A novel pollination mode,saprocantharophily, in Duguetia cadaverica (Annonaceae): A stinkhorn (Phallales) flower mimic

Duguetia cadaverica (Annonaceae), a small understory tree of humid primary forest from the Guianas to Pará state, Brazil, unites several unusual blossom and floral characters such as flagelliflory and putrid-smelling flowers, respectively. The few pollination studies conducted in the large genus Duguetia have shown that species are usually cantharophilous, pollinated by either small (mostly Nitidulidae) or large specialized dynastid (Scarabaeidae) beetles. Foul-smelling flowers are a novelty within the genus, and to better understand their significance, we undertook a study of the reproductive biology and flower scent chemistry of D. cadaverica. In a primary forest of French Guiana, we observed and measured morphology and phenology of trees and flowers; additionally, flower pollination chamber temperature was measured and insect visitors to flowers observed. Flower scent was collected in situ and later analyzed in the laboratory by GC–MS. Flowers are visited by small beetles of a single Pycnocnemus species (Nitidulidae), which are the only insects observed to enter the pollination chamber. Moreover, flowers evince a rhythm in sexual stage, scent emission and temperature, which finds correspondence in behavioral characters of the putative nitidulid pollinator, such as timing of entry and exit from the pollination chamber. Floral scent analysis revealed an unusual, previously undescribed combination of chemical odor classes. The earthy, rank flower scent contained 18 compounds, among them fatty acid derivatives, terpenoids and N- and S-bearing compounds. The most abundant volatiles were 1-octen-3-ol, 3-octanone, and (E)-2-octenol, which are characteristic earthy odors of fungi; additionally, there were sulfides and 4-methylpentanoic acid, which are molecules associated with carcass and cheese odors, respectively.     

The missing stink: sulphur compounds can mediate a shift between fly and wasp pollination systems

The radiation of the angiosperms is often attributed to repeated evolutionary shifts between different pollinators, as this process drives diversification of floral forms and can lead to reproductive isolation. Floral scent is an important functional trait in many pollination systems but has seldom been implicated as a key mechanism in pollinator transitions. In this study, we suggest a role for sulphur compounds in mediating a shift between specialized carrion-fly and pompilid-wasp pollination systems in Eucomis (Hyacinthaceae). Flowers of closely related Eucomis species pollinated by carrion flies or pompilid wasps have very similar greenish-white flowers, but differ markedly in floral scent chemistry (determined by GC–MS analysis of headspace extracts). Comparison of the floral colours of the four Eucomis species in the visual systems of flies and wasps suggests that colour plays little role in pollinator discrimination. Nectar properties and morphology also do not differ strongly between fly- and wasp-pollinated flowers. By comparing floral scent bouquets and experimentally manipulating the scent of plants in the field, we demonstrate that shifts between wasp and fly pollination in these four congeners can depend on the production or suppression of sulphur compounds (dimethyl disulphide and dimethyl trisulphide) in the fragrance bouquet. This suggests that mutations affecting the production of particular scent compounds could precipitate shifts between pollinators, independently of floral morphology, colour or nectar properties.     

Floral scent and pollination in Browneopsis disepala (Leguminosae: Caesalpinioideae) in western Ecuador

Aspects of the pollination ecology of Browneopsis disepala, including floral scent composition, were studied. Floral scent was collected with head space techniques and analyzed by coupled gas chromatography-mass spectrometry. Inflorescence and flower development were followed, and amount and concentration of nectar measured. Flower-visiting animals were observed nocturally and diurnally. Inflorescences of B. disepala emit a floral scent that is typical of neither moth- nor bat-pollinated plants, but contains some compounds related to both pollination types. Nectar is produced in quantities and with sugar concentrations falling within a range typical of both moth- and bat-pollinated plants. The inflorescences are visited by both moths and bats, but the behavior of the bats suggests that they are the more efficient pollinators. Browneopsis disepala has a mixed pollination system and is dependent on animals for pollination.     

Notes on pollination ecology and floral scent chemistry of the rare neotropical orchid Catasetum galeritum Rchb.f.

The neotropical orchid genus Catasetum embraces about 180 species that produce perfume as reward for pollinators (i.e. male euglossine bees). Among the ca. 1000 perfume‐rewarding plants, Catasetum species are the best studied with respect to their natural history. Nevertheless, the pollination ecology of most species (> 80%) remains unknown. Here, we investigated the pollination ecology and floral scent chemistry of C. galeritum, a rare species endemic to the poorly investigated Brazilian Amazon. Flowers of C. galeritum were visited only by male bees of Eufriesea superba. Its perfume bouquet was composed of six volatiles, with 1,4‐dimethoxybenzene accounting for about 85% of the total scent discharge. Curiously, this compound is a potent attractant of more than 40 euglossine species. The absence of euglossine species other than Ef. superba on flowers of C. galeritum might be, therefore, be mediated by a modifier effect of another compound(s) in its floral scent bouquet.     

Absence of pollinators and apomictic fruit production in an Atlantic rainforest population of Cymbopetalum brasiliense (Annonaceae)

Breeding system and pollination biology of an isolated population of Cymbopetalum brasiliense (Annonaceae), a large-flowered understory tree, was studied during two consecutive flowering seasons in October/November 2007 and September/October 2008. Flowers were morphologically comparable to other Cymbopetalum species and generally to other Annonaceae taxa adapted to pollination by large beetles, such as Annona spp. Flowers were thermogenic and emitted a strong scent during the pistillate and staminate flowering phases. Heating of the floral chamber was most intense during the pistillate phase between 1800 and 1900?h (up to 6°C difference to air temperature). Floral scent consisted almost entirely of p-methylanisole. None of the 133 flowers examined during two seasons received any visitation by dynastid beetles or other potential pollinators. Lycaenid larvae (Oenomaus ortygnus) attacked buds and flowers in both flowering seasons and destroyed about 20% of all buds in the 2007 season. Fruit set was high (72% of nonpredated flowers in 2007), despite the absence of pollinators. Field experiments showed that agamospermic reproduction rather than self-pollination was most likely responsible for fruit production. The study reports a probable case of apomixis, which would be the first in the Annonaceae family.     

Comparative analysis of floral scents in four sympatric species of Serapias L. (Orchidaceae): clues on their pollination strategies

Orchid species of Mediterranean genus Serapias often live in sympatry, exhibit similar floral morphology, bloom in the same period and share the same pollinators. Previous studies on Serapias species have ascertained that reproductive isolation is based on pre-pollination barriers, that secretory cells and trichomes are typically distributed on the floral labellum and that flowers produce aliphatic compounds. In this study we compare the floral scent composition of four widespread, co-occurring Serapias species, namely Serapias lingua, Serapias parviflora, Serapias vomeracea and Serapias cordigera. Our goals are to assess if differences in floral scent may act as interspecific pre-pollination barriers and if these olfactory signals may be involved in the pollination strategy of Serapias. We find that all the selected species produce C20–C29 alkanes and alkenes and, in addition, have detected the presence in S.?cordigera of large amounts of oleate and stearate ethyl ester. Our findings help to clarify that the sympatric Serapias species have slightly different floral scent signatures that may account for their relevant role as pre-pollination barriers. Therefore, the pollination strategy of Serapias relies not only on the tubular shape of their floral corolla but also on the production of olfactory signals that may lure potential pollinators and even assure a sufficient degree of pollinator fidelity.     

A new species of Aspidistra (Ruscaceae s.l., Asparagales) from southern Vietnam, field observations on its flowering and possible pollination by flies (Phoridae)

The genus Aspidistra with almost 100 species is the most diverse in southern China and northern Vietnam. We describe a new species Aspidistra phanluongii N.Vislobokov from southern Vietnam. Species of Aspidistra are herbs characteristic of Southeast Asian forests. Flowering of these plants can be considered cryptic. There are no recorded field observations on phenology, biology of flowering or pollination of Aspidistra. Previously proposed pollinators of Aspidistra include collembolans, amphipods, fungus gnats (Diptera: Mycetophilidae, Sciaridae) and even slugs. We present observation data on the flowering of A. phanluongii in the wild. Flowers were visited by flies of Megaselia (Phoridae) and ants. Megaselia flies, well-known pollinators of numerous tropical plant species, are shown to be likely pollinators of Aspidistra phanluongii. The present study does not provide evidence of pollination by fungus gnats.     

Experimental evidence for specialized bird pollination in the endangered South African orchid Satyrium rhodanthum and analysis of associated floral traits

The bird pollination syndrome is characterized by red, unscented flowers with dilute nectar in long nectar tubes. However, the extent to which plants with such traits actually depend on birds for seed production is seldom determined experimentally, and traits such as colour and scent production are often assessed only subjectively. We documented bird pollination and quantified floral traits in the critically endangered Satyrium rhodanthum (Orchidaceae) from mistbelt grasslands in the summer‐rainfall region of South Africa. Direct observations and motion trigger camera footage revealed amethyst sunbirds as the only pollinators, despite the presence of other potential pollinators. Experimental exclusion of sunbirds significantly reduced pollination and fruit set to near zero. Pollination success in naturally pollinated plants was close to 100% in one year, and fruit set varied from 23 to 64% in other years. Pollen transfer efficiency was 5.8%, which is lower than in related insect‐pollinated species, probably due to a tendency of birds to wipe pollinaria from their beak. Flowers of S. rhodanthum only reflect light in the red range of the spectrum, and they produce only a few aliphatic and monoterpene scent compounds at comparatively low emission rates. Nectar volume and sugar concentration varied between 2.7 and 3.7 μL and 23.7 and 25.9%, respectively. We conclude that S. rhodanthum is highly specialized for pollination by sunbirds. Colour, scent and nectar characteristics differ from insect‐pollinated Satyrium species and are consistent with those expected for bird‐pollinated flowers, and may contribute to lack of visitation by other potential long‐tongued pollinators. Habitat loss probably underlies the critically endangered conservation status of S. rhodanthum, but the specialization for pollination by a single bird species means that reproduction in this orchid is vulnerable to losses in surrounding communities of plants that subsidize the energetic requirements of sunbirds. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 177 , 141–150.     

Specialized pollination in the African milkweed Xysmalobium orbiculare: a key role for floral scent in the attraction of spider-hunting wasps

Specialized pollination by prey-hunting wasps is poorly documented in rewarding plants. Furthermore, the mechanisms of achieving specialization are not clear since flowers typically produce exposed nectar and have no morphological adaptations (such as long spurs) to exclude non-pollinating visitors. We investigated the pollination of Xysmalobium orbiculare and explored the functional roles of floral scent and nectar in attracting pollinators and deterring nectar robbers. Floral visitor observations showed that this milkweed is visited almost exclusively by pompilid wasps in the genus Hemipepsis. These wasps were the only insects to carry pollinia, and a cage experiment confirmed their effectiveness in removing and inserting pollinia on flowers. Hand-pollinations showed that plants are genetically self-incompatible and thus reliant on pollinators for seed set. Palatability experiments with honeybees showed that nectar is distasteful to non-pollinating insects and is therefore likely to play a functional role in deterring nectar thieves. Choice experiments in the field showed that the wasp pollinators are attracted primarily by floral scent rather than visual cues. Analysis of spectral reflectance of flowers revealed that flowers are dull colored and are unlikely to stand out from the background vegetation. We conclude that X. orbiculare is specialized for pollination by spider-hunting wasps in the genus Hemipepsis and utilizes floral scent to selectively attract its pollinators and unpalatable nectar to deter non-pollinating visitors.     

Nocturnal and diurnal pollination of Clerodendrum molle (Verbenaceae) in the Gal��pagos Islands

The primary hypothesis of this study was that in the Galápagos Islands, fruit and seed set via nocturnal pollination would exceed that of diurnal pollination because of the greater insect activity at night typical of hot, arid regions. Clerodendrum molle, a widespread member of the Galápagos flora was submitted to pollination experiments, visitor observations, nectar sampling, pollen transfer studies, pollen?Covule ratio studies, and pollen measurements. Flowers set fruit and seed via open pollination, autonomous autogamy, facilitated autogamy, facilitated cross-pollination, diurnal pollination, and nocturnal pollination. Results indicate no significant difference in fruit set. Cross-pollinated flowers showed a significant increase in seed set over all treatments except facilitated autogamy. Nocturnal and diurnal fruit and seed set did not differ significantly. Nocturnal visitors included ants, spiders, hawk moths, and roaches whereas diurnal visitors included carpenter bees and ants. Galápagos members of C. molle exhibit incomplete protandry and set fruit via autonomous autogamy as a result of natural selection in an environment with few faithful pollinators. Overall low fruit and seed set are likely because of a combination of pollen and resource limitation, the latter exacerbated by nectar robbing. Studies of island angiosperms are crucial for complete understanding of the population dynamics of indigenous plants, which can assist conservation officials in protecting these species.     

Active pollination favours sexual dimorphism in floral scent

Zoophilous flowers often transmit olfactory signals to attract pollinators. In plants with unisexual flowers, such signals are usually similar between the sexes because attraction of the same animal to both male and female flowers is essential for conspecific pollen transfer. Here, we present a remarkable example of sexual dimorphism in floral signal observed in reproductively highly specialized clades of the tribe Phyllantheae (Phyllanthaceae). These plants are pollinated by species-specific, seed-parasitic Epicephala moths (Gracillariidae) that actively collect pollen from male flowers and pollinate the female flowers in which they oviposit; by doing so, they ensure seeds for their offspring. We found that Epicephala-pollinated Phyllanthaceae plants consistently exhibit major qualitative differences in scent between male and female flowers, often involving compounds derived from different biosynthetic pathways. In a choice test, mated female Epicephala moths preferred the scent of male flowers over that of female flowers, suggesting that male floral scent elicits pollen-collecting behaviour. Epicephala pollination evolved multiple times in Phyllantheae, at least thrice accompanied by transition from sexual monomorphism to dimorphism in floral scent. This is the first example in which sexually dimorphic floral scent has evolved to signal an alternative reward provided by each sex, provoking the pollinator''s legitimate altruistic behaviour.     

Nocturnal pollination of the endemic <Emphasis Type="Italic">Silene sennenii</Emphasis> (Caryophyllaceae): an endangered mutualism?

Silene sennenii is an extremely narrow endemic species from the north-eastern Iberian Peninsula, with only five populations. Its habitat, severely affected by urban, industrial, and agricultural land use, is highly vulnerable, and makes of S. sennenii, a seriously endangered taxon. Its pollination ecology is studied and compared among populations. Flowers of S. sennenii are distinguished by several morphological and physiological characters, including night emission of scent, which are related to nocturnal pollination. Although visited by insects at night and during day, selective insect exclusion experiments show that this plant is pollinated mainly at night. However, differences among populations are observed in visitation rates and reproductive success, which indicates that the system composed by the plant and its pollinators show evidences of disruption in some populations. The causes and consequences of this disruption are analyzed, with a focus on differences in population size, habitat quality, and genetic diversity. The results are discussed from the perspective of the vulnerability of established mutualisms, and the consequences for the survival of the species.     

Beetle pollination of Luisia teres (Orchidaceae) and implications of a geographic divergence in the pollination system

The epiphytic orchid Luisia teres on Okinawa Island, the Ryukyus, Japan, sexually attracts male Protaetia beetles for pollination through floral scent. Here, the pollination system of L. teres on the Satsuma Peninsula, Kyushu, located approximately 600 km north of Okinawa Island, is reported. The inconspicuous flowers depend on the Cetoniinae beetles Protaetia orientalis submarumorea and Pseudotorynorrhina japonica, which both usually feed on fermented sap/ripe fruits, for pollination. The flower-visiting P. orientalis submarumorea beetles included both males and females, and pseudocopulation was never observed. Pollinaria removal and pollination were achieved while beetles fed on floral nectar. Although P. orientalis submarumorea did not necessarily remove pollinaria more frequently than Ps. japonica, the pollinaria attached precisely to the central part of their clypeus, unlike on Ps. japonica. Our findings suggest that a geographic divergence in the pollination system occurs in Japanese L. teres. In the Ryukyus, the orchid adopts a specialized pollination system with only male-attractive olfactory stimuli, whereas in Kyushu it has a relatively more generalized system based on only a food reward.     

Flowering biology of Aspidistra (Asparagaceae): new data on pollination by dipteran insects

The genus Aspidistra comprises about 160 species of herbaceous plants. In previous investigations, different authors suggested that Aspidistra is pollinated by flies, fungus gnats, slugs, amphipods and even collembolans. The vast majority of data was based on only one species, A. elatior, and was not confirmed by direct observations. Recent field observations of anthetic plants confirm the idea of pollination by flies for two other species of the genus. The present study summarizes direct observations of flowering phenology and pollination of five previously unstudied species of Aspidistra. Flowering biology was studied using visual observations as well as video and photo monitoring. Flowers and captured pollinators were investigated using scanning electron microscopy. As a result, knowledge of the flowering biology of Aspidistra has been increased. The absence of heat production and an ultraviolet pattern were verified. The present data show that flowers of Aspidistra can serve as a food resource for animals. The investigated species of Aspidistra are pollinated by dipteran insects: A. formosa, A. marasmioides and A. subrotata are pollinated by fungus gnats; A. multiflora and A. oviflora are pollinated by flies. The occurrence of fungus‐gnat pollination was directly demonstrated for the first time in the genus Aspidistra. The present study confirmed the idea of myiophily in the genus Aspidistra. Apparently, myiophily is common and diverse in Aspidistra. More likely, pollinators are attracted by scent, which is undetectable by humans, but the attraction mechanism is still not completely clear.     

Effect of pollination on floral longevity and costs of delaying fertilization in the out-crossing Polygala vayredae Costa (Polygalaceae)

Background and Aims

The effect of pollination on flower life span has been widely studied, but so far little attention has been paid to the reproductive consequences of delayed pollination in plants with long floral life spans. In the present study, Polygala vayredae was used to answer the following questions. (1) How does male and female success affect the floral longevity of individual flowers? (2) How does delaying fertilization affect the female fitness of this species?

Methods

Floral longevity was studied after experimental pollinations involving male and/or female accomplishment, bagging and open pollination. The reproductive costs of a delay in the moment of fertilization were evaluated through fruit set, seed–ovule ratio and seed weight, after pollination of flowers that had been bagged for 2–18 d.

Key Results

Senescence of the flowers of P. vayredae was activated by pollen reception on the stigmatic papillae, while pollen removal had no effect on floral longevity. Nonetheless, a minimum longevity of 8 d was detected, even after successful pollination and pollen dissemination. This period may be involved with the enhancement of male accrual rates, as the female accomplishment is generally achieved after the first visit. Floral life span of open-pollinated flowers was variable and negatively correlated with pollinator visitation rates. Delayed pollination had a major impact on the reproductive success of the plant, with fruit set, seed–ovule ratio and seed weight being significantly diminished with the increase of flower age at the moment of fertilization.

Conclusions

A strong relationship between pollination and floral longevity was observed. Flowers revealed the ability to extend or reduce their longevity, within some limits, in response to the abundance of efficient pollinators (i.e. reproductive fulfilment rates). Furthermore, with scarce or unpredictable pollinators, a long floral life span could maintain the opportunity for fertilization but would also have reproductive costs on production of offspring. Reduced female fitness late in the flower''s life could shift the cost–benefit balance towards a shorter life span, partially counteracting the selection for longer floral life span potentially mediated by scarce pollination services.Key words: Delayed pollination, endemic species, flower longevity, life span, pollen limitation, pollination, pollinator scarcity, Polygala vayredae, Polygalaceae, reproductive consequences, secondary pollen presentation     

Moonlight pollination in the gymnosperm Ephedra (Gnetales)

Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea. It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya, pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in most species of Ephedra subsequent an evolutionary shift to wind pollination in the clade. When the services of insects are no longer needed for successful pollination, the adaptive value of correlating pollination with the full moon is lost, and conceivably also the trait.     

The pollination of Habenaria rhodocheila (Orchidaceae) in South China: When butterflies take sides

Habenaria is one of the largest terrestrial genera in the family Orchidaceae. Most field studies on Habenaria species with greenish–white and nocturnal scented flowers are pollinated by nocturnal hawkmoths and settling moths. However, H. rhodocheila presents reddish flowers lacking a detectable scent and fails to fit the moth pollination syndrome. We investigated the pollinators, breeding system, and functional traits of H. rhodocheila in South China and found that two diurnal swallowtail butterflies Papilio helenus and Papilio nephelus (Papilionidae) were the effective pollinators. When butterflies foraged for nectar in the spur, the pollinia became attached between the palpi. A triangular projected median rostellar lobe was found at the entrance (sinus) of the spur of H. rhodocheila. This lobe divided the spur opening into two entrances forcing butterflies to enter their proboscides through the left or right side. When the projection of median rostellar lobe was removed, the site of pollinium attachment changed to the eyes of the butterflies, leading to a higher rate of pollinium removal but lower rate of pollinium deposition. Our quartz glass cylinder choice experiment suggested that visual rather than olfactory cues provided the major stimuli for butterflies to locate these flowers. Hand pollination experiments suggested this species was self‐compatible but pollinator‐dependent. However, the proportion of seeds with large embryos produced in self‐pollinated fruits was significantly lower than in cross‐pollinated fruits, indicating a significant inbreeding depression. Unlike many other orchid species, fruit set was higher than rates of pollinium removal, indicating a high level of pollination efficiency in a species with friable pollinia. Shifts from moth to butterfly pollination in the genus Habenaria parallel other orchid lineages providing insights into the potential for pollinator‐mediated floral trait selection.     

Spatio‐temporal patterns in pollination of deceptive Aristolochia rotunda L. (Aristolochiaceae)

• Pollination success of highly specialised flowers is susceptible to fluctuations of the pollinator fauna. Mediterranean Aristolochia rotunda has deceptive trap flowers exhibiting a highly specialised pollination system. The sole pollinators are kleptoparasitic flies in search of food. This study investigates these pollinators on a spatio‐temporal scale and the impact of weather conditions on their availability. Two potential strategies of the plants to cope with pollinator limitation, i.e. autonomous selfing and an increased floral life span, were tested.
• A total of 6156 flowers were investigated for entrapped pollinators in 10 Croatian populations. Availability of the main pollinator was correlated to meteorological data. Artificial pollination experiments were conducted and the floral life span was recorded in two populations according to pollinator availability.
• Trachysiphonella ruficeps (Chloropidae) was identified as dominant pollinator, along with less abundant species of Chloropidae, Ceratopogonidae and Milichiidae. Pollinator compositions varied among populations. Weather conditions 15–30 days before pollination had a significant effect on availability of the main pollinator. Flowers were not autonomously selfing, and the floral life span exhibited considerable plasticity depending on pollinator availability.
• A. rotunda flowers rely on insect pollen vectors. Plants are specialised on a guild of kleptoparasitic flies, rather than on a single species. Pollinator variability may result in differing selection pressures among populations. The availability/abundance of pollinators depends on weather conditions during their larval development. Flowers show a prolonged trapping flower stage that likely increases outcrossing success during periods of pollinator limitation.

     

Floral scent composition predicts bee pollination system in five butterfly bush (Buddleja,Scrophulariaceae) species

Traditionally, plant–pollinator interactions have been interpreted as pollination syndrome. However, the validity of pollination syndrome has been widely doubted in modern studies of pollination ecology. The pollination ecology of five Asian Buddleja species, B. asiatica, B. crispa, B. forrestii, B. macrostachya and B. myriantha, in the Sino‐Himalayan region in Asia, flowering in different local seasons, with scented inflorescences were investigated during 2011 and 2012. These five species exhibited diverse floral traits, with narrow and long corolla tubes and concealed nectar. According to their floral morphology, larger bees and Lepidoptera were expected to be the major pollinators. However, field observations showed that only larger bees (honeybee/bumblebee) were the primary pollinators, ranging from 77.95% to 97.90% of total visits. In this study, floral scents of each species were also analysed using coupled gas chromatography and mass spectrometry (GC‐MS). Although the five Buddleja species emitted differentiated floral scent compositions, our results showed that floral scents of the five species are dominated by substances that can serve as attractive signals to bees, including species‐specific scent compounds and principal compounds with larger relative amounts. This suggests that floral scent compositions are closely associated with the principal pollinator assemblages in these five species. Therefore, we conclude that floral scent compositions rather than floral morphology traits should be used to interpret plant–pollinator interactions in these Asian Buddleja species.     

Evolutionary disruption in the pollination system of Vanilla (Orchidaceae)

• Pollination of the pantropical Vanilla has been linked to melittophily and food deception.
• Here we investigated the role of flower traits on the reproduction of Neotropical Vanilla. We also studied the evolution of pollination systems in order to understand the origin of production of flower resources and the diversification of pollinators in this orchid genus. Our study was founded on data of adaptations in flower morphology, production of resources, scent release, pollinators and breeding systems of Vanilla and presenting new data on reproductive biology of V. palmarum. Data on reproductive biology of Vanilla were mapped onto a phylogeny to address our queries on the evolution of pollination systems in this genus.
• Vanilla palmarum shows a mixed mating system, with its facultative autogamous flowers being pollinated by hummingbirds. Its yellow flowers are scentless and produces nectar. Mapping of the pollination system onto trees resulted in one origin for bird pollination and at least two origins for autogamy in Vanilla. Nectar secretion has a single origin in the Neotropical thick-leafed lineage.
• Bird pollination of Vanilla is shown for the first time. The origin of ornithophily within a bee-pollinated clade is supported by flower morphology. Floral transitions to ornithophily have been favoured by the occupation of a distinct niche from that of the other thick-leafed Vanilla species. Despite its specialized pollination, V. palmarum is autogamous. A mixed mating system can promote reproductive assurance in the case of a decline in pollinator populations, or in areas where pollinator services are irregular or absent.