Pollen fates and the limits on male reproductive success in an orchid population

Johnson, Steven D.; Neal, Paul R.; Harder, Lawrence D.

doi:10.1111/j.1095-8312.2005.00541.x

Cited by 89 publications

(97 citation statements)

References 63 publications

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“…PTE was calculated as the percentage of removed pollinia that were inserted between guide rails. Since each pollinarium consists of two pollinia, the mean number of inserted pollinia was divided by twice the mean number of removed pollinaria (Johnson et al, 2005;Coombs et al, 2009Coombs et al, , 2011.…”

Section: Flower Visitors/pollinators and Pollen Transfer Efficiency (mentioning

confidence: 99%

Deceptive Ceropegia dolichophylla fools its kleptoparasitic fly pollinators with exceptional floral scent

et al. 2015

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Ceropegia species (Apocynaceae) have deceptive pitfall flowers and exploit small flies as pollinators, supposedly by chemical mimicry. Only preliminary data on the composition of flower scents are available for a single species so far, and the mimicry system is not yet understood in any species. We collected data on basic pollination aspects of C. dolichophylla, analyzed floral scent by gas chromatography linked to mass spectrometry (GC/MS), identified electrophysiologically active scent components by gas chromatography coupled with electroantennographic detection (GC/EAD), and determined compounds responsible for pollinator attraction in bioassays. We found that flowers of C. dolichophylla are visited by small flies of several taxa. Only Milichiidae and Chloropidae carried pollinaria and are, thus, pollinators. The pollen transfer efficiency (PTE) at two different sites was 2% and 4%, respectively. The floral scent was dominated by spiroacetals, mainly (2S,6R,8S)-8-methyl-2-propyl-1,7-dioxaspiro[5.5]undecane, n-tridecane, and N-(3-methylbutyl)acetamide. This spiroacetal and the acetamide elicited the most intense electrophysiological responses in fly antennae, and bioassays confirmed the capability of the spiroacetal in eliciting behavioral responses in pollinators. Most flies, determined as pollinators of C. dolichophylla, are kleptoparasites. They exploit insect prey of predatory arthropods as food source to which they are attracted by volatiles. undecane and N-(3-methylbutyl)acetamide have not been identified before as volatiles of other plants, however, they are known as insect volatiles. Both compounds occur in the venom glands of paper wasps, a potential food source for the pollinators of C. dolichophylla. We propose that C. dolichophylla shows a kleptomyiophilous pollination strategy. It mimics insect related odors to exploit the food-seeking behavior of its kleptoparasitic pollinators.

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Section: Flower Visitors/pollinators and Pollen Transfer Efficiency (mentioning

confidence: 99%

Deceptive Ceropegia dolichophylla fools its kleptoparasitic fly pollinators with exceptional floral scent

et al. 2015

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“…We also determined the number of flowers that showed any sign of visitation as well as flowers that had their anther caps disturbed, which represents a failed visit. Finally, we calculated the pollination transfer efficiency as the percentage of removed pollinia (removed pollinaria multiplied by two) that are deposited on the stigmas (Johnson et al, 2005a). The averages for each population, pooled where necessary across years, were compared using Mann-Whitney U-test.…”

Section: Visitation Rates and Pollen Transfer Efficiencymentioning

confidence: 99%

A pollinator shift explains floral divergence in an orchid species complex in South Africa

Peter

Johnson

2013

Annals of Botany

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Aims Floral diversification driven by shifts between pollinators has been one of the key explanations for the radiation of angiosperms. According to the Grant-Stebbins model of pollinator-driven speciation, these shifts result in morphologically distinct 'ecotypes' which may eventually become recognizable as species. The current circumscription of the food-deceptive southern African orchid Eulophia parviflora encompasses a highly variable monophyletic species complex. In this study, two forms were identified within this complex that differ in distribution, floral morphology, scent chemistry and phenology, and a test was made of whether these differences represent adaptations for different pollinators. † Methods and Results Multivariate analysis of floral and vegetative traits revealed that there are at least two discrete morphological forms in the species complex. Field observations revealed that each form is pollinated by a different insect species, and thus represent distinct ecotypes. The early-flowering coastal form which has long spurs and floral scent dominated by sesquiterpene compounds is pollinated exclusively by the long-tongued bee Amegilla fallax (Apidae, Anthophorinae), while the late-flowering inland form with short spurs and floral scent dominated by benzenoid compounds is pollinated exclusively by the beetle Cyrtothyrea marginalis (Cetoniinae; Scarabaeidae). Choice experiments in a Y-maze olfactometer showed that beetles are preferentially attracted to the scent of the short-spurred form. A spur-shortening experiment showed that long spurs are required for effective pollination of the bee-pollinated form. Although it was initially thought likely that divergence occurred across a geographical pollinator gradient, plants of the long-spurred form were effectively pollinated when transplanted to an inland locality outside the natural coastal range of this form. Thus, the underlying geographical basis for the evolution of ecotypes in the E. parviflora complex remains uncertain, although early flowering in the long-spurred form to exploit the emergence of naïve bees may restrict this form to coastal areas where there is no frost that would damage flower buds. Later flowering of the short-spurred form coincides closely with the emergence of the pollinating beetles following winter frosts. † Conclusions This study identifies a shift between bee and beetle pollination as the main driver of floral divergence in an orchid species complex. Floral scent and spur length appear to be key traits in mediating this evolutionary transition.

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“…Asclepias exaltata-0.3 (Apocynaceae; Broyles & Wyatt 1991) and Disa cooperi-1.6 (Orchidaceae; Johnson et al 2005). Studies using pollen tracking and paternity assignment (e.g.…”

Section: The Swafr Landscape and The Evolution Of Pollination Systemsmentioning

confidence: 99%

Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot

Phillips

Hopper

Dixon

2010

Phil. Trans. R. Soc. B

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The Southwest Australian Biodiversity Hotspot contains an exceptionally diverse flora on an ancient, low-relief but edaphically diverse landscape. Since European colonization, the primary threat to the flora has been habitat clearance, though climate change is an impending threat. Here, we review (i) the ecology of nectarivores and biotic pollination systems in the region, (ii) the evidence that trends in pollination strategies are a consequence of characteristics of the landscape, and (iii) based on these discussions, provide predictions to be tested on the impacts of environmental change on pollination systems. The flora of southwestern Australia has an exceptionally high level of vertebrate pollination, providing the advantage of highly mobile, generalist pollinators. Nectarivorous invertebrates are primarily generalist foragers, though an increasing number of colletid bees are being recognized as being specialized at the level of plant family or more rarely genus. While generalist pollination strategies dominate among insect-pollinated plants, there are some cases of extreme specialization, most notably the multiple evolutions of sexual deception in the Orchidaceae. Preliminary data suggest that bird pollination confers an advantage of greater pollen movement and may represent a mechanism for minimizing inbreeding in naturally fragmented populations. The effects of future environmental change are predicted to result from a combination of the resilience of pollination guilds and changes in their foraging and dispersal behaviour.

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Pollen fates and the limits on male reproductive success in an orchid population

Cited by 89 publications

References 63 publications

Deceptive Ceropegia dolichophylla fools its kleptoparasitic fly pollinators with exceptional floral scent

Deceptive Ceropegia dolichophylla fools its kleptoparasitic fly pollinators with exceptional floral scent

A pollinator shift explains floral divergence in an orchid species complex in South Africa

Pollination ecology and the possible impacts of environmental change in the Southwest Australian Biodiversity Hotspot

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