Are floral traits good predictors of effective pollinators? A test of pollination syndromes

This chapter examines pollination syndromes, floral constancy, and pollinator effectiveness. Flowers show enormous adaptive radiation, but the same kind of flower reappears by convergent evolution in many different families. Thus many families produce rather similar, simple bowl-shaped flowers like buttercups; many produce similar zygomorphic tubular lipped flowers; and many produce fluffy flower heads of massed (often white) florets. These broad flower types are the basis of the idea of pollination syndromes—the flowers have converged on certain morphologies and reward patterns because they are exploiting the abilities and preferences of particular kinds of visitor. After providing an overview of pollination syndromes, the chapter explains why pollination syndromes can be defended. It then considers flower constancy, along with the distinction between flower visitors and effective pollinators. It concludes with some observations on how flower visitors can contribute to speciation of plants through specialization and through their constancy.

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Are diel patterns of nectar production and anthesis associated with other floral traits in plants visited by potential bird and mammal pollinators?

Australian Journal of Botany ◽

10.1071/bt02056 ◽

2004 ◽

Vol 52 (1) ◽

pp. 87 ◽

Cited By ~ 4

Author(s):

V. M. Saffer

Keyword(s):

Western Australia ◽

Visual Cues ◽

Floral Traits ◽

Pollination Syndromes ◽

Nectar Production ◽

Diel Patterns ◽

Pollen Presentation ◽

Pollination Systems

Plants pollinated predominantly by vertebrates are thought to have suites of floral traits (e.g.�colour, conspicuousness, odour) that favour either birds or mammals, with brightly coloured, conspicuous flowers associated with birds and drab, concealed flowers with non-flying mammals. This study examined two other floral traits, diel patterns of nectar production and pollen presentation (anthesis). It would be expected that these would be nocturnal in putatively mammal-pollinated plants and diurnal in bird-pollinated plants. In four Banksia and two Dryandra species, all known to be visited by honeyeater birds and small marsupials at one site in south-western Australia, there was no clear correspondence between visual cues and diel patterns of resource presentation. This lack of correlation between floral traits does not support the idea of specialised pollination syndromes, but rather is consistent with generalised pollination systems.

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Variation in Manduca sexta Pollination-Related Floral Traits and Reproduction in a Wild Tobacco Plant

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.680463 ◽

2021 ◽

Vol 9 ◽

Author(s):

Julia Bing ◽

Xiang Li ◽

Alexander Haverkamp ◽

Ian T. Baldwin ◽

Bill S. Hansson ◽

...

Keyword(s):

Manduca Sexta ◽

Seed Set ◽

Tobacco Plant ◽

The Other ◽

Floral Traits ◽

Nicotiana Attenuata ◽

Pollination Syndromes ◽

Pollination Services ◽

Flower Opening ◽

Local Adaptations

Most flowering plants depend on animal pollination for successful sexual reproduction. Floral signals such as color, shape, and odor are crucial in establishing this (often mutualistic) interaction. Plant and pollinator phenotypes can vary temporally but also spatially, thus creating mosaic-like patterns of local adaptations. Here, we investigated natural variation in floral morphology, flower volatile emission, and phenology in four accessions of a self-compatible wild tobacco, Nicotiana attenuata, to assess how these traits match the sensory perception of a known pollinator, the hawkmoth Manduca sexta. These accessions differ in floral traits and also in their habitat altitudes. Based on habitat temperatures, the accession occurring at the highest altitude (California) is less likely to be visited by M. sexta, while the others (Arizona, Utah 1, and Utah 2) are known to receive M. sexta pollinations. The accessions varied significantly in flower morphologies, volatile emissions, flower opening, and phenology, traits likely important for M. sexta perception and floral handling. In wind tunnel assays, we assessed the seed set of emasculated flowers after M. sexta visitation and of natural selfed and hand-pollinated selfed flowers. After moth visitations, plants of two accessions (Arizona and Utah 2) produced more capsules than the other two, consistent with predictions that accessions co-occurring with M. sexta would benefit more from the pollination services of this moth. We quantified flower and capsule production in four accessions in a glasshouse assay without pollinators to assess the potential for self-pollination. The two Utah accessions set significantly more seeds after pollen supplementation compared with those of autonomous selfing flowers, suggesting a greater opportunistic benefit from efficient pollinators than the other two. Moreover, emasculated flowers of the accession with the most exposed stigma (Utah 2) produced the greatest seed set after M. sexta visitation. This study reveals intraspecific variation in pollination syndromes that illuminate the potential of a plant species to adapt to local pollinator communities, changing environments, and altered pollination networks.

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Pollinators drive floral evolution in an Atlantic Forest genus

AoB Plants ◽

10.1093/aobpla/plaa046 ◽

2020 ◽

Vol 12 (5) ◽

Cited By ~ 1

Author(s):

Beatriz Neves ◽

Igor M Kessous ◽

Ricardo L Moura ◽

Dayvid R Couto ◽

Camila M Zanella ◽

...

Keyword(s):

Functional Groups ◽

Atlantic Forest ◽

Incomplete Lineage Sorting ◽

Phylogenetic Analyses ◽

Floral Traits ◽

Lineage Sorting ◽

Pollination Syndromes ◽

Angiosperm Diversification ◽

Species Complexes ◽

As Species

Abstract Pollinators are important drivers of angiosperm diversification at both micro- and macroevolutionary scales. Both hummingbirds and bats pollinate the species-rich and morphologically diverse genus Vriesea across its distribution in the Brazilian Atlantic Forest. Here, we (i) determine if floral traits predict functional groups of pollinators as documented, confirming the pollination syndromes in Vriesea and (ii) test if genetic structure in Vriesea is driven by geography (latitudinal and altitudinal heterogeneity) or ecology (pollination syndromes). We analysed 11 floral traits of 58 Vriesea species and performed a literature survey of Vriesea pollination biology. The genealogy of haplotypes was inferred and phylogenetic analyses were performed using chloroplast (rps16-trnk and matK) and nuclear (PHYC) molecular markers. Floral traits accurately predict functional groups of pollinators in Vriesea. Genetic groupings match the different pollination syndromes. Species with intermediate position were found between the groups, which share haplotypes and differ morphologically from the typical hummingbird- and bat-pollinated flowers of Vriesea. The phylogeny revealed moderately to well-supported clades which may be interpreted as species complexes. Our results suggest a role of pollinators driving ecological isolation in Vriesea clades. Incipient speciation and incomplete lineage sorting may explain the overall low genetic divergence within and among morphologically defined species, precluding the identification of clear species boundaries. The intermediate species with mixed floral types likely represent a window into shifts between pollinator syndromes. This study reports the morphological-genetic continuum that may be typical of ongoing pollinator-driven speciation in biodiversity hotspots.

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Pollination syndromes in a Caatinga plant community in northeastern Brazil: seasonal availability of floral resources in different plant growth habits

Brazilian Journal of Biology ◽

10.1590/1519-6984.17212 ◽

2014 ◽

Vol 74 (1) ◽

pp. 62-71 ◽

Cited By ~ 11

Author(s):

ZGM Quirino ◽

IC Machado

Keyword(s):

Reproductive Success ◽

Plant Growth ◽

Rainy Season ◽

Temporal Dynamics ◽

Temporal Distribution ◽

Northeastern Brazil ◽

Floral Resources ◽

Floral Traits ◽

Pollination Syndromes ◽

Growth Habits

To describe plant phenological patterns and correlate functioning for the quantity and quality of resources available for the pollinator, it is crucial to understand the temporal dynamics of biological communities. In this way, the pollination syndromes of 46 species with different growth habits (trees, shrubs, herbs, and vines) were examined in an area of Caatinga vegetation, northeastern Brazil (7° 28′ 45″ S and 36° 54′ 18″ W), during two years. Flowering was monitored monthly in all the species, over two years (from January 2003 to December 2004). Pollination syndromes were characterised based on floral traits such as size, colour, morphology, symmetry, floral resources, as well as on direct visual observation of floral visitors on focal plants and published information. We observed differences among the plant growth habits with respect to floral traits, types of resources offered, and floral syndromes. The flowering periods of the species varied among floral syndrome groups. The majority of the melittophilous species flowered during the rainy season in the two study years, while the species of the other pollination syndroms flowered at the end of the dry season. An asynchrony of flowering was noted among the chiropterophilous species, while the phalenophilous group concentrated during the rainy season. The overall availability of floral resources was different during the rainy and the dry seasons, and also it varied among plants with different growth habits. The availability of oil-flowers coincided with the period of low nectar availability. We observed a relationship between the temporal distribution of the pollination syndromes and the availability of floral resources among each growth habits in this tropical ecosystem. Resource allocation in seasonal environments, such as the Caatinga, can function as a strategy for maintaining pollinators, facilitating therefore the reproductive success of plant species. The availability of floral resources during all the year, specially in seasonal environments such as the Caatinga, may function as a strategy to maintain pollinator populations ensuring the reproductive success of the plants.

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Genetic architecture of floral traits in bee- and hummingbird-pollinated sister species of Aquilegia (columbine)

10.1101/2021.04.12.439277 ◽

2021 ◽

Author(s):

Molly B. Edwards ◽

Gary P. T. Choi ◽

Nathan J. Derieg ◽

Ya Min ◽

Angie C. Diana ◽

...

Keyword(s):

Qtl Mapping ◽

Candidate Genes ◽

Genetic Architecture ◽

Genetic Basis ◽

Single Locus ◽

Floral Traits ◽

Pollination Syndromes ◽

Evolutionary Consequence ◽

Floral Color ◽

Hummingbird Pollination

Interactions with animal pollinators have helped shape the stunning diversity of flower morphologies across the angiosperms. A common evolutionary consequence of these interactions is that some flowers have converged on suites of traits, or pollination syndromes, that attract and reward specific pollinator groups. Determining the genetic basis of these floral pollination syndromes can help us understand the processes that contributed to the diversification of the angiosperms. Here, we characterize the genetic architecture of a bee-to-hummingbird pollination shift in Aquilegia (columbine) using QTL mapping of 17 floral traits encompassing color, nectar composition, and organ morphology. In this system, we find that the genetic architectures underlying differences in floral color are quite complex, and we identify several likely candidate genes involved in anthocyanin and carotenoid floral pigmentation. Most morphological and nectar traits also have complex genetic underpinnings; however, one of the key floral morphological phenotypes, nectar spur curvature, is shaped by a single locus of large effect.

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Pollination biology of Echinopsis leucantha (Cactaceae): passerine birds and exotic bees as effective pollinators

Botany ◽

10.1139/cjb-2016-0120 ◽

2017 ◽

Vol 95 (1) ◽

pp. 53-59 ◽

Cited By ~ 5

Author(s):

Pablo Gorostiague ◽

Pablo Ortega-Baes

Keyword(s):

South America ◽

Field Experiments ◽

First Record ◽

Passerine Bird ◽

Reproductive Period ◽

Floral Traits ◽

Passerine Birds ◽

Floral Visitors ◽

Pollination Systems ◽

Effective Pollinators

Cactus flowers have traditionally been considered to be specialized to certain pollination guilds, but pollination studies reveal that most species are actually generalists. This suggests that floral traits are not always predictive of the animal visitors that pollinate cactus flowers. Here, we studied the pollination of Echinopsis leucantha (Gillies ex Salm-Dyck) Walp., an endemic cactus of Argentina, whose floral traits would suggest that it is pollinated by moths. The floral lifespan and flower availability throughout the reproductive period were evaluated. Field experiments were carried out to study the reproductive system and the identity and effectiveness of floral visitors. Echinopsis leucantha flowers had a nocturnal anthesis time that extended into the following morning. The species was self-incompatible. Floral visitors included moths, bees, and passerine birds. However, diurnal visitors were more effective as pollinators than nocturnal ones. The flowers of E. leucantha were phenotypically specialized (sphingophily); however, the pollination system was functionally and ecologically generalized. The results confirm that generalized pollination systems are widespread among species of the Echinopsis genus with nocturnal flowers, for which diurnal pollinators seem to have a key role in fruit and seed production. Our study constitutes the first record of passerine bird pollination in the Cactaceae for mainland South America.

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Testing Pollination Syndromes in Oenothera (Onagraceae)

Journal of Pollination Ecology ◽

10.26786/1920-7603(2020)609 ◽

2021 ◽

Vol 26 ◽

Author(s):

Kyra N. Krakos ◽

Matthew W. Austin

Keyword(s):

Predictive Ability ◽

Floral Traits ◽

Pollination Syndrome ◽

Pollination Syndromes ◽

Floral Trait ◽

Moth Pollination ◽

Mixed Support ◽

Pollination Systems ◽

Floral Form ◽

The Relationship

Pollinators are considered a major selective force in shaping the diversification of angiosperms. It has been hypothesized that convergent evolution of floral form has resulted in “pollination syndromes” - i.e. suites of floral traits that correspond to attraction of particular pollinator functional groups. Across the literature, the pollination syndrome concept has received mixed support. This may be due to studies using different methods to describe floral traits and/or the pollination syndrome concept being supported more often in species highly reliant on pollinators for reproduction. Here, we assess the predictive ability of pollination syndromes in Oenothera, a species rich clade with pollination systems existing on a gradient of specialization, and in which species are either self-compatible or self-incompatible. We ask the following questions: Do Oenothera species follow the pollination syndrome concept using traditional, categorical floral trait descriptions and/or quantitative floral trait measurements? And, are floral traits more predictive of primary pollinators in species with specialized pollination systems and/or species that are self-incompatible? Mapping floral traits of 54 Oenothera species into morphospace, we do not find support for the pollination syndrome concept using either categorical or quantitative floral trait descriptions. We do not find support for specialization or breeding system influencing the prediction of primary pollinators. However, we find pollination syndromes were more predictive in Oenothera species with moth pollination systems. Collectively, these results suggest that the pollination syndrome concept cannot be generally applied across taxa and that evolutionary history is important to consider when evaluating the relationship between floral form and contemporary pollinators.

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Floral evolution and pollinator diversification in Hedychium J.Koenig (Zingiberaceae): one of Mr. Darwin’s tropical fantasies

10.1101/2021.12.06.471407 ◽

2021 ◽

Author(s):

Ajith Ashokan ◽

Piyakaset Suksathan ◽

Jana Leong-Škorničková ◽

Mark Newman ◽

W. John Kress ◽

...

Keyword(s):

Diversification Rate ◽

Floral Traits ◽

Tube Length ◽

Pollination Syndromes ◽

Bird Pollination ◽

Evolutionary Diversification ◽

Moth Pollination ◽

Floral Color ◽

Inflorescence Structure ◽

Pollination Systems

ABSTRACTPREMISEHedychium J.Koenig (ginger lilies: Zingiberaceae) is endemic to the Indo-Malayan Realm (IMR) and is known for its fragrant flowers. Two different pollination syndromes characterize the genus: diurnal or bird pollination and nocturnal or moth pollination systems. To date, no attempt has been undertaken to understand the evolution of floral traits in this genus.METHODSWe estimated ancestral character-states, phylogenetic signals, and character correlations for thirteen discrete and eight continuous floral traits representing 75% species diversity of Hedychium. Diversification rate estimation analyses were also employed to understand trait-dependent diversification in the genus.RESULTSInflorescence structure, cincinnus capacity, and curvature of floral tubes revealed strong phylogenetic dependence, whereas number of open flowers per inflorescence per day, color of the labellum, and exertion of the stigma characterized higher ecological effects. Diversification rate estimations suggested that the labellum width, floral tube length, and labellum color played a major role in the evolutionary diversification of Hedychium.CONCLUSIONSWe identified bract type and cincinnus capacity as synapomorphies for Hedychium, while the island-specific clade III was characterized by slender cylindrical inflorescence, coiling of floral tubes, and longer bract to calyx ratio. The circum-Himalayan clade IV is the most speciose, derived, and with most variable floral traits. Although floral color and size lacked any association with pollinator-specific traits (moth and bird pollination), pale colored flowers were most common in the early diverging clades (clade I, II-el., and II-de.), indicating their ancestral nature, when compared to brightly colored flowers.

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