Dataset Information

Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica.

ABSTRACT: Spatial patterns of genetic variation can reveal otherwise cryptic evolutionary and landscape processes. In northwestern Costa Rica, an approximately concordant genetic discontinuity occurs among populations of several plant species. We conducted phylogeographic analyses of an epiphytic orchid, Brassavola nodosa, to test for genetic discontinuity and to explore its underlying causes. We genotyped 18 populations with 19 nuclear loci and two non-coding chloroplast sequence regions. We estimated genetic diversity and structure, relative importance of pollen and seed dispersal, and divergence time to understand how genetic diversity was spatially partitioned. Nuclear genetic diversity was high with little differentiation among populations (G_STn?=?0.065). In contrast, chloroplast haplotypes were highly structured (G_STc?=?0.570) and reveal a discontinuity between northwestern and southeastern populations within Costa Rica. Haplotype differences suggest two formerly isolated lineages that diverged ~10,000-100,000 YBP. Haplotype mixing and greater genetic diversity occur in an intermediate transition zone. Patterns of nuclear and chloroplast data were consistent. Different levels of genetic differentiation for the two genomes reflect the relative effectiveness of biotic versus abiotic dispersers of pollen and seeds, respectively. Isolation of the two lineages likely resulted from the complex environmental and geophysical history of the region. Our results suggest a recent cryptic seed dispersal barrier and/or zone of secondary contact. We hypothesize that powerful northeasterly trade winds hinder movement of wind-borne seeds between the two regions, while the multi-directional dispersal of pollen by strong-flying sphinx moths resulted in lower differentiation of nuclear loci.

SUBMITTER: Trapnell DW

PROVIDER: S-EPMC6972751 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica.

Trapnell Dorset W DW Hamrick J L JL Smallwood Patrick A PA Kartzinel Tyler R TR Ishibashi Caitlin D CD Quigley Charlotte T C CTC

Heredity 20190423 5

Spatial patterns of genetic variation can reveal otherwise cryptic evolutionary and landscape processes. In northwestern Costa Rica, an approximately concordant genetic discontinuity occurs among populations of several plant species. We conducted phylogeographic analyses of an epiphytic orchid, Brassavola nodosa, to test for genetic discontinuity and to explore its underlying causes. We genotyped 18 populations with 19 nuclear loci and two non-coding chloroplast sequence regions. We estimated ge ...[more]

PMID: 31015580

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Project description:BackgroundThe Monteverde region of Costa Rica is a hotspot of endemism and biodiversity. The region is, however, disturbed by human activities such as agriculture and urbanisation. This study provides a list of orchid bees (Hymenoptera: Euglossini) compiled from field surveys conducted during January-October 2019 in the premontane wet forest of San Luis, Monteverde, Costa Rica. We collected 36 species of Euglossine bees across four genera. We provide new geographic distribution and elevation data for eight species in two genera. Due to their critical role in the pollination of orchids and other plants, the distribution and abundance of Euglossine bees has relevance to plant biodiversity and conservation efforts. This is especially important in a region with a high diversity of difficult-to-study epiphytic orchids, such as in the Monteverde region.New informationA total of 2,742 Euglossine male individuals across four genera (Eufriesea, Eulaema, Euglossa and Exaerete) were collected in this study. Updated geographic distributions and elevation ranges were established for eight species of Euglossini in two genera: Eufrieseamussitans (Fabricius, 1787), Eufriesearufocauda (Kimsey, 1977), Euglossadodsoni (Moure, 1965), Euglossadressleri (Moure, 1968), Euglossahansoni (Moure, 1965), Euglossaignita (Smith, 1874), Euglossatridentata (Moure, 1970) and Euglossaturbinifex (Dressler, 1978). These are the first recorded occurrences of these species in the Monteverde region of Costa Rica, according to the Global Biodiversity Information Facility (GBIF) database (https://doi.org/10.15468/9f9kgp). This study also established expanded elevation ranges for Euglossaallosticta, Euglossabursigera, Euglossamixta, Euglossaheterosticta and Euglossamaculabris, though these five species have been previously recorded in the Monteverde region and, thus, are not described in detail here. Additionally, our capture of 123 Eufrieseaconcava individuals is significant, as it indicates its abundance in this region. Prior to this study, there was a single record of E.concava in the Monteverde region, documented in 1993.

Dataset Information

Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica.

Publications

Phylogeography of the Neotropical epiphytic orchid, Brassavola nodosa: evidence for a secondary contact zone in northwestern Costa Rica.

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