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Birds are highly visually oriented and use plumage coloration as an important signalling trait in social communication. Hence, males and females may have different patterns of plumage coloration, a phenomenon known as sexual dichromatism. Because males tend to have more complex plumages, sexual dichromatism is usually attributed to female choice. However, plumage coloration is partly condition-dependent; therefore, other selective pressures affecting individuals' success may also drive the evolution of this trait. Here, we used tanagers as model organisms to study the relationships between dichromatism and plumage coloration complexity in tanagers with parasitism by haemosporidians, investment in reproduction and life-history traits. We screened blood samples from 2849 individual birds belonging to 52 tanager species to detect haemosporidian parasites. We used publicly available data for plumage coloration, bird phylogeny and life-history traits to run phylogenetic generalized least-square models of plumage dichromatism and complexity in male and female tanagers. We found that plumage dichromatism was more pronounced in bird species with a higher prevalence of haemosporidian parasites. Lastly, high plumage coloration complexity in female tanagers was associated with a longer incubation period. Our results indicate an association between haemosporidian parasites and plumage coloration suggesting that parasites impact mechanisms of sexual selection, increasing differences between the sexes, and social (non-sexual) selection, driving females to develop more complex coloration.

Abstract Infection by lineages of avian malaria parasites (Apicomplexa: Haemosporida) varies geographically, and some lineages exhibit disjunct distributions. These patterns might be related to differential resistance among host populations reflecting intrinsic characteristics of both the host and the pathogen. In hematophagous parasites in particular, the structure of host hemoglobin can influence parasite development and reproduction. Though variation in avian hemoglobin has been documented across altitudinal gradients, little is known about hemoglobin variation as it relates to infection by the parasites causing avian malaria. We sequenced the αA-globin subunit of the Bananaquit (Coereba flaveola), and related sequence variation to avian malaria infection frequency and parasite lineage identity. We found no association between αA-globin haplotype and infection by particular parasite lineages among all locations, nor any protective association between globin haplotype frequency and the proportion of individuals infected within populations. Phylogeographic structure and genetic variation at the αA-globin locus, including a highly variable intron, is largely concordant with the mitochondrial cytochrome b locus for these same populations, supporting this marker as an independent and variable target with potential application in biogeographic analyses. Keywords alpha-globin, avian malaria, Bananaquit, Coereba flaveola, West Indies Resumen La variación de la globina alfa no predice la infección por malaria aviar en Coereba flaveola • La infección por linajes de parásitos de la malaria aviar (Apicomplexa: Haemosporida) varía geográficamente y algunos linajes exhiben distribuciones discontinuas. Estos patrones podrían estar relacionados con la resistencia diferencial entre las poblaciones de huéspedes, y reflejan las características intrínsecas tanto del huésped como del patógeno. En los parásitos hematófagos, en particular, la estructura de la hemoglobina del huésped puede influir en el desarrollo y la reproducción del parásito. Aunque se ha documentado la variación de la hemoglobina aviar a través de gradientes altitudinales, se sabe poco sobre su variación en relación con la infección por los parásitos que causan la malaria aviar. Secuenciamos la subunidad de globina αA de Coereba flaveola y relacionamos la variación de la secuencia con la frecuencia de infección por malaria aviar y la identidad del linaje del parásito. No encontramos ninguna asociación entre el haplotipo de globina αA y la infección por determinados linajes de parásitos entre localidades; ni ninguna asociación protectora entre la frecuencia del haplotipo de globina y la proporción de individuos infectados dentro de las poblaciones. La estructura filogeográfica y la variación genética en el locus de la globina αA, que incluye un intrón muy variable, concuerdan en gran medida con el locus del citocromo b mitocondrial para estas mismas poblaciones; lo que respalda a este marcador como un objetivo independiente y variable con aplicación potencial en análisis biogeográficos. Palabras clave Caribe Insular, Coereba flaveola, globina alfa, malaria aviar Résumé La variation de l’alpha-globine ne permet pas de prédire l’infection par le paludisme aviaire chez le Sucrier à ventre jaune (Coereba flaveola) • L’infection par des lignées de parasites responsables du paludisme aviaire (Apicomplexa: Haemosporida) varie géographiquement, et certaines lignées présentent des répartitions disjointes. Ces schémas pourraient être liés à une résistance différentielle entre les populations d’hôtes reflétant des caractéristiques intrinsèques à la fois de l’hôte et du pathogène. Dans le cas particulier des parasites hématophages, la structure de l’hémoglobine de l’hôte peut influer sur le développe- ment et la reproduction du parasite. Bien que la variation de l’hémoglobine aviaire ait été documentée en fonction des gradients altitudinaux, peu de choses sont connues sur la variation de l’hémoglobine en relation avec l’infection par les parasites responsables du paludisme aviaire. Nous avons séquencé la sous-unité αA-globine du Sucrier à ventre jaune (Coereba flaveola), et nous avons mis en relation la variation de la séquence avec la fréquence d’infection du paludisme aviaire et l’identité de la lignée parasitaire. Nous n’avons trouvé aucune association entre l’haplotype αA-globine et l’infection par des lignées parasitaires particulières en fonction des sites, ni aucune association protectrice entre la fréquence de l’haplotype globine et la proportion d’individus infectés au sein des populations. La structure phylogéographique et la variation génétique au locus de l’αA-globine, y compris un intron hautement variable, est largement concordante avec le locus du cytochrome b mitochondrial pour ces mêmes populations, indiquant ce marqueur comme une cible indépendante et variable pouvant avoir une application potentielle dans les analyses biogéographiques. Mots clés alpha-globine, Antilles, Coereba flaveola, paludisme aviaire, Sucrier à ventre jaune

Migratory birds are implicated in dispersing haemosporidian parasites over great geographic distances. However, their role in sharing these vector-transmitted blood parasites with resident avian host species along their migration flyway is not well understood. We studied avian haemosporidian parasites in 10 localities where Chilean Elaenia, a long-distance Neotropical austral migrant species, spends part of its annual cycle to determine local parasite transmission among resident sympatric host species in the elaenia's distributional range across South America. We sampled 371 Chilean Elaenias and 1,818 birds representing 243 additional sympatric species from Brazilian wintering grounds to Argentinian breeding grounds. The 23 haemosporidian lineages found in Chilean Elaenias exhibited considerable variation in distribution, specialization, and turnover across the 10 avian communities in South America. Parasite lineage dissimilarity increased with geographic distance, and infection probability byParahaemoproteusdecreased in localities harbouring a more diverse haemosporidian fauna. Furthermore, blood smears from migrating Chilean Elaenias and local resident avian host species did not contain infective stages ofLeucocytozoon, suggesting that transmission did not take place in the Brazilian stopover site. Our analyses confirm that this Neotropical austral migrant connects avian host communities and transports haemosporidian parasites along its distributional range in South America. However, the lack of transmissive stages at stopover site and the infrequent parasite lineage sharing between migratory host populations and residents at breeding and wintering grounds suggest that Chilean Elaenias do not play a significant role in dispersing haemosporidian parasites, nor do they influence local transmission across South America.

Genomic studies are now poised to explore whole communities of species. The ~70 species of woody plants that anchor the coastal ecosystems of the tropics, collectively referred to as mangroves, are particularly suited to this exploration. In this study, we de novo sequenced the whole genomes of 32 mangroves, which we combined with other sequences of 30 additional species, comprising almost all mangroves globally. These community-wide genomic data will be valuable for ecology, evolution and biodiversity research. While the data revealed 27 independent origins of mangroves, the total phylogeny shows only modest increases in species number, even in coastal areas of active speciation, suggesting that mangrove extinction is common. A possible explanation for common extinction is the frequent sea-level rises and falls (SLRs and SLFs) documented in the geological record. Indeed, near-extinctions of species with extremely small population size (N) often happened during periods of rapid SLR, as revealed by the genome-wide heterozygosity of almost all mangroves. Reduction in N has possibly been further compounded by population fragmentation and the subsequent accumulation of deleterious mutations, thus pushing mangroves even closer to extinction. Crucially, the impact of the next SLR will be exacerbated by human encroachment into these mangrove habitats, potentially altering the ecosystems of tropical coasts irreversibly.

Vector-borne parasites are important ecological drivers influencing life-history evolution in birds by increasing host mortality or susceptibility to new diseases. Therefore, understanding why vulnerability to infection varies within a host clade is a crucial task for conservation biology and for understanding macroecological life-history patterns. Here, we studied the relationship of avian life-history traits and climate on the prevalence ofPlasmodiumandParahaemoproteusparasites. We sampled 3569 individual birds belonging to 53 species of the family Thraupidae. Individuals were captured from 2007 to 2018 at 92 locations. We created 2 phylogenetic generalized least-squares models withPlasmodiumandParahaemoproteusprevalence as our response variables, and with the following predictor variables: climate PC1, climate PC2, body size, mixed-species flock participation, incubation period, migration, nest height, foraging height, forest cover, and diet. We found thatParahaemoproteusandPlasmodiumprevalence was higher in species inhabiting open habitats. Tanager species with longer incubation periods had higherParahaemoproteusprevalence as well, and we hypothesize that these longer incubation periods overlap with maximum vector abundances, resulting in a higher probability of infection among adult hosts during their incubation period and among chicks. Lastly, we found thatPlasmodiumprevalence was higher in species without migratory behaviour, with mixed-species flock participation, and with an omnivorous or animal-derived diet. We discuss the consequences of higher infection prevalence in relation to life-history traits in tanagers.

Host phylogenetic relatedness and ecological similarity are thought to contribute to parasite community assembly and infection rates. However, recent landscape level anthropogenic changes may disrupt host-parasite systems by impacting functional and phylogenetic diversity of host communities. We examined whether changes in host functional and phylogenetic diversity, forest cover, and minimum temperature influence the prevalence, diversity, and distributions of avian haemosporidian parasites (genera Haemoproteus and Plasmodium) across 18 avian communities in the Atlantic Forest. To explore spatial patterns in avian haemosporidian prevalence and taxonomic and phylogenetic diversity, we surveyed 2241 individuals belonging to 233 avian species across a deforestation gradient. Mean prevalence and parasite diversity varied considerably across avian communities and parasites responded differently to host attributes and anthropogenic changes. Avian malaria prevalence (termed herein as an infection caused by Plasmodium parasites) was higher in deforested sites, and both Plasmodium prevalence and taxonomic diversity were negatively related to host functional diversity. Increased diversity of avian hosts increased local taxonomic diversity of Plasmodium lineages but decreased phylogenetic diversity of this parasite genus. Temperature and host phylogenetic diversity did not influence prevalence and diversity of haemosporidian parasites. Variation in the diversity of avian host traits that promote parasite encounter and vector exposure (host functional diversity) partially explained the variation in avian malaria prevalence and diversity. Recent anthropogenic landscape transformation (reduced proportion of native forest cover) had a major influence on avian malaria occurrence across the Atlantic Forest. This suggests that, for Plasmodium, host phylogenetic diversity was not a biotic filter to parasite transmission as prevalence was largely explained by host ecological attributes and recent anthropogenic factors. Our results demonstrate that, similar to human malaria and other vector-transmitted pathogens, prevalence of avian malaria parasites will likely increase with deforestation.

Species distributions and the mechanisms that produce patterns in the occupation space are recurrent themes in community ecology. Here, we examine beta diversity among assemblages of small mammals in the Cerrado domain of Brazil to partition the effects of turnover and nestedness on species distributions. Our objective was to evaluate whether balanced spatial variation in abundance (β bal) and abundance gradients (β gra) are congruent within and among habitats and localities of the Brazilian Cerrado. In addition, we wanted to understand whether ecological mechanisms, such as dispersal limitation, habitat filtering, and species sorting, drive the distribution patterns of the Cerrado small mammals. We analyzed the occurrence and abundances of small mammals from 16 localities widely distributed across the Cerrado biome, and grouped our data with respect to two distinct spatial scales. Baselga’s Bray–Curtis index of dissimilarity and its respective partitions, i.e., balanced variation in abundance (β bal) and abundance gradients (β gra), were estimated between sampling units at the two spatial scales. Thus, we used exponential models to search for distance decay in species similarity between pairs of localities and between similar habitats. Our results show that differences between small mammal assemblages in the Cerrado are driven mainly by species replacement rather than independent gain or loss of species, both at small and large scales. The spatial turnover patterns of small mammals in the Cerrado biome are determined by a combination of large scale (biogeographic, spatial) and local mechanisms (low dispersal and habitat specificity). However, processes occurring at small scales seem to be more important in species sorting than processes occurring at large scales. The spatial configuration of the landscape and the extent and quality of habitats strongly influence the rate of species turnover in Cerrado. Thus, protecting the different types of habitats should be of prime importance to conserving the diversity of Cerrado small mammals.

Parental care in birds varies among species and geographic regions. Incubation behavior influences embryonic development rate and varies substantially among species.We studied attendance at the nest by videoing nests or collecting data from the literature for 112 species in north temperate and lowland tropical sites, then associated patterns of incubation on‐ and off‐bouts with species and environmental traits.Songbirds nesting at low elevations incubate their eggs for an average of 74.1% (±12.9 SD, n = 60 species) of the time in temperate regions and 71.0% (±12.2 SD, n = 52 species) in tropical regions during daylight hours, and 84.3% (±8.2 SD) and 85.3% (±6.2 SD), respectively, of each 24‐hr cycle.While these attendance percentages do not differ significantly between latitudes, our data also show that lowland tropical songbirds make fewer visits to the nest and, consequently, have longer on‐bouts and off‐bouts during incubation. This pattern in attendance reflects a latitudinal contrast in parental care strategy, where lowland tropical birds reduce visits to the nest by increasing on‐ and off‐bout lengths while maintaining the same proportion of time spent incubating their eggs (constancy).Similar constancy across latitude suggests that tropical and temperate birds may be similarly constrained to maintain elevated egg temperatures for normal embryo growth.The different attendance strategies adopted in each region may reflect differences in ambient temperature, adult foraging time, and nest predation rate. Consistently warm ambient temperatures likely allow tropical birds to take longer off‐bouts, and thereby to reduce activity around the nest, compared to temperate birds., We compared avian attendance data during incubation of 112 New World temperate and tropical passerine species. The amount of time that parents incubated their eggs did not differ between regions, but tropical birds employed a different attendance strategy. Tropical parents spent longer periods of time on and off of the eggs, made fewer trips to the nest, but incubated for the same percentage of time.

Aim: Differences in physiography have been proposed to explain the diversity anomaly for vascular plants between environmentally similar regions of eastern Asia (EAS) and eastern North America (ENA). Here, we use plant species within disjunct genera to examine whether differences in topography contribute to the diversity anomaly and whether the richness–environment relationships differ between regions. Disjunct plants are used to ensure that the diversity anomaly relates to post-disjunction evolution and diversification rather than regional differences in clade ages or immigration. Location: EAS and ENA. Time period: Current. Major taxa studied: Plant taxa disjunctly distributed in EAS and ENA. Methods: We compiled county-level plant distribution data, and calculated species richness and variables of topography and climate within unit grid cells. We compared estimated coefficients of region effects among models, where richness was fitted with or without topography and climate. Topography and climate were also used to separately model within-region spatial diversity patterns using spatial simultaneous autoregressive error models. Results: The coefficients of region effects varied from −.776 for the model only including region to −.309 when topography was controlled for, but remained significant. Climate dominated the spatial diversity patterns in ENA. In contrast, the influence of climate (14.2%) on species richness was weaker than that of topography (18.3%) in the warm area of EAS. Relations to elevation and temperature varied between regions, shifting between positive and negative relationships in several cases. Main conclusions: Our results demonstrate that variability in local topography contributes to the strong regional anomaly in plant species richness between EAS and ENA. Nevertheless, the diversity anomaly persists after controlling for local topography and climate. EAS and ENA also exhibit contrasting richness–environment relationships, providing another divergent aspect between the EAS–ENA disjunct floras. Our findings highlight that regional differences in topography or other environmental factors may underlie the diversity anomaly.

Aim: Macroecological analyses provide valuable insights into factors that influence how parasites are distributed across space and among hosts. Amid large uncertainties that arise when generalizing from local and regional findings, hierarchical approaches applied to global datasets are required to determine whether drivers of parasite infection patterns vary across scales. We assessed global patterns of haemosporidian infections across a broad diversity of avian host clades and zoogeographical realms to depict hotspots of prevalence and to identify possible underlying drivers. Location: Global. Time period: 1994–2019. Major taxa studied: Avian haemosporidian parasites (genera Plasmodium, Haemoproteus, Leucocytozoon and Parahaemoproteus). Methods: We amalgamated infection data from 53,669 individual birds representing 2,445 species world-wide. Spatio-phylogenetic hierarchical Bayesian models were built to disentangle potential landscape, climatic and biotic drivers of infection probability while accounting for spatial context and avian host phylogenetic relationships. Results: Idiosyncratic responses of the three most common haemosporidian genera to climate, habitat, host relatedness and host ecological traits indicated marked variation in host infection rates from local to global scales. Notably, host ecological drivers, such as migration distance for Plasmodium and Parahaemoproteus, exhibited predominantly varying or even opposite effects on infection rates across regions, whereas climatic effects on infection rates were more consistent across realms. Moreover, infections in some low-prevalence realms were disproportionately concentrated in a few local hotspots, suggesting that regional-scale variation in habitat and microclimate might influence transmission, in addition to global drivers. Main conclusions: Our hierarchical global analysis supports regional-scale findings showing the synergistic effects of landscape, climate and host ecological traits on parasite transmission for a cosmopolitan and diverse group of avian parasites. Our results underscore the need to account for such interactions, in addition to possible variation in drivers across regions, to produce the robust inference required to predict changes in infection risk under future scenarios.

Species assemble into communities through ecological and evolutionary processes. Phylogenetic niche conservatism-the tendency of species to retain ancestral ecological distributions-is thought to influence which species from a regional species pool can persist in a particular environment. We analyzed data for seed plants in China to test hypotheses about the distribution of species within regional floras. Of 16 environmental variables, actual evapotranspiration, minimum temperature of the coldest month, and annual precipitation most strongly influenced regional species richness, phylogenetic dispersion, and phylogenetic diversity for both gymnosperms (cone-bearing plants) and angiosperms (flowering plants). For most evolutionary clades at, and above, the family level, the relationships between metrics of phylogenetic dispersion (i.e., average phylogenetic distance among species), or phylogenetic diversity, and the 3 environmental variables were consistent with the tropical niche conservatism hypothesis, which predicts closer phylogenetic relatedness and reduced phylogenetic diversity with increasing environmental stress. The slopes of the relationships between phylogenetic relatedness and the 3 environmental drivers identified in this analysis were steeper for primarily tropical clades, implying greater niche conservatism, than for primarily temperate clades. These observations suggest that the distributions of seed plants across large-scale environmental gradients in China are constrained by conserved adaptations to the physical environment, i.e., phylogenetic niche conservatism.

Whether ecological differences between species evolve in parallel with lineage diversification is a fundamental issue in evolutionary biology. These processes might be connected if conditions that favor the proliferation of species, such as release from competitors, facilitate the evolution of novel ecological relationships. Despite this, phylogenetic studies do not consistently identify such a connection. Conversely, if higher diversity caused species to become increasingly specialized ecologically, then lineage diversification might become dissociated from ecological diversification. In this analysis, we ask whether the rate of lineage diversification in a large clade of birds is correlated with morphological specialization and with rates of morphological evolution. We find that morphological variation is related to species richness within clades but that rates of morphological evolution are decoupled from the rate of lineage diversification. Additionally, morphological specialization within lineages is independent of the rate at which lineages diversify, with the results apparently robust against false negative inference. This dissociation is likely a consequence of the major ecomorphological differences between avian clades arising early in their evolutionary history, with comparatively little variation added subsequently, while avian diversification has been driven predominantly by geographic isolation and sexual selection. Accordingly, biodiversity appears to be limited by the extent to which taxa can subdivide exploited regions of ecological space and not just overall ecological opportunity.

Haemosporidian parasites of the genera Plasmodium, Haemoproteus, and Leucocytozoon are among the best studied parasites of Neotropical birds. Here, we describe variation in haemosporidian prevalence (i.e. the proportion of infected individuals in a sampled population) in Neotropical birds. We review correlates of haemosporidian prevalence (including several avian life-history traits, climate, and season) and the population and evolutionary consequences of infection for Neotropical birds. We find that prevalence varies among avian taxonomic families, genera, and even among species within the same genus, suggesting that prevalence reflects multiple factors, some of which (e.g., avian incubation period) are associated with avian family-level variation in prevalence while others (e.g., avian abundance) are associated with variation in prevalence among closely related host species. We find few correlates of prevalence that have been consistently demonstrated across studies. Prevalence in populations of many Neotropical birds has been estimated by microscopic examination of blood smears, which affords limited opportunity for comparison with data generated by molecular methods. However, at one site in the Brazilian Cerrado for which we have data, prevalence determined by microscopy does not correlate with prevalence determined by molecular methods for Plasmodium, but the 2 data types are positively correlated for Haemoproteus. Haemosporidians have been hypothesized to play a role in avian sexual selection, and we find the prevalence of Haemoproteus to be lower in polygynous species than in socially monogamous species in the Neotropics, confirming a pattern shown previously among Nearctic birds.LAY SUMMARYMany Neotropical birds are infected by insect-vectored blood parasites belonging to the order Haemosporida. These haemosporidian parasites, commonly known as “avian malaria” parasites, infect bird species to varying degrees.The proportion of birds in a population that are infected (parasite prevalence) has been related to variation in several avian traits, including length of incubation period and nesting height, climate, and other factors, but the patterns are not consistent among studies.We review proposed causes of variation in haemosporidian prevalence and potential consequences of infection for bird populations. Haemosporidian parasites have plausibly been involved in the evolution of colorful plumage and mating systems in birds.Here we find evidence for lower prevalence of haemosporidian infection associated with polygyny (where individual males mate with multiple females) in the Neotropics.Avian haemosporidian parasites exert an important influence on the health and adaptive responses of Neotropical birds.

Alpine floras (plants in the vegetation belts above the climatic treelines) experience cold climates, particularly in temperate mountains during winter, but they are generally species-rich. Yet, biogeographers have not determined whether these floras represent evolutionarily independent but convergent assemblages drawn from their regional floras, or whether they originated from particular clades pre-adapted to harsh conditions. Here, we analyse the evolutionary relationships of angiosperm (flowering plant) species in 63 alpine floras worldwide (~7,000 species) in comparison with their regional floras (~94,000 species) and with the entire global flora. We find that each of the alpine floras represents an assemblage of more closely related species than their respective regional floras. The degree of phylogenetic clustering of species in alpine floras in tropical mountains exceeds that in temperate mountains. However, in relation to the global flora, temperate alpine floras are phylogenetically closely related subsets of floras that colonized cold temperate areas during interglacial periods. We conclude that alpine floras include a few dominant families that have evolved tolerance to low temperature, and that evolutionary niche conservatism explains their phylogenetic clustering, compared with species in their regional species pools.