Malarial parasites as geographical markers in migratory birds?

Estimation in the multinomial reencounter model - Where do migrating animals go and how do they survive in their destination area?

Spatial variation in survival has individual fitness consequences and influences population dynamics. Which space animals use during the annual cycle determines how they are affected by this spatial variability. Therefore, knowing spatial patterns of survival and space use is crucial to understand demography of migrating animals. Extracting information on survival and space use from observation data, in particular dead recovery data, requires explicitly identifying the observation process. We build a fully stochastic model for animals marked in populations of origin, which were found dead in spatially discrete destination areas. The model acts on the population level and includes parameters for use of space, survival and recovery probability. It is based on the division coefficient and the multinomial reencounter model. We use a likelihood-based approach, derive Restricted Maximum Likelihood-like estimates for all parameters and prove their existence and uniqueness. In a simulation study we demonstrate the performance of the model by using Bayesian estimators derived by the Markov chain Monte Carlo method. We obtain unbiased estimates for survival and recovery probability if the sample size is large enough. Moreover, we apply the model to real-world data of European robins Erithacus rubecula ringed at a stopover site. We obtain annual survival estimates for different spatially discrete non-breeding areas. Additionally, we can reproduce already known patterns of use of space for this species.

Dynamics of prevalence and distribution pattern of avian Plasmodium species and its vectors in diverse zoogeographical areas - A review

Avian Plasmodium is of special interest to health care scientists and veterinarians due to the potency of causing avian malaria in non-adapted birds and their evolutionary phylogenetic relationship with human malaria species. This article aimed to provide a comprehensive list of the common avian Plasmodium parasites in the birds and mosquitoes, to specify the common Plasmodium species and lineages in the selected regions of West of Asia, East of Europe, and North of Africa/Middle East, and to determine the contribution of generalist and host-specific Plasmodium species and lineages. The final list of published infected birds includes 146 species, among which Passer domesticus was the most prevalent in the studied areas. The species of Acrocephalus arundinaceus and Sylvia atricapilla were reported as common infected hosts in the examined regions of three continents. The highest numbers of common species of infected birds between continent pairs were from Asia and Europe, and no common record was found from Europe and Africa. The species of Milvus migrans and Upupa epops were recorded as common species from Asia and Africa. The lineage of GRW11 and species of P. relictum were the most prevalent parasites among all the infection records in birds. The most prevalent genus of vectors of avian malaria belonged to Culex and species of Cx. pipiens. The lineage SGS1 with the highest number of occurrence has been found in various vectors comprising Cx. pipiens, Cx. modestus, Cx. theileri, Cx. sasai, Cx. perexiguus, Lutzia vorax, and Culicoides alazanicus. A total of 31 Plasmodium species and 59 Plasmodium lineages were recorded from these regions. SGS1, GRW04, and GRW11, and P. relictum and P. vaughani are specified as common generalist avian malaria parasites from these three geographic areas. The presence of avian Plasmodium parasites in distant geographic areas and various hosts may be explained by the movement of the infected birds through the migration routes. Although most recorded lineages were from Asia, investigating the distribution of lineages in some of the countries has not been done. Thus, the most important outcome of this review is the determination of the distribution pattern of parasite and vector species that shed light on gaps requiring further studies on the monitoring of avian Plasmodium and common vectors extension. This task could be achieved through scientific field and laboratory networking, performing active surveillance and designing regional/continental control programs of birds' malaria and other zoonotic diseases.

Integrating stable isotopes, parasite, and ring-reencounter data to quantify migratory connectivity-A case study with Barn Swallows breeding in Switzerland, Germany, Sweden, and Finland

Ecosystems around the world are connected by seasonal migration. The migrant animals themselves are influenced by migratory connectivity through effects on the individual and the population level. Measuring migratory connectivity is notoriously difficult due to the simple requirement of data conveying information about the nonbreeding distribution of many individuals from several breeding populations. Explicit integration of data derived from different methods increases the precision and the reliability of parameter estimates. We combine ring-reencounter, stable isotope, and blood parasite data of Barn Swallows Hirundo rustica in a single integrated model to estimate migratory connectivity for three large scale breeding populations across a latitudinal gradient from Central Europe to Scandinavia. To this end, we integrated a non-Markovian multistate mark-recovery model for the ring-reencounter data with normal and binomial mixture models for the stable isotope and parasite data. The integration of different data sources within a mark-recapture modeling framework enables the most precise quantification of migratory connectivity on the given broad spatial scale. The results show that northern-breeding populations and Southern Africa as well as southern-breeding populations and Western-Central Africa are more strongly connected through Barn Swallow migration than central European breeding populations with any of the African wintering areas. The nonbreeding distribution of Barn Swallows from central European breeding populations seems to be a mixture of those populations breeding further north and south, indicating a migratory divide.

Stable hydrogen isotope variability within and among plumage tracts (δ2HF) of a migratory wood warbler

Hydrogen isotope analysis of feather keratin (δ²H_F) has become an essential tool for tracking movements between breeding and wintering populations of migratory birds. In particular, δ²H_F has been used to create δ²H_F isoscapes that can be used to assign the geographic origins of molt. The majority of past studies have sampled a portion of a single feather as an isotopic proxy for the entire plumage although surprisingly little is known about variation of stable isotopes within and between feather tracts of individuals in local populations. Here we examine δ²H_F variation in 24 pterylographic variables (9 primaries, 6 secondaries, 6 rectrices, and 3 patches of ventral contour feathers) in individual specimens of black-throated blue warbler (Setophaga caerulescens) breeding in the Big Santeetlah Creek watershed (5350 ha), southern Appalachian Mountains. By restricting our study to territorial ASY males (after second year) inhabiting a small watershed, we could focus on δ²H_F variation generated during the complete prebasic annual molt in a circumscribed population while factoring out age and sexual differences in foraging behavior, isotopic incorporation, and post-breeding dispersal. Summed within-individual variation (δ²H_F) across 24 pterylographic variables ranged from 12 to 60‰ (= 21.8 ± 9.4‰), with 81% of the individuals exhibiting variation ≥ 16‰ (reproducibility of analyses was ≤ 4 ‰). Adjacent feathers in feather tracts tend to have more similar δ²H_F values than feathers grown weeks apart, consistent with the stepwise replacement of flight feathers. The pooled population sample exhibited significant δ²H_F variation in primaries (-78 to -21‰), secondaries (-80 to -17‰), rectrices (-78 to -23‰), and ventral contour feathers (-92 to -32‰). Strong year effects in δ²H_F variation were observed in each of the 24 pterylographic variables. Altitudinal effects were observed only in ventral contour feathers. The current findings demonstrate that within-individual variation (δ²H_F) may be much greater than previously thought in migratory species that molt on or near breeding territories. Our study also highlights the need for greater pterylographic precision in research design of isotope-based studies of avian movement. Within-individual and within-population δ²H_F variation should be incorporated in geographic assignment models. In a broader context, the staggered Staffelmauser pattern of molt in wood warblers provides an exceptional view of the seasonal variation of hydrogen isotopes circulating in blood plasma during the six-week period of annual molt.

Distribution and Prevalence of Haemosporidian Parasites in the Northern Cardinal (Cardinalis cardinalis)

Avian haemosporidian parasites provide a model system for understanding ecological and evolutionary host-parasite interactions. The diversity and distribution of these parasites remains incomplete, and, here, we provide the first range-wide assessment of avian haemosporidians in a continentally distributed host, the Northern Cardinal ( Cardinalis cardinalis ). Based on molecular techniques, we show geographical differences in prevalence and lineage diversity between host subspecies and identify several novel lineages. We use phylogenetic reconstruction to show where these lineages fit into the expanding evolutionary tree of avian haemosporidian lineages. All except 1 subspecies of Northern Cardinal are highly parasitized by a wide diversity of Plasmodium and Parahaemoproteus. Compared to published studies that used microscopy to determine prevalence in this host, we find a much higher number of infected individuals (67.4% vs. 45% or less). Consistent with previous studies, Parahaemoproteus from the Northern Cardinal was found to be highly host specific and geographically structured, whereas Plasmodium was less host specific and geographically unstructured.

Local parasite lineage sharing in temperate grassland birds provides clues about potential origins of Galapagos avian Plasmodium

Oceanic archipelagos are vulnerable to natural introduction of parasites via migratory birds. Our aim was to characterize the geographic origins of two Plasmodium parasite lineages detected in the Galapagos Islands and in North American breeding bobolinks (Dolichonyx oryzivorus) that regularly stop in Galapagos during migration to their South American overwintering sites. We used samples from a grassland breeding bird assemblage in Nebraska, United States, and parasite DNA sequences from the Galapagos Islands, Ecuador, to compare to global data in a DNA sequence registry. Homologous DNA sequences from parasites detected in bobolinks and more sedentary birds (e.g., brown‐headed cowbirds Molothrus ater, and other co‐occurring bird species resident on the North American breeding grounds) were compared to those recovered in previous studies from global sites. One parasite lineage that matched between Galapagos birds and the migratory bobolink, Plasmodium lineage B, was the most common lineage detected in the global MalAvi database, matching 49 sequences from unique host/site combinations, 41 of which were of South American origin. We did not detect lineage B in brown‐headed cowbirds. The other Galapagos‐bobolink match, Plasmodium lineage C, was identical to two other sequences from birds sampled in California. We detected a close variant of lineage C in brown‐headed cowbirds. Taken together, this pattern suggests that bobolinks became infected with lineage B on the South American end of their migratory range, and with lineage C on the North American breeding grounds. Overall, we detected more parasite lineages in bobolinks than in cowbirds. Galapagos Plasmodium had similar host breadth compared to the non‐Galapagos haemosporidian lineages detected in bobolinks, brown‐headed cowbirds, and other grassland species. This study highlights the utility of global haemosporidian data in the context of migratory bird–parasite connectivity. It is possible that migratory bobolinks bring parasites to the Galapagos and that these parasites originate from different biogeographic regions representing both their breeding and overwintering sites.

Local host specialization, host-switching, and dispersal shape the regional distributions of avian haemosporidian parasites

The drivers of regional parasite distributions are poorly understood, especially in comparison with those of free-living species. For vector-transmitted parasites, in particular, distributions might be influenced by host-switching and by parasite dispersal with primary hosts and vectors. We surveyed haemosporidian blood parasites (Plasmodium and Haemoproteus) of small land birds in eastern North America to characterize a regional parasite community. Distributions of parasite populations generally reflected distributions of their hosts across the region. However, when the interdependence between hosts and parasites was controlled statistically, local host assemblages were related to regional climatic gradients, but parasite assemblages were not. Moreover, because parasite assemblage similarity does not decrease with distance when controlling for host assemblages and climate, parasites evidently disperse readily within the distributions of their hosts. The degree of specialization on hosts varied in some parasite lineages over short periods and small geographic distances independently of the diversity of available hosts and potentially competing parasite lineages. Nonrandom spatial turnover was apparent in parasite lineages infecting one host species that was well-sampled within a single year across its range, plausibly reflecting localized adaptations of hosts and parasites. Overall, populations of avian hosts generally determine the geographic distributions of haemosporidian parasites. However, parasites are not dispersal-limited within their host distributions, and they may switch hosts readily.

Coevolutionary patterns and diversification of avian malaria parasites in African sunbirds (Family Nectariniidae)

The coevolutionary relationships between avian malaria parasites and their hosts influence the host specificity, geographical distribution and pathogenicity of these parasites. However, to understand fine scale coevolutionary host–parasite relationships, robust and widespread sampling from closely related hosts is needed. We thus sought to explore the coevolutionary history of avianPlasmodiumand the widespread African sunbirds, family Nectariniidae. These birds are distributed throughout Africa and occupy a variety of habitats. Considering the role that habitat plays in influencing host-specificity and the role that host-specificity plays in coevolutionary relationships, African sunbirds provide an exceptional model system to study the processes that govern the distribution and diversity of avian malaria. Here we evaluated the coevolutionary histories using a multi-gene phylogeny for Nectariniidae and avianPlasmodiumfound in Nectariniidae. We then assessed the host–parasite biogeography and the structuring of parasite assemblages. We recoveredPlasmodiumlineages concurrently in East, West, South and Island regions of Africa. However, severalPlasmodiumlineages were recovered exclusively within one respective region, despite being found in widely distributed hosts. In addition, we inferred the biogeographic history of these parasites and provide evidence supporting a model of biotic diversification in avianPlasmodiumof African sunbirds.

Distribution, prevalence and host specificity of avian malaria parasites across the breeding range of the migratory lark sparrow (Chondestes grammacus)

The lark sparrow (Chondestes grammacus) is a ground-nesting passerine that breeds across much of the central North American steppe and sand barrens. Through genotyping and sequencing of avian malaria parasites we examined levels of malaria prevalence and determined the distribution of Haemoproteus and Plasmodium lineages across the breeding range of the lark sparrow. Analysis of 365 birds collected from five breeding locations revealed relatively high levels of malaria prevalence in adults (80 %) and juveniles (46 %), with infections being primarily of Haemoproteus (91 % of sequenced samples). Levels of genetic diversity and genetic structure of malaria parasites with respect to the avian host populations revealed distinct patterns for Haemoproteus and Plasmodium, most likely as a result of their distinct life histories, host specificity, and transmission vectors. With the exception of one common Haemoproteus haplotype detected in all populations, all other haplotypes were either population-specific or shared by two to three populations. A hierarchical analysis of molecular variance of Haemoproteus sequences revealed that 15-18 % of the genetic variation can be explained by differences among host populations/locations (p < 0.001). In contrast to the regional patterns of genetic differentiation detected for the lark sparrow populations, Haemoproteus parasites showed high levels of population-specific variation and no significant differences among regions, which suggests that the population dynamics of the parasites may be driven by evolutionary processes operating at small spatial scales (e.g., at the level of host populations). These results highlight the potential effects of host population structure on the demographic and evolutionary dynamics of parasites.

Multiple lineages of Avian malaria parasites (Plasmodium) in the Galapagos Islands and evidence for arrival via migratory birds

Haemosporidian parasites in the genus Plasmodium were recently detected through molecular screening in the Galapagos Penguin (Spheniscus mendiculus). We summarized results of an archipelago-wide screen of 3726 endemic birds representing 22 species for Plasmodium spp. through a combination of molecular and microscopy techniques. Three additional Plasmodium lineages were present in Galapagos. Lineage A-infected penguins, Yellow Warblers (Setophaga petechia aureola), and one Medium Ground Finch (Geospiza fortis) and was detected at multiple sites in multiple years [corrected]. The other 3 lineages were each detected at one site and at one time; apparently, they were transient infections of parasites not established on the archipelago. No gametocytes were found in blood smears of infected individuals; thus, endemic Galapagos birds may be dead-end hosts for these Plasmodium lineages. Determining when and how parasites and pathogens arrive in Galapagos is key to developing conservation strategies to prevent and mitigate the effects of introduced diseases. To assess the potential for Plasmodium parasites to arrive via migratory birds, we analyzed blood samples from 438 North American breeding Bobolinks (Dolichonyx oryzivorus), the only songbird that regularly migrates through Galapagos. Two of the ephemeral Plasmodium lineages (B and C) found in Galapagos birds matched parasite sequences from Bobolinks. Although this is not confirmation that Bobolinks are responsible for introducing these lineages, evidence points to higher potential arrival rates of avian pathogens than previously thought. Linajes Múltiples de Parásitos de Malaria Aviar (Plasmodium) en las Islas Galápagos y Evidencia de su Arribo por Medio de Aves Migratorias.

North American transmission of hemosporidian parasites in the Swainson's thrush (Catharus ustulatus), a migratory songbird

The geographic structuring of parasite communities across the range of a single host species can illuminate patterns of host-population connectivity. To determine the location of parasite transmission in a Neotropical migrant bird species, we sampled adult and hatch-year (HY) birds across the breeding and wintering range of the Swainson's thrush (SWTH), an abundant passerine with a migratory divide. We examined the phylogenetic relationships among cytochrome b lineages of the avian blood parasite genera Haemoproteus, Plasmodium, and Leucocytozoon and determined the transmission location of unique lineages. We found that Haemoproteus and Plasmodium lineages are transmitted on California breeding grounds, whereas Leucocytozoon transmission occurs on Alaskan breeding grounds. The presence of hemosporidians on wintering grounds and shared lineages between the SWTH and resident species suggests that transmission of some of these lineages occurs on both breeding and wintering grounds. We emphasize that the sampling of HY birds and local resident heterospecifics will supplement vector studies to determine the key players in hemosporidian host switching and range-expansion events.

Biogeography of avian blood parasites (Leucocytozoon spp.) in two resident hosts across Europe: phylogeographic structuring or the abundance-occupancy relationship?

Relationships between hosts and parasites represent complex co-evolving systems that can vary both temporally and spatially. This variation may result in different phylogeographic outcomes, ranging from highly geographically structured parasite populations comprised of specialist lineages that are locally abundant but have restricted global occupancy to geographically unstructured parasite populations consisting of widespread parasites. Here, we present results from a large biogeographic study of the Leucocytozoon blood parasites of two nonmigrant bird species, conducted at nine sites across Europe. The aim was to determine whether the parasite lineages of the two hosts were phylogeographically structured across Europe. Employing molecular methods, we found a large diversity of parasites, and although overall prevalence varied greatly, the parasites were not genetically structured. Several measures of local parasite abundance were associated with the number of sites that the lineage occurred in, which is consistent with the macroecological phenomenon of the abundance-occupancy relationship. Taken together, our results show that parasite dispersal is somewhat uncoupled to that of the host in this system: we suggest that broad host and/or vector preference may play an important role in determining the distribution of these parasites and in affecting host-parasite coevolution in this system.

Evolutionary diversification, coevolution between populations and their antagonists, and the filling of niche space

The population component of a species' niche corresponds to the distribution of individuals across environments within a region. As evolutionary clades of species diversify, they presumably fill niche space, and, consequently, the rate of increase in species numbers slows. Total niche space and species numbers appear to be relatively stable over long periods, and so an increase in the species richness of one clade must be balanced by decrease in others. However, in several analyses, the total population niche space occupied per clade is independent of the number of species, suggesting that species in more diverse clades overlap more in niche space. This overlap appears to be accommodated by variation in the populations of each species, including their absence, within suitable niche space. I suggest that the uneven filling of niche space results from localized outcomes of the dynamic coevolutionary interactions of populations with their pathogens or other antagonists. Furthermore, I speculate that relationships with pathogens might constrain diversification if pathogen diversity increased with host diversity and resulted in more frequent host switching and emergent disease. Many indirect observations are consistent with these scenarios. However, the postulated influence of pathogens on the filling of niche space and diversification of clades primarily highlights our lack of knowledge concerning the space and time dimensions of coevolutionary interactions and their influence on population distribution and species diversification.

Phylogenetic relationships of haemosporidian parasites in New World Columbiformes, with emphasis on the endemic Galapagos dove

DNA-sequence analyses of avian haemosporidian parasites, primarily of passerine birds, have described the phylogenetic relationships of major groups of these parasites, which are in general agreement with morphological taxonomy. However, less attention has been paid to haemosporidian parasites of non-passerine birds despite morphological and DNA-sequence evidence for unique clades of parasites in these birds. Detection of haemosporidian parasites in the Galapagos archipelago has raised conservation concerns and prompted us to characterise the origins and diversity of these parasites in the Galapagos dove (Zenaida galapagoensis). We used partial mitochondrial cytochrome b (cyt b) and apicoplast caseinolytic protease C (ClpC) genes to develop a phylogenetic hypothesis of relationships of haemosporidian parasites infecting New World Columbiformes, paying special attention to those parasites infecting the endemic Galapagos dove. We identified a well-supported and diverse monophyletic clade of haemosporidian parasites unique to Columbiformes, which belong to the sub-genus Haemoproteus (Haemoproteus). This is a sister clade to all the Haemoproteus (Parahaemoproteus) and Plasmodium parasites so far identified from birds as well as the Plasmodium parasites of mammals and reptiles. Our data suggest that the diverse Haemoproteus parasites observed in Galapagos doves are not endemic to the archipelago and likely represent multiple recent introductions.

Mesoscale patterns of altitudinal tenancy in migratory wood warblers inferred from stable carbon isotopes

We analyzed carbon isotope ratios (delta13C) of liver and pectoral muscle of Black-throated Blue Warblers (Dendroica caerulescens) to provide a mesoscale perspective on altitudinal tenancy in the Appalachian Mountains, North Carolina, U.S.A. Movements of males are poorly understood, particularly the degree to which yearlings (first breeding season) and older males (second or later breeding season) wander altitudinally during the breeding season. Liver and muscle delta13C values of warblers exhibited significant year and altitude effects, but yearling and older males were isotopically indistinguishable. Liver delta13C values increased with altitude at the rate of approximately 0.5% per hundred per 1000 m. The altitudinal lapse rate of muscle delta13C (approximately l1.1% per hundred per 1000 m) was nearly identical to the average rate of increase reported in several groups of C3 plants (approximately 1.1% per hundred per 1000 m). This suggests that the majority of males foraged within relatively narrow altitudinal zones during the breeding season. We caution, however, that the discrimination of altitudinal trends in carbon isotope ratios depends on relatively large multiyear samples. Given the scatter in data, it is unlikely that individuals can be accurately assigned to a particular altitude from carbon isotope values. Rapid adjustment of liver and muscle delta13C values to local altitudinal environments is consistent with the results of experimental dietary studies that show carbon turnover rates are relatively rapid in small migratory passerines. In a broader context, carbon isotope data have been increasingly used as proxies for wintering habitat use of Nearctic-Neotropical migratory passerines. However, tissues with high metabolic rates are unlikely to retain much isotopic signal of wintering habitat use by the time migrants reach their breeding territories.

Host associations and evolutionary relationships of avian blood parasites from West Africa

The host specificity of blood parasites recovered from a survey of 527 birds in Cameroon and Gabon was examined at several levels within an evolutionary framework. Unique mitochondrial lineages of Haemoproteus were recovered from an average of 1.3 host species (maximum=3) and 1.2 host families (maximum=3) while lineages of Plasmodium were recovered from an average of 2.5 species (maximum=27) and 1.6 families (maximum=9). Averaged within genera, lineages of both Plasmodium and Haemoproteus were constrained in their host distribution relative to random expectations. However, while several individual lineages within both genera exhibited significant host constraint, host breadth varied widely among related lineages, particularly within the genus Plasmodium. Several lineages of Plasmodium exhibited extreme generalist host-parasitism strategies while other lineages appeared to have been constrained to certain host families over recent evolutionary history. Sequence data from two nuclear genes recovered from a limited sample of Plasmodium parasites indicated that, at the resolution of this study, inferences regarding host breadth were unlikely to be grossly affected by the use of parasite mitochondrial lineages as a proxy for biological species. The use of divergent host-parasitism strategies among closely related parasite lineages suggests that host range is a relatively labile character. Since host specificity may also influence parasite virulence, these results argue for considering the impact of haematozoa on avian hosts on a lineage-specific basis.