LONG‐TONGUED FLY POLLINATION AND EVOLUTION OF FLORAL SPUR LENGTH IN THE DISA DRACONIS COMPLEX (ORCHIDACEAE)

@article{Johnson1997LONGTONGUEDFP,
  title={LONG‐TONGUED FLY POLLINATION AND EVOLUTION OF FLORAL SPUR LENGTH IN THE DISA DRACONIS COMPLEX (ORCHIDACEAE)},
  author={Steven D. Johnson and Kim E. Steiner},
  journal={Evolution},
  year={1997},
  volume={51}
}
Field studies in South Africa showed that floral spur length in the Disa draconis complex (Orchidaceae) varies enormously between populations in the southern mountains (means = 32–38 mm), lowland sandplain (mean = 48 mm), and northern mountains (means = 57–72 mm). We tested the hypothesis that divergence in spur length has resulted from selection exerted through pollinator proboscis length. Short‐spurred plants in several southern mountain populations, as well as long‐spurred plants in one… 

EVOLUTION AND COEXISTENCE OF POLLINATION ECOTYPES IN AN AFRICAN GLADIOLUS (IRIDACEAE)

Positive directional selection on tube length was found to occur in both morphs of the African iris Gladiolus longicollis, a trait that could be used as a cue for morph‐specific foraging by hawkmoths.

Effective pollinia transfer by settling moths’ legs in an orchid Habenaria aitchisonii

This finding of efficient pollen transfer by the pollinators’ legs in H. aitchisonii adds a new example of diverse pollinia placement on pollinators (here settling moths) in the Orchidaceae.

Pollinator shifts and the evolution of spur length in the moth-pollinated orchid Platanthera bifolia.

The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts.

Pollinator–mediated selection on flower–tube length in a hawkmoth–pollinated Gladiolus (Iridaceae)

It is demonstrated that selection may occur among plants with natural phenotypic variation in flower‐tube length, and supports Darwin's model of pollinator‐mediated selection.

Mixed hummingbird: Long‐proboscid‐fly pollination in ‘ornithophilous’Embothrium coccineum (Proteaceae) along a rainfall gradient in Patagonia, Argentina

The pollination ecology of eight populations of the tree Embothrium coccineum was studied along a steep rainfall gradient in NW Patagonia, Argentina and found a highly significant increase in nectar concentration towards the drier end of the gradient, but this change was not related to the turnover of species in the flower-visitor assemblage of E. coccines.

Armament Imbalances: Match and Mismatch in Plant-Pollinator Traits of Highly Specialized Long-Spurred Orchids

The findings indicate that pollinator-mediated selection may vary through time and space according to local variations in pollinator assemblages, and Phenotypic selection is dependent on the mutual match between pollinator and flower morphologies.

Diverse pollination systems of the twin-spurred orchid genus Satyrium in African grasslands

Most taxa exhibited high levels of pollination success, a trend that can be attributed to the presence of nectar in the twin spurs, and Floral morphology differs markedly among plants with different pollinators, while nectar volume, concentration, and sugar composition are fairly uniform across species.
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