Pollination ecology of the tropical weed Triumfetta semitriloba Jacq. ( tiliaceae), in the south- eastern Brazil

This work aimed to study the pollination ecology of the tropical weed Triumfetta semitriloba Jacq. (Tiliaceae), in Viçosa, South-eastern Brazil, during the flowering season of 1993 and 1994. Two patches located in pasture (P1 and P2) and one patch in a forest trail (P3) were chosen and ten plants on each patch were sorted. The number of opened flowers were counted during one day, in each flowering month and patch. All observed flower visitors were identified and their behavior while visiting flowers was recorded. Frequency of visits to flowered branches was obtained and some pollinator individuals were captured for analysis of pollen load. Flowers are conspicuously yellow and actinomorphic, with five nectaries around the ovary base, and opened sequentially in the afternoon. Flower phenology followed a modified steady-state Gentry's pattern. The number of opened flowers was higher in P2, but differences between months were not homogeneous between patches. Considering behaviour when collecting pollen or nectar, which permitted impregnation of stigma with pollen, visiting frequency and percent of T. semitriloba pollen on pollen load (100% for all of them, except for Augochlorella michaelis which was 81%) the following species were the mainly pollinators: Augochloropsis cupreola, Augochlorella michaelis, Cressomiella aff. sussurans, Cressomiella sussurans, Cressomiella sp., Pseudocentron paulistana, Ceratinula sp1, Ceratinula sp2 and Ceratinula sp3, Melissodes sexcincta, Apis mellifera, Plebeia cf. nigriceps, Plebeia droryana. Frequency of pollinators visitation was not different between patches and not uniform during anthesis. There was a higher pollinator activity between 15:00 and 17:00 hr.Este trabalho tem por objetivo estudar a ecologia da polinização da planta invasora Triumfetta semitriloba Jacq. (Tiliaceae), em Viçosa, MG, Brasil, durante a estação de floração de 1993 e 1994. Foram escolhidas duas manchas de plantas localizadas em pastos abandonados (P1 e P2) e uma mancha em clareira de mata (P3). Dez plantas, em cada mancha, foram sorteadas. Durante um dia de cada mês de floração foi contado o número de flores abertas por planta. Todos os visitantes florais foram identificados e registrado o comportamento. Foi obtida a freqüência de visitas aos ramos floridos e alguns polinizadores foram coletados para análise da carga de pólen. As flores de T. semitriloba são actinomórficas com cinco nectários em torno da base do ovário, e abrem, seqüencialmente, no período da tarde. A fenologia floral seguiu o padrão "steady-state" modificado de Gentry. O número de flores abertas foi maior em P2, mas as diferenças entre meses não foram homogêneas entre as manchas. Considerando o comportamento enquanto coletavam pólen ou néctar, a freqüência de visita e a porcentagem de pólen de T. semitriloba na carga polínica (100% para todas as espécies de abelhas, exceto para Augochlorella michaelis que foi igual a 81%) as seguintes abelhas foram consideradas como principais polinizadoras: Augochloropsis cupreola, Augochlorella michaelis, Cressomiella aff. sussurans, Cressomiella sussurans, Cressomiella sp., Pseudocentron paulistana, Ceratinula sp1, Ceratinula sp2 e Ceratinula sp3, Melissodes sexcincta, Apis mellifera, Plebeia cf. nigriceps, Plebeia droryana. A distribuição de freqüência de visitas dos polinizadores não foi diferente entre manchas e não foi uniforme durante a antese. Houve uma maior atividade dos visitantes entre 15 e 17 horas

Adjacency and Area Explain Species Bioregional Shifts in Neotropical Palms

Environmental and geographical variables are known drivers of community assembly, however their influence on phylogenetic structure and phylogenetic beta diversity of lineages within different bioregions is not well-understood. Using Neotropical palms as a model, we investigate how environmental and geographical variables affect the assembly of lineages into bioregions across an evolutionary time scale. We also determine lineage shifts between tropical (TRF) and non-tropical (non-TRF) forests. Our results identify that distance and area explain phylogenetic dissimilarity among bioregions. Lineages in smaller bioregions are a subset of larger bioregions and contribute significantly to the nestedness component of phylogenetic dissimilarity, here interpreted as evidence for a bioregional shift. We found a significant tendency of habitat shifts occurring preferentially between TRF and non-TRF bioregions (31 shifts) than from non-TRF to TRF (24) or from TRF to TRF (11) and non-TRF to non-TRF (9). Our results also present cases where low dissimilarity is found between TRF and non-TRF bioregions. Most bioregions showed phylogenetic clustering and larger bioregions tended to be more clustered than smaller ones, with a higher species turnover component of phylogenetic dissimilarity. However, phylogenetic structure did not differ between TRF and non-TRF bioregions and diversification rates were higher in only two lineages, Attaleinae and Bactridinae, which are widespread and overabundant in both TRF and non-TRF bioregions. Area and distance significantly affected Neotropical palm community assembly and contributed more than environmental variables. Despite palms being emblematic humid forest elements, we found multiple shifts from humid to dry bioregions, showing that palms are also important components of these environments

Effects of Brazil's political crisis on the science needed for biodiversity conservation

The effects of Brazil’s political crisis on science funding necessary for biodiversity conservation are likely to be global. Brazil is not only the world’s most biodiverse nation, it is responsible for the greater part of the Amazon forest, which regulates the climate and provides rain to much of southern South America. Brazil was a world leader in satellite monitoring of land-use change, in-situ biodiversity monitoring, reduction in tropical-forest deforestation, protection of indigenous lands, and a model for other developing nations. Coordinated public responses will be necessary to prevent special-interest groups from using the political crisis to weaken science funding, environmental legislation and law enforcement. Keywords: Brazil, biodiversity, climate change, governance, fundin

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Role of pollinators in seed·set and a test of polleo limitation hypothesis in the tropical weed Triumfetta semitriloba (Tiliaceae)

Two patches of the tropical weed Triumfetta semitrilóba Jacq. (Tiliaceae) were studied in Viyosa, Southeastem Brazil, in the 1994 flowering season (March to May). Ten plants per patch, and five flowers per plant were randomly chosen for the following pollination tests: self-pollination; control; bee control; high load of crosspollen and high load of self-pollen. Fruits were collected to study seeds. Results for role of pollinators and pollen linútation in seed production were different between patches, probably because of differences in patch "quality" (nutrient availability, nÍlmber of flowers per plant and per patch, pollinator abundance). Seeds initiation. was independent of pollinators, but seed initiation and seed set were increased by pollinators. Seed production was Unútedby pollen, as seed initiation and seed set were jn¡:reased by high load of cross-pollen, only in one patch. Nevertheless, nutrients may also be limiting seed production, because ahigh load of cross-pollen did not maximize seed production, in either patch. Fruit abortion was higher in se1f-pollination and high load of se1f-pollen treatments, possibly because of selective abortion of self-progeny and fruits with less seeds. As expected for a weed species, T. semitrilobil has a breeding system where seed production is guaranteed by self-pollination, but the presence of bee pollinators increases seed set, and probably improves seed quality by cross-pollination. Differences between.patches showed that this species may experience spatial differences in reproductive success, with patches where seed production is limited by nutrients, patches limited by pollen, and patches where seed production is limited by both.Two patches of the tropical weed Triumfetta semitrilóba Jacq. (Tiliaceae) were studied in Viyosa, Southeastem Brazil, in the 1994 flowering season (March to May). Ten plants per patch, and five flowers per plant were randomly chosen for the following pollination tests: self-pollination; control; bee control; high load of crosspollen and high load of self-pollen. Fruits were collected to study seeds. Results for role of pollinators and pollen linútation in seed production were different between patches, probably because of differences in patch "quality" (nutrient availability, nÍlmber of flowers per plant and per patch, pollinator abundance). Seeds initiation. was independent of pollinators, but seed initiation and seed set were increased by pollinators. Seed production was Unútedby pollen, as seed initiation and seed set were jn¡:reased by high load of cross-pollen, only in one patch. Nevertheless, nutrients may also be limiting seed production, because ahigh load of cross-pollen did not maximize seed production, in either patch. Fruit abortion was higher in se1f-pollination and high load of se1f-pollen treatments, possibly because of selective abortion of self-progeny and fruits with less seeds. As expected for a weed species, T. semitrilobil has a breeding system where seed production is guaranteed by self-pollination, but the presence of bee pollinators increases seed set, and probably improves seed quality by cross-pollination. Differences between.patches showed that this species may experience spatial differences in reproductive success, with patches where seed production is limited by nutrients, patches limited by pollen, and patches where seed production is limited by both

Population genetic structure of the endangered tropical tree species at microsatellite loci

We report the population genetic structure of the endangered tropical tree species Caryocar brasiliense , based on variability at 10 microsatellite loci. Additionally, we compare heterozygosity and inbreeding estimates for continuous and fragmented populations and discuss the consequences for conservation. For a total of 314 individuals over 10 populations, the number of alleles per locus ranged from 20 to 27 and expected and observed heterozygosity varied from 0.129 to 0.924 and 0.067 to 1.000, respectively. Significant values of q and R ST showed important genetic differentiation among populations. q was much lower than R ST , suggesting that identity by state and identity by descent have diverged in these populations. Although a significant amount of inbreeding was found under the identity by descent model (f = 0.11), an estimate of inbreeding for microsatellite markers based on a more adequate stepwise mutation model showed no evidence of nonrandom mating ( R IS = 0.04). Differentiation (pairwise F ST ) was positively correlated with geographical distance, as expected under the isolation by distance model. No effect of fragmentation on heterozygosity or inbreeding could be detected. This is most likely due to the fact that Cerrado fragmentation is a relatively recent event (~60 years) compared to the species life cycle. Also, the populations surveyed from both fragmented and disturbed areas were composed mainly of adult individuals, already present prior to ecosystem fragmentation. Adequate hypothesis testing of the effect of habitat fragmentation will require the recurrent analysis of juveniles across generations in both fragmented and nonfragmented areas

Reproductive success in the tropical weed Triumfetta semitriloba (Tiliaceae): spatial and temporal variation in seed set

Reproduction of Triumfetta semitriloba Jacq. (Tiliaceae), a facultatively autogamous tropical shrub weed, was studied in tbree patches of different habitat "quality", in ViReproduction of Triumfetta semitriloba Jacq. (Tiliaceae), a facultatively autogamous tropical shrub weed, was studied in tbree patches of different habitat "quality", in Vicosa, Southeastern Brazil. In each patch ten plants were randomly chosen to collect 25 fruits per plant, during each flowc::ring month (March, April and May) in 1994. Mean seed initiation and seed set, pooling all patches,and flowering months were.2.535 (sd=O.l45) and 1.487 (sd=o.102), respectively (maximum: six seeds per fruit). Mean seed abortion was 41.3%. There was a higher number pf initiated seeds per fruit in one patch, probably caused by differences in patch "quality" and pollinátor abundance, and not by spatial differences on seed abortion, which was not different among patches. Two patches had the same temporal variation (among flowering months) in seed seto The greater brood size during the first and last months was caused by a higher seed initiation on the first flowering month and bigher proportipn of seed abortion on the second month. On the second month there were more flowersJl,er plant, which my lead to a lower rate of cross-polJination and, consequently, lower seed set. The differing patchhad a greater brood size during the first and second months. This pattern could be a . result of a higher seed initiation 'on the first flowering month, or of other patch charíÍcteristics such as lower number of flowers per plant, or lower abundallce of pollinators, especially during the last month, and a high rate of flower predation by beetle species, but not by differencés in seed abortion among months

Design and evaluation of a sequence capture system for genome-wide SNP genotyping in highly heterozygous plant genomes: a case study with a keystone Neotropical hardwood tree genome

Targeted sequence capture coupled to high-throughput sequencing has become a powerful method for the study of genome-wide sequence variation. Following our recent development of a genome assembly for the Pink Ipê tree (Handroanthus impetiginosus), a widely distributed Neotropical timber species, we now report the development of a set of 24,751 capture probes for single-nucleotide polymorphisms (SNPs) characterization and genotyping across 18,216 distinct loci, sampling more than 10 Mbp of the species genome. This system identifies nearly 200,000 SNPs located inside or in close proximity to almost 14,000 annotated protein-coding genes, generating quality genotypic data in populations spanning wide geographic distances across the species native range. To provide recommendations for future developments of similar systems for highly heterozygous plant genomes we investigated issues such as probe design, sequencing coverage and bioinformatics, including the evaluation of the capture efficiency and a reassessment of the technical reproducibility of the assay for SNPs recall and genotyping precision. Our results highlight the value of a detailed probe screening on a preliminary genome assembly to produce reliable data for downstream genetic studies. This work should inspire and assist the development of similar genomic resources for other orphan crops and forest trees with highly heterozygous genomes