@article{RakosyStreinzerPaulusetal.2012,
  author    = {Rakosy, Demetra and Streinzer, Martin and Paulus, Hannes F. and Spaethe, Johannes},
  title     = {Floral visual signal increases reproductive success in a sexually deceptive orchid},
  series = {Arthropod-Plant Interactions},
  volume    = {6},
  journal   = {Arthropod-Plant Interactions},
  number    = {4},
  doi       = {10.1007/s11829-012-9217-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127209},
  pages     = {671-681},
  year      = {2012},
  abstract  = {Sexually deceptive orchids mimic signals emitted by female insects in order to attract mate-searching males. Specific attraction of the targeted pollinator is achieved by sex pheromone mimicry, which constitutes the major attraction channel. In close vicinity of the flower, visual signals may enhance attraction, as was shown recently in the sexually deceptive orchid Ophrys heldreichii. Here, we conducted an in situ manipulation experiment in two populations of O. heldreichii on Crete to investigate whether the presence/absence of the conspicuous pink perianth affects reproductive success in two natural orchid populations. We estimated reproductive success of three treatment groups (with intact, removed and artificial perianth) throughout the flowering period as pollinaria removal (male reproductive success) and massulae deposition (female reproductive success). Reproductive success was significantly increased by the presence of a strong visual signal—the conspicuous perianth—in one study population, however, not in the second, most likely due to the low pollinator abundance in the latter population. This study provides further evidence that the coloured perianth in O. heldreichii is adaptive and thus adds to the olfactory signal to maximise pollinator attraction and reproductive success.},
  language  = {en}
}
@article{StejskalStreinzerDyeretal.2015,
  author    = {Stejskal, Kerstin and Streinzer, Martin and Dyer, Adrian and Paulus, Hannes F. and Spaethe, Johannes},
  title     = {Functional Significance of Labellum Pattern Variation in a Sexually Deceptive Orchid (Ophrys heldreichii): Evidence of Individual Signature Learning Effects},
  series = {PLoS One},
  volume    = {10},
  journal   = {PLoS One},
  number    = {11},
  doi       = {10.1371/journal.pone.0142971},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-137582},
  pages     = {e0142971},
  year      = {2015},
  abstract  = {Mimicking female insects to attract male pollinators is an important strategy in sexually deceptive orchids of the genus Ophrys, and some species possess flowers with conspicuous labellum patterns. The function of the variation of the patterns remains unresolved, with suggestions that these enhance pollinator communication. We investigated the possible function of the labellum pattern in Ophrys heldreichii, an orchid species in which the conspicuous and complex labellum pattern contrasts with a dark background. The orchid is pollinated exclusively by males of the solitary bee, Eucera berlandi. Comparisons of labellum patterns revealed that patterns within inflorescences are more similar than those of other conspecific plants. Field observations showed that the males approach at a great speed and directly land on flowers, but after an unsuccessful copulation attempt, bees hover close and visually scan the labellum pattern for up to a minute. Learning experiments conducted with honeybees as an accessible model of bee vision demonstrated that labellum patterns of different plants can be reliably learnt; in contrast, patterns of flowers from the same inflorescence could not be discriminated. These results support the hypothesis that variable labellum patterns in O. heldreichii are involved in flower-pollinator communication which would likely help these plants to avoid geitonogamy.},
  language  = {en}
}