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Background: Synchronopatric plant species, coexisting and flowering simultaneously, often engage in intense competition for pollen deposition on shared pollinators. This study focuses on the intricate dynamics of chiropterophilous flowers within the neotropical bat-pollination plant guild, specifically investigating the mechanical fit of reproductive structures to pollinating bats at the community level. Methods: Utilizing a diverse guild of bat-pollinated plant species from the Caatinga, the largest dry forest in the Neotropics, our research integrates various key components. Initially, we identified specific contact sites for floral reproductive structures on the bat's body, exploring diverse pollen placement strategies. Subsequent efforts involved characterizing floral traits within the guild and examining their associations with different pollen placement strategies. Precision in the contact of floral reproductive structures was estimated, and findings were integrated by associating pollen placement strategies and precision with the investment in pollen production. Results: We found that certain bat body parts, particularly the face and neck, were more frequently contacted by reproductive structures. The three identified categories of pollen placement strategies were evenly distributed among plant species, each linked to specific floral traits. Notably, the absence of oriented herkogamy prevailed in 70% of the species. Morphometric analyses unveiled significant variations in operative distances among species, emphasizing exceptional variability in certain outliers. While precision in pollen transfer was influenced by key factors, surprisingly, investment in pollen production did not differ among plants with distinct pollen placement strategies. Furthermore, it showed no correlation with fundamental accuracy. Conclusions: The subsequent exploration delves into the intricate associations between distinct floral characteristics and various pollen placement strategies, shaping the complex pollen landscape on bat bodies. This research provides valuable insights into the community-level dynamics of chiropterophilous flowers in the Caatinga Dry Forest, emphasizing the role of different pollen deposition strategies in facilitating the coexistence of multiple plant species within the chiropterophilous guild. [ABSTRACT FROM AUTHOR]

Context: Resupination is the movement of developing buds that leads to a vertical inversion of the flowers at an angle of 180°. Chamaecrista nictitans exhibits two anther sizes, and nonresupinate and resupinate flowers in the same individual, which is known as monomorphic resupinate dimorphy. Aims: We aimed to investigate the influence of monomorphic resupinate dimorphy upon pollen deposition on pollinators, capture by the stigma and on plant reproduction, using three populations of C. nictitans from NE Brazil as a model. Methods: We assessed the floral biology, the proportion of nonresupinate and resupinate flowers in the populations, dynamics of pollen transfer between floral morphs, and the plant's reproductive system. Key results: All flowers have two anther sizes with similar pollen viability. The proportion of nonresupinate:resupinate flowers was 3:1 in all populations. The bee Florilegus (Euflorilegus) sp. was the only pollinator observed and had pollen of both flower morphs deposited on the underside part of the thorax and abdomen. The stigma of nonresupinate flowers received pollen from the pollinators' underside of the abdomen, whereas the stigma of resupinate flowers received pollen from the pollinators' underside of the thorax. The species is self-compatible but does not set fruits by spontaneous self-pollination. Therefore, natural fruit set had resulted from both intramorph- and intermorph-pollination in the same or in different individuals. Conclusions: Both flower types have a similar pattern of pollen deposition on the pollinator's body (underside of the abdomen and thorax) and only differ in relation to areas of pollen capture by the stigma (underside of the abdomen or underside of thorax). Implications: The monomorphic resupinate dimorphy observed here improves the area of pollen deposition by the anthers on pollinator's body and makes the capture of pollen by stigma sectored in the different floral types, similar to what is observed in other species presenting floral polymorphisms. Resupination is the movement of floral buds that leads to flowers turning upside down. We tested the reproductive functioning of this characteristic in the native legume Chamaecrista nictitans and found that it causes pollen to be deposited in particular portions of pollinators' bodies, improving pollination. Image by Natan Messias Almeida and Paulo Estêvão Araújo Vilaça Júnior. [ABSTRACT FROM AUTHOR]

Studies about reproductive aspects of angiosperms rarely refer to herbaceous and anemophilous groups. Cyperaceae are cosmopolitan and diverse in terms of sexuality, inflorescence architecture, and pollination modes, such as anemophily, entomophily, and ambophily. Therefore, the evolution of reproductive traits can clarify some questions about the reproductive biology of angiosperms, especially regarding the transitions between biotic and abiotic pollination. This study was designed to investigate the evolution of reproductive traits in Cyperaceae through comparative phylogenetic methods, such as reconstruction of ancestral states and evolutionary correlation. If spicoids in Mapanioideae are indeed inflorescences, the bisexual flower in Cyperaceae would be derived, a rare case in angiosperms. In Cyperoideae, a decrease in the number of flowers and an increase in stamen loss events were observed. This result contradicts the hypothesized increase in reproductive structures in anemophilous species, in which a greater amount of pollen is produced to compensate for the waste generated by wind. Only one correlation was found: between the number of inflorescence branches and the number of reproductive units per inflorescence. Finally, the analyses showed the great diversity of reproductive biology in Cyperaceae and made evident the need to expand the theoretical studies to refine the discovery of correlated traits. [ABSTRACT FROM AUTHOR]

Plant phenology reflects the reproductive responses of plants to seasonal cycles and climate change. Herbarium collections can be valuable tools for filling in gaps in phenological studies. We investigated the seasonality of the reproductive phenology of Xiquexique species using circular statistics, estimated their flowering and fruiting periods by interpolation via inverse distance weighting based on herbarium specimens (n = 290), and analyzed the relationships among phenophases, temperature, and precipitation using generalized linear models. Xiquexique species flowered and fruited throughout the year, with X. gounellei exhibiting peak flowering in February and peak fruiting in March, while X. tuberculatus exhibited those peaks in August–October and August, respectively, with decreased intensity during the austral winter. The maps produced through interpolation showed higher probabilities of flowering and fruiting between February and August at sites with mean annual rainfall rates between 500 and 800 mm. Temperature and precipitation were positively correlated with flowering. Xiquexique tuberculatus is important for providing continuous resources to pollinators and seed dispersers in the Caatinga. Herbarium collections and interpolation methods for filling in gaps concerning the reproductive ecology of Cactaceae can aid in better understanding altered phenological patterns resulting from environmental changes. [ABSTRACT FROM AUTHOR]

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Spathiphyllum is a Neotropical aroid genus whose inflorescences are composed of protogynous bisexual flowers that emit strong perfumes. These scents serve as both attractants and rewards for male euglossine pollinators. We investigated the inflorescence scent of S. cannifolium, asking whether inflorescence at female and male phases differ in scent traits. For this, we collected scent samples from inflorescence at the two phases using dynamic headspace methods and analyzed them by a gas chromatograph coupled to a mass spectrometer (GC‐MS). The inflorescence scent of S. cannifolium consisted of 26 compounds, with benzyl acetate as major component (ca. 80% of the scent bouquet). We found no quantitative or qualitative differences between scents of inflorescences at female and male phases, nor in the emission time. However, when considering the timing of scent emission among individuals, we observed two general plant groups. Some individuals emitted more scent at 06:00, while others emitted more scent at 09:00, independent of the sexual phase. The similarity of floral scents between the sexes might promote floral constancy by male euglossine pollinators and consequently alternate pollinator flow between inflorescences at female and male phases. The occurrence of the two general patterns of scent emission can be interpreted as a way to ensure the pollination service. Since plants emit scents in the morning, even outside the peak emission period, this would enable these plants to attract pollinators that are active at different times than the peak emission of floral scents. This way, it would ensure the flow of pollen, even if it occurs at a low frequency. [ABSTRACT FROM AUTHOR]

Background and Aims: Spatial variation in plant-pollinator interactions is a key driver of floral trait diversification. A so far overlooked qualitative aspect of this variation is the behavioural component on flowers that relates to the pollinator fit. We tested the hypothesis that variation in pollinator behaviour influences the geographical pattern of phenotypic selection across the distribution range of the oil-producing Krameria grandiflora (Krameriaceae). This variation mainly involves the presence or absence of flag petal grasping, which is only performed by representatives of Centris (Centridini, Apidae), an oil-collecting bee group highly associated with Krameriaceae pollination., Methods: We quantified variation in floral traits and fitness and estimated pollinator-mediated selection in five populations at a large geographical scale comprising the entire species range. In each population, we sampled individual pollen arrival and germination as a fitness measure, indicating pollination success and pollination performance, which was then relativized and regressed on standardized flower-pollinator fit (flag-stigma distance), advertisement (sepal length) and reward (oil volume) traits. This generated mean-scaled selection gradients used to calculate geographical selection dispersion., Key Results: Unexpectedly, stronger selection was detected on the flower-pollinator fit trait in populations highly associated with the absence of flag petal grasping. Geographical variation in selection was mainly attributed to differential selection on the flag-stigma distance generating a selection mosaic. This may involve influences of a spatial variation in pollinator behaviour as well as composition and morphology., Conclusions: Our results show the adaptive significance of the specialized flag petals of Krameria in the absence of the grasping behaviour and highlight the contribution of geographical variation in pollinator behaviour on flowers in driving selection mosaics, with implications for floral evolution, adaptation to pollinator fit and phenotypic diversity in specialized systems., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)