Variation in floral morphology and plant reproductive success in four Ipomoea species (Convolvulaceae) with contrasting breeding systems

• This study tested the hypothesis that self‐compatibility would be associated with floral traits that facilitate autonomous self‐pollination to ensure reproduction under low pollinator visitation. In a comparison of two pairs of Ipomoea species with contrasting breeding systems, we predicted that self‐compatible (SC) species would have smaller, less variable flowers, reduced herkogamy, lower pollinator visitation and higher reproductive success than their self‐incompatible (SI) congeners.
• We studied sympatric species pairs, I. hederacea (SC)– I. mitchellae (SI) and I. purpurea (SC)–I. indica (SI), in Mexico, over two years. We quantified variation in floral traits and nectar production, documented pollinator visitation, and determined natural fruit and seed set. Hand‐pollination and bagging experiments were conducted to determine potential for autonomous self‐pollination and apomixis.
• Self‐compatible Ipomoea species had smaller flowers and lower nectar production than SI species; however, floral variation and integration did not vary according to breeding system. Bees were primary pollinators of all species, but visitation rates were seven times lower in SC than SI species. SC species had a high capacity for autonomous self‐pollination due to reduced herkogamy at the highest anther levels. Self‐compatible species had two to six times higher fruit set than SI species.
• Results generally support the hypothesis that self‐compatibility and autonomous self‐pollination ensure reproduction under low pollinator visitation. However, high variation in morphological traits of SC Ipomoea species suggests they maintain variation through outcrossing. Furthermore, reduced herkogamy was associated with high potential for autonomous self‐pollination, providing a reproductive advantage that possibly underlies transitions to self‐compatibility in Ipomoea.

     

Reproductive biology and pollinators in two enantiostylous Qualea species (Vochysiaceae) in the Brazilian Cerrado

• Enantiostyly is a floral polymorphism in which two floral forms in the same species differ in deflection of the stigma to right or left position. In monomorphic enantiostylous plants, flowers of the two morphs occur within the same individual, usually in the same proportion. In self‐compatible species the function of monomorphic enantiostyly is proposed to increase outcrossing rates and offer a reproductive advantage under pollination limitation. Enantiostylous species are usually self‐compatible and show heteranthery, with poricide anthers and pollen as pollinator reward; however, there are families, such as Vochysiaceae, that have different characteristics.
• We analysed the reproductive system and pollination biology of Qualea parviflora and Q. multiflora, two enantiostylous species from the Brazilian Cerrado that have specific morphological and physiological traits. For this, we characterized flower traits, performed hand pollinations and studied floral visitors.
• We found no differences between morphs in the proportion of flowers, nectar produced or its concentration, pollen quantity and fruit set. Both species were self‐incompatible and quite generalist regarding floral visitors.
• Enantiostyly in self‐incompatible plants seems to confer a reproductive advantage by reducing self‐interference resulting from stigma clogging. This novel result helps to expand our knowledge on this complex floral polymorphism and opens new avenues for future research on this topic.

     

Pollinator‐mediated selection in a specialized pollination system: matches and mismatches across populations

Most studies on pollinator‐mediated selection have been performed in generalized rather than specialized pollination systems. This situation has impeded evaluation of the extent to which selection acts on attraction or specialized key floral traits involved in the plant‐pollinator phenotypic interphase. We studied pollinator‐mediated selection in four populations of Nierembergia linariifolia, a self‐incompatible and oil‐secreting plant pollinated exclusively by oil‐collecting bees. We evaluated whether floral traits experience variable selection among populations and whether attraction and fit traits are heterogeneously selected across populations. Populations differed in every flower trait and selection was consistently observed for corolla size and flower shape, two traits involved in the first steps of the pollination process. However, we found no selection acting on mechanical‐fit traits. The observation that selection occurred upon attraction rather than mechanical‐fit traits, suggests that plants are not currently evolving fine‐tuned morphological adaptations to local pollinators and that phenotypic matching is not necessarily an expected outcome in this specialized pollination system.     

Divergence on floral traits and vertebrate pollinators of two endemic Encholirium bromeliads

Shifts in pollen vectors favour diversification of floral traits, and differences in pollination strategies between congeneric sympatric species can contribute to reproductive isolation. Divergence in flowering phenology and selfing could also reduce interspecific crossing between self‐compatible species. We investigated floral traits and visitation rates of pollinators of two sympatric Encholirium species on rocky outcrops to evaluate whether prior knowledge of floral characters could indicate actual pollinators. Data on flowering phenology, visitation rates and breeding system were used to evaluate reproductive isolation. Flowering phenology overlapped between species, but there were differences in floral characters, nectar volume and concentration. Several hummingbird species visited flowers of both Encholirium spp., but the endemic bat Lonchophylla bokermanni and an unidentified sphingid only visited E. vogelii. Pollination treatments demonstrated that E. heloisae and E. vogelii were partially self‐compatible, with weak pollen limitation to seed set. Herbivores feeding on inflorescences decreased reproductive output of both species, but for E. vogelii the damage was higher. Our results indicate that actual pollinators can be known beforehand through floral traits, in agreement with pollination syndromes stating that a set of floral traits can be associated with the attraction of specific groups of pollinators. Divergence on floral traits and pollinator assemblage indicate that shifts in pollination strategies contribute to reproductive isolation between these Encholirium species, not divergence on flowering phenology or selfing. We suggest that hummingbird pollination might be the ancestral condition in Encholirium and that evolution of bat pollination made a substantial contribution to the diversification of this clade.     

A test for Allee effects in the self‐incompatible wasp‐pollinated milkweed Gomphocarpus physocarpus

It has been suggested that plants that are good colonizers will generally have either an ability to self‐fertilize or a generalist pollination system. This prediction is based on the idea that these reproductive traits should confer resistance to Allee effects in founder populations and was tested using Gomphocarpus physocarpus (Asclepiadoideae: Apocynaceae), a species native to South Africa that is invasive in other parts of the world. We found no significant relationships between the size of G. physocarpus populations and various measures of pollination success (pollen deposition, pollen removal and pollen transfer efficiency) and fruit set. A breeding system experiment showed that plants in a South African population are genetically self‐incompatible and thus obligate outcrossers. Outcrossing is further enhanced by mechanical reconfiguration of removed pollinaria before the pollinia can be deposited. Self‐pollination is reduced when such reconfiguration exceeds the average duration of pollinator visits to a plant. Observations suggest that a wide variety of wasp species in the genera Belonogaster and Polistes (Vespidae) are the primary pollinators. We conclude that efficient pollination of plants in small founding populations, resulting from their generalist wasp‐pollination system, contributes in part to the colonizing success of G. physocarpus. The presence of similar wasps in other parts of the world has evidently facilitated the expansion of the range of this milkweed.     

Crane flies and microlepidoptera also function as pollinators in Epidendrum (Orchidaceae: Laeliinae): the reproductive biology of E. avicula

Crane flies and microlepidoptera have been recorded as pollinators in unrelated orchid groups, but these insects have never been recorded in Epidendroideae, the most species‐rich orchid subfamily, which includes one of the most diverse genera among Orchidaceae, Epidendrum. Based on data on phenology, floral morpho‐anatomy, pollinators, pollination mechanisms and breeding system, the reproductive biology of E. avicula was studied in south‐eastern Brazil. Epidendrum avicula possess osmophores that produce a citric fragrance at night. The flowers attract Tipulidae flies and several families of microlepidoptera that drink the nectar produced in a tube formed by the adnation of the labellum and column. As is common in Epidendrum, after removing the pollinarium, both crane flies and micro‐moths get trapped by the proboscis, which frightens the insects and inhibits any possible intent to immediately visit another flower. The behavior of the pollinators on flowers, plus the retention of the anther cap by the pollinarium, results in a reduction in the occurrence of geitonogamy. Because E. avicula is self‐incompatible, the consequence of pollinator behavior and the floral mechanisms tend to reduce the pollen loss. As far as we know, this is the first study to report the reproductive biology of a species of Epidendroideae pollinated by crane flies and microlepidoptera. Based on more recent concepts of plant–pollinator interactions, although E. avicula is pollinated by several species belonging to two distinct orders, suggesting an unspecialized pollination system is involved, nectar‐seeking microlepidoptera and Tipulidae flies can be recognized as a single functional group.     

Convergence beyond flower morphology? Reproductive biology of hummingbird‐pollinated plants in the Brazilian Cerrado

Convergent reproductive traits in non‐related plants may be the result of similar environmental conditions and/or specialised interactions with pollinators. Here, we documented the pollination and reproductive biology of Bionia coriacea (Fabaceae), Esterhazya splendida (Orobanchaceae) and Ananas ananassoides (Bromeliaceae) as case studies in the context of hummingbird pollination in Cerrado, the Neotropical savanna of Central South America. We combined our results with a survey of hummingbird pollination studies in the region to investigate the recently suggested association of hummingbird pollination and self‐compatibility. Plant species studied here differed in their specialisation for ornithophily, from more generalist A. ananassoides to somewhat specialist B. coriacea and E. splendida. This continuum of specialisation in floral traits also translated into floral visitor composition. Amazilia fimbriata was the most frequent pollinator for all species, and the differences in floral display and nectar energy availability among plant species affect hummingbirds' behaviour. Most of the hummingbird‐pollinated Cerrado plants (60.0%, n = 20), including those studied here, were self‐incompatible, in contrast to other biomes in the Neotropics. Association to more generalist, often territorial, hummingbirds, and resulting reduced pollen flow in open savanna areas may explain predominance of self‐incompatibility. But it is possible that mating system is more associated with the predominance of woody hummingbird plants in the Cerrado plant assemblage than to the pollination system itself.     

Does intraspecific behavioural variation of pollinator species influence pollination? A quantitative study with hummingbirds and a Neotropical shrub

• Floral visitors differ in their efficacy as pollinators, and the impact of different pollinator species on pollen flow and plant reproduction has been frequently evaluated. In contrast, the impact of intraspecific behavioural changes on their efficacy as pollinators has seldom been quantified.
• We studied a self‐incompatible shrub Palicourea rigida (Rubiaceae) and its hummingbird pollinators, which adjust their behaviour according to floral resource availability. Fluorescence microscopy was used to access pollen tube growth and incompatibility reaction in pistils after a single visit of territorial or intruder hummingbirds in two populations. To characterise the plant populations and possible differences in resource availability between areas we used a three‐term quadrat variance method to detect clusters of floral resources.
• Within‐species variation in foraging behaviour, but not species identity, affected pollinator efficacy. Effectively, hummingbirds intruding into territories deposited more compatible pollen grains on P. rigida stigmas than territory holders in both study areas. Additionally, territory holders deposited more incompatible than compatible pollen grains.
• Our results imply that intraspecific foraging behaviour variation has consequences for pollination success. Quantifying such variation and addressing the implications of intraspecific variability contribute to a better understanding of the dynamics and consequences of plant–pollinator interactions.

     

Florally rich habitats reduce insect pollination and the reproductive success of isolated plants

Landscape heterogeneity in floral communities has the potential to modify pollinator behavior. Pollinator foraging varies with the diversity, abundance, and spatial configuration of floral resources. However, the implications of this variation for pollen transfer and ultimately the reproductive success of insect pollinated plants remains unclear, especially for species which are rare or isolated in the landscape. We used a landscape‐scale experiment, coupled with microsatellite genotyping, to explore how the floral richness of habitats affected pollinator behavior and pollination effectiveness. Small arrays of the partially self‐compatible plant Californian poppy (Eschscholzia californica) were introduced across a landscape gradient to simulate rare, spatially isolated populations. The effects on pollinator activity, outcrossing, and plant reproduction were measured. In florally rich habitats, we found reduced pollen movement between plants, leading to fewer long‐distance pollination events, lower plant outcrossing, and a higher incidence of pollen limitation. This pattern indicates a potential reduction in per capita pollinator visitation, as suggested by the lower activity densities and richness of pollinators observed within florally rich habitats. In addition, seed production reduced by a factor of 1.8 in plants within florally rich habitats and progeny germination reduced by a factor of 1.2. We show this to be a consequence of self‐fertilization within the partially self‐compatible plant, E. californica. These findings indicate that locally rare plants are at a competitive disadvantage within florally rich habitats because neighboring plant species disrupt conspecific mating by co‐opting pollinators. Ultimately, this Allee effect may play an important role in determining the long‐term persistence of rarer plants in the landscape, both in terms of seed production and viability. Community context therefore requires consideration when designing and implementing conservation management for plants which are comparatively rare in the landscape.     

Pollination of Campomanesia phaea (Myrtaceae) by night‐active bees: a new nocturnal pollination system mediated by floral scent

• Bees are the most important diurnal pollinators of angiosperms. In several groups of bees a nocturnal/crepuscular habit developed, yet little is known about their role in pollination and whether some plants are adapted specifically to these bees. We used a multidisciplinary approach to investigate the reproductive biology and to understand the role of nocturnal/crepuscular bees in pollination of Campomanesia phaea (Myrtaceae), popularly named cambuci.
• We studied the floral biology and breeding system of C. phaea. We collected the floral visitors and tested the pollinators' effectiveness. We also determined the floral scents released at night and during daytime, and studied behavioural responses of crepuscular/nocturnal bees towards these scents.
• The flowers of cambuci were self‐incompatible and had pollen as the only resource for flower visitors. Anthesis lasted around 14 h, beginning at 04:30 h at night. The flowers released 14 volatile compounds, mainly aliphatic and aromatic compounds. We collected 52 species of floral visitors, mainly bees. Nocturnal and crepuscular bees (four species) were among the most frequent species and the only effective pollinators. In field bioassays performed at night, nocturnal/crepuscular bees were attracted by a synthetic scent blend consisting of the six most abundant compounds.
• This study describes the first scent‐mediated pollination system between a plant and its nocturnal bee pollinators. Further, C. phaea has several floral traits that do not allow classification into other nocturnal pollination syndromes (e.g. pollinator attraction already before sunrise, with pollen as the only reward), instead it is a plant specifically adapted to nocturnal bees.

     

Self‐compatibility and autonomous selfing of plants in meadow communities

• One of the most fundamental, although controversial, questions related to the evolution of plant mating systems is the distribution of outcrossing rates. Self‐compatibility, and especially autonomous self‐pollination, can become particularly beneficial in anthropogenically degraded habitats with impoverished pollinator assemblages and increased pollen limitation.
• In a hand‐pollination experiment with 46 meadow plants from the ?elezné hory Mts., Czech Republic, we evaluated the species' ability to adopt different mating systems. For a subset of the species, we also tested seed germination for inbreeding depression. Subsequently, we analysed relationships between the species' mating systems and 12 floral and life‐history traits.
• We found a relatively discrete distribution of the studied species into four groups. Fully and partially self‐incompatible species formed the largest group, followed by self‐compatible non‐selfers and mixed mating species. The germination experiment showed an absence of inbreeding depression in 19 out of 22 examined species. Nectar sugar per flower, nectar sugar per shoot and dichogamy were significant associated with the mating system.
• Spontaneous selfing ability and self‐incompatibility in species of the meadow communities had a discrete distribution, conforming to the general distribution of mating and breeding systems in angiosperms. The low frequency of spontaneous selfers and the lack of inbreeding depression at germination suggest the existence of a selection against selfing at the later ontogenetic stages. Some floral traits, such as the level of dichogamy and amount of nectar reward, may strongly impact the balance between selfing and outcrossing rates in the self‐compatible species and thus shape the evolution of mating systems.

     

Reproductive success in fragmented habitats: do compatibility systems and pollination specialization matter?

Abstract. This paper explores whether plant breeding system and pollination specialization influence the reproductive response of plants to habitat fragmentation. It is meaningful for conservation to predict a plant species’ extinction risk. We found 25 studies in the literature assessing the effects of habitat fragmentation on either pollination or reproductive success of 46 plant species to answer the following questions: 1. Are pollination and reproductive success of self‐incompatible species more likely to decline with habitat fragmentation than the pollination and reproductive success of self‐compatible species? Although most of the species showed statistically significant negative effects, the pollination and reproduction of self‐incompatible species were as likely to decline with fragmentation as those of self‐compatible species. 2. Are pollination and reproductive success of specialist plants more affected than the pollination and reproduction of generalist plants? Comparisons of fragmentation‐related changes in pollination and reproductive success between specialists and generalists do not support the hypothesis that specialization in pollination increases the risk of plant extinction. 3. Can self‐incompatible species offset their expected higher vulnerability to fragmentation by being, on average, more pollination generalist than self‐compatible species? In a larger data set on 260 species, we did not find significant differences in either the mean number or frequency distribution of numbers of flower‐visiting species or orders between self‐compatible and self‐incompatible species. Our review suggests that no generalizations can be made on susceptibility to fragmentation based on compatibility system and pollination specialization.     

Phenotypic selection on flowering phenology and pollination efficiency traits between Primula populations with different pollinator assemblages

Floral traits have largely been attributed to phenotypic selection in plant–pollinator interactions. However, the strength of this link has rarely been ascertained with real pollinators. We conducted pollinator observations and estimated selection through female fitness on flowering phenology and floral traits between two Primula secundiflora populations. We quantified pollinator‐mediated selection by subtracting estimates of selection gradients of plants receiving supplemental hand pollination from those of plants receiving open pollination. There was net directional selection for an earlier flowering start date at populations where the dominant pollinators were syrphid flies, and flowering phenology was also subjected to stabilized quadratic selection. However, a later flowering start date was significantly selected at populations where the dominant pollinators were legitimate (normal pollination through the corolla tube entrance) and illegitimate bumblebees (abnormal pollination through nectar robbing hole which located at the corolla tube), and flowering phenology was subjected to disruptive quadratic selection. Wider corolla tube entrance diameter was selected at both populations. Furthermore, the strength of net directional selection on flowering start date and corolla tube entrance diameter was stronger at the population where the dominant pollinators were syrphid flies. Pollinator‐mediated selection explained most of the between‐population variations in the net directional selection on flowering phenology and corolla tube entrance diameter. Our results suggested the important influence of pollinator‐mediated selection on floral evolution. Variations in pollinator assemblages not only resulted in variation in the direction of selection but also the strength of selection on floral traits.     

Phenotypic selection on floral traits in the arctic plant Parrya nudicaulis (Brassicaceae)

The evolution of floral traits is often attributed to pollinator‐mediated selection; however, the importance of pollinators as selective agents in arctic environments is poorly resolved. In arctic and subarctic regions that are thought to be pollen limited, selection is expected to either favor floral traits that increase pollinator attraction or promote reproductive assurance through selfing. We quantified phenotypic selection on floral traits in two arctic and two subarctic populations of the self‐compatible, but largely pollinator‐dependent, Parrya nudicaulis. Additionally, we measured selection in plants in both open pollination and pollen augmentation treatments to estimate selection imposed by pollinators in one population. Seed production was found to be limited by pollen availability and strong directional selection on flower number was observed. We did not detect consistently greater magnitudes of selection on floral traits in the arctic relative to the subarctic populations. Directional selection for more pigmented flowers in one arctic population was observed, however. In some populations, selection on flower color was found to interact with other traits. We did not detect consistently stronger selection gradients across all traits for plants exposed to pollinator selection relative to those in the pollen augmentation treatment; however, directional selection tended to be higher for some floral traits in open‐pollinated plants.     

Floral integration,phenotypic covariance structure and pollinator variation in bumblebee‐pollinated Helleborus foetidus

By analysing patterns of phenotypic integration and multivariate covariance structure of five metric floral traits in nine Iberian populations of bumblebee‐pollinated Helleborus foetidus (Ranunculaceae), this paper attempts to test the general hypothesis that pollinators enhance floral integration and selectively modify phenotypic correlations between functionally linked floral traits. The five floral traits examined exhibited significant phenotypic integration at all populations, and both the magnitude and the pattern of integration differed widely among populations. Variation in extent and pattern of integration was neither distance‐dependent nor significantly related to between‐population variation in taxonomical composition and morphological diversity of the pollinator assemblage. Patterns of floral integration were closer to expectations derived from consideration of developmental affinities between floral whorls than to expectations based on a pollinator‐mediated adaptive hypothesis. Taken together, results of this study suggest that between‐population differences in magnitude and pattern of floral integration in H. foetidus are probably best explained as a consequence of random genetic sampling in the characteristically small and ephemeral populations of this species, rather than reflecting the selective action of current pollinators.     

Reproductive biology of two Himalayan alpine gingers (Roscoea spp., Zingiberaceae) in China: pollination syndrome and compensatory floral mechanisms

According to the concept of pollination syndromes, floral traits reflect specialisation to a particular pollinator or set of pollinators. However, the reproductive biology of endemic, and often specialised, plants may require increased attention as climate change accelerates worldwide. Species of Roscoea endemic to the Himalayan region have striking orchid-like flowers with long corolla tubes, suggesting pollination by long-tongued insects. Until now, the reproductive biology of species of Roscoea has been poorly documented. We investigated the floral biology, breeding system and pollination ecology of R. cautleoides and R. humeana, from Hengduan Mountains, a global biodiversity hotspot in southwest China. We also tested whether floral longevity increases pollination success. Pollination experiments showed that the two species were self-compatible and depended on insects for fruit production. Over several flowering seasons we did not observe any potential pollinators with long tongues that matched the corolla tube visiting flowers in centres of distribution. The principal pollinators observed were pollen-collecting generalist bees, with low visitation frequencies. In general, members of the ginger family are characterised by short-lived (usually 1 day) flowers, but flowers of R. cautleoides and R. humeana last 8 and 6 days, respectively. Removing stigmas decreased fruit set in both study populations. Our results suggest that the original pollinators may have been long-tongued insects that are now absent from the Chinese Himalayas because habitats have responded to climate change. However, long-lived and self-compatible flowers, coupled with the presence of generalist pollinators, are traits that have allowed these gingers to reproduce and continue to persist in the alpine habitats.     

A quantitative review of pollination syndromes: do floral traits predict effective pollinators?

The idea of pollination syndromes has been largely discussed but no formal quantitative evaluation has yet been conducted across angiosperms. We present the first systematic review of pollination syndromes that quantitatively tests whether the most effective pollinators for a species can be inferred from suites of floral traits for 417 plant species. Our results support the syndrome concept, indicating that convergent floral evolution is driven by adaptation to the most effective pollinator group. The predictability of pollination syndromes is greater in pollinator‐dependent species and in plants from tropical regions. Many plant species also have secondary pollinators that generally correspond to the ancestral pollinators documented in evolutionary studies. We discuss the utility and limitations of pollination syndromes and the role of secondary pollinators to understand floral ecology and evolution.     

Self‐ and intra‐morph incompatibility and selection analysis of an inconspicuous distylous herb growing on the Tibetan plateau (Primula tibetica)

There is discussion over whether pollen limitation exerts selection on floral traits to increase floral display or selects for traits that promote autonomous self‐fertilization. Some studies have indicated that pollen limitation does not mediate selection on traits associated with either pollinator attraction or self‐fertilization. Primula tibetica is an inconspicuous cross‐fertilized plant that may suffer from pollen limitation. We conducted a selection analysis on P. tibetica to investigate whether pollen limitation results in selection for an increased floral display in case the evolution of autonomous self‐fertilization has been difficult for this plant. The self‐ and intra‐morph incompatibility features, the capacity for autonomous self‐fertilization, and the magnitude of pollen limitation were examined through hand‐pollination experiments. In 2016, we applied selection analysis on the flowering time, corolla width, stalk height, flower tube length, and flower number in P. tibetica by tagging 76 open‐pollinated plants and 37 hand‐pollinated plants in the field. Our results demonstrated that P. tibetica was strictly self‐ and intra‐morph incompatible. Moreover, the study population underwent severe pollen limitation during the 2016 flowering season. The selection gradients were found to be significantly positive for flowering time, flower number, and corolla width, and marginally significant for the stalk height. Pollinator‐mediated selection was found to be significant on the flower number and corolla width, and marginally significant on stalk height. Our results indicate that the increased floral display may be a vital strategy for small distylous species that have faced difficulty in evolving autonomous self‐fertilization.     

Comparative reproductive biology and pollinator specificity among sympatric Gomesa (Orchidaceae: Oncidiinae)

• The incredible pollination mechanisms displayed by orchid flowers has inspired biologists over the centuries. Based on the intriguing flower structures, the relationship among orchid species and their pollinators has been frequently regarded as very specialised.
• Given that visits on flowers pollinated by oil‐collecting bees are regularly rare, and in Oncidiinae the flowers frequently attractexclusively species that act as effective pollinators, the comparative reproductive biology and pollinator specificity of two sympatric Gomesa (G. varicosa and G. montana; Oncidiinae) were analysedbased on records of floral morphology, production of floral rewards, pollinators and pollination mechanisms. Furthermore, experimental pollinations were carried out in order to examine the breeding systems.
• The results have show that in the studied population, both Gomesa are visited by several bee species, but these orchids present a specific pollination system.Pollinaria are deposited on the head of Centridini (G. varicosa and G. montana) and Epicharitini (G. varicosa) bees when landed on the central callus of the labellumto collect lipoidal substances produced by glandular elaiophores on lateral lobes of the labellum. Both species are dependent on a biotic pollen vector to set fruits. Gomesamontana is completely self‐incompatible, while G. varicosa is partially self‐compatible.
• Our results indicate that although the occurrence of self‐sterile species seems to be common in Oncidiinae, in partially self‐incompatible species, as is the case of G. varicosa, self‐compatibility has been considered as an important factor favouring reproductive assurance in populations with low visitation frequencies, despite occurrence of inbreeding depression.

     

Floral display and habitat fragmentation: Effects on the reproductive success of the threatened mass‐flowering Conospermum undulatum (Proteaceae)

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