Observations on the pollination of Pelargonium tricolor, section Campylia (Geraniaceae)

Mcdonald, D. J.; Walt, J.J.A. van der

doi:10.1016/s0254-6299(16)30826-2

Cited by 26 publications

(16 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While mate-seeking responses probably account for male flies landing repeatedly on the spots without feeding, simple aggregation responses may attract both males and females to G. diffusa. McDonald and van der Walt (1992) found both male and female Megapalpus capensis Wiedemann (a species which is very closely related to M. nitidus) in samples of flies collected from Pelargonium tricolor flowers with black spots. Aggregation of both male and female insects is well known (Wiesman, 1962;Turner, 1975;Monteith, 1982).…”

Section: Do the Spots Of G Diffusa Mimic Flies?-our Resultsmentioning

confidence: 98%

“…This appears to be a form of pseudocopulation based solely on visual stimuli. Recently, McDonald and van der Walt (1992) found that Pelargonium tricolor (Geraniaceae), a South African shrub with conspicuous dark spots on the petals, attracts both male and female Megapalpus bee-flies (Bombyliidae). Attraction of bee-flies to flowers with dark spots is also known from the Mediterranean flora (S. Johnson and A.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Fly pollination of Gorteria diffusa (Asteraceae), and a possible mimetic function for dark spots on the capitulum

Johnson

Midgley

1997

American J of Botany

113

View full text Add to dashboard Cite

We investigated the functional significance of raised black spots on the ray florets of Gorteria diffusa (Asteraceae) in South Africa. Field observations showed that G. diffusa is pollinated by a small bee-fly, Megapalpus nitidus (Bombyliidae), which is strikingly similar to the raised spots that occur on some of the ray florets. Removal of the spots resulted in a significant decrease in the rate of fly visits to capitula, but did not significantly affect seed set. Replacement of the spots with simple ink spots also significantly reduced the rate of pollinator visits, suggesting that flies respond to details in the structure of the spots. Investigations using scanning electron microscopy showed that the spots of G. diffusa consist of a complex of different cell types. Differences in epidermal sculpturing may partly explain the UV reflectance pattern of these spots, which is similar to that of the flies. Male flies are strongly attracted to the spots, as well as to other flies sitting in the capitula, although female flies also visit the capitula. We conclude that the spots of G. diffusa mimic resting flies, thereby eliciting mate-seeking and aggregation responses in fly pollinators. Similar dark spots have evolved in unrelated South African Gazania, Dimorphotheca, and Pelargonium species pollinated by bee-flies.

show abstract

Section: Do the Spots Of G Diffusa Mimic Flies?-our Resultsmentioning

confidence: 98%

mentioning

confidence: 99%

Fly pollination of Gorteria diffusa (Asteraceae), and a possible mimetic function for dark spots on the capitulum

Johnson

Midgley

1997

American J of Botany

113

View full text Add to dashboard Cite

show abstract

“…More recent studies have demonstrated a direct relationship between black spots in flowers and pollination by small bee‐flies. McDonald & van der Walt (1992) found that small bee‐flies ( Megapalpus spp.) pollinate South African Pelargonium species with raised black spots on the petals.…”

Section: Discussionmentioning

confidence: 99%

“…Bee‐flies (Bombyliidae) play an important role as pollinators in semiarid regions, including Israel and the western interior of South Africa (McDonald & van der Walt 1992; Johnson & Midgley 1996). Not much is known about visual discrimination ability in these flies, except for the early observation by Knoll (1921) that Bombyllius uses visual cues when approaching flowers (see also Grimaldi 1988).…”

Section: Introductionmentioning

confidence: 99%

Response of bee‐flies to the shape and pattern of model flowers: implications for floral evolution in a Mediterranean herb

1998

View full text Add to dashboard Cite

1. The functional significance of floral traits in Linum pubescens (Linaceae), a Mediterranean annual that is pollinated almost exclusively by the bee‐fly Usia bicolor (Bombyliidae), was investigated. The flies feed on both pollen and nectar, and use the flowers as mating rendezvous sites in the afternoon. 2. Choice experiments with model flowers were used to determine the response of U. bicolor to visual cues, such as shape, size, colour and pattern. 3. Bee‐flies strongly preferred models with a dissected outline over models with a simple outline. They also preferred pink models over other colours, and larger models over smaller models. 5. Flies landing on models with converging lines (‘nectar guides’) tended to follow the lines to the point where they meet in the centre of the model, while flies landing on plain models showed undirected behaviour, often moving to the edge of the model. 6. Flies were strongly attracted to flowers of L. pubescens which had a fly glued on to one of the petals, as well as flowers with a dark spot painted onto one of the petals. In addition, models with a dark spot were strongly preferred over plain models during the afternoon when flies exhibit mating behaviour. This evidence suggests that the dark centre of the L. pubescens flower may function as an attractant to mate‐seeking bee‐flies.

show abstract

“…In the orchid genus Disa, for example, 19 different pollination systems were found in the 27 species examined, and pollination systems showed repeated independent evolution (Johnson et al, 1998a). Other plant genera that show similar liability in pollination systems include Gladiolus, Ixia, Sparaxis (all Iridaceae), and Pelargonium (Geraniaceae) (McDonald and van der Walt, 1992;Goldblatt and Manning, 1996;Struck, 1997;Goldblatt et al, 2000a,b). On the other hand, floral evolution in Disperis is not characterized by pollinator shifts (most species are pollinated by oilbees), but rather in the site of pollen placement on the body of the insect (Steiner, 1989;Manning and Linder, 1992).…”

Section: Evolutionary Processesmentioning

confidence: 99%

An overview of plant–pollinator relationships in southern Africa

Johnson

2004

JTI

View full text Add to dashboard Cite

A particularly rich array of pollination systems is represented in the flora of southern Africa. Hopliine beetles, long-proboscid flies, satyrine butterflies, hawk moths, birds and rodents appear to assume greater importance as pollinators than they do in other temperate regions. These 'alternative' pollination systems may have developed because the bee-fauna of southern Africa is not particularly rich relative to the flora. Pollination by moths, for example, is relatively frequent in the eastern half of southern Africa where bee diversity is lowest. Pollination systems in southern Africa are relatively specialized and shifts between pollinators have been shown to be an important driving force in plant diversification and speciation. Changes in land-use, particularly afforestation and ploughing of grasslands, invasion of alien plants, overgrazing and urban developments have disrupted these mutualisms with mostly unknown consequences for ecosystem functioning. Future research will be directed at expanding our knowledge of pollination systems, with a strong focus on the conservation of mutualistic ecological interactions.Résumé. La flore Sud Africaine est particulièrement riche en systèmes de pollinisation. Ainsi les scarabés de la famille des Hopliinae, les mouches a long proboscis, les papillons de la famille des Satyrinae, les sphingides, les oiseaux et les rongeurs ont un rô le plus important comme pollinisateurs que celui qu'ils jouent dans les autres régions tempérées du globe. Ces systèmes de pollinisation alternatifs se seraient développés parce que la faune des abeilles Sud Africaine n'est pas très riche au regard de la flore. Ainsi, la pollinisation par les papillons de nuit est relativement fréquente dans l'Est de l'Afrique du Sud où la diversité des abeilles est plus faible. En Afrique du Sud les systèmes de pollinisation sont relativement spécialisés et on a montré que des changements de pollinisateurs pouvaient jouer un rô le important dans la diversification des plantes et leur spéciation. Des modifications de la gestion des terres, en particulier la déforestation, le labour des prairies, l'introduction de plantes invasives, le surpâturage et le développement des villes out perturbé ces associations mutualistes et ont des consequences inconnues sur le fonctionnement des écosystèmes. Les recherches futures devront approfondir les connaissances sur les systèmes de pollinisation, et s'intéresser en particulier au maintien des interactions écologiques mutualistes.

show abstract

Observations on the pollination of Pelargonium tricolor, section Campylia (Geraniaceae)

Cited by 26 publications

References 13 publications

Fly pollination of Gorteria diffusa (Asteraceae), and a possible mimetic function for dark spots on the capitulum

Fly pollination of Gorteria diffusa (Asteraceae), and a possible mimetic function for dark spots on the capitulum

Response of bee‐flies to the shape and pattern of model flowers: implications for floral evolution in a Mediterranean herb

An overview of plant–pollinator relationships in southern Africa

Contact Info

Product

Resources

About