First experimental observation on biology of the avian malaria parasite Plasmodium (Novyella) homonucleophilum (lineage pSW2), with remarks on virulence and distribution.

Species of subgenus Novyella remain most fragmentarily studied amongst avian malaria agents. Transmission of the recently described Plasmodium (Novyella) homonucleophilum (lineage pSW2) occurs broadly in the Old World, including Europe, however biology of this pathogen remains insufficiently investigated. This study provided the first data on the development of P. homonucleophilum in the experimentally infected Eurasian siskins Spinus spinus exposed by inoculation of infected blood. The parasite strain was isolated from a naturally infected song thrush Turdus philomelos, multiplied in vivo, and inoculated to six Eurasian siskins. The same number of birds were used as negative controls. All exposed birds were susceptible, and the controls remained uninfected during the entire study (172 days). Prepatent period was 8-12 days post exposure (dpe). Maximum parasitaemia reached 50-90 % of infected erythrocytes between 20 and 44 dpe. Then, parasitaemia decreased but remained relatively high during the entire observation. Three of six exposed birds died, indicating high virulence of this infection. The parasitaemia increase coincided with a decline of haematocrit value, indicating anaemia. Polychromasia was evident in all infected birds but not in controls. Body mass of exposed birds increased, coinciding with increased food intake. The latter probably is an adaptation to compensate energy loss of hosts due to the long-lasting parasitism. Exo-erythrocytic stages were not found, suggesting that long-lasting parasitaemia was entirely due to erythrocytic merogony. The lineage pSW2 has been reported broadly in the Old World and is likely a generalist infection. Neglected avian Novyella malaria parasites are worth more attention of researchers due to their cosmopolitan distribution and high virulence.

The association between haemosporidian infection and non-breeding moult location in great reed warblers revisited by combining feather stable isotope profiles and geolocator data.

Stable isotope analysis provides valuable insights into the ecology of long-distance migratory birds during periods spent away from a specific study site. In a previous study, Swedish great reed warblers (Acrocephalus arundinaceus) infected with haemosporidian parasites differed in feather isotope ratios compared to non-infected birds, suggesting that infected and non-infected birds spent the non-breeding season in different locations or habitats. Here, we use a novel dataset comprising geolocator data, isotopes, and haemosporidian infection status of 92 individuals from four Eurasian populations to investigate whether parasite transmission varies with geography or habitats. We found that the probability of harbouring Plasmodium and Leucocytozoon parasites was higher in birds moulting in the eastern region of the non-breeding grounds. However, no geographic pattern occurred for Haemoproteus infections or overall infection status. In contrast to the previous study, we did not find any relationship between feather isotope ratios and overall haemosporidian infection for the entire current dataset. Plasmodium-infected birds had lower feather δ15N values indicating that they occupied more mesic habitats. Leucocytozoon-infected birds had higher feather δ34S values suggesting more coastal sites or wetlands with anoxic sulphate reduction. As the composition and prevalence of haemosporidian parasites differed between the old and the current dataset, we suggest that the differences might be a consequence of temporal dynamics of haemosporidian parasites. Our results emphasize the importance of replicating studies conducted on a single population over a restricted time period, as the patterns can become more complex for data from wider geographical areas and different time periods.

Contribution to ecological environmental factors and the occurrence of haemosporidians in birds in Zhongar Alatau National Park, Kazakhstan.

In addition to the presence of a suitable host and vector, the prevalence of haemosporidians is influenced by several important factors, including the environmental conditions of the habitat, which depend on broader geographic characteristics. The aim of this study is to perform a preliminarily assessment of the distribution of blood parasites in birds from the mountainous area of Zhongar Alatau NP and to find potential new sites for research on their ecology in Kazakhstan. The results of this research constitute the first report on the occurrence of blood parasites from this area. A total of 58 birds, from the order Passeriformes and one individual from the order Caprimulgiformes, were examined during the study. The overall prevalence of infections caused by haemosporidian parasites (Haemoproteus, Leucocytozoon) was 18.6%. Neither the genus Plasmodium nor the presence of trypanosomes and microfilariae was detected in the birds examined. Three birds (5.1% prevalence) were infected with parasites of the genus Haemoproteus, in all eleven positive birds the analyses showed the presence of parasites of the genus Leucocytozoon (18.6% prevalence). The presence of parasites genus Haemoproteus was detected only in birds that were also infected with Leucocytozoon parasites. More infections with parasites of the genus Leucocytozoon are predicted due to the higher altitude and ecological factors at the capture sites, which are more favourable for the development of vectors of this genus. The species Haemoproteus majoris was detected in the host Emberiza cioides and species Haemoproteus minutus in host Turdus merula. Other species of this genus in the hosts Cyanistes cyanus and Turdus atrogularis were not determined. The species Leucocytozoon fringilinarum was detected in the hosts Cyanistes cyanus and Parus major, Leucocytozoon dubreuili was detected in Turdus atrogularis and Turdus merula. In the other host species Aegithalos caudatus, Emberiza cioides and Periparus aterus, it was not possible to dermine the species of the genus Leucocytozoon.

Plasticity in the timing of detachment of an Eurasian-African songbird tick, Ixodes frontalis.

In non-permanent parasites, host detachment should take place in an environment that ensures the continuation of their life cycle. Timing of detachment - in combination with the host's space use - affects dispersal and transmission success of the parasites and of the pathogens they vector. Before reaching the adult reproductive stage, ticks need to go through multiple immature developmental stages (larva and nymph), each feeding on host blood. In between the feeding bouts, they often remain in the off-host environment for considerable periods of time. With this study, we aimed to obtain more insight in Ixodes frontalis' off-host habitat use by comparing its detachment pattern in different life stages with that of two habitat-specialized ticks also found on birds: the endophilic tree-hole tick (Ixodes arboricola) and the exophilic sheep tick (Ixodes ricinus), the latter living in humid understory vegetation of forests. For this, we artificially infested hole-roosting (great tits, Parus major) and open-roosting (blackbirds, Turdus merula) birds with ticks under laboratory conditions, and recorded whether detachment occurred during the day or the night. We hypothesize that nocturnal detachment improves off-host mating opportunities and host localization, whereas diurnal detachment optimizes tick dispersal. Ixodes frontalis nymphs detached during the night, especially when feeding on blackbirds. This behaviour was very similar to that of I. arboricola (larva and nymph) feeding on great tits. In contrast, I. frontalis larvae detached during the day, especially when feeding on great tits, which resembles that of I. ricinus' feeding behaviour (larva and nymph). Ixodes frontalis left the host within seven days, immediately after completion of the blood meal. This is similar to both developmental stages of I. ricinus but contrasts with the very long (up to 20 days) feeding duration in I. arboricola. Thus I. frontalis shows strong plasticity, switching from dispersal-centered (larvae) to host-centered (nymphs) detachment behaviour. Findings are discussed with regard to the ticks' habitat use, dispersal, life history and host specificity.

A New Isospora (Apicomplexa: Eimeriidae) from the Carolina Wren, Thryothorus ludovicianus ludovicianus (Passeriformes: Certhioidea: Troglodytidae), in Southeastern Oklahoma, USA.

PURPOSE: Nothing is known of the coccidian parasites of the Carolina wren, Thryothorus ludovicianus ludovicianus (Latham, 1790). Here, we report a new species of Isospora from T. l. ludovicianus from Oklahoma, USA. METHODS: Faecal samples were collected between September and December 2021 from five adult T. l. ludovicianus taken with a mist net from McCurtain County, Oklahoma, USA, and examined for coccidian parasites. Samples were placed in individual vials containing aqueous potassium dichromate. They were examined for coccidia after flotation in Sheather's sugar solution, measured, and photographed. Tissue samples from the intestine of a single positive bird were removed and placed in 10% neutral-buffered formalin for examination of coccidian endogenous stages. RESULTS: A single Carolina wren (20%) was found to be passing a new species of Isospora. Oocysts of Isospora edwardwilsoni n. sp. were subspheroidal to ovoidal with a smooth bi-layered wall, measured (L × W) 23.8 × 20.3 µm, and had a length/width (L/W) ratio of 1.2; a micropyle and oocyst residuum was absent but typically one to up to four polar granule(s) was present. Sporocysts are ovoidal to ellipsoidal and measured 15.3 × 9.7 µm, L/W 1.6; a knob-like Stieda body was present as well as a distinct rounded sub-Stieda body. The sporocyst residuum was composed of various-sized granules in a compact irregular mass or dispersed between and across the sporozoite, or a combination of both within the same sporocyst. Information is also presented on the endogenous development of this coccidian. CONCLUSION: This is the first coccidian reported from T. l. ludovicianus and, more importantly, the first known from the members of the family Troglodytidae in North America.

Exo-erythrocytic development of Plasmodium matutinum (lineage pLINN1) in a naturally infected roadkill fieldfare Turdus pilaris.

BACKGROUND: Species of Plasmodium (Haemosporida, Plasmodiidae) are remarkably diverse haemoparasites. Information on genetic diversity of avian malaria pathogens has been accumulating rapidly, however exo-erythrocytic development of these organisms remains insufficiently addressed. This is unfortunate because, contrary to Plasmodium species parasitizing mammals, the avian malaria parasites undergo several cycles of exo-erythrocytic development, often resulting in damage of various organs. Insufficient knowledge on the exo-erythrocytic development in most described Plasmodium species precludes the understanding of mechanisms of virulence during avian malaria. This study extends information on the exo-erythrocytic development of bird malaria parasites. METHODS: A roadkill fieldfare (Turdus pilaris) was sampled in Switzerland and examined using pathologic, cytologic, histologic, molecular and microbiologic methods. Avian malaria was diagnosed, and erythrocytic and exo-erythrocytic stages of the parasite were identified using morphologic characteristics and barcode DNA sequences of the cytochrome b gene. The species-specific characteristics were described, illustrated, and pathologic changes were reported. RESULTS: An infection with Plasmodium matutinum lineage pLINN1 was detected. Parasitaemia was relatively low (0.3%), with all erythrocytic stages (trophozoites, meronts and gametocytes) present in blood films. Most growing erythrocytic meronts were markedly vacuolated, which is a species-specific feature of this parasite's development. Phanerozoites at different stages of maturation were seen in leukocytes, macrophages, and capillary endothelial cells in most organs examined; they were particularly numerous in the brain. Like the erythrocytic meronts, growing phanerozoites were markedly vacuolated. Conspicuous exo-erythrocytic development and maturation in leucocytes suggests that this fieldfare was not adapted to the infection and the parasite was capable to escape from cellular immunity. CONCLUSIONS: This is the first report of exo-erythrocytic development of the malaria parasite lineage pLINN1 during single infection and the first report of this lineage in the fieldfare. The findings of multiple phanerozoites in brain, skeletal muscle, and eye tissue in combination with signs of vascular blockage and thrombus formation strongly suggest an impaired vision and neuromuscular responsiveness as cause of the unexpected collision with a slowly moving car. Further studies on exo-erythrocytic stages of haemosporidian parasites are pivotal to understand the true level of populational damage of avian malaria in wild birds.

Parasite island syndromes in the context of nidicolous ectoparasites: Fleas (Insecta: Siphonaptera) in wild passerine birds from Azores Archipelago.

Island syndrome, previously established for isolation process of insular vertebrates' populations, have been adapted to insular parasites communities, termed parasite island syndromes. In this work, were studied for the first time the insular syndromes for nidicolous ectoparasites of the bird species, Turdus merula, Sylvia atricapilla, Fringilla coelebs and Erithacus rubecula from Azores and the mainland Portugal. Flea species were only recorded on Azorean birds, namely Dasypsyllus gallinulae and Ctenocephalides felis felis, known as not host-specific parasites. In the absence of shared flea species between mainland and islands birds, a comparison among our fleas prevalence to Azores Islands and mainland fleas prevalence, recorded to others European studies, showed that Azorean host populations undergo higher prevalence than the mainland one. This result was consistent with parasite island syndromes predictions recorded to ectoparasites, hippoboscid flies and chewing lice, that fleas have higher prevalence on the Azores Islands compared to mainland Portugal. However, our results provide a new perspective to parasite island syndromes assumptions, namely in the context of nidicolous ectoparasites that spend only brief periods on the hosts' body.

The interplay between host biogeography and phylogeny in structuring diversification of the feather louse genus Penenirmus.

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 2395 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.

Morishitium polonicum as a Cause of Severe Respiratory Disease in Eurasian Blackbirds (Turdus merula) in Central Italy.

Two Eurasian Blackbirds (Turdus merula) from central Italy were found with severe cyclocoelid trematodosis associated with airsacculitis. The birds were submitted with severe respiratory distress; one died shortly after hospitalization, while the second bird was euthanized. At necropsy, a massive presence of cyclocoelid flukes was observed in the coelomic cavity and air sacs of both birds. The air sacs were diffusely opaque, thickened, and covered by scant fibrinous exudate mixed with numerous parasites. Histologically, the air sacs showed diffuse and severe oedema with fibrinous exudate. Diffuse mononucleated and heterophilic infiltration mixed with multiple granulomas contained degenerated trematodes. Morishitium polonicum was identified using morphologic keys and molecular analysis of extracted DNA. Infections caused by M. polonicum are poorly documented in blackbirds and the findings in these birds support the pathogenic role of this trematode as a potential cause of death in blackbirds in Italy. Extended epidemiologic surveys are required to properly assess the potential importance of M. polonicum as a life-threatening pathogen in Blackbird populations.

Low MSP-1 haplotype diversity in the West Palearctic population of the avian malaria parasite Plasmodium relictum.

BACKGROUND: Although avian Plasmodium species are widespread and common across the globe, limited data exist on how genetically variable their populations are. Here, the hypothesis that the avian blood parasite Plasmodium relictum exhibits very low genetic diversity in its Western Palearctic transmission area (from Morocco to Sweden in the north and Transcaucasia in the east) was tested. METHODS: The genetic diversity of Plasmodium relictum was investigated by sequencing a portion (block 14) of the fast-evolving merozoite surface protein 1 (MSP1) gene in 75 different P. relictum infections from 36 host species. Furthermore, the full-length MSP1 sequences representing the common block 14 allele was sequenced in order to investigate if additional variation could be found outside block 14. RESULTS: The majority (72 of 75) of the sequenced infections shared the same MSP1 allele. This common allele has previously been found to be the dominant allele transmitted in Europe. CONCLUSION: The results corroborate earlier findings derived from a limited dataset that the globally transmitted malaria parasite P. relictum exhibits very low genetic diversity in its Western Palearctic transmission area. This is likely the result of a recent introduction event or a selective sweep.

Atypical Knemidokoptosis in Two Dunnocks (Prunella modularis) in Southern England.

Avian knemidokoptosis, caused by knemidokoptid mites (Knemidokoptinae: Epidermoptidae), has been reported in wild and domestic birds globally. We report two cases of severe knemidokoptosis in Dunnocks (Prunella modularis) from separate sites in Great Britain, where the disease has previously been reported predominantly in finches and, less frequently, in corvids.

Diplotriaena obtusa infection in an Eurasian blue tit (Cyanistes caeruleus) in Germany. Pathology and phylogenetic analysis.

Diplotriaena obtusa is a nematode found in air sacs of a wide number of birds, including Passerine species. During a period of increased mortality of blue tits (Cyanistes caeruleus) in Germany, we collected adult nematode worms from the air sacs of a deceased male blue tit. The nematodes showed morphological features consistent with Diplotriaena ssp. A polymerase chain reaction (PCR) assay targeting the small subunit (SSU) 18S rRNA gene identified the parasite species as Diplotriaena obtusa. Phylogenetic analysis confirmed species identification. Further examinations against infectious pathogens like Suttonella ornithocola, Salmonella spp., Pasteurella spp., Chlamydia spp., Influenza A virus, Usutu virus and West Nile virus were negative. This is the first report of D. obtusa in a blue tit from Germany.

A New Isospora (Apicomplexa: Eimeriidae) from the Summer Tanager, Piranga rubra (Aves: Passeriformes: Cardinalidae), in Oklahoma.

The summer tanager, Piranga rubra (L., 1758) is a medium-sized songbird formerly belonging to the tanager family Thraupidae but now has been placed within the family Cardinalidae. Nothing is known about the coccidian parasites of this stunningly colorful bird. Feces from 2 P. rubra found dead in McCurtain County, Oklahoma were collected and examined for coccidia; 1 was found to be passing a new species of Isospora. Oocysts of Isospora mccurtainensis n. sp. are subspheroidal to ovoidal with a smooth bilayered wall, measure (length × width [L × W]) 21.7 × 19.5 µm, and have a L/W ratio of 1.1; a micropyle and oocyst residuum were absent but a bilobed and refractile polar granule is present. Sporocysts are ellipsoidal and measure 13.9 × 8.6 µm, L/W 1.6; a knoblike Stieda body is present as well as a distinct sub-Stieda body. The sporocyst residuum is composed of a granular compact cluster with a dense, irregular mass of granules lying between and dispersed among the sporozoites. This is the first coccidian reported from P. rubra and, most important, only the first known from the Cardinalidae in the mainland of the United States.

Parasitism is always costly to the host.

Recent studies have examined the cost of raising parasitic cuckoos and highlighted the importance of "no extra cost" in explaining the low levels of defense in hosts. To clarify the reasons for parasitization in typical hosts, we present a simple model to explore the immediate and future costs of parasitism in shaping the evolution of defense behavior in hosts. Our results suggest that any cost of parasitization is maladaptive to the host and learned egg recognition is always favored to overcome these costs. Furthermore, although facing a potential cost of mis-imprinting, learned nestling recognition may still evolve when there is a non-zero immediate cost from raising a parasitic nestling. Therefore, we contend that "no extra cost" does not provide sufficient evidence to explain the low levels of defense behavior in hosts per se.

Sex-specific effects of experimental ectoparasite infestation on telomere length in great tit nestlings.

Telomere length is a biomarker of biological ageing and lifespan in various vertebrate taxa. Evidence is accumulating that telomeres shorten more rapidly when an individual is exposed to environmental stressors. Parasites are potent selective agents that can cause physiological stress directly or indirectly through the activation of the host's immune system. Yet to date, empirical evidence for a role of parasites in telomere dynamics in natural populations is limited. Here, we show experimentally that exposure to ectoparasitic hen fleas (Ceratophyllus gallinae) during growth results in shorter telomeres in female, but not male, great tit (Parus major) nestlings. Females had longer telomeres than males when growing up in experimentally deparasitized nests but, likely because of the sex-specific effects of ectoparasitism on telomere length, this sexual dimorphism was absent in birds growing up in experimentally infested nests. Our results provide the first experimental evidence for a role of ectoparasitism in telomere dynamics in a natural vertebrate population, and suggest that the costs of infection manifest in sex-specific ways.

Emerging helminthiases of song thrush (Turdus philomelos) in Central Europe.

Turdus philomelos is a common Western Palearctic thrush species of forests and agricultural landscapes, where it relies on the presence of hedgerows, patches of trees, and shrubs. In the present study, we address long-term changes in component communities of trematodes in T. philomelos across the timespan of over half a century. Based on our preliminary observations, we hypothesized that component communities of trematodes in T. philomelos in the study area are more diverse and species-rich compared with several decades ago. In the 1961-2019, we performed full-body necropsies of T. philomelos, which originated from the southern Czech Republic, and examined them for the presence of trematodes. We compared the trematode species richness and diversity of the analyzed component communities. The number of trematode species per host steadily increased in time in adult females and males. In juveniles, the highest numbers of trematode species per host were reached already in 1961-1990, then dropped and slowly raised up again in the latter time periods. The newly accumulated evidence suggests that trematodes with intermediate hosts previously restricted to T. philomelos wintering grounds increased in abundance in the study area. Some of them (Morishitium polonicum, Psilotornus confertus) sporadically appeared in juveniles or first-year birds, from which they were previously completely absent. Some of the spreading species, such as Lutztrema attenuatum, are present in high prevalence and high intensities of infection. Yet unknown part of observed changes could be related to changes in food composition; however, direct evidence for changes in T. philomelos diet is lacking despite clear evidence for a decline in earthworms in agricultural landscapes.

Evolution of vector transmitted parasites by host switching revealed through sequencing of Haemoproteus parasite mitochondrial genomes.

Parasite species evolve by switching to new hosts, cospeciating with their current hosts, or speciating on their current hosts. Vector transmitted parasites are expected to speciate by host switching, but confirming this hypothesis has proved challenging. Parasite DNA can be difficult to sequence, thus well resolved parasite phylogenies that are needed to distinguish modes of parasite speciation are often lacking. Here, we studied speciation in vector transmitted avian haemosporidian parasites in the genus Haemoproteus and their warbler hosts (family Acrocephalidae). We overcome the difficulty of generating parasite genetic data by combining nested long-range PCR with next generation sequencing to sequence whole mitochondrial genomes from 19 parasite haplotypes confined to Acrocephalidae warblers, resulting in a well-supported parasite phylogeny. We also generated a well-supported host phylogeny using five genes from published sources. Our phylogenetic analyses confirm that these parasites have speciated by host switching. We also found that closely related host species shared parasites which themselves were not closely related. Sharing of parasites by closely related host species is not due to host geographic range overlap, but may be the result of phylogenetically conserved host immune systems.

Artificial light at night amplifies seasonal relapse of haemosporidian parasites in a widespread songbird.

Urban habitats can shape interactions between hosts and parasites by altering not only exposure rates but also within-host processes. Artificial light at night (ALAN) is common in urban environments, and chronic exposure can impair host immunity in ways that may increase infection. However, studies of causal links between this stressor, immunity, and infection dynamics are rare, particularly in migratory animals. Here, we experimentally tested how ALAN affects cellular immunity and haemosporidian parasite intensity across the annual cycle of migrant and resident subspecies of the dark-eyed junco (Junco hyemalis). We monitored an experimental group exposed to light at night and a control group under natural light/dark cycles as they passed through short days simulating early spring to longer days simulating the breeding season, followed by autumn migration. Using generalized additive mixed models, we show that ALAN increased inflammation, and leucocyte counts were greatest in early spring and autumn. At the start of the experiment, few birds had active infections based on microscopy, but PCR revealed many birds had chronic infections. ALAN increased parasitaemia across the annual cycle, with strong peaks in spring and autumn that were largely absent in control birds. As birds were kept in indoor aviaries to prevent vector exposure, this increased parasitaemia indicates relapse of chronic infection during costly life-history stages (i.e. reproduction). Although the immunological and parasitological time series were in phase for control birds, cross-correlation analyses also revealed ALAN desynchronized leucocyte profiles and parasitaemia, which could suggest a general exaggerated inflammatory response. Our study shows how a common anthropogenic influence can shape within-host processes to affect infection dynamics.

Morphological and molecular data reveal a new species of Lueheia (Acanthocephala: Plagiorhynchidae) from Turdus migratorius (Turdidae) in central Mexico and its phylogenetic implications within the family.

Members of the genus Lueheia Travassos, 1919, are endoparasites of birds, particularly passerines, throughout the Americas. Adults of Lueheia sp., (Plagiorhynchidae Golvan, 1960; Porrorchinae Golvan, 1956) were recovered from the intestine of the American robin (Turdus migratorius phillipsi Bangs) in Mexico City, and two other species of acanthocephalans identified as Porrorchis nickoli, (Plagiorhynchidae: Porrorchinae) Salgado-Maldonado and Cruz-Reyes, 2002 and Centrorhynchus microcephalus (Bravo-Hollis, 1947) Golvan, 1956 (Centrorhynchidae Van Cleave, 1916), were recovered from the Virginia opossum (Didelphis virginiana Allen) and groove-billed ani (Crotophaga sulcirostris Swainson), respectively in southeastern Mexico. Specimens of three species were sequenced at two molecular markers, the small subunit (SSU) and large subunit (LSU) of the nuclear rDNA and compared with other sequences available in GenBank. Maximum likelihood and Bayesian inference analyses of the combined (LSU + SSU) dataset and each individual dataset revealed that the specimens of Lueheia sp. formed an independent lineage, which is recognized herein as a new species, Lueheia aztecae n. sp., representing the fifth species of the genus in the Americas, and the second in the Nearctic region. The new species can be morphologically distinguished from the other five species in the genus by having a cylindrical proboscis, armed with 24-26 longitudinal rows with 9-10 hooks each. Phylogenetic inference performed with the combined dataset consisting of two genes (LSU + SSU) revealed that Lueheia aztecae n. sp. and P. nickoli belonging to subfamily Porrorchinae, formed two independent lineages, indicating that the subfamily is paraphyletic. Porrorchis nickoli and C. microcephalus formed a clade with other species of the genus Centrorhynchus, suggesting that P. nickoli should be transferred to genus Centrorhynchus, to form C. nickoli n. comb. In addition, we briefly discuss the ecological associations between the members of the families Plagiorhynchidae and Centrorhynchidae.

Female-female aggression and male responses to the two colour morphs of female common cuckoos.

Female-only colour polymorphism is rare in birds, but occurs in brood parasitic cuckoos (Cuculidae). Obligate brood parasites leave incubation and parental care to other species (hosts), so female-female interactions can play a role in how parasites guard critical resources (host nests) within their laying areas. The plumage of adult female common cuckoos (Cuculus canorus) is either rufous (typically rare) or grey (common), whereas adult male conspecifics are monochromatic (grey). In previous studies, hosts and conspecific males responded with less intensity toward the rare female morph in support of a negative frequency-dependent benefit of female plumage polychromatism. Here, we assessed responses of both conspecific females and males to vocal playbacks of female calls, coupled with one of two 3D models of the different morphs of female cuckoos. At our study population, the rufous female morph was as common as the grey morph; therefore, we predicted similarly high rates of conspecific responses in both treatments. Both female and male cuckoos responded to playbacks acoustically, which demonstrated the primary role of acoustic communication in social interactions amongst cuckoos. Following this, some cuckoos flew closer to the models to inspect them visually. As predicted, no significant differences were detected between the live cuckoos' responses toward the two colour morphs in this population. We conclude that dichromatism in female cuckoos evolved to serve one or more functions other than conspecific signalling.