Generalized pollination, floral scent chemistry, and a possible case of hybridization in the African orchid Disa fragrans

Johnson, Steven D.; Hobbhahn, Nina

doi:10.1016/j.sajb.2010.07.008

Cited by 31 publications

(30 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The small differences observed in the orchid scent pattern between the Czech and Austrian regions may have been a result of the use of different sampling methods. Other studies have shown a high level of reproducibility of scent data across different thermal and solvent elution methods and GC‐MS instruments (Johnson & Hobbhahn, ; Peter & Johnson, ), and it is thus also possible that the differences in scent profiles between the regions reflect underlying biological differences. Single compounds that were recorded in only one of the regions may have evolved in order to resemble a locally abundant model plant.…”

Section: Discussionmentioning

confidence: 99%

DoesTraunsteinera globosa(the globe orchid) dupe its pollinators through generalized food deception or mimicry?

et al. 2015

View full text Add to dashboard Cite

Non‐rewarding orchids rely on various ruses to attract their pollinators. One of the most common is for them to resemble flowers sought by insects as food sources. This can range from generalized food deception to the mimicry of specific sympatric food plants. We investigated the basis of pollinator deception in the European food‐deceptive orchid Traunsteinera globosa, which has unusually compact flowerheads resembling those of sympatric rewarding species of Knautia and Scabiosa (Dipsacaceae), and Valeriana (Caprifoliaceae). Visual signals of T. globosa are similar in both fly and bee vision models to those of the sympatric food plants used in the choice experiments, but scent signals are divergent. Field experiments conducted in Austria and the Czech Republic showed that both naive and experienced (with respect to visitation of T. globosa) insect species approached the orchids at the same rate as food plants, but direct contact with orchid flowers was taxon specific. Flies were most easily duped into probing the orchid, and, in doing so, frequently received and deposited pollinaria, whereas most bees and butterflies avoided landing on orchid flowers. We conclude that T. globosa is a mimic of a guild of fly‐pollinated plants, but the ecological dependence of the orchid on its models remains to be fully tested. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180, 269–294.

show abstract

Section: Discussionmentioning

confidence: 99%

DoesTraunsteinera globosa(the globe orchid) dupe its pollinators through generalized food deception or mimicry?

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Furthermore, the absolute floral scent emission of D. pulchra (227·2 ± 55·2 ng) was relatively low compared with other Disa species also indicating the dominance of visual cues for pollinator attraction. Using the same method, Johnson & Hobbhahn () reported emission rates between 570 ng ( Disa sankeyi ; pollinated by spider hunting wasps) and 19 100 ng ( Disa fragrans ; pollinated by a wide range of insects including flies, beetles, bees and moths) per hour per inflorescence in nectariferous Disa species. It is not known whether the scent emitted by W. lepida and D. pulchra is actually detected by P. aethiopica .…”

Section: Discussionmentioning

confidence: 99%

The evolution of floral mimicry: identifying traits that visually attract pollinators

et al. 2012

View full text Add to dashboard Cite

Summary1. Some orchids have been proposed to be Batesian floral mimics imitating flowers of sympatric rewarding species to attract pollinators. It is not yet well understood which traits are critical for pollinator attraction, although colour, shape and scent have all been implicated. 2. We conducted field-based behavioural experiments using pairwise combinations of plastic flowers differing in spectral and shape properties offered to long-proboscid tabanid flies (Philoliche aethiopica) at two sites -one where the fly-pollinated orchid mimic Disa pulchra occurs with its pink-flowered model, the iris Watsonia lepida and another where the flies forage on a blue-flowered rewarding plant Agapanthus campanulatus. 3. Flies intensively visited and probed plastic flowers of colours indistinguishable in a fly vision model from those of the rewarding plants. Inflorescence architecture and brightness of plastic flowers made little difference to fly attraction, but those that matched the shape and nectar guides of Watsonia flowers were significantly more attractive. 4. Flowers of the three focal plant species are weakly scented and divergent in scent chemistry. 5. This study shows that traits that mimic, in order of importance, the spectra, shape and nectar guide patterns of flowers of rewarding plants would be under strong selection in fooddeceptive orchids as they maximize attractiveness to their pollinators. Our experiments also help to explain why deceptive orchids in general often seem to match the flowers of sympatric rewarding plants more in visual attributes than in scent chemistry.

show abstract

“…(2007); 13, Steiner et al . (1994); 14, Johnson & Hobbhahn (2010); 15, S. D. Johnson, unpubl. data; 16, G. Coombs, unpubl.…”

Section: Methodsmentioning

confidence: 99%

The Hemipepsis wasp-pollination system in South Africa: a comparative analysis of trait convergence in a highly specialized plant guild

Shuttleworth

Johnson

2012

Botanical Journal of the Linnean Society

View full text Add to dashboard Cite

Pollinator-mediated convergence in floral traits is the fundamental basis for pollination syndromes, but it has seldom been rigorously analysed. Here we synthesize information on a guild of South African plants that are pollinated by functionally similar pompilid wasps in the genus Hemipepsis and investigate the extent of trait convergence in guild members. The guild includes members from three plant families (Apocynaceae, Orchidaceae and Asparagaceae subfamily Scilloideae) and contains remarkably high levels of functional specialization with 18 of the 23 known guild members being pollinated exclusively by Hemipepsis wasps. The distribution of the guild is centred in the moist upland grasslands of eastern South Africa. Qualitative similarities among guild members include dull greenish-or brownish-white flowers, often with purple blotches, mid-summer flowering, sweet spicy scent and exposed nectar. To assess the extent of convergent evolution within the guild, we compared floral traits of guild members with those of congeneric non-wasp-pollinated species. Guild members typically produce moderate volumes (> 4 mL per flower per day) of concentrated (> 50% sugar by weight) sucrose-dominant nectar. The nectar properties of guild members did not, however, differ significantly from those of congeneric species pollinated by other vectors. Non-metric multidimensional scaling of scent data for 15 guild members and 17 congeners (obtained through gas chromatography-mass spectrometry of headspace samples and supplemented with published data) yielded little evidence for convergent evolution in the overall scent composition of guild members. However, convergence in floral spectral reflectance was evident in the guild members; in particular, loci for colours of guild members were significantly closer to the guild centroid than loci for colours of congeners, and they formed a distinct cluster in the blue to blue-green region of the hymenopteran colour hexagon. The colours of guild members were also significantly closer to the colour of background vegetation than those of congeneric species, suggesting a role for cryptic colouring in this system. These results confirm convergence in the floral colours of plants that are pollinated by Hemipepsis spider-hunting wasps, but also suggest that other traits, such as nectar properties, do not necessarily evolve during shifts between pollination systems. Identification of particular scent compounds and non-sugar nectar constituents that influence wasp behaviour will be essential for illuminating the extent of biochemical convergence in the guild members.

show abstract

Generalized pollination, floral scent chemistry, and a possible case of hybridization in the African orchid Disa fragrans

Cited by 31 publications

References 29 publications

DoesTraunsteinera globosa(the globe orchid) dupe its pollinators through generalized food deception or mimicry?

DoesTraunsteinera globosa(the globe orchid) dupe its pollinators through generalized food deception or mimicry?

The evolution of floral mimicry: identifying traits that visually attract pollinators

The Hemipepsis wasp-pollination system in South Africa: a comparative analysis of trait convergence in a highly specialized plant guild

Contact Info

Product

Resources

About