Title: Strong postzygotic isolation prevents introgression between two hybridizing Neotropical orchids, Epidendrum denticulatum and E. fulgens
Author: Pinheiro, Fábio; Cardoso-gustavson, Poliana; Suzuki, Rogério Mamoru; Abrão, Monique Cristine R.; Guimarães, Leonardo R. S.; Draper, David; Moraes, Ana Paula
Is part of: EVOLUTIONARY ECOLOGY, v. 29, p. 229 - 248
Citation: Pinheiro, Fábio; Cardoso-gustavson, Poliana; Suzuki, Rogério Mamoru; Abrão, Monique Cristine R.; Guimarães, Leonardo R. S.; Draper, David; Moraes, Ana Paula; Strong postzygotic isolation prevents introgression between two hybridizing Neotropical orchids, Epidendrum denticulatum and E. fulgens. EVOLUTIONARY ECOLOGY, v.29, p. 229-248, 2015
Abstract: Studies on hybrid zones are essential to understand the origin and evolution of reproductive barriers in plants. To achieve this goal, multidisciplinary approaches are often required to investigate the role of multiple reproductive isolation (RI) mechanisms. For Epidendrum denticulatum and E. fulgens, two Neotropical food-deceptive orchid species, we used molecular, cytogenetic and morphological analyses, experimental crosses and environmental envelope models to assess the strength of the RI and the mechanisms that prevent species collapse when hybridization occurs. Based on genetic assignment tests, hybrids between E. denticulatum and E. fulgens were detected. However, the low frequency of hybrid specimens found, coupled with the high morphological differentiation between parental species, suggested that strong barriers exist to interspecific gene exchange. Indeed, hybrid plants were largely sterile, as determined by meiotic data and crossing experiments. In the hybrid zone studied here, strong postzygotic barriers maintain species integrity, and these RI mechanisms may be also important during early stages of speciation.
Keywords: biologia reprodutiva; Especiação; Fluxo gênico; Hibridação; introgresão; Isolamento reprodutivo;
Subjects: CIENCIAS_BIOLOGICAS; Hibridação; CIENCIAS_BIOLOGICAS; Botânica; evolução;
Funding: We thank A. Ferreira and R.C. Marques for help during fieldwork. Funding for this study was provided by grants from FAPESP to FP (2009/15052-0), LRSG (2010/16353-1) and APM (2011/22215-3 and 2012/22077-2), and a PNPD/CAPES fellowship to F.P.