-toed lizard (Uma inornata): Genetic diversity and phylogenetic relationships of an endangered species. Molecular Phylogenetics and Evolution 18:327–334.
Uy, J. A. C., R. G. Moyle, and C. E. Filardi. 2009. Plumage and song differences mediate species recognition between incipient flycatcher species of the Solomon Islands. Evolution 63:153–164.
Vásquez, T., and K. S. Pfennig. 2007. Looking on the bright side: Females prefer coloration indicative of male size and condition in the sexually dichromatic spadefoot toad, Scaphiopus couchii. Behavioral Ecology and Sociobiology 62:127–135.
Velásquez, N. A., D. Opazo, J. Díaz, and M. Penna. 2014. Divergence of acoustic signals in a widely distributed frog: relevance of inter-male interactions. PLoS ONE 9.
Wagner, C. E., I. Keller, S. Wittwer, O. M. Selz, S. Mwaiko, L. Greuter, A. Sivasundar, and O. Seehausen. 2013. Genome-wide RAD sequence data provide unprecedented resolution of species boundaries and relationships in the Lake Victoria cichlid adaptive radiation. Molecular Ecology 22:787–798.
Wang, Y.-H., Y.-W. Hsiao, K.-H. Lee, S. Komaki, Y.-P. Lin, and S.-M. Lin. 2017. Acoustic differentiation and behavioral response reveals cryptic speciation within Buergeria treefrogs (Anura, Rhacophoridae) from Taiwan. PLoS One 12(9): e0184005.
Wilkins, M. R., N. Seddon, and R. J. Safran. 2013. Evolutionary divergence in acoustic signals: causes and consequences. Trends in Ecology and Evolution 28:156–166.
Wu, C.-I. 2001. The genic view of the process of speciation. Journal of Evolutionary Biology 14:851–865.
Wyttenbach, A., Y. Narain, and K. Fredga. 1999. Genetic structuring and gene flow in a hybrid zone between two chromosome races of the common shrew (Sorex araneus, Insectivora) revealed by microsatellites. Heredity 82:79–88.