The eco-evolutionary significance of rainfall constancy for facultative CAM photosynthesis.

A flexible use of the crassulacean acid metabolism (CAM) has been hypothesised to represent an intermediate stage along a C3 to full CAM evolutionary continuum, when relative contributions of C3 vs CAM metabolism are co-determined by evolutionary history and prevailing environmental constraints. However, evidence for such eco-evolutionary interdependencies is lacking. We studied these interdependencies for the leaf-succulent genus Drosanthemum (Aizoaceae, Southern African Succulent Karoo) by testing for relationships between leaf δ13 C diagnostic for CAM dependence (i.e. contribution of C3 and CAM to net carbon gain), and climatic variables related to temperature and precipitation and their temporal variation. We further quantified the effects of shared phylogenetic ancestry on CAM dependence and its relation to climate. CAM dependence is predicted by rainfall and its temporal variation, with high predictive power of rainfall constancy (temporal entropy). The predictive power of rainfall seasonality and temperature-related variables was negligible. Evolutionary history of the tested clades significantly affected the relationship between rainfall constancy and CAM dependence. We argue that higher CAM dependence might provide an adaptive advantage in increasingly unpredictable rainfall environments when the anatomic exaptation (succulence) is already present. These observations might shed light on the evolution of full CAM.

Specialized cockroach pollination in the rare and endangered plant Vincetoxicum hainanense in China.

PREMISE: Species of Apocynaceae are pollinated by a diverse assemblage of animals. Here we report the first record of specialized cockroach pollination in the family, involving an endangered climbing vine species, Vincetoxicum hainanense in China. Experiments were designed to provide direct proof of cockroach pollination and compare the effectiveness of other flower visitors. METHODS: We investigated the reproductive biology, pollination ecology, pollinaria removal, pollinia insertion, and fruit set following single visits by the most common insects. In addition, we reviewed reports of cockroaches as pollinators of other plants and analyzed the known pollination systems in Vincetoxicum in a phylogenetic context. RESULTS: The small, pale green flowers of V. hainanense opened during the night. The flowers were not autogamous, but were self-compatible. Flower visitors included beetles, flies, ants and bush crickets, but the most effective pollinator was the cockroach Blattella bisignata, the only visitor that carried pollen between plants. Less frequent and effective pollinators are ants and Carabidae. Plants in this genus are predominantly pollinated by flies, moths and wasps. CONCLUSIONS: Globally, only 11 plant species are known to be cockroach-pollinated. Because their range of floral features encompass similarities and differences, defining a "cockroach pollination syndrome" is difficult. One commonality is that flowers are often visited by insects other than cockroaches, such as beetles, that vary in their significance as pollinators. Cockroach pollination is undoubtedly more widespread than previously thought and requires further attention.

Diversification in evolutionary arenas-Assessment and synthesis.

Understanding how and why rates of evolutionary diversification vary is a key issue in evolutionary biology, ecology, and biogeography. Evolutionary rates are the net result of interacting processes summarized under concepts such as adaptive radiation and evolutionary stasis. Here, we review the central concepts in the evolutionary diversification literature and synthesize these into a simple, general framework for studying rates of diversification and quantifying their underlying dynamics, which can be applied across clades and regions, and across spatial and temporal scales. Our framework describes the diversification rate (d) as a function of the abiotic environment (a), the biotic environment (b), and clade-specific phenotypes or traits (c); thus, d ~ a,b,c. We refer to the four components (a-d) and their interactions collectively as the "Evolutionary Arena." We outline analytical approaches to this framework and present a case study on conifers, for which we parameterize the general model. We also discuss three conceptual examples: the Lupinus radiation in the Andes in the context of emerging ecological opportunity and fluctuating connectivity due to climatic oscillations; oceanic island radiations in the context of island formation and erosion; and biotically driven radiations of the Mediterranean orchid genus Ophrys. The results of the conifer case study are consistent with the long-standing scenario that low competition and high rates of niche evolution promote diversification. The conceptual examples illustrate how using the synthetic Evolutionary Arena framework helps to identify and structure future directions for research on evolutionary radiations. In this way, the Evolutionary Arena framework promotes a more general understanding of variation in evolutionary rates by making quantitative results comparable between case studies, thereby allowing new syntheses of evolutionary and ecological processes to emerge.

Phylogenetic relationships in the southern African genus Drosanthemum (Ruschioideae, Aizoaceae).

BACKGROUND: Drosanthemum, the only genus of the tribe Drosanthemeae, is widespread over the Greater Cape Floristic Region in southern Africa. With 114 recognized species, Drosanthemum, together with the highly succulent and species-rich tribe Ruschieae, constitute the 'core ruschioids' in Aizoaceae. Within Drosanthemum, nine subgenera have been described based on flower and fruit morphology. Their phylogenetic relationships, however, have not yet been investigated, hampering understanding of monophyletic entities and patterns of geographic distribution. METHODS: Using chloroplast and nuclear DNA sequence data, we performed network- and tree-based phylogenetic analyses of 73 species of Drosanthemum with multiple accessions for widespread species. A well-curated, geo-referenced occurrence dataset comprising the 134 genetically analysed and 863 further accessions was used to describe the distributional ranges of intrageneric lineages and the genus as a whole. RESULTS: Phylogenetic inference supports nine clades within Drosanthemum, seven of which group in two major clades, while the remaining two show ambiguous affinities. The nine clades are generally congruent to previously described subgenera within Drosanthemum, with exceptions such as cryptic species. In-depth analyses of sequence patterns in each gene region were used to reveal phylogenetic affinities inside the retrieved clades in more detail. We observe a complex distribution pattern including widespread, species-rich clades expanding into arid habitats of the interior (subgenera Drosanthemum p.p., Vespertina, Xamera) that are genetically and morphologically diverse. In contrast, less species-rich, genetically less divergent, and morphologically unique lineages are restricted to the central Cape region and more mesic conditions (Decidua, Necopina, Ossicula, Quastea, Quadrata, Speciosa). Our results suggest that the main lineages arose from an initial rapid radiation, with subsequent diversification in some clades.

Quantitative ethnopharmacological documentation and molecular confirmation of medicinal plants used by the Manobo tribe of Agusan del Sur, Philippines.

BACKGROUND: The Philippines is renowned as one of the species-rich countries and culturally megadiverse in ethnicity around the globe. However, ethnopharmacological studies in the Philippines are still limited especially in the most numerous ethnic tribal populations in the southern part of the archipelago. This present study aims to document the traditional practices, medicinal plant use, and knowledge; to determine the relative importance, consensus, and the extent of all medicinal plants used; and to integrate molecular confirmation of uncertain species used by the Agusan Manobo in Mindanao, Philippines. METHODS: Quantitative ethnopharmacological data were obtained using semi-structured interviews, group discussions, field observations, and guided field walks with a total of 335 key informants comprising of tribal chieftains, traditional healers, community elders, and Manobo members of the community with their medicinal plant knowledge. The use-report (UR), use categories (UC), use value (UV), cultural importance value (CIV), and use diversity (UD) were quantified and correlated. Other indices using fidelity level (FL), informant consensus factors (ICF), and Jaccard's similarity index (JI) were also calculated. The key informants' medicinal plant use knowledge and practices were statistically analyzed using descriptive and inferential statistics. RESULTS: This study enumerated the ethnopharmacological use of 122 medicinal plant species, distributed among 108 genera and belonging to 51 families classified in 16 use categories. Integrative molecular approach confirmed 24 species with confusing species identity using multiple universal markers (ITS, matK, psbA-trnH, and trnL-F). There was strong agreement among the key informants regarding ethnopharmacological uses of plants, with ICF values ranging from 0.97 to 0.99, with the highest number of species (88) being used for the treatment of abnormal signs and symptoms (ASS). Seven species were reported with maximum fidelity level (100%) in seven use categories. The correlations of the five variables (UR, UC, UV, CIV, and UD) were significant (rs ≥ 0.69, p < 0.001), some being stronger than others. The degree of similarity of the three studied localities had JI ranged from 0.38 to 0.42, indicating species likeness among the tribal communities. Statistically, the medicinal plant knowledge among respondents was significantly different (p < 0.001) when grouped according to education, gender, social position, occupation, civil status, and age but not (p = 0.379) when grouped according to location. This study recorded the first quantitative ethnopharmacological documentation coupled with molecular confirmation of medicinal plants in Mindanao, Philippines, of which one medicinal plant species has never been studied pharmacologically to date. CONCLUSION: Documenting such traditional knowledge of medicinal plants and practices is highly essential for future management and conservation strategies of these plant genetic resources. This ethnopharmacological study will serve as a future reference not only for more systematic ethnopharmacological documentation but also for further pharmacological studies and drug discovery to improve public healthcare worldwide.

The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study.

Background and Aims: Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods: The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results: Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions: Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades.

Ixora (Rubiaceae) on the Philippines - crossroad or cradle?

BACKGROUND: The Philippine archipelago is globally one of the most important model island systems for studying evolutionary processes. However, most plant species on this archipelago have not yet been studied in sufficient detail. The main aim of this study is to unravel the evolutionary history and biogeographic relationships of the Philippine members of the pantropical genus Ixora. RESULTS: The complex plastid and nuclear divergence patterns in Philippine Ixora, documented using tree and network approaches, reveal a highly dynamic evolution in Ixora, involving several phases of radiation and recolonization. Philippine Ixora comprises at least five lineages, of which one is most closely related to species from Wallacea, and the remaining four to species from Asia. CONCLUSIONS: Our study highlights the importance of Philippine species for understanding phytogeographic patterns in the Indomalayan-Australasian eco-region. The overall genetic differentiation, as well as the incongruence between genealogies based on the biparentally inherited nucleome and the maternally inherited plastome in Ixora, reflect the complex tectonic history of the Philippine archipelago. The Ixora lineage related to Wallacean species supports the delimitation of different ecozones along Huxley's line, because it is absent from Palawan. The remaining four lineages are all allied with Asian taxa, reflecting several waves of colonization. Close relationships between some widespread Philippine species and locally adapted narrow endemics suggest that the widespread, genetically diverse species act as pools for the formation of new species in a process of ongoing speciation. Our results suggest that the species concepts of some of the more widespread taxa need to be revised.

Pro-toxic 1,2-Dehydropyrrolizidine Alkaloid Esters, Including Unprecedented 10-Membered Macrocyclic Diesters, in the Medicinally-used Alafia cf. caudata and Amphineurion marginatum (Apocynaceae: Apocynoideae: Nerieae and Apocyneae).

INTRODUCTION: Within the Apocynoideae (Apocynaceae) pro-toxic dehydropyrrolizidine alkaloids have been reported only in Echiteae. However, attraction of pyrrolizidine alkaloid-pharmacophagous insects suggested their presence in Alafia cf. caudata Stapf (Nerieae: Alafiinae) and Amphineurion marginatum (Roxb.) D.J. Middleton (Apocyneae: Amphineuriinae), both used as medicinal plants. OBJECTIVE: To confirm the presence of dehydropyrrolizidine alkaloids in Alafia cf. caudata and Amphineurion marginatum and identify their structures. METHODS: Methanol extracts of air-dried roots, stems and leaves of non-flowering plants were analysed using HPLC-ESI(+)MS and MS/MS or collision-induced dissociation MS in low and/or high resolution modes. Pyrrolizidine alkaloids were tentatively identified based on the mass spectrometry data. Solid phase extraction combined with semi-preparative HPLC were used to isolate major alkaloids. Structures were elucidated using NMR spectroscopy. RESULTS: Monoesters of retronecine with senecioic, hydroxysenecioic or syringic acids were identified in roots of Alafia cf. caudata. Two unprecedented 10-membered macrocyclic dehydropyrrolizidine alkaloid diesters were isolated from roots of Amphineurion marginatum. Pyrrolizidine alkaloids were detected in root and leaf material of Alafia cf. caudata at 0.34 and 0.01% dry weight (DW), and 0.13, 0.02 and 0.09% DW in root, leaf and stem material of Amphineurion marginatum. CONCLUSIONS: The presence of pro-toxic dehydropyrrolizidine alkaloids suggests that medical preparations of these plants pose potential health risks to consumers. Dehydropyrrolizidine alkaloids are evidently more widespread in Apocynoideae than previously assumed, and it would seem rewarding to study other members of this family for the presence of pyrrolizidines, dehydropyrrolizidines and dihydropyrrolizines. Copyright © 2016 John Wiley & Sons, Ltd.

Going west - A subtropical lineage (Vincetoxicum, Apocynaceae: Asclepiadoideae) expanding into Europe.

Vincetoxicum sensu lato is a tropical lineage comprising two clades that have reached high northern latitudes. Of the temperate clades, one is restricted to the Far East, the other one (Vincetoxicum s. str. Clade) extends into Europe, but their ranges overlap in Central China and Japan. Three species invasive in North America, V. hirundinaria, V. nigrum and V. rossicum, are members of the Vincetoxicum s. str. Clade. We explore the prerequisites for the range expansion in the Vincetoxicum s. str. Clade performing Bayesian and Maximum Likelihood phylogenetic analyses on sequences of the nuclear internal transcribed spacer (ITS) region, the nuclear external transcribed spacer region (ETS), and five plastid markers. The resulting phylogeny is used to conduct biogeographic analysis using BioGeoBEARS to reconstruct ancestral species ranges. Moreover, we map the known occurrences of two rare characters in Asclepiadoideae, the possession of phenanthroindolizidine alkaloids and reported cases of autogamy onto our phylogeny. Finally, we have conducted ecological niche modelling using Maxent on a total of 220 spatially unique occurrences of nine Vincetoxicum s. str. species spanning more than 4,000 km along the east-west gradient to learn about the climatic conditions along the presumed migration route. Our results indicate a north-westward migration in Vincetoxicum s. str. along the Asian mountain chains to Europe. Climatic preferences of the nine species sampled are dissimilar, except for the common exposure to at least one month of subfreezing temperatures, indicating a rather wide climatic tolerance for the clade as a whole. The three species invasive in North America belong to the northern Eurasian subclade and show the rare combination of phenanthroindolizidine alkaloids and autogamy.

Polyphyly of Mussaenda inferred from ITS and trnT-F data and its implication for generic limits in Mussaendeae (Rubiaceae).

Although recognition of Mussaenda as a separate genus has been widely accepted, its generic circumscriptions have always been controversial. In this first molecular phylogenetic study focused specifically on Mussaenda sensu lato (s.l.) and its allied genera, parsimony analyses were based on both ITS and trnT-F sequence data to (1) test the monophyly of Mussaenda s.l. as presently circumscribed, (2) assess the phylogenetic relationships within the tribe Mussaendeae as currently delimited, (3) evaluate the phylogenetic value of the morphological characters traditionally and/or currently used to circumscribe Mussaendeae, (4) and make inferences on the biogeographical origin of Mussaenda. Of the 63 trnT-F and 38 ITS sequences included in our studies, 52 and 36 sequences, respectively, are newly published here. Our results highly support the polyphyly of Mussaenda s.l. as currently delimited but further support the monophyly of Mussaendeae sensu Bremer and Thulin. The Malagasy Mussaenda are more closely related to Landiopsis than they are to the African and Asian Mussaenda. Pseudomussaenda and the Afro-Asian Mussaenda clade are resolved as sister groups. Aphaenandra is nested within the Afro-Asian Mussaenda clade. As a result, we merge Aphaenandra in Mussaenda, which is now restricted to include only the African and Asian Mussaenda representatives. We describe a new genus Bremeria to accommodate all Indian Ocean (Madagascar and the Mascarenes) Mussaenda species and make 19 new combinations. The newly delimited Mussaenda is diagnosed by reduplicate-valvate aestivation and glabrous styles, whereas Bremeria can be distinguished from the remaining Mussaendeae genera by having both reduplicate- and induplicate-valvate aestivation and densely pubescent styles. Our studies strongly suggest an African origin of the newly delimited Mussaenda. Finally, descriptions of the newly circumscribed Mussaenda and Bremeria are provided.