Macroevolution of floral scent chemistry across radiations of male euglossine bee-pollinated plantsMacroevolución de olores florales a través de radiaciones de plantas polinizadas por abejas euglosinas machosMacroevolução dos voláteis florais em radiações de plantas polinizadas por machos de abelhas Euglossini.

Floral volatiles play key roles as signaling agents that mediate interactions between plants and animals. Despite their importance, few studies have investigated broad patterns of volatile variation across groups of plants that share pollinators, particularly in a phylogenetic context. The "perfume flowers," Neotropical plant species exhibiting exclusive pollination by male euglossine bees in search of chemical rewards, present an intriguing system to investigate these patterns due to the unique function of their chemical phenotypes as both signaling agents and rewards. We leverage recently developed phylogenies and knowledge of biosynthesis, along with decades of chemical ecology research, to characterize axes of variation in the chemistry of perfume flowers, as well as understand their evolution at finer taxonomic scales. We detect pervasive chemical convergence, with many species across families exhibiting similar volatile phenotypes. Scent profiles of most species are dominated by compounds of either the phenylpropanoid or terpenoid biosynthesis pathways, while terpenoid compounds drive more subtle axes of variation. We find recapitulation of these patterns within two independent radiations of perfume flower orchids, in which we further detect evidence for the rapid evolution of divergent floral chemistries, consistent with the putative importance of scent in the process of adaptation and speciation.

The contribution of the BIOTA/FAPESP Program to the knowledge on pollination and plant reproduction / Contribuição do Programa BIOTA/FAPESP para o conhecimento sobre polinização e reprodução em plantas

Abstract Interactions between plant and pollinators are associated with the origin and maintenance of species diversity, as well as ecosystem functioning. The potential of pollination as an ecosystem service is evidenced by its association with food production. Understanding pollination at the landscape scale is essential for characterizing the pollination service for several crops that depend on pollinators for fruit and seed set that make up the human diet. Our aim was to carry out a literature review of studies and projects funded by BIOTA/FAPESP to illustrate the main research approaches developed in the field of Pollination Biology, especially related to plant-pollinator interactions. Plant-pollinator interactions in the Atlantic forest were leveraged as a result of this long-term research program, during which several papers were published in international journals. Pollination by bees (melittophily) was the most representative pollination system studied. In addition to melittophily, other interactions were studied such as pollination by hawkmoths (sphingophily), by hummingbirds (ornithophily) and by bats (chiropterophily). The specific mutualistic relationships between fig trees and fig wasps were also subject of studies within the Program. At the beginning of the BIOTA/FAPESP Program, there were many gaps in basic information about pollination and breeding systems of Brazilian native plant species. Thus, the Program was fundamental to fuel research on the natural history of plants and pollinators from the Atlantic forest. Overall, the Program funded studies that investigated themes such as functional pollination ecology, pollinator effectiveness, plant population genetics, structure and dynamics of plant-pollinator interaction networks, as well as geographic distribution and macroevolution of pollination systems, as well as genetic and molecular studies of native plant populations focusing on pollen flow and genetic structure of populations. Additionally, studies on pollination in the context of landscape ecology had the aim of assessing the effects of forest fragmentation on the functioning of plant populations and their interactions with pollinators and the relationships between landscape structure and ecological processes, biodiversity, and ecosystem service. Therefore, the Program had a prominent role in producing basic data with great implications for understanding the ecology and promoting the conservation of plant-pollinator interactions.

Resumo A interação planta-polinizador está associada à origem e manutenção da diversidade de espécies de plantas e ao funcionamento dos ecossistemas. O potencial da polinização como serviço ecossistêmico é destacado quando associado à produção de alimentos. Compreender esta interação na escala da paisagem é essencial para caracterizar o serviço de polinização para muitos cultivos que dependem dos polinizadores para a formação de frutos e sementes que integram a dieta humana. O objetivo deste trabalho foi realizar uma revisão bibliográfica de estudos e projetos financiados pelo BIOTA/FAPESP para ilustrar as principais abordagens de pesquisa desenvolvidas no campo da Biologia da Polinização, especialmente relacionadas à interação planta-polinizador. As interações planta-polinizador na Mata Atlântica foram alavancadas como resultado desse programa de pesquisa de longo prazo, durante o qual vários artigos foram publicados em revistas internacionais. A polinização por abelhas (melitofilia) foi o sistema de polinização mais representativo estudado. Além da melitofilia, outras interações foram estudadas, como a polinização por mariposas (esfingofilia), por beija-flores (ornitofilia) e por morcegos (quiropterofilia). As relações mutualísticas específicas entre figueiras e vespas do figo também foram objeto de estudos no âmbito do Programa. No início do Programa BIOTA/FAPESP, havia muitas lacunas sobre informações básicas sobre polinização e sistemas de reprodução de espécies vegetais nativas brasileiras. Assim, o Programa foi fundamental para desenvolver pesquisas sobre a história natural de plantas e polinizadores da Mata Atlântica. No geral, o Programa financiou estudos que investigaram temas como ecologia funcional da polinização, eficácia de polinizadores, genética de populações de plantas, estrutura e dinâmica de redes de interação planta-polinizador, bem como distribuição geográfica e macroevolução dos sistemas de polinização, além de estudos genéticos e moleculares de populações de plantas nativas com foco no fluxo de pólen. Adicionalmente, estudos sobre polinização no contexto da ecologia da paisagem tiveram como objetivo avaliar os efeitos da fragmentação florestal no funcionamento das populações de plantas e suas interações com os polinizadores e as relações entre a estrutura da paisagem e os processos ecológicos, biodiversidade e serviços ecossistêmicos. Portanto, o Programa teve um papel de destaque na produção de dados básicos com grandes implicações para o entendimento da ecologia e promoção da conservação das interações planta-polinizador.

Reproductive development and genetic structure of the mycoheterotrophic orchid Pogoniopsis schenckii Cogn.

BACKGROUND: Pogoniopsis schenckii Cogn. is a mycoheterotrophic orchid that can be used as a model to understand the influence of mycoheterotrophy at different stages of the reproductive cycle. We aimed to verify the presence of endophytic and epiphytic fungi at each stage of the reproductive process and investigated how the breeding system may relate to genetic structure and diversity of populations. In this study we performed anatomical and ultrastructural analyses of the reproductive organs, field tests to confirm the breeding system, and molecular analysis to assess genetic diversity and structure of populations. RESULTS: During the development of the pollen grain, embryo sac and embryogenesis, no fungal infestation was observed. The presence of endophytic fungal hyphae was observed just within floral stems and indehiscent fruit. Beyond assuring the presence of fungus that promote seed germination, specific fungi hyphae in the fruit may affect other process, such as fruit ripening. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. CONCLUSIONS: We discuss an interesting interaction: fungal hyphae in the indehiscent fruit. These fungal hyphae seem to play different roles inside fruit tissues, such as acting in the fruit maturation process and increasing the proximity between fungi and plant seeds even before dispersion occurs. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. Altogether, our findings provide important novel information about the mechanisms shaping ecology and evolution of fragmented populations of mycoheterotrophic plant.

Biomechanical properties of a buzz-pollinated flower.

Approximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterized the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum, and measure vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300 Hz) as they are transmitted throughout the flower. We also found that vibration amplitude at anthers and petals can be up to greater than 400% higher than input amplitude applied at the receptacle at the base of the flower, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

Deep in the Jelly: Histochemical and Functional Aspects of Mucilage-Secreting Floral Colleters in the Orchids Elleanthus brasiliensis and E. crinipes.

Colleters are trichomes or emergencies that produce a sticky exudate consisting of a mixture of mucilage, lipids, terpenes, and phenolic compounds. Colleters occur in at least 60 families of angiosperms; however, reports of them are scarce for the Orchidaceae. Elleanthus brasiliensis is distinguished by the presence of an abundant gelatinous secretion that covers almost all of its inflorescences. We aimed to describe the histology of colleters in inflorescences of E. brasiliensis and Elleanthus crinipes, and to analyze the chemical composition of their secretion to better understand the functions of these secretory structures. Due to the low frequency of colleters and lack of visible secretion in E. crinipes, histochemical tests and chemical analyses were not performed for this species. Colleters are of a brush type and their secretion has, at the same time, hydrophilic and lipophilic components. Histochemical tests further revealed the presence of pectin, mucilage, lipids, terpenes, phenolic compounds, and proteins. The GC-MS analysis confirmed the presence of γ-sitosterol and palmitic, linoleic, and stearic acids in the secretion of E. brasiliensis. Infrared analysis indicated the possible presence of polysaccharides in the secretion. The occurrence of colleters in both species studied and in other orchids described in the literature suggests that these structures are common in the inflorescences of tropical orchids. In these environments, the hydrated polysaccharides in the secretion form a dense matrix that can act as a physical barrier, and terpenes may help to protect against herbivores and pathogenic microorganisms. This information broadens our knowledge of the morphological and chemical diversity of the secretions produced by orchid colleters.

Neuropharmacological effects of essential oil from the leaves of Croton conduplicatus Kunth and possible mechanisms of action involved.

ETHNOPHARMACOLOGICAL RELEVANCE: Croton conduplicatus Kunth (Euphorbiaceae) is a Brazilian aromatic medicinal plant, widely known as "quebra-faca". In folk medicine, its leaves and stem-barks are used as a natural analgesic for the treatment of headaches. AIM OF THE STUDY: In this study, we describe for the first time the neuropharmacological potential of the essential oil obtained from the leaves of Croton conduplicatus (EO) in experimental models of pain, anxiety and insomnia. The mechanisms of action involved in these activities were also investigated. MATERIAL AND METHODS: Different experimental models were used to evaluate the antinociceptive (acetic acid, formalin-induced nociception and hot plate tests), anxiolytic (elevated plus maze and hole board tests) and sedative (thiopental-induced sleeping time) effects of EO in mice. EO was evaluated in three different doses (25, 50 and 100 mg/kg, i.p.) and compared with positive and negative controls in all experimental protocols. When appropriate, animals were pretreated with pharmacological antagonists (naloxone, atropine and flumazenil) in order to evaluate the mechanisms of action involved. A docking study also was performed to identify possible targets involved. RESULTS: EO (25, 50 and 100 mg/kg, i.p.) demonstrated a significant antinociceptive activity in all experimental models. Pretreatment with naloxone or atropine reversed the antinociceptive response (p < 0.05), suggesting the involvement of opioid and muscarinic receptors, respectively. A docking study was performed with the major components identified in EO (1,8 cineole - 21.42%, spathulenol - 15.47%, p-cymene - 12.41% and caryophyllene oxide - 12.15%), demonstrating favorable interaction profile with different subtypes of muscarinic (M2, M3 and M4) and opioids (delta and mu) receptors. EO also showed anxiolytic (mainly at doses of 25 and 50 mg/kg, i.p.) and sedative (only at the dose of 100 mg/kg, i.p.) effects in mice. These pharmacological responses were reversed by flumazenil (p < 0.05), indicating possible involvement of GABAA receptors. CONCLUSION: Our findings support the traditional use of this plant as a natural analgesic and suggest that EO is a multi-target natural product, presenting not only antinociceptive effect but also anxiolytic and sedative activities depending on the dose used.

Parasitoids Turn Herbivores into Mutualists in a Nursery System Involving Active Pollination.

Nursery pollination involves pollinators that lay eggs on the flowers they pollinate and have their brood fed on flower parts or developing ovules [1-4]. Active pollination, a ritualistic behavioral sequence shown by nursery pollinators when transferring pollen from anthers to stigmas, is known in only four plant lineages [5-8], including the classical examples of fig trees-fig wasps and yuccas-yucca moths [5, 6]. We report in detail a system in which weevils actively pollinate orchids prior to having their larvae fed on the developing fruits. Sampling over five years revealed that although weevils trigger fruit set, this interaction is negative for the plant as weevil larvae often consume all contents of infested fruits. However, part of weevil-infested fruits is often "rescued" by parasitoid wasps, which kill the weevil larvae before all fruit content is consumed (Figure 1). "Rescued" fruits present high seed viability and biomass similar to that of non-infested fruits, much higher than that of fruits with weevils only. Hence, parasitoids mediate the fitness consequences of the interaction between the plant and its parasitic pollinator. Weevils constitute a megadiverse group of herbivores commonly reported as florivores [9] but are also appreciated as flower-ovipositing pollinators of cycads and palms [4, 10-13] and were previously recorded carrying orchid pollinaria [14-16]. The orchid-weevil system presented here shows that plant-floral visitor interaction outcome can be mediated by a third party (parasitoids) and illustrates a way by which the biological context may allow the emergence and persistence of active nursery pollination behavior in nature.