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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.

We reconstruct the species-level phylogenetic relationship among toucans, toucan-barbets, New World barbets using phylogenomic data to assess the monophyly and relationships at the family, generic, and specific levels. Our analyses confirmed (1) the monophyly of toucans (Aves: Ramphastidae), toucan-barbets (Aves: Semnornithidae), and New World barbets (Aves: Capitonidae) and that the toucan-barbets are sister to the toucans, an arrangement suggested, but poorly supported, in previously published phylogenies; (2) the paraphyly of lowland Selenidera toucanets with respect to Andigena mountain-toucans; and (3) evidence of some mitonuclear discordance, suggesting introgression or incomplete lineage sorting. For example, mitonuclear conflict in the phylogenetic placement of Ramphastos vitellinus subspecies suggests that Amazonian populations of Ramphastos vitellinus ariel may have introgressed mitogenomes derived from other Amazonian vitellinus taxa. To reconstruct the phylogenetic history of toucans, toucan-barbets, and New World barbets, we included all species-level taxa from the three families, with the addition of outgroups from the two major clades of Old World barbets (Megalaimidae and Lybiidae). We analyzed a combination of UCE sequences and whole mitochondrial genome sequences to reconstruct phylogenetic trees.

The factors that influence whether a parasite is likely to cause death in a given host species are not well known. Generalist parasites with high local abundances, broad distributions and the ability to infect a wide phylogenetic diversity of hosts are often considered especially dangerous for host populations, though comparatively little research has been done on the potential for specialist parasites to cause host mortality. Here, using a novel database of avian mortality records, we tested whether phylogenetic host specialist or host generalist haemosporidian blood parasites were associated with avian host deaths based on infection records from over 81 000 examined hosts. In support of the hypothesis that host specialist parasites can be highly virulent in novel hosts, we found that the parasites that were associated with avian host mortality predominantly infected more closely related host species than expected under a null model. Hosts that died tended to be distantly related to the host species that a parasite lineage typically infects, illustrating that specialist parasites can cause death outside of their limited host range. Overall, this study highlights the overlooked potential for host specialist parasites to cause host mortality despite their constrained ecological niches.

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.

Studies contrasting parasite prevalence and host-parasite community structure between pristine and disturbed environments will improve our understanding of how deforestation affects disease transmission and parasite extinction. To determine how infection rates of a common and diverse group of avian blood parasites (Plasmodium and Haemoproteus) respond to changes in avian host composition after mining, we surveyed 25 bird communities from pristine forests (two forest types: plateau and hillside) and reforested sites in Northeast Amazonia. Infection rates and both parasite and avian host community structure exhibited considerable variation across the deforestation gradient. In opposition to the emerging pattern of lower avian haemosporidian prevalence in disturbed tropical forests in Africa, we show that secondary forests had higher haemosporidian prevalence in one of the largest mining areas of Amazonia. The dissimilarity displayed by bird communities may explain, in part, the higher prevalence of Haemoproteus in reforested areas owing to the tolerance of some bird species to open-canopy forest habitat. On the other hand, deforestation may cause local extinction of Plasmodium parasites due to the loss of their avian hosts that depend on closed-canopy primary forest habitats. Our results demonstrate that forest loss induced by anthropogenic changes can affect a host-parasite system and disturb both parasite transmission and diversity.

Avian haemosporidians from the genera Plasmodium and Haemoproteus are vector transmitted parasites. A growing body of evidence suggests that variation in their prevalence within avian communities is correlated with a variety of avian ecological traits. Here, we examine the relationship between infection probability and diversity of haemosporidian lineages and avian host ecological traits (average body mass, foraging stratum, migratory behavior, and nest type). We used molecular methods to detect haemosporidian parasites in blood samples from 642 individual birds of 149 species surveyed at four localities in the Brazilian Pantanal. Based on cytochrome b sequences, we recovered 28 lineages of Plasmodium and 17 of Haemoproteus from 31 infected avian species. Variation in lineage diversity among bird species was not explained by avian ecological traits. Prevalence was heterogenous across avian hosts. Bird species that forage near the ground were less likely to be infected by Haemoproteus, whereas birds that build open cup nests were more likely infected by Haemoproteus. Furthermore, birds foraging in multiple strata were more likely to be infected by Plasmodium. Two other ecological traits, often related to host resistance (body mass and migratory behavior), did not predict infection probability among birds sampled in the Pantanal. Our results suggest that avian host traits are less important determinants of haemosporidian diversity in Pantanal than in other regions, but reinforces that host attributes, related to vector exposure, are to some extent important in modulating infection probability within an avian host assemblage.

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.

The avian feather louse Philopterus-complex (Phthiraptera: Ischnocera: Philopteridae) currently contains 12 genera that have been grouped together because of shared morphological characteristics. Although previously lumped into a single genus (Philopterus), more recent morphological treatments have separated the group into several different genera. Here we evaluate the status of these genera using DNA sequence data from 118 ingroup specimens belonging to ten genera in the Philopterus-complex: Australophilopterus Mey, 2004, Cinclosomicola Mey 2004, Clayiella Eichler, 1940, Corcorides Mey, 2004, Mayriphilopterus Mey, 2004, Paraphilopterus Mey 2004, Philopteroides Mey 2004, Philopterus Nitzsch, 1818, Tyranniphilopterus Mey, 2004, and Vinceopterus Gustafsson, Lei, Chu, Zou, and Bush, 2019. Our sampling includes 97 new louse-host association records. Our analyses suggest that the genus Debeauxoecus Conci, 1941, parasitic on pittas (Aves: Pittidae), is outside of the Philopterus-complex, and that there is strong support for the monophyly of a group containing the remaining genera from the complex. Some diverse genera, such as Philopterus (sensu stricto) and Mayriphilopterus are supported as monophyletic, whereas the genera Australophilopterus, Philopteroides, and Tyranniphilopterus are not. The present study is the largest phylogenetic reconstruction of avian lice belonging to the Philopterus-complex to date and suggests that further generic revision is needed in the group to integrate molecular and morphological information.

More than one-third of the bird species found in the Caribbean are endemic to a set of neighboring islands or a single island. However, we have little knowledge of the evolutionary history of the Caribbean avifauna, and the lack of phylogenetic studies limits our understanding of the extent of endemism in the region. The Sharp-shinned Hawk (Accipiter striatus) occurs widely across the Americas and includes 3 endemic Caribbean taxa: venator on Puerto Rico, striatus on Hispaniola, and fringilloides on Cuba. These island populations have undergone extreme declines presumably due to ecosystem changes caused by anthropogenic factors, as well as due to severe hurricanes. Sharp-shinned Hawks, in general, and Caribbean Sharp-shinned Hawks, in particular, have not been placed in a modern phylogenetic context. However, the island taxa have historically been presumed to have some ongoing gene flow with mainland populations. Here we sequenced ultraconserved elements (UCEs) and their flanking regions from 38 samples, focusing on Caribbean taxa. Using a combination of UCEs, mitochondrial genome sequences, and single-nucleotide polymorphisms, we investigated the phylogenetic relationships among Caribbean lineages and their relationships to mainland taxa. We found that Caribbean Sharp-shinned Hawks are reciprocally monophyletic in all datasets with regard to mainland populations and among island taxa (with no shared mtDNA haplotypes) and that divergence in the NADH dehydrogenase 2 gene (ND2) between these mainland and island groups averaged 1.83%. Furthermore, sparse non-negative matrix factorization (sNMF) analysis indicated that Hispaniola, Puerto Rico, and mainland samples each form separate populations with limited admixture. We argue that our findings are consistent with the recognition of the 3 resident Caribbean populations as species-level taxa because nuclear and mitochondrial genetic data indicate reciprocal monophyly and have species-level divergences, there is no sharing of mitochondrial haplotypes among or between island taxa and those on the mainland; and they are diagnosable by plumage.

Parasite diversification is influenced by many of the same factors that affect speciation of free-living organisms, such as biogeographic barriers. However, the ecology and evolution of the host lineage also has a major impact on parasite speciation. Here we explore the interplay between biogeography and host-association on the pattern of diversification in a group of ectoparasitic lice (Insecta: Phthiraptera: Penenirmus) that feeds on the feathers of woodpeckers, barbets, and honeyguides (Piciformes) and some songbirds (Passeriformes). We use whole genome sequencing of 41 ingroup and 12 outgroup samples to develop a phylogenomic dataset of DNA sequences from a reference set of 2,395 single copy ortholog genes, for a total of nearly four million aligned base positions. The phylogenetic trees resulting from both concatenated and gene-tree/species-tree coalescent analyses were nearly identical and highly supported. These trees recovered the genus Penenirmus as monophyletic and identified several major clades, which tended to be associated with one major host group. However, cophylogenetic analysis revealed that host-switching was a prominent process in the diversification of this group. This host-switching generally occurred within single major biogeographic regions. We did, however, find one case in which it appears that a rare dispersal event by a woodpecker lineage from North America to Africa allowed its associated louse to colonize a woodpecker in Africa, even though the woodpecker lineage from North America never became established there.

Variation in susceptibility is ubiquitous in multi-host, multi-parasite assemblages, and can have profound implications for ecology and evolution in these systems. The extent to which susceptibility to parasites is phylogenetically conserved among hosts can be revealed by analysing diverse regional communities. We screened for haemosporidian parasites in 3983 birds representing 40 families and 523 species, spanning ~ 4500 m elevation in the tropical Andes. To quantify the influence of host phylogeny on infection status, we applied Bayesian phylogenetic multilevel models that included a suite of environmental, spatial, temporal, life history and ecological predictors. We found evidence of deeply conserved susceptibility across the avian tree; host phylogeny explained substantial variation in infection status, and results were robust to phylogenetic uncertainty. Our study suggests that susceptibility is governed, in part, by conserved, latent aspects of anti-parasite defence. This demonstrates the importance of deep phylogeny for understanding present-day ecological interactions.

Hylexetastes woodcreepers are endemic to the terra firme forests of the Amazon basin. Currently, most taxonomic sources recognize two species of Hylexetastes (H. perrotii and H. stresemanni), each divided into three subspecies. Some authors maintain that the H. perrotii subspecies should be elevated to full species status. In particular, Hylexetastes perrotii brigidai is endemic to the eastern Amazon, the second Amazonian area of endemism (Xingu) most affected by deforestation and habitat degradation. Consequently, the taxonomic status of H. p. brigidai is of particular concern for conservation. Thus far, only morphological characters have been evaluated for the taxonomic delimitation of species and subspecies of Hylexetastes. We present a molecular phylogenetic analysis of all subspecies to help delimit Hylexetastes interspecific limits. Fragments of two mitochondrial (Cytb and ND2) and three nuclear genes (FGB5, G3PDH and MUSK) from 57 Hylexetastes specimens were sequenced. An ecological niche model was estimated to describe more accurately the potential distributions of taxa and to evaluate their vulnerability to ongoing deforestation. Phylogenetic analyses support the paraphyly of the polytypic H. perrotii as currently delimited and the elevation of Hylexetastes perrotii uniformis to full species rank, as well as the presence of three evolutionary significant units (ESUs) within this newly delimited species, including one grouping all H. p. brigidai specimens. Alternatively, under lineage‐based species concepts, our results support at least five evolutionary species in Hylexetastes: H. stresemanni, H. undulatus, H. perrotii, H. uniformis and H. brigidai. Each of these taxa and ESUs are distributed in different interfluvial areas of the Amazon basin, which have different degrees of disturbance. Because they occupy the most heavily impacted region among all Hylexetastes ESUs, regular assessments of the conservation statuses of H. p. brigidai and both H. uniformis ESUs are paramount.

Within animal hybrid zones, parasites may determine competitive outcomes between host species and thus affect hybridization dynamics. We addressed this hypothesis by evaluating haemosporidian prevalence and community composition in a rapidly moving hybrid zone between Black-capped Chickadees (Poecile atricapillus) and Carolina Chickadees (P. carolinensis). Using molecular methods, we screened for haemosporidians in multiple chickadee populations across the hybrid zone and investigated whether parasite prevalence varied as a function of admixture among these birds. We identified 36 parasite lineages from 3 haemosporidian genera (Plasmodium, Haemoproteus, and Leucocytozoon) but found no genera or lineages more likely to infect any particular chickadee taxon. Instead, haemosporidian prevalence varied across sites and seasons: Leucocytozoon was more prevalent during chickadees' breeding season, whereas Haemoproteus prevalence peaked during nonbreeding periods. Leucocytozoon infected proportionally fewer birds at the leading edge of the hybrid zone than near its center. However, haemosporidian communities were similar among chickadee populations, and evidence for parasite exchanges between chickadee taxa was lacking. These results underscore the complexity of bird–parasite relationships and suggest that haemosporidians are unlikely to play a major role in the ongoing movement of this hybrid zone.LAY SUMMARYWe tested whether patterns of parasite diversity and prevalence support the hypothesis that parasite communities may determine competitive outcomes within an iconic avian hybrid zone.We used molecular methods to detect and identify haemosporidian lineages infecting Black-capped, Carolina, and hybrid chickadees across their hybrid zone in southeastern Pennsylvania.Analyses revealed 36 unique haemosporidian lineages, the prevalence and richness of which varied little across chickadee taxa.For some parasites, locality and season predicted haemosporidian prevalence.Haemosporidians are likely not key drivers underlying movement of this chickadee hybrid zone.

Neotropical birds are mostly parasitized by immature ticks and act as reservoir hosts of tick-borne pathogens of medical and veterinary interest. Hence, determining the factors that enable ticks to encounter these highly mobile hosts and increase the potential for tick dispersal throughout migratory flyways are important for understanding tick-borne disease transmission. We used 9682 individual birds from 572 species surveyed across Brazil and Bayesian models to disentangle possible avian host traits and climatic drivers of infestation probabilities, accounting for avian host phylogenetic relationships and spatiotemporal factors that may influence tick prevalence. Our models revealed that the probability of an individual bird being infested with tick larvae and nymphs was lower in partial migrant hosts and during the wet season. Notably, infestation probability increased in areas with a higher proportion of partial migrant birds. Other avian ecological traits known to influence tick prevalence (foraging habitat and body mass) and environmental condition that might constrain tick abundance (annual precipitation and minimum temperature) did not explain infestation probability. Our findings suggest that migratory flyways harbouring a greater abundance of migrant bird hosts also harbour a higher prevalence of immature ticks with potential to enhance the local transmission of tick-borne pathogens and spread across regions.

Megascops is the most species-rich owl genus in the New World, with 21 species currently recognized. Phylogenetic relationships within this genus are notoriously difficult to establish due to the considerable plumage similarity among species and polymorphism within species. Previous studies have suggested that the widespread lowland Amazonian M. watsonii might include more than one species, and that the Atlantic Forest endemic M. atricapilla is closely related to the M. watsonii complex, but these relationships are as yet poorly understood. A recently published phylogeny of Megascops demonstrated that M. watsonii is paraphyletic with respect to M. atricapilla and that genetic divergences among some populations of M. watsonii are equal to or surpass the degree of differentiation between some M. watsonii and M. atricapilla. To shed light on the taxonomic status of these species and populations within them, we conducted a multi-character study based on molecular, morphological, and vocal characters. We sequenced three mitochondrial (cytb, CO1 and ND2) and three nuclear genes (BF5, CHD and MUSK) for 49 specimens, covering most of the geographic ranges of M. watsonii and M. atricapilla, and used these sequences to estimate phylogenies under alternative Bayesian, Maximum Likelihood, and multilocus coalescent species tree approaches. We studied 252 specimens and vocal parameters from 83 recordings belonging to 65 individuals, distributed throughout the ranges of M. watsonii and M. atricapilla. We used Discriminant Function Analysis (DFA) to analyze both morphometric and vocal data, and a pairwise diagnostic test to evaluate the significance of vocal differences between distinct genetic lineages. Phylogenetic analyses consistently recovered six statistically well-supported clades whose relationships are not entirely in agreement with currently recognized species limits in M. watsonii and M. atricapilla. Morphometric analyses did not detect significant differences among clades. High plumage variation among individuals within clades was usually associated with the presence of two or more color morphs. By contrast, vocal analyses detected significant differentiation among some clades but considerable overlap among others, with some lineages (particularly the most widespread one) exhibiting significant regional variation. The combined results allow for a redefinition of species limits in both M. watsonii and M. atricapilla, with the recognition of four additional species, two of which we describe here as new. We estimated most cladogenesis in the Megascops atricapilla-M. watsonii complex as having taken place during the Plio-Pleistocene, with the development of the modern Amazonian and São Francisco drainages and the expansion and retraction of forest biomes during interglacial and glacial periods as likely events accounting for this relatively recent burst of diversification.

Studies contrasting parasite prevalence and host-parasite community structure between pristine and disturbed environments will improve our understanding of how deforestation affects disease transmission and parasite extinction. To determine how infection rates of a common and diverse group of avian blood parasites (Plasmodium and Haemoproteus) respond to changes in avian host composition after mining, we surveyed 25 bird communities from pristine forests (two forest types: plateau and hillside) and reforested sites in Northeast Amazonia. Infection rates and both parasite and avian host community structure exhibited considerable variation across the deforestation gradient. In opposition to the emerging pattern of lower avian haemosporidian prevalence in disturbed tropical forests in Africa, we show that secondary forests had higher haemosporidian prevalence in one of the largest mining areas of Amazonia. The dissimilarity displayed by bird communities may explain, in part, the higher prevalence of Haemoproteus in reforested areas owing to the tolerance of some bird species to open-canopy forest habitat. On the other hand, deforestation may cause local extinction of Plasmodium parasites due to the loss of their avian hosts that depend on closed-canopy primary forest habitats. Our results demonstrate that forest loss induced by anthropogenic changes can affect a host-parasite system and disturb both parasite transmission and diversity.

The eukaryotic blood parasite genus Trypanosoma includes several important pathogens of humans and livestock, but has been understudied in wildlife broadly. The trypanosomes that infect birds are in particular need of increased attention, as these parasites are abundant and globally distributed, yet few studies have addressed their evolutionary origins and diversity using modern molecular and analytical approaches. Of specific interest are the deep evolutionary relationships of the avian trypanosomes relative to the trypanosome species that are pathogenic in humans, as well as their species level diversity in regions where they have been understudied such as North America. Here, we address these unresolved areas of study using phylogenomic data for two species of avian trypanosomes that were isolated as "bycatch" from host transcriptome assemblies, as well as a large 18S DNA barcode sequence dataset that includes 143 novel avian Trypanosoma 18S sequences from North America. Using a phylogenomic approach, we find that the avian trypanosomes are nested within a clade of primarily mammalian trypanosomes that includes the human pathogen Trypanosoma cruzi, and are paraphyletic with respect to the ruminant trypanosome Trypanosoma theileri. DNA barcode sequences showed that T. avium and an unidentified small, non-striated trypanosome that was morphologically similar to T. everetti are each represented by highly abundant and divergent 18S haplotypes in North America. Community-level sampling revealed that additional species-level Trypanosoma lineages exist in this region. We compared the newly sequenced DNA barcodes from North America to a global database, and found that avian Trypanosoma 18S haplotypes generally exhibited a marked lack of host specificity with at least one T. avium haplotype having an intercontinental distribution. This highly abundant T. avium haplotype appears to have a remarkably high dispersal ability and cosmopolitan capacity to evade avian host immune defenses, which warrant further study.

Ticks are ectoparasites that feed on blood of a broad taxonomic range of terrestrial and flying vertebrates and are distributed across a wide range of environmental conditions. Here, we explore the biotic and abiotic factors on infestation probability of ticks of the genus Amblyomma and assess the degree of host specificity based on analysis of 1028 birds surveyed across Brazil. We show that tick infestation rates exhibited considerable variation across the 235 avian species analyzed and that the probability of an individual bird being parasitized by immature ticks (larvae and nymphs) increased with annual precipitation. Host phylogeny and two host ecological traits known to promote tick exposure (body mass and foraging behavior) did not predict infestation probability. Moreover, immature ticks displayed a low degree of host specificity at the family level. Lastly, tick occurrence in birds carrying infection with avian malaria and related parasites did not differ from those free of these haemosporidian parasites, indicating a lack of parasite avoidance by immature ticks. Our findings demonstrate that tick occurrence in birds across Brazilian biomes responds to environmental factors rather than ecological and evolutionary host attributes.

Geographic variation in environmental conditions as well as host traits that promote parasite transmission may impact infection rates and community assembly of vector-transmitted parasites. Identifying the ecological, environmental and historical determinants of parasite distributions and diversity is therefore necessary to understand disease outbreaks under changing environments. Here, we identified the predictors and contributions of infection probability and phylogenetic diversity of Leucocytozoon (an avian blood parasite) at site and species levels across the New World. To explore spatial patterns in infection probability and lineage diversity for Leucocytozoon parasites, we surveyed 69 bird communities from Alaska to Patagonia. Using phylogenetic Bayesian hierarchical models and high-resolution satellite remote-sensing data, we determined the relative influence of climate, landscape, geography and host phylogeny on regional parasite community assembly. Infection rates and parasite diversity exhibited considerable variation across regions in the Americas. In opposition to the latitudinal gradient hypothesis, both the diversity and prevalence of Leucocytozoon parasites decreased towards the equator. Host relatedness and traits known to promote vector exposure neither predicted infection probability nor parasite diversity. Instead, the probability of a bird being infected with Leucocytozoon increased with increasing vegetation cover (NDVI) and moisture levels (NDWI), whereas the diversity of parasite lineages decreased with increasing NDVI. Infection rates and parasite diversity also tended to be higher in cooler regions and higher latitudes. Whereas temperature partially constrains Leucocytozoon diversity and infection rates, landscape features, such as vegetation cover and water body availability, play a significant role in modulating the probability of a bird being infected. This suggests that, for Leucocytozoon, the barriers to host shifting and parasite host range expansion are jointly determined by environmental filtering and landscape, but not by host phylogeny. Our results show that integrating host traits, host ancestry, bioclimatic data and microhabitat characteristics that are important for vector reproduction are imperative to understand and predict infection prevalence and diversity of vector-transmitted parasites. Unlike other vector-transmitted diseases, our results show that Leucocytozoon diversity and prevalence will likely decrease with warming temperatures. Fil: Fecchio, Alan. Universidade Federal de Mato Grosso; Brasil Fil: Bell, Jeffrey. University of North Dakota; Estados Unidos Fil: Bosholn, Mariane. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; Brasil Fil: Vaughan, Jefferson. University Of North Dakota; Estados Unidos Fil: Tkach, Vasyl. University Of North Dakota; Estados Unidos Fil: Lutz, Holly. Field Museum Of Natural History; Estados Unidos. University of Chicago; Estados Unidos Fil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Gorosito, Cristian Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: González-Acuña, Daniel. Universidad de Concepción; Chile Fil: Stromlund, Chad. University of North Dakota; Estados Unidos Fil: Kvasager, Danielle. University of North Dakota; Estados Unidos Fil: Comiche, Kiba. Universidade de Sao Paulo; Brasil Fil: Kirchgatter, Karin. Universidade de Sao Paulo; Brasil Fil: Pinho, João. Universidade Federal de Mato Grosso; Brasil Fil: Berv, Jacob. Cornell University; Estados Unidos Fil: Anciães, Marina. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; Brasil Fil: Fontana, Carla S.. Pontificia Universidade Católica do Rio Grande do Sul; Brasil Fil: Zyskowski, Kristof. University of Yale; Estados Unidos Fil: Sampaio, Sidnei. Universidade Federal da Bahia; Brasil Fil: Dispoto, Janice. Academy Of Natural Sciences Philadelphia; Estados Unidos Fil: Galen, Spencer. Academy Of Natural Sciences Philadelphia; Estados Unidos Fil: Weckstein, Jason. Academy Of Natural Sciences Philadelphia; Estados Unidos. Drexel University; Estados Unidos Fil: Clark, Nicholas. The University Of Queensland; Australia

The chewing louse genus Colpocephalum parasitizes nearly a dozen distantly related orders of birds. Such a broad host distribution is relatively unusual in lice. However, the monophyly of the genus Colpocephalum has never been tested using molecular characters. Using one nuclear and one mitochondrial gene, we inferred a phylogeny for 54 lice from the genus Colpocephalum and other morphologically similar genera. The resulting phylogeny demonstrates that Colpocephalum itself is not monophyletic. However, these data support the existence of a Colpocephalum complex within which several lineages are restricted to particular host orders. These lineages corresponded to previously described genera, some of which are morphologically distinct and currently considered subgenera. Maddison–Slatkin tests were performed on the resulting phylogeny and showed that host order, host family and biogeographic region had significant phylogenetic signal when mapped onto the Colpocephalum complex phylogeny. A PARAFIT analysis comparing the overall Colpocephalum complex phylogeny to a host phylogeny revealed significant congruence between host and parasite trees. We also compared the cophylogenetic history of Colpocephalum and their hosts to that of a second distantly related feather louse genus, Degeeriella, which also infests diurnal birds of prey. Using PARAFIT to identify individual host–parasite links that contributed to overall congruence, there was no evidence of correlated cophylogenetic patterns between these two louse groups, suggesting that their host distribution patterns have been shaped by different evolutionary processes.

Identifying the mechanisms driving the distribution and diversity of parasitic organisms and characterizing the structure of parasite assemblages are critical to understanding host-parasite evolution, community dynamics, and disease transmission risk. Haemosporidian parasites of the genera Plasmodium and Haemoproteus are a diverse and cosmopolitan group of bird pathogens. Despite their global distribution, the ecological and historical factors shaping the diversity and distribution of these protozoan parasites across avian communities and geographic regions remains unclear. Here we used a region of the mitochondrial cytochrome b gene to characterize the diversity, biogeographical patterns and phylogenetic relationships of Plasmodium and Haemoproteus infecting Amazonian birds. Specifically, we asked whether, and how, host community similarity and geography (latitude and area of endemism) structure parasite assemblages across 15 avian communities in the Amazon Basin. We identified 265 lineages of haemosporidians recovered from 2661 sampled birds from 330 species. Infection prevalence varied widely among host species, avian communities, areas of endemism, and latitude. Composition analysis demonstrated that both malarial parasites and host communities differed across areas of endemism and as a function of latitude. Thus, areas with similar avian community composition were similar in their parasite communities. Our analyses, within a regional biogeographic context, imply that host switching is the main event promoting diversification in malarial parasites. Although dispersal of haemosporidian parasites was constrained across six areas of endemism, these pathogens are not dispersal-limited among communities within the same area of endemism. Our findings indicate that the distribution of malarial parasites in Amazonian birds is largely dependent on local ecological conditions and host evolutionary relationships. This article is protected by copyright. All rights reserved.

Nearly all lineages of birds host parasitic feather lice. Based on recent phylogenomic studies, the three major lineages of modern birds diverged from each other before the Cretaceous-Paleogene (K-Pg) mass extinction event. In contrast, studies of the phylogeny of feather lice on birds, indicate that these parasites diversified largely after this event. However, these studies were unable to reconstruct the ancestral avian host lineage for feather lice. Here we use genome sequences of a broad diversity of lice to reconstruct a phylogeny based on 1,075 genes. By comparing this louse evolutionary tree to the avian host tree, we show that feather lice began diversifying on the common ancestor of waterfowl and landfowl, then radiated onto other avian lineages by extensive host-switching. Dating analyses and cophylogenetic comparisons revealed that two of three lineages of birds that diverged before the K-Pg boundary acquired their feather lice after this event via host-switching., Robert de Moya et al. use comparative genomics of avian lice to reconstruct the phylogeny of these parasites. They show that feather lice diversified on the common ancestor of waterfowl and landfowl, and then radiated onto other avian lineages through host-switching.

Birds harbor a diverse group of haemosporidian parasites that reproduce and develop in the host blood cells, muscle tissue, and various organs, which can cause negative effects on the survival and reproduction of their avian hosts. Characterization of the diversity, distribution, host specificity, prevalence patterns, and phylogenetic relationships of these parasites is critical to the study of avian host-parasite ecology and evolution and for understanding and preventing epidemics in wild bird populations. Here, we tested whether muscle and liver samples collected as part of standard ornithological museum expeditions can be examined to study the diversity and distributions of haemosporidians in the same way as blood collected from individual birds that are typically banded and released. We used a standard molecular diagnostic screening method for mitochondrial DNA (cytochrome

Unlike most bird species, individual kingfisher species (Aves: Alcedinidae) are typically parasitized by only a single genus of louse (Alcedoffula,Alcedoecus, orEmersoniella). These louse genera are typically specific to a particular kingfisher subfamily. Specifically,AlcedoecusandEmersoniellaparasitize Halcyoninae, whereasAlcedoffulaparasitizes Alcedininae and Cerylinae. AlthoughEmersoniellais geographically restricted to the Indo-Pacific region,AlcedoecusandAlcedoffulaare geographically widespread. We used DNA sequences from two genes, the mitochondrial COI and nuclear EF-1αgenes, to infer phylogenies for the two geographically widespread genera of kingfisher lice,AlcedoffulaandAlcedoecus. These phylogenies included 47 kingfisher lice sampled from 11 of the 19 currently recognized genera of kingfishers. We compared louse phylogenies to host phylogenies to reconstruct their cophylogenetic history. Two distinct clades occur withinAlcedoffula, one that infests Alcedininae and a second that infests Cerylinae. All species ofAlcedoecuswere found only on host species of the subfamily Halcyoninae. Cophylogenetic analysis indicated thatAlcedoecus, as well as the clade ofAlcedoffulaoccurring on Alcedininae, do not show evidence of cospeciation. In contrast, the clade ofAlcedoffulaoccurring on Cerylinae showed strong evidence of cospeciation.

Identifying the ecological factors that shape parasite distributions remains a central goal in disease ecology. These factors include dispersal capability, environmental filters and geographic distance. Using 520 haemosporidian parasite genetic lineages recovered from 7,534 birds sampled across tropical and temperate South America, we tested (a) the latitudinal diversity gradient hypothesis and (b) the distance–decay relationship (decreasing proportion of shared species between communities with increasing geographic distance) for this host–parasite system. We then inferred the biogeographic processes influencing the diversity and distributions of this cosmopolitan group of parasites across South America. We found support for a latitudinal gradient in diversity for avian haemosporidian parasites, potentially mediated through higher avian host diversity towards the equator. Parasite similarity was correlated with climate similarity, geographic distance and host composition. Local diversification in Amazonian lineages followed by dispersal was the most frequent biogeographic events reconstructed for haemosporidian parasites. Combining macroecological patterns and biogeographic processes, our study reveals that haemosporidian parasites are capable of circumventing geographic barriers and dispersing across biomes, although constrained by environmental filtering. The contemporary diversity and distributions of haemosporidian parasites are mainly driven by historical (speciation) and ecological (dispersal) processes, whereas the parasite community assembly is largely governed by host composition and to a lesser extent by environmental conditions. Fil: Fecchio, Alan. Universidade Federal da Bahia; Brasil Fil: Bell, Jeffrey A.. University Of North Dakota; Estados Unidos Fil: Pinheiro, Rafael B.P.. Universidade Federal de Minas Gerais; Brasil Fil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Gorosito, Cristian Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Lutz, Holly L.. Field Museum Of Natural History; Estados Unidos. University of Chicago; Estados Unidos Fil: Gaiotti, Milene G.. Universidade do Brasília; Brasil Fil: Paiva, Luciana V.. Universidade Federal Rural Do Semiárido; Brasil Fil: França, Leonardo F.. Universidade Federal Rural Do Semiárido; Brasil Fil: Toledo-Lima, Guilherme. Universidade Federal do Rio Grande do Norte; Brasil Fil: Tolentino, Mariana. Ministério da Ciência, Tecnologia, Inovações. Instituto Nacional de Pesquisas da Amazônia; Brasil Fil: Pinho, João B.. Universidade Federal de Mato Grosso; Brasil Fil: Tkach, Vasyl V.. University Of North Dakota; Estados Unidos Fil: Fontana, Carla S.. Pontificia Universidade Católica do Rio Grande do Sul; Brasil Fil: Grande, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Pampa; Argentina Fil: Santillan, Miguel Angel. Museo de Historia Natural de la Pampa; Argentina Fil: Caparroz, Renato. Universidade do Brasília; Brasil Fil: Roos, Andrei L.. Instituto Chico Mendes de Conservacao Da Biodiversidade; Brasil. Universidade Federal de Santa Catarina; Brasil Fil: Bessa, Rafael. Sustentar Meio Ambiente Ltda Me; Brasil Fil: Nogueira, Wagner. Universidade Federal de Vicosa; Brasil Fil: Moura, Thiago. Universidade Estadual de Feira de Santana; Brasil Fil: Nolasco, Erica C.. Universidade Estadual de Feira de Santana; Brasil Fil: Comiche, Kiba J.M.. Universidade de Sao Paulo; Brasil Fil: Kirchgatter, Karin. Universidade de Sao Paulo; Brasil Fil: Guimarães, Lilian O.. Universidade de Sao Paulo; Brasil Fil: Dispoto, Janice H.. Drexel University; Estados Unidos Fil: Marini, Miguel Â.. Universidade do Brasília; Brasil Fil: Weckstein, Jason D.. Drexel University; Estados Unidos Fil: Batalha Filho, Henrique. Universidade Federal da Bahia; Brasil Fil: Collins, Michael D.. Rhodes College; Estados Unidos

Corticosterone (CORT) is the main glucocorticoid hormone of amphibians, reptiles, birds and some mammals. This hormone may have evolved as an adaptive metabolic mechanism, in part because increased concentrations of CORT are essential for individuals to manage energy resources and thus cope with negative perturbations such as predation and storms. The benefits of CORT are offset by costs, because elevated levels can suppress inflammatory responses of individuals, making them more susceptible to parasites and pathogens. In this study, we investigated the relationships between feather CORT levels, infection status and diversity of haemosporidian parasites in the Blue-crowned Manakin Lepidothrix coronata, considering possible effects related to the sex and age of individuals. We predicted higher levels of feather CORT in infected individuals. We observed that feather CORT levels were similar among individuals of different sexes and ages. Although haemosporidian infection status did not vary among sexes, occurrence probability was higher among younger individuals, which may indicate that the less developed immune system of these individuals makes them more susceptible to avian malaria. Contrary to expectations, we found that feather CORT levels were not associated with the infection status and diversity of haemosporidian parasites. That haemosporidian occurrence probability does not increase with elevated feather CORT levels suggests that individuals are not immunosuppressed by elevated levels of this hormone, at least to the extent that feather CORT truly reflects individual differences in the level of this hormone., The field data collection was based upon research supported by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (UNIVERSAL number 471092/2012-6 Faixa C to M.A.) and by Fundacao de Amparo a Pesquisa do Estado do Amazonas (PRONEX proj. 003/2009, number 653/2009 to M.A. and Albertina Lima). Hormone analysis was funded by Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (Ciencia sem Fronteiras Chamada No. 71/2013 to M.A., D.G. and Regina Macedo). Haemosporidian laboratory work was funded by NSF DEB-1503804 to J.D.W. During the project, M.B. received a fellowship from Fundacao de Amparo a Pesquisa do Estado do Amazonas (FAPEAM) and Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (CNPq). A.F. was supported by a postdoctoral fellowship (PNPD scholarship) from Coordenacao de Aperfeicoamento de Pessoal de Nıvel Superior (CAPES).

Parasites with low host specificity (e.g. infecting a large diversity of host species) are of special interest in disease ecology, as they are likely more capable of circumventing ecological or evolutionary barriers to infect new hosts than are specialist parasites. Yet for many parasites, host specificity is not fixed and can vary in response to environmental conditions. Using data on host associations for avian malaria parasites (Apicomplexa: Haemosporida), we develop a hierarchical model that quantifies this environmental dependency by partitioning host specificity variation into region- and parasite-level effects. Parasites were generally phylogenetic host specialists, infecting phylogenetically clustered subsets of available avian hosts. However, the magnitude of this specialization varied biogeographically, with parasites exhibiting higher host specificity in regions with more pronounced rainfall seasonality and wetter dry seasons. Recognizing the environmental dependency of parasite specialization can provide useful leverage for improving predictions of infection risk in response to global climate change.

Songbirds host one of the largest, and most poorly understood, groups of lice: the Brueelia-complex. The Brueelia-complex contains nearly one-tenth of all known louse species (Phthiraptera), and the genus Brueelia has over 300 species. To date, revisions have been confounded by extreme morphological variation, convergent evolution, and periodic movement of lice between unrelated hosts. Here we use Bayesian inference based on mitochondrial (COI) and nuclear (EF-1α) gene fragments to analyze the phylogenetic relationships among 333 individuals within the Brueelia-complex. We show that the genus Brueelia, as it is currently recognized, is paraphyletic. Many well-supported and morphologically unified clades within our phylogenetic reconstruction of Brueelia were previously described as genera. These genera should be recognized, and the erection of several new genera should be explored. We show that four distinct ecomorphs have evolved repeatedly within the Brueelia-complex, mirroring the evolutionary history of feather-lice across the entire order. We show that lice in the Brueelia-complex, with some notable exceptions, are extremely host specific and that the host family associations and geographic distributions of these lice are significantly correlated with our understanding of their phylogenetic history. Several ecological phenomena, including phoresis, may be responsible for the macroevolutionary patterns in this diverse group.

Data is presented in support of a phylogenetic reconstruction of one of the largest, and most poorly understood, groups of lice: the Brueelia-complex (Bush et al., 2015 [1]). Presented data include the voucher information and molecular data (GenBank accession numbers) of 333 ingroup taxa within the Brueelia-complex and 30 outgroup taxa selected from across the order Phthiraptera. Also included are phylogenetic reconstructions based on Bayesian inference analyses of combined COI and EF-1α sequences for Brueelia-complex species and outgroup taxa.

Tinamous host the highest generic diversity of lice of any group of birds, as well as hosting representatives of all four avian feather louse ecomorphs. Although the generic diversity of tinamou feather lice is well documented, few attempts have been made to reconstruct the phylogenetic relationships among these lice. To test whether tinamou feather lice form a monophyletic group as a whole, we used whole-genome sequencing to estimate a higher-level phylogeny of tinamou feather lice, together with a broad diversity of other avian feather louse groups. In total, we analysed sequences from over 1000 genes for 48 genera of avian lice using both concatenated and coalescent approaches to estimate the phylogeny of this diverse group of avian feather lice. Although the body louse ecomorph of tinamou feather lice formed a monophyletic group, they did not strictly form a monophyletic group together with the other three ecomorphs of tinamou feather lice. In particular, a clade comprised of several feather louse genera, mainly from South America, is nested phylogenetically within tinamou lice, which also have their main centre of diversity in South America. These results suggest in situ radiation of these parasites in South America.

Variation in susceptibility is ubiquitous in multi-host, multi-parasite assemblages, and can have profound implications for ecology and evolution. The extent to which susceptibility is phylogenetically conserved among hosts is poorly understood and has rarely been appropriately tested. We screened for haemosporidian parasites in 3983 birds representing 40 families and 523 species, spanning ~4500 meters elevation in the tropical Andes. To quantify the influence of host phylogeny on infection status, we applied Bayesian phylogenetic multilevel models that included a suite of environmental, spatial, temporal, life history, and ecological predictors. We found evidence of deeply-conserved susceptibility across the avian tree; host phylogeny explained substantial variation in infection rate, and results were robust to phylogenetic uncertainty. Our study suggests that susceptibility is governed, in part, by conserved, latent aspects of anti-parasite defense. This demonstrates the importance of deep phylogeny for understanding the outcomes of present-day ecological interactions.

Understanding how pathogens and parasites diversify through time and space is fundamental to predicting emerging infectious diseases. Here, we use biogeographic, coevolutionary and phylogenetic analyses to describe the origin, diversity, and distribution of avian malaria parasites in the most diverse avifauna on Earth. We first performed phylogenetic analyses using the mitochondrial cytochrome b (cyt b) gene to determine relationships among parasite lineages. Then, we estimated divergence times and reconstructed ancestral areas to uncover how landscape evolution has shaped the diversification of Parahaemoproteus and Plasmodium in Amazonia. Finally, we assessed the coevolutionary patterns of diversification in this host-parasite system to determine how coevolution may have influenced the contemporary diversity of avian malaria parasites and their distribution among Amazonian birds. Biogeographic analysis of 324 haemosporidian parasite lineages recovered from 4178 individual birds provided strong evidence that these parasites readily disperse across major Amazonian rivers and this has occurred with increasing frequency over the last five million years. We also recovered many duplication events within areas of endemism in Amazonia. Cophylogenetic analyses of these blood parasites and their avian hosts support a diversification history dominated by host switching. The ability of avian malaria parasites to disperse geographically and shift among avian hosts has played a major role in their radiation and has shaped the current distribution and diversity of these parasites across Amazonia.

In the 1850s, two species of "Spotted" Nightingale-Thrush (Aves: Catharus) were independently described from montane rainforests of Guatemala, C. dryas (Gould, 1855) and Ecuador, C. maculatus (Sclater, 1858). However, due to similarities in plumage color, C. maculatus was reclassified as a subspecies of C. dryas in 1878, a decision that has been upheld for 137 years. We collected multiple lines of evidence including phylogenetic analysis of mitochondrial DNA sequences (ND2), discriminant and principal components analysis of morphometric and vocal data, and statistical modeling of ecological niches, that collectively indicate that C. d. dryas and C. d. maculatus are independent species. We recommend restoring species status to C. maculatus of South America and applying the common name Sclater’s Nightingale-Thrush to this species.

Summary Background Patients with metastatic colon cancer (mCRC) are at increased risk of venous thromboembolism (VTE). Limited preclinical data suggest that the oncogene (KRAS) mutational status of the tumor represents a plausible clinical link to systemic hypercoagulability in cancer patients. Objectives To determine if a tumor genetic characteristic, KRAS mutational status, is associated with an increased risk of VTE in patients with mCRC. Patients/methods A retrospective cohort study of patients with mCRC and KRAS test results was conducted at multiple practice sites across New England in the United States. The primary outcome was a VTE event, defined as deep venous thrombosis (DVT) and/or pulmonary embolism (PE), either 6 months before or at any time after the diagnosis of mCRC. KRAS status (mutated vs. wild type) and other relevant predictors of thrombosis were collected. Results Of 172 histologically confirmed patients with mCRC, 40 developed a VTE (23.3%). Sixty-five patients (37.8%) had a mutant KRAS status. The incidence of VTE and DVT among patients with mutated KRAS was 32.3 and 23.1%, respectively. The corresponding incidence among patients with wild-type KRAS was 17.8 and 9.4%. Odd ratios for the association were 2.21 (95% CI, 1.08–4.53) for VTE and 2.62 (95% CI, 1.12–6.12) for DVT, and remained significant despite adjustment for Khorana score and bevacizumab use. Conclusion Tumor mutant KRAS status is associated with an increased risk of VTE in patients with mCRC. The tumor genetic profile may represent a novel and important risk factor for thrombosis in patients with cancer.

The diversity of permanent ectoparasites is likely underestimated due to the difficulty of collecting samples. Lice (Insecta: Phthiraptera) are permanent ectoparasites of birds and mammals; there are approximately 5,000 species described and many more undescribed, particularly in the Neotropics. We document the louse genera collected from birds sampled in Peru (2006–2007) and Colombia (2009–2016), from 22 localities across a variety of ecosystems, ranging from lowland tropical forest and Llanos to high elevation cloud forest. We identified 35 louse genera from a total of 210 bird species belonging to 37 avian families and 13 orders. These genera belong to two suborders and three families of lice: Amblycera, families Menoponidae (present on 131 bird species) and Ricinidae (39 bird species); and Ischnocera, family Philopteridae (119 bird species). We compared our bird-louse associations with data in Price et al. (2003) and recently published Neotropical studies. The majority of bird-louse associations (51.9%) were new, with most of these coming from Passeriformes, the most diverse avian order, with the most poorly known louse fauna. Finally, we found geographical variation in louse infestation and prevalence rates. With this study, we report the first comprehensive documentation of bird-louse associations for Colombia and substantially increase the known associations documented for Peru.

Comparisons of host and parasite phylogenies often show varying degrees of phylogenetic congruence. However, few studies have rigorously explored the factors driving this variation. Multiple factors such as host or parasite morphology may govern the degree of phylogenetic congruence. An ideal analysis for understanding the factors correlated with congruence would focus on a diverse host–parasite system for increased variation and statistical power. In this study, we focused on the Brueelia-complex, a diverse and widespread group of feather lice that primarily parasitise songbirds. We generated a molecular phylogeny of the lice and compared this tree with a phylogeny of their avian hosts. We also tested for the contribution of each host–parasite association to the overall congruence. The two trees overall were significantly congruent, but the contribution of individual associations to this congruence varied. To understand this variation, we developed a novel approach to test whether host, parasite or biogeographic factors were statistically associated with patterns of congruence. Both host plumage dimorphism and parasite ecomorphology were associated with patterns of congruence, whereas host body size, other plumage traits and biogeography were not. Our results lay the framework for future studies to further elucidate how these factors influence the process of host–parasite coevolution.