Wagner et al. 2015 (Conference Paper) Fosterella

Breaking down all barriers - reproduction biology and speciation processes in Fosterella (Pitcairnioideae s.str.)

Author(s):—N. Wagner, T. Wöhrmann, N. Schütz, K. Schubert & K. Weising in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—The mesophytic genus Fosterella (31 species) belongs to the bromeliad subfamily Pitcairnioideae s.str. Its main distribution areas are the eastern slopes of the central Andes. Recent studies suggest that Fosterella originated in the mid-Miocene about 10 Mya in the Andean seasonally dry tropical forests (SDTF; Wagner et al., 2013). A well resolved, multilocus phylogeny of Fosterella based on six chloroplast DNA regions (matK, rps16 intron, atpB-rbcL, psbB-psbH, rpl32-trnL, rps16-trnK) demonstrated the monophyly of the genus and its division into six evolutionary lineages. These findings were supported by a nuclear phylogeny based on phyC. We conducted crossing experiments to study fertilization barriers within and between several Fosterella species. The so-called micrantha-group comprises three morphologically very similar species that show a disjunct distribution pattern, probably caused by one or more long distance dispersal events. Our results of population genetically approaches based on SSR and AFLP data show that most of the populations of the Central American F. micrantha are genetically separated from those of the Bolivian F. christophii and F. villosula. Species delimitation due to morphological characters is difficult within the micrantha-group. Our crossing experiments showed that all species are capable of selfing but can also form interspecific hybrids, indicating that reproductive barriers are low. Further in-situ crossing experiments between Fosterella speciesfrom several subgroups with differences in flower morphology (F. spectabilis, red, tubular flowers; F. gracilis, yellow flowers; F. rusbyi, small, whitish flowers with recoiled petals; F. penduliflora, relatively large, white flowers) were conducted. Again all treatments were successfull. These results support our suggestion of weak crossing barriers within the whole genus, indicating other isolation mechanisms like geographical and ecological isolation to avoid cross-species hybridisation in the field.

Keywords:—Fosterella; Speciation Processes; Crossing Experiments.