Feather mites (Acari: Astigmata) and body condition of their avian hosts: a large correlative study

Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative effects of feather mites on their hosts and others reporting positive or no effects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing‐dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). The overall effect size was only slightly positive (r =0.066). The effect of feather mite abundance explained <10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefit from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefit from the presence of feather mites.     

Unexpected bird–feather mite associations revealed by DNA metabarcoding uncovers a dynamic ecoevolutionary scenario

The high relevance of host‐switching for the diversification of highly host‐specific symbionts (i.e., those commonly inhabiting a single host species) demands a better understanding of host‐switching dynamics at an ecological scale. Here, we used DNA metabarcoding to study feather mites on passerine birds in Spain, sequencing mtDNA (COI) for 25,540 individual mites (representing 64 species) from 1,130 birds (representing 71 species). Surprisingly, 1,228 (4.8%) mites from 84 (7.4%) birds were found on host species that were not the expected to be a host according to a recent bird–feather mite associations catalog. Unexpected associations were widespread across studied mite (40.6%) and bird (43.7%) species and showed smaller average infrapopulation sizes than typical associations. Unexpected mite species colonized hosts being distantly related to the set of their usual hosts, but with similar body size. The network of bird–mite associations was modular (i.e., some groups of bird and mite species tended to be more associated with each other than with the others), with 75.9% of the unexpected associations appearing within the module of the typical hosts of the mite species. Lastly, 68.4% of mite species found on unexpected hosts showed signatures of genetic differentiation, and we found evidence for reproduction or the potential for it in many of the unexpected associations. Results show host colonization as a common phenomenon even for these putatively highly host‐specific symbionts. Thus, host‐switching by feather mites, rather than a rare phenomenon, appears as a relatively frequent phenomenon shaped by ecological filters such as host morphology and is revealed as a fundamental component for a dynamic coevolutionary and codiversification scenario.     

The phenomenon of phylogenetic synhospitality in acariform mites (acari: acariformes)--the permanent parasites of vertebrates

The term synhospitality means the association of two or more closely related parasite species with one host species (Eichler, 1966). The cases of two or three synhospitalic species are known from the same host species, and especially ones where parasites were recorded from different parts of the host range, are quite common. The most ordinary reason causing synhospitality in permanent parasites is the host switching. Nevertheless, there are a number of synhospitality cases, where the parasite complex is monophyletic because evolved on a single host species. The special term--"phylogenetic synhospitality" (FS) is proposed for these cases of synhospitality. Most known cases of FS in acariform mites, permanent parasites of vertebrates, are analysed. It is found out that both astigmatan and prostigmatan parasite mites demonstrate a numbers of FS. The majority of these examples represent parasitism of two or three synhospitalic parasite species. Impressive examples of FS involving a number of synhospitalic species is shown by only astigmatan mites inhabiting the fur of mammals or plumage of birds. Most known examples involving four or more mite species are discussed: 51 mite species of the genus Schizocarpus (Chirodiscidae) parasitizing Castor fiber and C. canadensis (Castoridae); 6 species of Listrophorus spp. (Listrophoridae) from Ondatra zibethicus (Cricetidae); 23 species of Listrophoroides s. 1. (Atopomelidae) from Maxomys surifer (Muridae); 21 species of Cytostethum (Atomelidae) from Potorous tridactylus (Potoridae); 4 species of Listrophoroides (Afrolistrophoroides) from Malacomys longipes (Muridae); 7 species of Fainalges (Xolalgidae) from Aratinga holochlora (Psittacidae); 4 species of Zygepigynia (Pteronyssidae) from Chrysocolaptes lucidus (Picidae). The main reason of FS is that, in spite of the Fahrenholz's rule, the speciation of many parasites proceeds much more intensively than in their hosts because of the more rapid replacement of the parasitic generations. The first factor causing FS is the mite speciation it temporary segregated populations of the host (allopatric speciation). In this case, the "multispecies complexes" appeared after the subsequent reintegration of the host populations formerly isolated. The second factor is the speciation due to the specialization of mites to local microhabitats in the fur or plumage of host (sympatric or synxenic speciation). The second way of speciation is most characteristic for mites with highly specialized attaching structures. The phenomenon of FS more resides in ectoparasites of mammals rather than in feather mites in spite of much more structural complicacy of plumage rather than the fur. The high mobility of birds and wide dispersion of their new generations probably embarrass the process of sympatric speciation in their parasites. As a rule, only really significant geographical barriers play role for population isolation in birds. Thus, it could be concluded that two independent factors or their combination lead to FS. (i) The complex and/or disjunctive host range giving a possibility for allopatric speciation in parasites. (ii) The deep mite specialization to local microhabitats on the host body causing sympatric (synxenic) speciation. Fur of mammals and plumage of birds are very complicated in structure and microconditions and provide a considerable number of different microhabitats for mites inhabiting them. The prevalence of one of these two factors depends on the biological peculiarities of both parasites and their hosts. In mites with lesser specialized attaching organs, for example in atopomelids, allopatric speciation dominates. In mites with strongly specialized attaching organs, for example in listrophorids or chirodiscids, both pathways of speciation may take place. In feather mites, sympatric speciation should be more probable due to quite complicate and various structure of feathers in avian hosts. In fur mites, sympatric speciation is more likely in mites parasitizing hosts with peculiar ecology, for example in semiaquatic rodents possessing quite different fur structure in different parts of the body.     

Origin and Evolution of Feather Mites (Astigmata)

Feather mites are highly specialized plumage and skin ectoparasites that are variously adapted for inhabiting certain microhabitats on a bird's body. Different feather mite taxa of higher (familial) rank adapted to the same microhabitats display similar main morphological adaptations even if they are rather distantly related to one another. Hypotheses on the evolution of general adaptations in morphology of feather mites during colonization and establishment in different microhabitats are presented. According to recent data, feather mites are a paraphyletic group consisting of three superfamilies: Analgoidea, Pterolichoidea and Freyanoidea. We present our view on the general feather mite phylogeny course at the familial rank for the Analgoidea by means of cladistic analysis. Co-speciation of parasites with their hosts is postulated as a main factor driving feather mite evolution. Examples are given of non-coevolutionary events, for example recolonization from one host species onto another, extinction and multiple speciation.     

Feather mite abundance increases with uropygial gland size and plumage yellowness in Great Tits Parus major

Plumicolous feather mites are ectosymbiotic organisms that live on bird feathers. Despite their abundance and prevalence among birds, the ecology of the interaction between these organisms and their hosts is poorly known. As feather mites feed on oil that birds spread from their uropygial gland, it has been hypothesized, but never tested, that the number of feather mites increases with the size of the uropygial gland of their hosts. In this study the number of feather mites is considered with respect to uropygial gland size in a breeding population of Great Tits Parus major in order to test this hypothesis. As predicted, the number of feather mites correlated positively with the uropygial gland size of their hosts, showing for the first time that uropygial gland size can explain the variance in feather mite load among conspecifics. Previous studies relating feather mite load to plumage colour have suggested that feather mites may be parasitic or neutral. To confirm this, the yellowness of breast feathers was also assessed. However, the results ran in the opposite direction to that expected, showing a positive correlation between mite load and plumage yellowness, which suggests that further work is needed to give clear evidence for a specific nature of feather mites. However, Great Tits with higher mite loads had lower hatching and breeding success, which may support the idea that feather mites are parasites, although this effect must be taken with caution because it was only found in males. Age or sex effects were not found on the number of feather mites, and it is proposed that hormonal levels may not be sufficient to explain the variation in feather mite loads. Interestingly, a positive correlation was detected between uropygial gland size and plumage brightness, which could be a novel factor to take into account in studies of plumage colour.     

Fine‐tuned distribution of feather mites (Astigmata) on the wing of birds: the case of blackcaps Sylvia atricapilla

The distribution of feather mites (Astigmata) along the wing of passerine birds could change dramatically within minutes because of the rapid movement of mites between feathers. However, no rigorous study has answered how fine‐tuned is the pattern of distribution of feather mites at a given time. Here we present a multiscale study of the distribution of feather mites on the wing of non‐moulting blackcaps Sylvia atricapilla in a short time period and at a single locality. We found that the number and distribution of mites differed among birds, but it was extremely similar between the wings of each bird. Moreover, mites consistently avoided the first secondary feather, despite that it is placed at the centre of the feathers most used by them. Thus, our results suggest that feather mites do precise, feather‐level decisions on where to live, contradicting the current view that mites perform “mass”, or “blind” movements across wing feathers. Moreover, our findings indicate that “rare” distributions are not spurious data or sampling errors, but each distribution of mites on the wing of each bird is the outcome of the particular conditions operating on each ambient‐bird‐feather mite system at a given time. This study indicates that we need to focus on the distribution of feather mites at the level of the individual bird and at the feather level to improve our understanding of the spatial ecology of mites on the wings of birds.     

Feather mites and birds: an interaction mediated by uropygial gland size?

Feather mites (Arachnida: Acari: Astigmata) feed mainly on secretions of the uropygial gland of birds. Here, we use analyses corrected for phylogeny and body size to show that there is a positive correlation between the size of this gland and mite abundance in passerine birds at an interspecific level during the breeding season, suggesting that the gland mediates interactions between mites and birds. As predicted on the basis of hypothesized waterproofing and antibiotic functions of uropygial gland secretions, riparian/marsh bird species had larger glands and higher mite loads than birds living in less mesic terrestrial environments. An unexpected pattern was a steeper relationship between mite load and gland size in migratory birds than in residents. If moderate mite loads are beneficial to a host but high loads detrimental, this could create complex selection regimes in which gland size influences mite load and vice versa. Mites may exert selective pressures on gland size of their hosts that has resulted in smaller glands among migratory bird species, suggesting that smaller glands may have evolved in these birds to attenuate a possible detrimental effect of feather mites when present in large numbers.     

Fine-tuned distribution of feather mites (Astigmata) on the wing of birds: the case of blackcaps Sylvia atricapilla

The distribution of feather mites (Astigmata) along the wing of passerine birds could change dramatically within minutes because of the rapid movement of mites between feathers. However, no rigorous study has answered how fine-tuned is the pattern of distribution of feather mites at a given time. Here we present a multiscale study of the distribution of feather mites on the wing of non-moulting blackcaps Sylvia atricapilla in a short time period and at a single locality. We found that the number and distribution of mites differed among birds, but it was extremely similar between the wings of each bird. Moreover, mites consistently avoided the first secondary feather, despite that it is placed at the centre of the feathers most used by them. Thus, our results suggest that feather mites do precise, feather-level decisions on where to live, contradicting the current view that mites perform "mass", or "blind" movements across wing feathers. Moreover, our findings indicate that "rare" distributions are not spurious data or sampling errors, but each distribution of mites on the wing of each bird is the outcome of the particular conditions operating on each ambient-bird-feather mite system at a given time. This study indicates that we need to focus on the distribution of feather mites at the level of the individual bird and at the feather level to improve our understanding of the spatial ecology of mites on the wings of birds.     

Different scales of spatial segregation of two species of feather mites on the wings of a passerine bird

The "condition-specific competition hypothesis" proposes that coexistence of 2 species is possible when spatial or temporal variations in environmental conditions exist and each species responds differently to those conditions. The distribution of different species of feather mites on their hosts is known to be affected by intrinsic host factors such as structure of feathers and friction among feathers during flight, but there is also evidence that external factors such as humidity and temperature can affect mite distribution. Some feather mites have the capacity to move through the plumage rather rapidly, and within-host variation in intensity of sunlight could be one of the cues involved in these active displacements. We analyzed both the within- and between-feather spatial distribution of 2 mite species, Trouessartia bifurcata and Dolichodectes edwardsi , that coexist in flight feathers of the moustached warbler Acrocephalus melanopogon. A complex spatial segregation between the 2 species was observed at 3 spatial levels, i.e., "feather surfaces," "between feathers," and "within feathers." Despite certain overlapping distribution among feathers, T. bifurcata dominated proximal and medial regions on dorsal faces, while D. edwardsi preferred disto-ventral feather areas. An experiment to check the behavioral response of T. bifurcata to sunlight showed that mites responded to light exposure by approaching the feather bases and even leaving its dorsal face. Spatial heterogeneity across the 3 analyzed levels, together with response to light and other particular species adaptations, may have played a role in the coexistence and segregation of feather mites competing for space and food in passerine birds.     

Geographical structuring of feather mite assemblages from the Australian brush-turkey (Aves: Megapodiidae)

Populations of a host species may exhibit different assemblages of parasites and other symbionts. The loss of certain species of symbionts (lineage sorting, or "missing-the-boat") is a mechanism by which geographical variation in symbiont assemblages can arise. We studied feather mites and lice from Australian brush-turkeys (Aves: Megapodiidae: Alectura lathami) and expected to observe geographical structuring in arthropod assemblages for several reasons. First, because the brush-turkey is a sedentary ground-dwelling bird, we predicted that geographically close host populations should share more similar arthropod assemblages than distant ones. Second, because brush-turkeys do not brood their young, vertical transfer of arthropods is unlikely, and brush-turkeys probably acquire their mites and lice at social maturity through contact with other birds. Young birds could disperse and found new populations without carrying complete sets of symbionts. We predicted that young birds would have fewer species of arthropods than older birds; in addition, we expected that males (which are polygynous) would have more species than females. Birds were sampled from 12 sites (=populations) along the east coast of Queensland, Australia, that were separated by a distance of 12.5-2,005 km. In total, 5 species of mites from the Pterolichidae and 1 species from the Ascouracaridae were found. Two species of lice were collected but in numbers too low to be statistically useful. Differentiation of mite assemblages was evident; in particular, Leipobius sp. showed 100% prevalence in 3 host populations and 0% in the remaining 9. A dendrogram of brush-turkey populations based on mite assemblages showed 2 geographically correlated clusters of sites, plus 1 cluster that contained 2 sites near Brisbane and 1 approximately at a distance of 1,000 km. There was no strong effect of host age or sex on number of mite species carried. Horizontal transfer of feather mites by hippoboscid flies, in addition to physical contact between hosts, may play a role in homogenizing symbiont assemblages within populations.     

Cophylogenetic assessment of New World warblers (Parulidae) and their symbiotic feather mites (Proctophyllodidae)

Host–symbiont relationships are ubiquitous in nature, yet evolutionary and ecological processes that shape these intricate associations are often poorly understood. All orders of birds engage in symbioses with feather mites, which are ectosymbiotic arthropods that spend their entire life on hosts. Due to their permanent obligatory association with hosts, limited dispersal and primarily vertical transmission, we hypothesized that the cospeciation between feather mites and hosts within one avian family (Parulidae) would be perfect (strict cospeciation). We assessed cophylogenetic patterns and tested for congruence between species in two confamiliar feather mite genera (Proctophyllodidae: Proctophyllodes, Amerodectes) found on 13 species of migratory warblers (and one other closely related migratory species) in the eastern United States. Based on COI sequence data, we found three Proctophyllodes lineages and six Amerodectes lineages. Distance‐ and event‐based cophylogenetic analyses suggested different cophylogenetic trajectories of the two mite genera, and although some associations were significant, there was little overall evidence supporting strict cospeciation. Host switching is likely responsible for incongruent phylogenies. In one case, we documented prairie warblers Setophaga discolor harboring two mite species of the same genus. Most interestingly, we found strong evidence that host ecology may influence the likelihood of host switching occurring. For example, we documented relatively distantly related ground‐nesting hosts (ovenbird Seiurus aurocapilla and Kentucky warbler Geothlypis formosa) sharing a single mite species, while other birds are shrub/canopy or cavity nesters. Overall, our results suggest that cospeciation is not the case for feather mites and parulid hosts at this fine phylogenetic scale, and raise the question if cospeciation applies for other symbiotic systems involving hosts that have complex life histories. We also provide preliminary evidence that incorporating host ecological traits into cophylogenetic analyses may be useful for understanding how symbiotic systems have evolved.     

Species mtDNA genetic diversity explained by infrapopulation size in a host‐symbiont system

Understanding what shapes variation in genetic diversity among species remains a major challenge in evolutionary ecology, and it has been seldom studied in parasites and other host‐symbiont systems. Here, we studied mtDNA variation in a host‐symbiont non‐model system: 418 individual feather mites from 17 feather mite species living on 17 different passerine bird species. We explored how a surrogate of census size, the median infrapopulation size (i.e., the median number of individual parasites per infected host individual), explains mtDNA genetic diversity. Feather mite species genetic diversity was positively correlated with mean infrapopulation size, explaining 34% of the variation. As expected from the biology of feather mites, we found bottleneck signatures for most of the species studied but, in particular, three species presented extremely low mtDNA diversity values given their infrapopulation size. Their star‐like haplotype networks (in contrast with more reticulated networks for the other species) suggested that their low genetic diversity was the consequence of severe bottlenecks or selective sweeps. Our study shows for the first time that mtDNA diversity can be explained by infrapopulation sizes, and suggests that departures from this relationship could be informative of underlying ecological and evolutionary processes.     

First detection of Anaplasma phagocytophilum in quill mites (Acari: Syringophilidae) parasitizing passerine birds

Forest passerine birds and their ectoparasites: Ixodes ricinus ticks and Syringophilidae quill mites were surveyed for infection with Anaplasma phagocytophilum in west-central Poland. Of 126 birds captured from May to June of 2002, 71 (56.3%) comprising eight species, hosted immature I. ricinus ticks. A total of 383 ticks and 71 blood samples collected from tick-infested birds were investigated by PCR. The pathogen was not detected in either bird-derived ticks or in blood samples. Among the captured birds, a total of 14 individuals representing four species hosted quill mites from the family Syringophilidae. Three of the 14 mite pools recovered from the 14 mite-infested birds harbored A. phagocytophilum DNA by amplifying both the epank1 and p44 gene. The PCR-positive pools originated from one blackbird and two starlings. The specific biology of syringophilid mites, which parasitize exclusively inside the quill of feathers, feeding on host subcutaneous fluids, implies that they must have acquired the pathogen from a bacteremic bird. These results provide the first indirect evidence that at least some passerine hosts are prone to develop systemic infection with A. phagocytophilum under natural conditions. Consequently, the infected quill mites may serve as a "biological marker" of past or current infection with the agent within birds.     

Feather mites play a role in cleaning host feathers: New insights from DNA metabarcoding and microscopy

Parasites and other symbionts are crucial components of ecosystems, regulating host populations and supporting food webs. However, most symbiont systems, especially those involving commensals and mutualists, are relatively poorly understood. In this study, we have investigated the nature of the symbiotic relationship between birds and their most abundant and diverse ectosymbionts: the vane‐dwelling feather mites. For this purpose, we studied the diet of feather mites using two complementary methods. First, we used light microscopy to examine the gut contents of 1,300 individual feather mites representing 100 mite genera (18 families) from 190 bird species belonging to 72 families and 19 orders. Second, we used high‐throughput sequencing (HTS) and DNA metabarcoding to determine gut contents from 1,833 individual mites of 18 species inhabiting 18 bird species. Results showed fungi and potentially bacteria as the main food resources for feather mites (apart from potential bird uropygial gland oil). Diatoms and plant matter appeared as rare food resources for feather mites. Importantly, we did not find any evidence of feather mites feeding upon bird resources (e.g., blood, skin) other than potentially uropygial gland oil. In addition, we found a high prevalence of both keratinophilic and pathogenic fungal taxa in the feather mite species examined. Altogether, our results shed light on the long‐standing question of the nature of the relationship between birds and their vane‐dwelling feather mites, supporting previous evidence for a commensalistic–mutualistic role of feather mites, which are revealed as likely fungivore–microbivore–detritivore symbionts of bird feathers.     

Dynamics of infection of Fringilla coelebs chaffinch nestlings with feather mites (Acari: Analgoidea)

A process of infecting the chaffinch nestlings Fringilla coelebs with three analgoid feather mites, Analges passerinus L., 1758, Monojoubertia microphylla (Robin, 1877), and Pteronyssoides striatus (Robin, 1977), commonly occurred on this bird species was investigated. 15 nests contained totally 65 nestlings, from 2 to 6 individuals in a brood, have been examined from the day of hatching till 11th day. Observations were held in the neighbourhood of the bird banding station "Rybachy" (Russia, Kaliningrad Province) in June of 1982. Number of mites on alive nestlings taken temporarily from their nest was counted by means of binocular lens under the magnification x12.5 and x25. The nestlings receive the mites from the chaffinch female during the night time, when the female sits together with the young birds and heats them. In the condition of this prolonged direct contact the mites migrate from the female onto the nestlings. As it was shown in our study of seasonal dynamics of mites on the chaffinch (Mironov, 2000), the chaffinch female only gives its mites to young generation and looses about three quarter of its mite micropopulation during the nesting period (June), hile in the chaffinch males the number of mites continues to increase during all summer. The infections with three feather mite species happen in the second part of the nestling's stay in the nest. The starting time of this process, its intensity, and sex and age structure of mite micropopulations on the nestlings just before their leaving the nest are different in the mite species examined. These peculiarities of feather mite species are determined by the biology of examined species, and first of all by their morphological characteristic and specialisation to different microhabitats, i.e. certain structural zones of plumage. Pteronyssoides striatus (Pteronyssidae) is rather typical mite specialised to feathers with vanes. In adult birds with completely developed plumage this species occupies the ventral surface of the big upper coverts of primary flight feathers. This species appears on the chaffinch nestlings in a significant number on 7th day. The mites occupy the basal parts of primary flight feathers represented in that moment by the rods only. They sit on practically open and smooth surface of this microhabitat, which is uncommon for them, because the vanes of the big upper coverts are not yet open and also represented by thin rods. During the period of the last 5 days (from 7 to 11th day) the mean number of mites per one nestling increases from 2.3 +/- 0.5 to 17.1 +/- 1.8 mites. Just before the day, when the nestling leave the nest, the tritonymphs absolutely predominate (82.4%) in the micropopulation of P. striatus. Analges passerinus (Analgidae) is specialised to live in the friable layer formed by numerous not-engaged thread barbles of the down feathers and basal parts of the body covert feathers. Mites have special hooks on legs used for hard attaching to the barbles and for fast moving in the friable layer of feathers. On the chaffinch nestlings, these mites appear usually on 8th day, when the rod-like body covert feathers begin to open on apices and form short brushes; however some individuals occur on the skin of nestlings even on 6th day. The mean number of mites per nestling on the 11th day reaches 16.5 +/- 1.4 individuals. The micropopulation of A. passerinus is represented on the nestlings mainly by the females (45.5%), tritonymphs (23.6%) and males (11.5%). Monojobertia microphylla (Proctophyllodidae) is a typical dweller of feathers with large vanes. Mites of this species commonly occupy the ventral surface of primary and secondary flight feathers and also respective big upper covert feathers of wings. M. microphylla appears on the nestlings in a significant number (7.1 +/- 1.2 mites) on 9th day, only when the primary flight feathers already have short vanes about 10 mm in length. In next three days the number of mites increases very fast and reaches on 11th day 60.3 +/- 5.7 mites per nestling. In the micropopulation of this species, the tritonymphs count 38.3%, and the quota of males and females is 25.3% each. The migration of this species goes most intensively, than in two other species. An analitic selection of logistic curves shows, that the increasing of mite number during the process of infection with three mite species may be most adequately described by the sigmoid curves with clearly recognizable levels of saturation, which can be theoretically reached. Indeed, the number of mite individuals being able to migrate onto the nestlings is limited by their number on a respective chaffinch female. In a contrast, the increasing of plumage indices, for instance the length of flight feathers, has almost linear character during the period of observation. The beginning of mite migration is determined by the development of respective microhabitats in the plumage of nestlings, or at least by the development of certain structure elements of plumage, where mites are able to attach for a while, before that moment, when the nestlings will develop the plumage completely and begin to fly. In three mite species examined, the process of infection was performed by older stages, namely by the imago and/or tritonymphs. This can be explained by two reasons. On the one hand, the older stages are most active in their movement, resistible and able to survive successfully on new host individuals. On the other hand, the older stage are ready for the reproduction or will be ready after one moulting. The older stages of mites can quickly create a large and self-supporting micropopulations on the birds, therefore this strategy ensures a successful subsequent existence of the parasite species. In cases, when mites (A. passerinus, M. microphylla) migrate into the respective microhabitats structurally corresponding to their normal microhabitats on adult birds, the micropopulations of these mite species include a significant or dominant quota of females and males. When the normal microhabitat is not yet formed, feather mites migrate into neighboring structure elements of plumage, where they can survive and wait for the development of normal microhabitat, to which they are well adapted. Therefore, in the case of P. striatus, its micropopulations on the chaffinch nestlings are represented mainly by the tritonymphs.     

New hosts for the mite Ornithonyssus bursa in Argentina

The mite Ornithonyssus bursa (Berlese) (Mesostigmata: Macronyssidae) is considered a poultry pest causing important infestations in chickens and it is considered a potential vector of arbovirus. Despite being considered a common parasite in wild birds, there is scarce published information about its potential hosts and effects on them. Here we present new bird hosts for O. bursa, assess the presence of Alphavirus, Flavivirus and Bunyavirus in mites from three host species, and discuss its potential impact on wild bird populations. We found O. bursa infecting five raptor and six passerine wild bird species. For nine of these species, this is the first record of infection by O. bursa. Although all analysed mites were negative for the examined arboviruses, the small sample size of mites does not allow further conclusions at the present moment. Because of the general nature of this ectoparasite, its presence in migratory long dispersal and endangered bird species, and the seropositivity for arboviruses in some of the species studied here, we consider it critical to assess the role of O. bursa and other ectoparasites as vectors and reservoirs of pathogens and as potential deleterious agents in wild bird populations.     

Detecting ancient codispersals and host shifts by double dating of host and parasite phylogenies: Application in proctophyllodid feather mites associated with passerine birds

Inferring cophylogeographic events requires matching the timing of these events on both host and symbiont (e.g., parasites) phylogenies because divergences of hosts and their symbionts may not temporally coincide, and host switches may occur. We investigate a large radiation of birds (Passeriformes) and their permanent symbionts, the proctophyllodid feather mites (117 species from 116 bird species; six genes, 11,468 nt aligned) using two time‐calibration strategies for mites: fossils only and host phylogeography only. Out of 10 putative cophylogeographic events 4 agree in timing for both symbiont and host events being synchronous co‐origins or codispersals; three were based on host shifts, but agree in timing being very close to the origin of modern hosts; two disagree; and one large basal mite split was seemingly independent from host phylogeography. Among these events was an ancient (21–25.3 Mya), synchronous codispersal from the Old World leading to the origin and diversifications of New World emberizoid passerids and their mites, the thraupis + quadratus species groups of Proctophyllodes. Our framework offers a more robust detection of host and symbiont cophylogeographic events (as compared to host‐symbiont reconciliation analysis and using host phylogeography for time‐calibration) and provides independent data for testing alternative hypotheses on timing of host diversification and dispersal.     

DNA barcoding and minibarcoding as a powerful tool for feather mite studies

Feather mites (Astigmata: Analgoidea and Pterolichoidea) are among the most abundant and commonly occurring bird ectosymbionts. Basic questions on the ecology and evolution of feather mites remain unanswered because feather mite species identification is often only possible for adult males, and it is laborious even for specialized taxonomists, thus precluding large‐scale identifications. Here, we tested DNA barcoding as a useful molecular tool to identify feather mites from passerine birds. Three hundred and sixty‐one specimens of 72 species of feather mites from 68 species of European passerine birds from Russia and Spain were barcoded. The accuracy of barcoding and minibarcoding was tested. Moreover, threshold choice (a controversial issue in barcoding studies) was also explored in a new way, by calculating through simulations the effect of sampling effort (in species number and species composition) on threshold calculations. We found one 200‐bp minibarcode region that showed the same accuracy as the full‐length barcode (602 bp) and was surrounded by conserved regions potentially useful for group‐specific degenerate primers. Species identification accuracy was perfect (100%) but decreased when singletons or species of the Proctophyllodes pinnatus group were included. In fact, barcoding confirmed previous taxonomic issues within the P. pinnatus group. Following an integrative taxonomy approach, we compared our barcode study with previous taxonomic knowledge on feather mites, discovering three new putative cryptic species and validating three previous morphologically different (but still undescribed) new species.     

Ecological correlates of feather mite prevalence in passerines

The relationship between host ecology and feather mite prevalence was analysed in birds. Feather mites are small arthropods (fam. Pterolichoidea and Analgoidea) commonly found on birds, although the nature of their interactions with the host (commensalism, mutualism or parasitism), still remains unclear. Host body mass and migratory behaviour were unrelated to feather mite prevalence. Contrary to expectation, there was no differences in mite prevalence between colonial and solitary-breeding species. However, winter sociality was associated with increased prevalence, suggesting that winter and breeding sociality affected the distribution patterns of feather mites in different ways. Plumage dichromatism was negatively correlated with feather mite prevalence, a result that is opposite to that predicted by the Hamilton and Zuk hypothesis for the evolution of host secondary sexual characteristics in relation to parasitism.     

Parasite-host associations and life cycles of spring-living water mites (Hydrachnidia, Acari) from Luxembourg

Larval water mites are parasites of various insect species. The main aim of the present study was to analyse the host range of spring dwelling water mites. The investigation focuses on seven spring sites in Luxembourg. Some 24 water mite species were recorded either from the benthos or as parasites attached to flying insects captured in emergence traps. For 20 mite species 35 host species from four Nematocera (Diptera) families were recorded. About 80% of the host species and over 90% of the host individuals were Chironomidae, the others were Limoniidae, Dixidae and Simuliidae. For all water mite species recorded we present the observed host spectrum and/or potential hosts as well as the intensity of parasitism and the phenology of the mites. For 10 mite species the hosts were previously unknown. For another ten species the known host spectrum can be confirmed and extended. The host spectrum ranged from one host species (e.g. for Sperchon insignis) to at least 10 host species (for Sperchon thienemanni, Ljania bipapillata), but the effective host range could not be definitively estimated due to the lack of corresponding data. The hypothesised host preference of the water mites, of which most are strictly confined to spring habitats, for similarly spring-preferring hosts could not be proven. The mean intensity of parasitism was highest for Thyas palustris (10.8 larvae/host) and lowest for Sperchon insignis and Hygrobates norvegicus (1.2 larvae per host for each). The hydryphantid mite Thyas palustris occurred at maximal intensity (41 larvae per host) and the two abdominal parasites Ljania bipapillata and Arrenurus fontinalis showed higher mean intensities than the thoracic parasites did. Larval water mites parasitising chironomids did not exhibit a preference for host sex. The phenology of the larval mite species was varied, some species were only present in samples early in the year and others exclusively in the summer. Another species showed two peaks of occurrence, springtime/early summer and late summer/autumn. In conclusion, the water mite larvae in the studied springs showed differences in host spectra and phenology but there are no clear evidences in both for host partitioning. Maybe, the relative low species diversity of water mites in individual springs and the low inter-specific competition for suitable hosts in combination with the high host abundances and species richness makes springs such favourable habitats for the mites.