Does pollination syndrome reflect pollinator efficiency in Silene nutans?

Conostephium (Epacridaceae) has flowers that conform with a buzz-pollination syndrome but, unlike most plants with this form of pollination, the anthers are hidden within the corolla tube. Vibrations generated by bees grasping the apices of the corolla tubes must be transferred via short broad filaments to the anthers. The anthers do not have pores but each dehisces from the apex by a slit that elongates over the time the flowers take to senesce (up to 10 days). This may limit self-fertilisation as the stigma is receptive as soon as it appears from between the very short corolla lobes, so little pollen is released at first but later this would increase as the slit elongates. Visitation by pollinators has rarely been seen but several observations of native bees (Leioproctus and Lasioglossum) working the flowers are presented. The bees visit the nectarless flowers of Conostephium only for pollen and must forage at other kinds of flowers to obtain nectar. Pollen tubes occurred in the stigmas of most older flowers of C. pendulum, so pollen delivery does not seem to limit seed set. Despite this, the species sets few fruit. From examination of the taxonomic positions of likely buzz-pollinated taxa in the family, it appears that pollination by sonication has arisen independently several times in the Epacridaceae, with primarily two different floral configurations.

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Changes in plant life-form, pollination syndrome and breeding system at a regional scale promoted by land use intensity

Diversity and Distributions ◽

10.1111/ddi.12353 ◽

2015 ◽

Vol 21 (11) ◽

pp. 1319-1328 ◽

Cited By ~ 4

Author(s):

Dietmar Moser ◽

Stefan Dullinger ◽

Thomas Mang ◽

Karl Hülber ◽

Franz Essl ◽

...

Keyword(s):

Land Use ◽

Breeding System ◽

Life Form ◽

Regional Scale ◽

Pollination Syndrome ◽

Land Use Intensity ◽

Plant Life ◽

Plant Life Form

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Linking pollinator efficiency to patterns of pollen limitation: small bees exploit the plant–pollinator mutualism

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0635 ◽

2018 ◽

Vol 285 (1880) ◽

pp. 20180635 ◽

Cited By ~ 18

Author(s):

Matthew H. Koski ◽

Jennifer L. Ison ◽

Ashley Padilla ◽

Angela Q. Pham ◽

Laura F. Galloway

Keyword(s):

Pollen Limitation ◽

Pollen Deposition ◽

Pollinator Efficiency ◽

Flower Visitation ◽

Female Phase ◽

Male Phase ◽

Single Flower ◽

Floral Visitation ◽

Low Efficiency ◽

Plant Pollinator

Seemingly mutualistic relationships can be exploited, in some cases reducing fitness of the exploited species. In plants, the insufficient receipt of pollen limits reproduction. While infrequent pollination commonly underlies pollen limitation (PL), frequent interactions with low-efficiency, exploitative pollinators may also cause PL. In the widespread protandrous herb Campanula americana , visitation by three pollinators explained 63% of the variation in PL among populations spanning the range. Bumblebees and the medium-sized Megachile campanulae enhanced reproductive success, but small solitary bees exacerbated PL. To dissect mechanisms behind these relationships, we scored sex-specific floral visitation, and the contributions of each pollinator to plant fitness using single flower visits. Small bees and M. campanulae overvisited male-phase flowers, but bumblebees frequently visited female-phase flowers. Fewer bumblebee visits were required to saturate seed set compared to other bees. Scaling pollinator efficiency metrics to populations, small bees deplete large amounts of pollen due to highly male-biased flower visitation and infrequent pollen deposition. Thus, small bees reduce plant reproduction by limiting pollen available for transfer by efficient pollinators, and appear to exploit the plant–pollinator mutualism, acting as functional parasites to C. americana . It is therefore unlikely that small bees will compensate for reproductive failure in C. americana when bumblebees are scarce.

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Evolution of pollination syndromes and corolla symmetry in Balsaminaceae reconstructed using phylogenetic comparative analyses

Annals of Botany ◽

10.1093/aob/mcaa184 ◽

2020 ◽

Author(s):

Saroj Ruchisansakun ◽

Arne Mertens ◽

Steven B Janssens ◽

Erik F Smets ◽

Timotheüs van der Niet

Keyword(s):

Phylogenetic Trees ◽

Sequence Data ◽

Phylogenetic Analyses ◽

Plastid Dna ◽

Pollination Syndrome ◽

Pollination Syndromes ◽

Bee Pollination ◽

Floral Symmetry ◽

Considerable Uncertainty ◽

Pollination Systems

Abstract Background and Aims Floral diversity as a result of plant–pollinator interactions can evolve by two distinct processes: shifts between pollination systems or divergent use of the same pollinator. Although both are pollinator driven, the mode, relative importance and interdependence of these different processes are rarely studied simultaneously. Here we apply a phylogenetic approach using the Balsaminaceae (including the species-rich genus Impatiens) to simultaneously quantify shifts in pollination syndromes (as inferred from the shape and colour of the perianth), as well as divergent use of the same pollinator (inferred from corolla symmetry). Methods For 282 species we coded pollination syndromes based on associations between floral traits and known pollination systems, and assessed corolla symmetry. The evolution of these traits was reconstructed using parsimony- and model-based approaches, using phylogenetic trees derived from phylogenetic analyses of nuclear ribosomal and plastid DNA sequence data. Key Results A total of 71 % of studied species have a bee pollination syndrome, 22 % a bimodal syndrome (Lepidoptera and bees), 3 % a bird pollination syndrome and 5 % a syndrome of autogamy, while 19 % of species have an asymmetrical corolla. Although floral symmetry and pollination syndromes are both evolutionarily labile, the latter shifts more frequently. Shifts in floral symmetry occurred mainly in the direction towards asymmetry, but there was considerable uncertainty in the pattern of shift direction for pollination syndrome. Shifts towards asymmetrical flowers were associated with a bee pollination syndrome. Conclusion Floral evolution in Impatiens has occurred through both pollination syndrome shifts and divergent use of the same pollinator. Although the former appears more frequent, the latter is likely to be underestimated. Shifts in floral symmetry and pollination syndromes depend on each other but also partly on the region in which these shifts take place, suggesting that the occurrence of pollinator-driven evolution may be determined by the availability of pollinator species at large geographical scales.

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Co-expression clustering across flower development identifies modules for diverse floral forms in Achimenes (Gesneriaceae)

PeerJ ◽

10.7717/peerj.8778 ◽

2020 ◽

Vol 8 ◽

pp. e8778 ◽

Cited By ~ 1

Author(s):

Wade R. Roberts ◽

Eric H. Roalson

Keyword(s):

Flower Development ◽

Complex Traits ◽

Regulatory Networks ◽

Linear Models ◽

Developmental Stages ◽

Flower Color ◽

Evolutionary Rates ◽

Pollination Syndrome ◽

Pollination Syndromes ◽

Hummingbird Pollination

Background Genetic pathways involved with flower color and shape are thought to play an important role in the development of flowers associated with different pollination syndromes, such as those associated with bee, butterfly, or hummingbird pollination. Because pollination syndromes are complex traits that are orchestrated by multiple genes and pathways, the gene regulatory networks have not been explored. Gene co-expression networks provide a systems level approach to identify important contributors to floral diversification. Methods RNA-sequencing was used to assay gene expression across two stages of flower development (an early bud and an intermediate stage) in 10 species of Achimenes (Gesneriaceae). Two stage-specific co-expression networks were created from 9,503 orthologs and analyzed to identify module hubs and the network periphery. Module association with bee, butterfly, and hummingbird pollination syndromes was tested using phylogenetic mixed models. The relationship between network connectivity and evolutionary rates (dN/dS) was tested using linear models. Results Networks contained 65 and 62 modules that were largely preserved between developmental stages and contained few stage-specific modules. Over a third of the modules in both networks were associated with flower color, shape, and pollination syndrome. Within these modules, several hub nodes were identified that related to the production of anthocyanin and carotenoid pigments and the development of flower shape. Evolutionary rates were decreased in highly connected genes and elevated in peripheral genes. Discussion This study aids in the understanding of the genetic architecture and network properties underlying the development of floral form and provides valuable candidate modules and genes for future studies.

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Pollination in Australian Orchids: a Critical-Assessment of the Literature 1882-1992

Australian Journal of Botany ◽

10.1071/bt9930553 ◽

1993 ◽

Vol 41 (5) ◽

pp. 553 ◽

Cited By ~ 34

Author(s):

PB Adams ◽

SD Lawson

Keyword(s):

Reward System ◽

Solitary Bees ◽

Critical Assessment ◽

Pollination Syndrome ◽

Floral Display ◽

Reward Systems ◽

Bee Pollination ◽

Terrestrial Species ◽

Number Of Species ◽

Review Criteria

A century of pollination studies of Australian orchids is reviewed. Descriptions of pollination events and conclusions about pollination status are inadequate in many reports. In this review criteria for establishing 'confirmed', 'probable' and 'suggested' pollinator status are defined and recommended. When applied to 153 published pollination reports there are 24 terrestrial species with 'confirmed' pollinators and a further 47 species with 'probable' pollinators. The major syndromes confirmed are wasp pollination by pseudocopulation (15 species) and the bee pollination syndrome of food mimicry (5 species). Nectar and pollen reward systems operate in a small number of species. Eleven epiphytic species have 'confirmed' pollinators, and four have 'probable' pollinators. Thirteen of the fourteen confirmed reports of epiphyte pollination describe social or solitary bees, mainly of the genus Trigona, apparently attracted by floral display and intense fragrance, which may constitute a chemical reward system. Dendrobium is the main epiphytic genus with confirmed pollinators.

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Australia's wasp-pollinated flying duck orchids revised (Paracaleana: Orchidaceae)

Australian Systematic Botany ◽

10.1071/sb05020 ◽

2006 ◽

Vol 19 (3) ◽

pp. 211 ◽

Cited By ~ 13

Author(s):

Stephen D. Hopper ◽

Andrew P. Brown

Keyword(s):

Sequence Data ◽

South Australia ◽

Pollination Syndrome ◽

The South ◽

Geographical Differences ◽

Sexual Deception ◽

Dna Sequence Data ◽

South West ◽

Morphological Differences ◽

Putative Hybrids

We uphold the generic rank of Paracaleana on the basis of its divergent pollination syndrome (sexual deception of male thynnid wasps compared with pollination of Caleana by male sawflies), recent DNA sequence data demonstrating monophyly, and nomenclatural stability. Ten of the 13 species recognised herein are new, all endemic to the South-west Australian Floristic Region: Paracaleana alcockii, P. brockmanii, P. dixonii, P. gracilicordata, P. granitica, P. hortiorum, P. lyonsii, P. parvula, P. terminalis and P. triens. Although some of these taxa have subtle morphological differences, primarily of labellum morphology, evidence from other Australian orchid genera whose flowers sexually deceive wasp pollinators indicates that reproductive isolation is probable among close sister taxa in Paracaleana. Moreover, phenological, ecological and geographical differences help separate morphologically close sister taxa. P. disjuncta D.L. Jones is considered to extend from Victoria and South Australia west into the South-west Australian Floristic Region, where James Drummond first collected the species, probably in 1838. Additional research is needed on pollinators, molecular phylogeny, possibly undescribed taxa within P. nigrita and on the few putative hybrids identified in the genus.

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