Thais Vasconcelos

Aim: The factors underlying large disjunct distributions among closely related species have long been debated by biogeographers. In general, lineages crossing several trans‐marine barriers should be able to establish more easily where conditions are similar to their ancestral environments, while adaptation to diverse environmental conditions would be more frequent where dispersal is less limited by geographical barriers, such as within landmasses. Here, we test this assumption by contrasting biogeographical history and environmental niche evolution in the large tree clade Eugeniinae (Myrtaceae). Location: Pantropical. Taxon: Subtribe Eugeniinae, including the genera Eugenia and Myrcianthes (Myrtaceae). Methods: We employed the largest available phylogeny of subtribe Eugeniinae to date in a comparative framework for biogeographical models to assess the likelihood of different dispersal routes. We then integrated soil and climatic data to estimate species' environmental niches and used trait evolution models to obtain rates of niche evolution across different regimes and within Eugeniinae clades. Finally, we compared the number of dispersals with rates of niche evolution within each clade. Results: Eugeniinae originated in South America and achieved a pantropical distribution through a series of predominantly easterly trans‐marine dispersals in the last 25 million years. In general, colonisations of new areas were decoupled from accelerated changes in environmental preferences. Old World Eugeniinae exhibited the highest rates of colonisation of new landmasses and more conserved environmental niches than many exclusively New World clades of the subtribe. High rates of niche evolution in Neotropical Eugeniinae seem to be associated with diversification along elevational gradients and into soils of diverse properties. Finally, the persistence of Eugeniinae within the tropical zone during its geographic expansion may reflect slow evolution of temperature tolerance across all clades. Main Conclusion: Our findings show that a complex interaction between geographical movement and niche evolution explains the modern distribution of Eugeniinae. Different factors are likely responsible for each trans‐marine long‐distance dispersal event, and further comparative studies across diverse pantropical clades will be useful for determining whether general patterns exist that explain why certain lineages are particularly successful at dispersing across long distances globally.

Premise: Herbarium specimens are increasingly used to extract morphological traits for ecological and evolutionary studies, yet the effects of tissue desiccation on trait measurements remain poorly understood. Here, we tested two hypotheses: (H1) whether higher tissue water content leads to greater measurement changes after herborization and (H2) whether fresh trait values can be reliably predicted from measurements of herborized specimens. Methods: We evaluated the reliability of herbarium‐based measurements by comparing fresh and dried traits of leaves, flowers, fleshy fruits, and seeds across 262 individuals representing 133 Neotropical Myrtaceae species. Phylogenetic least squares models and machine learning regressions were used to test H1 and H2. Results: Leaves and flowers generally shrank after herborization, fruits size metrics tended to increase, and seeds were largely unaffected. Water content was significantly associated with the magnitude of herborization effects in flowers and some leaf and seed traits. Fresh trait values were accurately predicted from measurements of herborized specimens. Prediction errors were lowest for leaf traits, followed by fruits, flowers, and seeds. Discussion: These results partially support H1 and support H2, indicating that herborized specimens can be reliably used for trait analyses when organ‐specific responses are considered, providing a practical framework to account for potential desiccation bias in functional trait research.

This work explores inflorescence development patterns in Eugenia (Myrtaceae), one of the largest genera of woody plants with over 1200 species. The central hypothesis is that all variation in inflorescence arrangements in Eugenia is homologous. This is addressed as specific aims: (i) to identify the main inflorescence developmental patterns, (ii) to test the homology of inflorescence architectures using a time-calibrated phylogeny, and (iii) to assess and update traditional terminology. Taxonomically representative samples of Eugenia inflorescences were analysed to provide an evolutionary and comparative framework. Comparative ontogenetic analysis incorporated 24 taxa, while mature material analysis encompassed 66 species included in a dated phylogeny. Racemose branching is the ancestral condition of Eugenia. Seven development inflorescence patterns were recognized and combined into five patterns (auxotelic + auxotelic cataphylls, fasciculiform + glomeruliform, umbelliform, racemiform, and thyrsoid) to focus on evolutionary traits. The auxotelic pattern is the ancestral condition of Eugenia recovered in the early nodes and in the backbone with the highest probabilities of the reconstructed phylogeny, whereas auxotelic and fasciculiform were the most recurrent patterns in Eugenia sect. Umbellatae. The relative length and number of main axes that arise from an axil are shown to be systematically relevant, while racemiform pattern is exclusive to Eugenia sect. Racemosae. Flexible inflorescence arrangements found in Eugenia reflect a continuous spectrum of morphologies derived from a common ancestral scaffold. The combination of intense floral display in the fasciculiform pattern and flexibility may represent a key innovation in E. sect. Umbellatae. This work highlights the evolutionary significance of inflorescences and improves existing terminology.

Premise: Herbarium specimens are increasingly used to extract morphological traits for ecological and evolutionary studies, yet the effects of tissue desiccation on trait measurements remain poorly understood. Here, we tested whether higher tissue water content leads to greater measurement changes after herborization (H1) and whether fresh trait values can be reliably predicted from herbarium measurements (H2). Methods: We evaluated the reliability of herbarium-based measurements by comparing fresh and dried traits of leaves, flowers, fleshy fruits, and seeds across 262 individuals representing 133 Neotropical Myrtaceae species. Phylogenetic least square models and machine-learning regressions were used to test H1 and H2. Results: Leaves and flowers generally shrank after herborization, fruits size metrics tended to increase, and seeds were largely unaffected. Water content was significantly associated with the magnitude of herborization effects in flowers and some leaf and seed traits. Fresh trait values were accurately predicted from herbarium measurements. Prediction errors were lowest for leaf traits, followed by fruits, flowers, and seeds. Discussion: These results partially support H1 and support H2, indicating that herbarium specimens can be reliably used for trait analyses when organ-specific responses are considered, providing a practical framework to account for potential desiccation bias in functional trait research.

Bees are dominant pollinators across native and agricultural plant communities, yet the drivers of their patterns of geographic distribution and functional diversity remain poorly understood. Notably, bees exhibit a bimodal latitudinal diversity gradient, peaking in species diversity in temperate and arid regions rather than the tropics despite their close ecological and evolutionary ties to flowering plants, which show the opposite pattern. Here, we investigated whether two key life history traits thought to shape where bees can live—sociality and nesting strategy—may influence this pattern. We compiled data on sociality and nesting strategy for 4,293 bee species and combined it with a comprehensive phylogeny, curated global occurrence records, and newly-developed models of trait evolution to test 1) whether sociality and nesting biology are evolutionarily correlated, 2) how these life history traits shape bees’ climatic niches and niche breadths, and 3) whether the evolutionary dynamics of these traits may explain the bimodal latitudinal gradient in bee diversity. We find that the evolution of above-ground nesting is closely tied to the evolution of social behavior, but this trait combination has evolved rarely across the evolutionary history of bees. Where this combination does arise, species that are both social and above-ground nesters tend to have narrower climatic niches and are associated with environments that are warmer, wetter, and experience little seasonal temperature variation, making them more prevalent in tropical bee communities. Together, our results indicate that the bimodal diversity gradient in bees is driven by phylogenetic niche conservatism, where most bee lineages retain ancestral traits suited to arid environments and the derived syndrome necessary for thriving in the tropics evolves rarely.

Aim: All bees depend on angiosperms for survival, while many angiosperms depend on bees for reproduction. However, bee and flowering plant species richness do not peak in the same geographical regions of the world, suggesting that the flora in regions where bees are not as diverse, such as the tropics, may be relatively less bee‐dependent. We test this assumption by analysing whether local relative bee diversity can predict the proportion of angiosperm species that attract bees (i.e., “bee flowers”).Location: The Americas.Time Period: Present.Major Taxa Studied: Bees and angiosperms.Methods: We map the proportion of bees to angiosperm species using recently available datasets of geographic distribution for both taxa. We then combine data from surveys on pollination systems for 56 floristic communities to estimate the proportion of angiosperm species with bee flowers in different regions. Finally, we test whether the proportion of bee flowers in a community can be predicted by a combination of relative bee species richness and abiotic environmental variables.Results: Broad distribution maps show that the relative richness of bees in relation to angiosperms decreases in tropical areas; however, there is no evidence that tropical floristic communities are less dependent on bees. Interestingly, the proportion of angiosperm species with bee flowers was almost always found to be around 50% across biomes, with some variation depending on the habitat type and method of data collection.Main Conclusions: Our results suggest that plant communities can be highly bee‐dependent even where bees are relatively less diverse. While lower species richness does not mean lower abundance, and fewer bee species of specific life histories can still provide adequate pollination supply for a large number of angiosperm species, this pattern may impact how bee flowers interact with bees in different areas, and consequently how bees and bee flower specialisations have evolved over time.

Insects, especially those distributed in tropical forests, are greatly impacted by shortfalls in biodiversity knowledge. It is no surprise, then, that there are considerable gaps of knowledge on geographic distribution and taxonomy in the most diverse group of Amazonian bees, stingless bees (tribe Meliponini). Addressing these knowledge gaps is crucial for directing future research efforts and funding effectively, especially given the relevance of meliponiculture in the local economy. Here, we assess the geographic and taxonomic gaps in knowledge for Meliponini in the Amazon basin. We found that there are 27 genera and 239 valid species of native Meliponini in the region, but, among these, 78 species have five or less occurrence points available in open datasets of biodiversity data, while 7 have no available occurrence data. This issue stems from both a lack of collection efforts—especially in areas far from rivers and roads—and insufficient digitization of existing collections. We argue that future research should prioritize resolving taxonomic uncertainties in species complexes that suffer from both geographic and phylogenetic knowledge gaps. Some of these species are also important for meliponiculture, such as Melipona ( Michmelia ) seminigra and Tetragonisca angustula . Besides, to overcome the large geographical shortfall, both digitization and new collection effort should be employed, including new standardized methods to access the canopy, the largest frontier of biodiversity knowledge in the Amazon.

Summary: The digitization of vast herbarium collections has made millions of plant specimen images freely available online, which can now be used to generate phenotypic datasets of unprecedented scope. Here, we assess the potential of computer vision tools to automate the extraction of predicted leaf mass per area (LMA _pred ) from digitized herbarium specimens. We use an automated pipeline to extract leaf area and petiole width from 22 680 leaves, representing a phylogenetic informed sample of 1580 species of woody angiosperms. LMA _pred is estimated using a proxy equation that models the scaling relationship between petiole width and leaf mass. We assess potential sources of error in LMA _pred estimates and evaluate whether documented LMA–climate patterns are recovered using this dataset and phylogenetic comparative methods. Our LMA _pred dataset responds mainly to temperature and solar radiation and presents a positive correlation with latitude. The proxy equation, not the automated pipeline, is responsible for most of the error in LMA _pred estimates. Our pipeline underscores the power of combining herbarium digitization with new techniques for automated trait scoring. The increased size of datasets generated using this tool allows investigation of potential LMA–climate relationships with a geographically balanced sample while also utilizing comprehensive phylogenetic information.

Premise: Recent advances in imaging herbarium specimens have enhanced their use in biodiversity studies. However, user‐friendly tools that facilitate the assembly of customized sets of herbarium specimen images on personal devices are still lacking.Methods and Results: Here we present the R package mvh (“my virtual herbarium”), which includes functions designed to search and download metadata and openly available images associated with herbarium specimens based on taxon or geography. We tested the functionalities of mvh by searching metadata associated with five sets of 10 vascular plant species and five sets of 10 terrestrial coordinates. The download function had a success rate of 99%, downloading 291 out of the 293 images found in the search. Possible reasons for download failure are discussed.Conclusions: As long as an internet connection is available, mvh simplifies the assembly and organization of virtual herbaria, thereby facilitating the investigation of novel empirical questions as well as trends in digitization efforts.

In this paper, we present comprehensive data on two endemic and threatened species of Myrcia (Myrtaceae) from the Brazilian Atlantic Forest. Both belong to Myrcia sect. Aulomyrcia and were previously known only from a few collections made in the state of Rio de Janeiro. Apart from the type specimens and our recent collections, each species has been recollected on only three occasions. Considering the last collections of each species, Myrcia colpodes was rediscovered by our team after a collection gap of 64 years, while M. rubiginosa was found after 16 years. Myrcia colpodes can be recognized by vinaceous, exfoliating bark on the trunk, strongly bullate leaves and relatively long, glabrous panicles. Myrcia rubiginosa is characterized by fissured, greyish-brown bark on the trunk, conspicuous brownish and tomentose indumentum on young leaves and inflorescences, and pendular panicles with relatively small flowers. Data provided here include updated morphological descriptions for the taxa, along with notes on their morphological affinities and geographic distribution. Their fruits are here described and illustrated for the first time.