Abstract Microbial symbionts are increasingly recognized as key contributors to bee health, yet their roles in solitary bee brood cells remain largely unexplored. Here, we characterize the bacterial and fungal communities associated with brood cell compartments (cocoon, meconium, and prepupa) of the oil-collecting bee Centris aethyctera , and compare them with gut microbiota from adult Centris species. Using 16S rRNA and ITS amplicon sequencing, we show that microbiota are strongly compartmentalized, with distinct diversity patterns, taxonomic compositions, and inferred functional profiles across brood cell components. Contrary to our initial hypothesis, antibiotic-producing bacteria, particularly Actinomycetia, are most diverse and abundant in the meconium rather than the cocoon. Cocoons are enriched in hydrocarbon-degrading and nitrogen-cycling bacteria, while pre-pupae harbor distinct bacterial and fungal taxa, including genera with potential antimicrobial and symbiotic functions. Fungal communities are likewise structured, with taxa such as Aspergillus and Lecanicillium suggesting possible roles in pathogen defense. Core gut microbiota of adult Centris include acetic acid bacteria shared across species, with partial overlap with brood cell taxa, indicating potential transmission pathways. Together, our results reveal that Centris brood cells form a highly structured, antimicrobial-rich microenvironment likely shaped by maternal provisioning and environmental acquisition. These findings provide the first comprehensive description of microbiota across brood cell compartments in a solitary bee and identify ground-nesting bee systems as promising reservoirs for novel antimicrobial discovery.

Mutualistic interactions between plants and pollinators are fundamental to biodiversity maintenance and ecosystem resilience, yet their dynamics across space and time in tropical dry forests have not been widely examined. We analyzed plant-pollinator networks across seasons and habitat types in the highly seasonal and fragmented dry forest of Puerto Rico, to assess how diversity, network structure, and species roles contribute to network stability. Over 35 months, standardized observations and video recordings documented 126 plant species and 154 taxa of floral visitors across shrublands, disturbed habitats, and forests during dry and rainy seasons. Networks exhibited strong spatiotemporal variation: Shrublands supported the highest plant and pollinator richness and formed the largest, most connected, and most nested networks, especially during the rainy season. In contrast, forest networks were smaller, more specialized, and more modular, particularly in the dry season, indicating higher vulnerability. Most species functioned as peripheral specialists; however, a few generalists, especially the non-native bee species Apis mellifera, played central roles as hubs and connectors. Although these generalists enhance short-term stability, their dominance may reduce interaction diversity and threaten long-term network resilience. Interaction dissimilarity was high among habitats and between seasons, with interaction rewiring as the dominant driver. This capacity for rewiring allows networks to maintain cohesion despite environmental fluctuations, enhancing resilience and buffering against potential disruptions. However, the relative importance of rewiring versus species turnover varied: Forest networks depended more on species turnover, whereas shrubland and disturbed habitats relied more on rewiring and showed greater functional redundancy. Our results show that Caribbean dry forest pollination networks are dynamic and resilient, largely sustained by rewiring among generalist species. Conservation strategies should prioritize habitat heterogeneity and support native pollinators to maintain functional diversity and reduce reliance on non-native generalists. By highlighting the critical role of interaction flexibility, this study advances understanding of mutualistic network persistence in seasonal, disturbance-prone tropical systems and informs conservation strategies aimed at sustaining pollination services under changing environmental conditions.

The pollination syndrome hypothesis predicts that plants pollinated by the same pollinator group exhibit convergent combinations of specific floral traits. However, studies show these combinations often predict pollinators with relatively low accuracy. This discrepancy may result from shifts in the relative importance of floral traits for different pollinator groups under varying environmental conditions. In particular, the role of phenological patterns (e.g. seasonality) and habitat type in shaping pollination syndromes remains understudied. Understanding these influences is crucial, especially in seasonally tropical systems where environmental fluctuations can strongly impact plant-pollinator interactions. To investigate this, we collected data on floral traits and documented plant-pollinator interactions across multiple seasons and habitat types in a tropical dry forest. Using machine learning models, we evaluated how the relative importance of floral traits shifts among primary pollinator groups and examined the extent to which seasonality and habitat type influence trait inclusion and importance. This approach allowed us to disentangle the interplay between floral traits, environmental factors and pollinator visitation patterns across different ecological contexts, revealing nonlinear relationships and subtle patterns that traditional methods might overlook. Our results demonstrate that floral trait importance is context-dependent and dynamic, varying across seasons, habitat types and pollinator groups. We found that preferences for floral traits among primary pollinator groups are largely consistent with traditional pollination syndromes; however, the floral trait most important to a pollinator group often shifts depending on habitat and season. Furthermore, traits that ranked highly in one habitat or season were often less critical in others, suggesting that plant-pollinator interactions are influenced by a combination of temporal and spatial factors. These findings challenge the static view of pollination syndromes at the community level and reveal their inherent flexibility. Synthesis. This study highlights the dynamic nature of pollination syndromes, showing that floral trait importance shifts across time and space. Future research should incorporate temporal and spatial variability when examining pollination syndromes to avoid oversimplifying these complex systems. Recognizing the flexibility of trait associations is essential for understanding plant-pollination networks and their resilience in a changing world.

Orchidaceae is one of the most species-rich families of flowering plants, with most current diversity having evolved within the last 5 My. Patterns associated with species richness and rapid diversification have been identified but have not often been associated with evolutionary processes. We review the most frequently identified correlates of diversity and suggest that the processes and rate by which they occur vary geographically and are largely dependent on persistent pulses of habitat instabilities, especially for epiphytes. Aggressive orogenesis creates fragmented habitats while global climatic cycles exacerbate the ecological instabilities. The need for repeated cycles of dispersal results in frequent founder events, which sets the stage for allopatric diversification via bouts of genetic drift and natural selection. The allopatry requirement can be bypassed by pollination systems involving flowers attracting pollinators through the production of sex signaling semiochemicals. The drift–selection model of diversification, coupled with persistent habitat instability throughout ecological and geological time scales, and sex signaling are the likely components of a multifactorial process leading to the rapid, recent diversification in this family.

Plant–pollinator mutualisms are key to sustaining ecosystem function and biodiversity. The study of plant–pollinator networks has conventionally focused on diurnal interactions, while flower‐settling moths are among the most diverse yet least understood pollinator groups. Previous network studies provide a valuable lesson on the important role of settling moths in supporting pollination systems. However, little is known regarding the structure of flower‐settling moth networks or the ecological and evolutionary mechanisms that may shape these interactions. Our main objective was to bring to focus the structure of a flower‐settling moth network, using records from a previous pollination study in the Florida Sandhill. We integrated key taxonomic, life history and functional traits of moths as potential drivers of network structure and discussed potential implications for the structure and long‐term stability of plant–pollinator networks in general. Flower‐settling moth networks were robust, diverse and significantly structured (modular), with functionally similar moths linked more often to particular modules (micro, small and macro). Notably, the average proboscis length and wingspan of moths varied significantly among modules (macro vs. micro/small), further suggesting that modules were at least partially determined by the similar function of moths. In addition, we provide the following scale to categorise moths by size guild or potential functional group: (1) micro‐settling (wingspan ≤14.5 mm; proboscis ≤4.39 mm); (2) small‐settling (14.5 < wingspan < 25.0; 4.40 ≤ proboscis ≤ 7.49) and (3) macro‐settling (wingspan ≥25.0 mm, proboscis ≥7.50 mm). Given the immense diversity and abundance of settling moths, it is not surprising that a continuum of functional traits (such as body size and proboscis length) has helped shape pollination niches among settling moths. We conclude that flower‐settling moth assemblages are more functionally diverse than previously understood and offer a glimmer of hope in the darkness for pollinator conservation.

Investigating the ability of non-native species to establish and invade different habitats is one of the most important approaches in the analysis of biological invasion mechanisms. In this study, we used a regional dataset of non-native plant species compiled for Caribbean islands to estimate the level of invasion of major habitat types in this region. Our results show that although non-native species are successfully invading all habitat types evaluated, they are exhibiting considerably higher affinity toward human-made habitats. Across these islands, highly anthropogenically altered habitats such as ruderal sites, pastures, and cultivated lands are the habitats showing higher levels of invasion compared to natural habitats with low levels of disturbance. We found a significant association between geographical origin and habitat invaded, with species originating from Asia, South America, and Africa overrepresented as invaders in the Caribbean. Additionally, a significant association between life-form and habitat invaded was detected, with more trees and herbaceous species than expected successfully invading ruderal habitats, and more trees and vines than expected invading natural forests. In general, non-native species invading habitats across Caribbean islands seem to be adapted to a broad range of successional stages ranging from highly disturbed human-made habitats to least disturbed natural forests. Our results highlight how complex interactions among human activity, geographical origin, plant life-form, and habitat affinity can determine patterns of invasions across broad landscapes.

Orchids constitute one of the most spectacular radiations of flowering plants. However, their origin, spread across the globe, and hotspots of speciation remain uncertain due to the lack of an up-to-date phylogeographic analysis. We present a new Orchidaceae phylogeny based on combined high-throughput and Sanger sequencing data, covering all five subfamilies, 17/22 tribes, 40/49 subtribes, 285/736 genera, and c. 7% (1921) of the 29 524 accepted species, and use it to infer geographic range evolution, diversity, and speciation patterns by adding curated geographical distributions from the World Checklist of Vascular Plants. The orchids' most recent common ancestor is inferred to have lived in Late Cretaceous Laurasia. The modern range of Apostasioideae, which comprises two genera with 16 species from India to northern Australia, is interpreted as relictual, similar to that of numerous other groups that went extinct at higher latitudes following the global climate cooling during the Oligocene. Despite their ancient origin, modern orchid species diversity mainly originated over the last 5 Ma, with the highest speciation rates in Panama and Costa Rica. These results alter our understanding of the geographic origin of orchids, previously proposed as Australian, and pinpoint Central America as a region of recent, explosive speciation.

In this chapter, we review key studies of orchids on Barro Colorado Island (BCI) and consider the history of the place from the context of taxonomic status and ecological and evolutionary theory. The contributions are varied yet played a key role in our understanding of orchid taxonomy, pollination, evolution of ant-plant interactions, and plant physiological ecology in epiphytic plants. The demography of epiphytic orchids is described in the context of epiphytism and meta-population dynamics. Along with information on reproduction and gene flow from BCI studies, a distinct characterization emerges of the tempo of evolution in orchids and how this has contributed to the extreme diversity of the group.

Traits associated with successful biological invasions across environmental gradients or geographical distances may vary depending on processes such as founder effects, ecological sorting, or adaptation to local conditions. Consequently, drivers of success are not necessarily consistent throughout the invasive range. We evaluate how plant traits, reproductive success and climatic preferences vary in populations of a naturalized orchid on islands in the Atlantic, Pacific and Indian oceans. Populations of Arundina graminifolia (bamboo orchid) were located on Puerto Rico, Hawaiian Islands (Hawai’i, O’ahu, Kaua’i), and Mauritius. Vegetative and reproductive traits were measured, and male and female success were assessed. Populations were compared using multivariate approaches. Species distribution modeling was used to assess potential climatic preferences within and among islands. Floral morphology differed among islands but considerable overlap in trait distributions exists. Reproductive success significantly differed among islands and was linked to floral traits, local pollinator pools and perhaps variable levels of florivory. Hawaiian populations occupied the broadest climatic niche space and Mauritius the most restricted. The effectiveness of using present points from the native range to reveal climatic suitability on invaded islands varied among islands. Successful invasions across a broad geographical range can occur even when morphology, reproductive success and climatic conditions are variable. As expected, some aspects of this global invasion are similar, but others differ among islands underscoring the context dependency of biological invasions and the difficulty of overall predictions.

We explore phorophyte suitability for germination and establishment of the epiphytic orchid, Psychilis kraenzlinii. We found that the orchid grows on a subset of the available tree species and shows preference for the endemic Machaonia portoricensis (Rubiaceae). The orchid preferred trees with smoother bark with high water holding capacity and low water retention capacity. Microclimatic conditions under which embryos began pre-germination stages mirrored that of the adult orchid, but germination did not, suggesting that suitable germination sites are not necessarily the best sites for later stages of development.

Climate change plays an increasing role in the global biodiversity crisis. Alteration in local climatic conditions not only can negatively affect native biodiversity but also can accelerate the introduction and spread of invasive species. In this study the ecological niche modelling approach was used to evaluate possible changes in the distribution of suitable niches of invasive orchid Eulophia graminea within its native (Asia) and non-native geographical range (America, Australia). We mapped the current potential range of this species and analysed three various projections of future climate (for 2100) each with four different climate change scenarios (SSPs). Calculated niche overlap indexes indicated low similarity of niches occupied by native and invasive populations of E. graminea and Australian populations seem to be the most unique, while American and Asian groups share partially similar niches. The occurrence of the American population of E. graminea was correlated especially with the temperature seasonality, while the Asian and Australian populations with annual precipitation and precipitation of the wettest quarter. As indicated in our analyses within Asia and America, E. graminea does not occupy all climatically suitable niches. On the other hand, in Australia the species studied already occupies all appropriate niche space. Climate change will likely be favorable for species studied to expand its range if the biotic components of its niche space (e.g., mycorrhizal fungi) will respond similarly. The most significant range expansion is predicted to occur in Australia which is interesting considering the marginally suitable habitats that E. graminea currently occupies.

AimTo better understand the potential impact of climate change on butterfly assemblages across a tropical island, we model the potential for taxonomic and functional homogenization and determine climate- and trait-mediated shifts in projected species distributions.LocationPuerto Rico.MethodsWe used thousands of museum records of diurnal Lepidoptera to model current (1970-2000) and forecast future (2061-2080) species distributions and combined these to test for taxonomic and functional homogenization. We then quantified climatic-mediated effects on current and forecasted taxonomic and functional composition and, specifically, whether temperature was a primary driver, as predicted by the temperature-size rule and the thermal melanism hypotheses. Finally, we measured wing traits important in thermoregulation (size and colour) and determined trait-mediated changes in forecasted species distributions over time.ResultsBased on ensemble model outputs, taxonomic and functional richness and turnover were predicted to vary across the island's complex topography. Our models projected an increase in taxonomic and functional richness over time, and a decrease in taxonomic and functional turnover - a signature of biotic homogenization. Under future climate scenarios, models projected a decrease in wing length and an increase in wing brightness at higher elevations. One variable, temperature seasonality, was the strongest predicted driver of both the current spatial distribution and the projected per cent change over time for not only wing traits but also taxonomic and functional richness and turnover.Main conclusionsThe species distribution models generated here identify several priority regions and species for future research and conservation efforts. Our work also highlights the role of seasonality and climatic variability on diverse tropical Lepidoptera assemblages, suggesting that climatic variability may be an important, albeit overlooked, driver of climate change responses.

Orchidaceae show remarkable diversity in pollination strategies, but how these strategies vary globally is not entirely clear. To identify regions and taxa that are data-rich and lend themselves to rigorous analyses or are data-poor and need attention, we introduce a global database of orchid reproductive biology. Our database contains > 2900 species representing all orchid subfamilies and 23 of 24 tribes. We tabulated information on habit, breeding systems, means of pollinator attraction and the identity of pollinators. Patterns of reproductive biology by habit, geography and taxonomy are presented graphically and analysed statistically. On the basis of our database, most orchid species sampled are pollinator dependent (76%) and self-compatible (88%). Pollinator attraction based on rewards occurs in 54% of the species, whereas 46% use some means of deceit. Orchids generally have highly specific pollinator interactions (median number of pollinator species = 1). Nonetheless, on average, specificity is lower for species offering rewards, occurring in multiple continental regions or Northern America (as defined by the Taxonomic Database Working Group Level 1 regions). Although our database reveals impressive knowledge gains, extensive gaps in basic observations of orchid reproductive biology exist, particularly in tropical regions and diverse lineages of fly-pollinated species. The database is expected to facilitate targeted studies, further elucidating the ecological and evolutionary drivers of orchid diversity.

Little is known about the pollination mechanisms of species belonging to the genus Vanilla (Orchidaceae). Both autonomous self-pollination and animal-mediated pollination mechanisms seem to exist amongst the Vanilla species, yet few studies provided real evidence on pollination events. The aim of this study was to better understand the pollination mechanism of Vanilla hartii. Four V. hartii populations were selected within our study area in southern Costa Rica to observe pollination events and identify the natural pollinators of this Neotropical Vanilla species. We tested for nectar presence, analysed nectar composition, and examined floral fragrances. Furthermore, we identified floral visitors and documented their behaviour, quantified fruit set during two years, and compared morphological traits of flowers and their visitors. Sampled flowers contained 1.85 +/- 1.07 mu L nectar that averaged 34.79% sugar, dominated by sucrose. We observed orchid bees belonging to the genus Euglossa entering the tube formed by the labellum to search for nectar, indicated by their extended proboscis and prolonged visits, some of which exited the labellar tube with pollen masses attached to their scutellum. Combining our behavioural and phytochemical data, we demonstrate the presence of a nectar-rewarding pollination mechanism in the genus Vanilla that shows a higher natural fruit set compared to deceptive Vanilla species. An overview of the pollination mechanisms known so far provides insights into the potential evolution of reproductive strategies within this commercially important orchid genus.

Introduction:Interest for bee microbiota has recently been rising, alleviating the gap in knowledge in regard to drivers of solitary bee gut microbiota. However, no study has addressed the microbial acquisition routes of tropical solitary bees. For both social and solitary bees, the gut microbiota has several essential roles such as food processing and immune responses. While social bees such as honeybees maintain a constant gut microbiota by direct transmission from individuals of the same hive, solitary bees do not have direct contact between generations. They thus acquire their gut microbiota from the environment and/or the provision of their brood cell. To establish the role of life history in structuring the gut microbiota of solitary bees, we characterized the gut microbiota of Centris decolorata from a beach population in Mayagüez, Puerto Rico. Females provide the initial brood cell provision for the larvae, while males patrol the nest without any contact with it. We hypothesized that this behavior influences their gut microbiota, and that the origin of larval microbiota is from brood cell provisions.Methods:We collected samples from adult females and males of C. decolorata (n = 10 each, n = 20), larvae (n = 4), and brood cell provisions (n = 10). For comparison purposes, we also sampled co-occurring female foragers of social Apis mellifera (n = 6). The samples were dissected, their DNA extracted, and gut microbiota sequenced using 16S rRNA genes. Pollen loads of A. mellifera and C. decolorata were analyzed and interactions between bee species and their plant resources were visualized using a pollination network.Results:While we found the gut of A. mellifera contained the same phylotypes previously reported in the literature, we noted that the variability in the gut microbiota of solitary C. decolorata was significantly higher than that of social A. mellifera. Furthermore, the microbiota of adult C. decolorata mostly consisted of acetic acid bacteria whereas that of A. mellifera mostly had lactic acid bacteria. Among C. decolorata, we found significant differences in alpha and beta diversity between adults and their brood cell provisions (Shannon and Chao1 p < 0.05), due to the higher abundance of families such as Rhizobiaceae and Chitinophagaceae in the brood cells, and of Acetobacteraceae in adults. In addition, the pollination network analysis indicated that A. mellifera had a stronger interaction with Byrsonima sp. and a weaker interaction with Combretaceae while interactions between C. decolorata and its plant resources were constant with the null model.Conclusion:Our data are consistent with the hypothesis that behavioral differences in brood provisioning between solitary and social bees is a factor leading to relatively high variation in the microbiota of the solitary bee.

Transmission dynamics of viruses within and among cultivated plant species are often well known. Much less studied, especially in the tropics, is the dynamic of virus exchange between cultivated and nearby wild or weedy species, even though such exchanges are known to occur. To develop the best strategies for crop protection and general disease control, spatial distribution of viruses in non-cultivated plants needs to be understood. This research focuses on the potyviruses that infect Momordica charantia (Cucurbitaceae), an alien naturalized invasive vine in Puerto Rico. A total of 390 symptomatic and asymptomatic plants were sampled throughout Puerto Rico, including adjacent islands of Culebra and Vieques. Samples were subjected to an enzyme linked immunosorbent assay (ELISA) for general potyvirus screening, and to ELISAs specific for Papaya ringspot virus (PRSV) and Zucchini yellow mosaic virus (ZYMV). The species distribution model algorithm MaxEnt was used to predict suitable environments for the potential presence of potyvirus symptoms, potyvirus, PRSV or ZYMV in M. charantia. Almost half of the samples of M. charantia tested positive for ZYMV, PRSV or both viruses. Twice as many samples were positive for PRSV (39%) than for ZYMV (21%). About 14% of samples were positive for both potyviruses. Plants that tested positive for PRSV were three times more likely to be positive for ZYMV than were plants that were negative for PRSV. Plants that tested positive using the general potyvirus ELISA were much more likely to exhibit symptoms than plants testing negative for potyvirus. In comparison, PRSV and ZYMV samples testing positive or negative were equally likely to exhibit virus-like symptoms. When we classified samples according to habitat (agricultural, rural-nonagricultural, or urban), the presence/absence of symptoms and test results for potyvirus, PRSV and ZYMV were not dependent on habitat classification. By contrast, a MaxEnt model using 20 environmental variables was able to predict areas of Puerto Rico where environmental conditions are favorable for the potential presence of virus symptoms, potyvirus, PRSV or ZYMV in M. charantia. Conditions predicted by our model to be moderately to strongly suitable for the presence of PRSV in M. charantia covered a much larger area of Puerto Rico than they did for ZYMV. The vegetable growing region in the central to eastern south coast was predicted to have highly suitable environmental conditions for the presence of both potyviruses in M. charantia.

A new species of Melocactus is described from Puerto Rico. This miniature species, with a stem no more than 70 mm in diameter, is of uncertain affiliation but is unlikely to be a close relative of M. intortus, the only other Melocactus known from Puerto Rico, due to the lack of a pink-coloured stigma, smaller stem dimensions and distinct seed structure. There are morphological similarities with some other Caribbean species: M. lemairei and M. praerupticola of Hispaniola, and M. guitartii (= M. curvispinus) from Cuba.

AbstractUnderstanding the role of alien species in forest communities, and how native and alien species interact to shape the composition and structure of contemporary forests, is of critical importance to invasion ecology and natural resource management. We used vegetation data collected over a 20‐year period in 341 permanent plots representing remnants of closed‐canopy forests and post‐agricultural secondary forests across Puerto Rico to compare changes in the composition and abundance of native and alien woody species in plots with and without aliens across different forest types and to assess whether aliens and natives show divergence or convergence regarding functional roles and ecological strategies. We also tested the applicability of Grime's CSR (competitive, stress‐tolerant, and ruderal strategies) theory to explain naturalization success. Species richness and abundance of natives are consistently lower in plots in which aliens are present compared with those without them. This negative association between aliens and natives has been consistent over the 20 years and across all forest types. Both native and total richness slightly increased over the 20 years, but the increase in native species richness was three times lower in plots with aliens relative to those without aliens. The CSR classification provided insight into the naturalization success of aliens. Corroborating the “join the locals” hypothesis, aliens use the same functional spaces as natives. The exception is in dry forests, where aliens and natives differ in the use of functional spaces, a result that corroborates the “try harder” hypothesis. Generally, aliens were better competitors compared with natives, and natives were more stress‐tolerant than aliens. Our combined results suggest that alien species may inhibit population growth or even drive local changes in native plant communities by transforming the assembly and dynamics of tropical forests. Ultimately, modifications linked to invasive species may have significant implications for local forests, affecting their regeneration and productivity. More definitive conclusions require additional plot censuses, and analyses of disturbance regimes and stand‐age structure to reveal the long‐term implications of alien species on regenerating tropical forests, including their vulnerability, resilience, and adaptive capacity to cope with various aspects of climate change.