@article{BreitkopfOnsteinCafassoetal.2015,
  author    = {Breitkopf, Hendrik and Onstein, Renske E. and Cafasso, Donata and Schl{\"u}ter, Philipp M. and Cozzolino, Salvatore},
  title     = {Multiple shifts to different pollinators fuelled rapid diversification in sexually deceptive Ophrys orchids},
  series = {New phytologist : international journal of plant science},
  volume    = {207},
  journal   = {New phytologist : international journal of plant science},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0028-646X},
  doi       = {10.1111/nph.13219},
  pages     = {377 -- 389},
  year      = {2015},
  abstract  = {Episodes of rapid speciation provide unique insights into evolutionary processes underlying species radiations and patterns of biodiversity. Here we investigated the radiation of sexually deceptive bee orchids (Ophrys). Based on a time-calibrated phylogeny and by means of ancestral character reconstruction and divergence time estimation, we estimated the tempo and mode of this radiation within a state-dependent evolutionary framework. It appears that, in the Pleistocene, the evolution of Ophrys was marked by episodes of rapid diversification coinciding with shifts to different pollinator types: from wasps to Eucera bees to Andrena and other bees. An abrupt increase in net diversification rate was detected in three clades. Among these, two phylogenetically distant lineages switched from Eucera to Andrena and other bees in a parallel fashion and at about the same time in their evolutionary history. Lack of early radiation associated with the evolution of the key innovation of sexual deception suggests that Ophrys diversification was mainly driven by subsequent ecological opportunities provided by the exploitation of novel pollinator groups, encompassing many bee species slightly differing in their sex pheromone communication systems, and by spatiotemporal fluctuations in the pollinator mosaic.},
  language  = {en}
}
@article{LumagaCozzolinoKocyanetal.2014,
  author    = {Lumaga, Maria Rosaria Barone and Cozzolino, Salvatore and Kocyan, Alexander and Menale, Bruno and Rudall, Paula J.},
  title     = {Exine micromorphology and ultrastructure in Neottieae (Epidendroideae, Orchidaceae)},
  series = {Plant systematics and evolution},
  volume    = {300},
  journal   = {Plant systematics and evolution},
  number    = {3},
  publisher = {Springer},
  address   = {Wien},
  issn      = {0378-2697},
  doi       = {10.1007/s00606-013-0899-2},
  pages     = {505 -- 515},
  year      = {2014},
  abstract  = {The diverse epidendroid orchid tribe Neottieae is characterized by multiple transitions between autotrophy and mycoheterotrophy, allogamous and autogamous mating systems, pollen released as tetrads or monads, and pollen exine tectate or semitectate. We use transmission and scanning electron microscopy on pollen of ten species of Neottieae to investigate whether the differences in pollen aggregation and exine micromorphology and ultrastructure reflect phylogenetic relationships, or whether this variation is subject to ecological constraints. Our results showed that differences in exine micromorphology are mostly concordant with phylogenetic relationships in Neottieae, i.e. an ascending tendency of pollen ornamentation from tectate (Cephalanthera) to semitectate (e.g. Neottia). In contrast, pollen aggregation, when plotted on the most recent phylogeny, shows repeated transitions between monads and tetrads that could be related to ecological constraints. Tetrads are present in species that are nectar rewarding, whereas monads are common in deceptive species. Cephalanthera is characterized by recalcitrant pollen, including the frequent occurrence of collapsed pollen. In this genus, the observed shifts from allogamous to autogamous or cleistogamous mating systems could help to reduce pollen damage caused by exposure to dry habitats.},
  language  = {en}
}