Empirically tuned theory reveals why symbiont abundance 'mite' vary across hosts.

Research Highlight: del Mar Labrador, M., Serrano, D., Doña, J., Aguilera, E., Arroyo, J. L., Atiénzar, F., Barba, E., Bermejo, A., Blanco, G., Borràs, A., Calleja, J. A., Cantó, J. L., Cortés, V., de la Puente, J., de Palacio, D., Fernández-González, S., Figuerola, J., Frías, Ó., Fuertes-Marcos, B. Garamszegi, L. Z., Gordo, Ó., Gurpegui, M., Kovács, I., Martínez, J. L., Meléndez, L., Mestre, A., Møller, A. P., Monrós, J. S., Moreno-Opo, R., Navarro, C., Pap, P. L., Pérez-Tris, J., Piculo, R., Ponce, C., Proctor, H., Rodríguez, R., Sallent, Á., Senar, J., Tella, J. L., Vágási, C. I., Vögeli, M., & Jovani, R. (2023). Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.14032. Symbionts represent crucial links between species in ecosystems. Consequently, understanding their patterns of abundance is a major goal in the study of symbioses. However, multiple biotic and abiotic factors may regulate symbionts, and disentangling the mechanisms that drive variation in their abundance across host species is challenging. One promising strategy to approach this challenge is to incorporate biologically relevant data into theoretical models. In a recent study, Labrador et al. (2023) used this strategy to investigate the poorly understood symbiosis between feather mites and their avian hosts. They integrate a remarkable amount of empirical data with models based on the metabolic theory of ecology to determine what factors limit feather mite abundance across European passerines. Their quantitative analyses indicate that the number of feather barbs limits mite abundance across host species, suggesting that mite populations are spatially, but not energetically, constrained. These findings not only reveal mechanisms that may drive the variation in feather mite abundances across hosts, but also advance our understanding of the ecology of interspecific interactions more generally.

Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species.

Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constrains symbiont populations. We parameterized metabolic theory equations to investigate how bird species' body size and the body size of their feather mites relate to mite abundance according to four potential energy (uropygial gland size) and space constraints (wing area, total length of barbs and number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance across 106 passerine bird species (26,604 individual birds sampled), using phylogenetic modelling and quantile regression. Feather mite abundance was strongly constrained by host space (number of feather barbs) but not by energy. Moreover, feather mite species' body size was unrelated to the body size of their host species. We discuss the implications of our results for our understanding of the bird-feather mite system and for symbiont abundance in general.

New feather mites of the Nycteridocaulus generic group (Acariformes: Proctophyllodidae) from passerines (Passeriformes) in Panama.

Three new feather mite species of the Nycteridocaulus generic group (Proctophyllodidae: Proctophyllodinae) are described from passerines in Panama: Atrichophyllodes myrmotherulae sp. n. from the Slaty Antwren, Myrmotherula schisticolor (Lawrence) (Thamnophilidae), Nycteridocaulus apanaskevichi sp. n. from the Grey-breasted Wood Wren, Henicorhina leucophrys (Tschudi) (Troglodytidae), and N. empidonicus sp. n. from the Yellowish Flycatcher Empidonax flavescens Lawrence (Tyrannidae). Nycteridocaulus apanaskevichi, presenting the second record of the genus from a host of oscine passerines, differs from N. guaratubensis Hernandes, 2014 in having the anterolateral extensions of the prodorsal shield rounded and the hysteronotal shield lacking any ornamentation. Males of N. empidonicus differ from N. myiobius Mironov, 2017 in having the supranal concavity open posteriorly and tarsus IV with rounded apical process; and females are distinguished by macrosetae h2 having long filiform apices. Males of A. myrmotherulae most clearly differ from A. mentalis Hernandes et al. 2007 in having the terminal lamellae rectangular and tarsus IV with triangular ventral process, and females are distinguished in having a noticeably longer idiosoma, 400-430 µm long. Comments on systematics and host associations of the genera Atrichophyllodes and Nycteridocaulus are provided.

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.

Enabling large-scale feather mite studies: an Illumina DNA metabarcoding pipeline.

Feather mites are among the most common and diverse ectosymbionts of birds, yet basic questions such as the nature of their relationship remain largely unanswered. One reason for feather mites being understudied is that their morphological identification is often virtually impossible when using female or young individuals. Even for adult male specimens this task is tedious and requires advanced taxonomic expertise, thus hampering large-scale studies. In addition, molecular-based methods are challenging because the low DNA amounts usually obtained from these tiny mites do not reach the levels required for high-throughput sequencing. This work aims to overcome these issues by using a DNA metabarcoding approach to accurately identify and quantify the feather mite species present in a sample. DNA metabarcoding is a widely used molecular technique that takes advantage of high-throughput sequencing methodologies to assign the taxonomic identity to all the organisms present in a complex sample (i.e., a sample made up of multiple specimens that are hard or impossible to individualise). We present a high-throughput method for feather mite identification using a fragment of the COI gene as marker and Illumina Miseq technology. We tested this method by performing two experiments plus a field test over a total of 11,861 individual mites (5360 of which were also morphologically identified). In the first experiment, we tested the probability of detecting a single feather mite in a heterogeneous pool of non-conspecific individuals. In the second experiment, we made 2 × 2 combinations of species and studied the relationship between the proportion of individuals of a given species in a sample and the proportion of sequences retrieved to test whether DNA metabarcoding can reliably quantify the relative abundance of mites in a sample. Here we also tested the efficacy of degenerate primers (i.e., a mixture of similar primers that differ in one or several bases that are designed to increase the chance of annealing) and investigated the relationship between the number of mismatches and PCR success. Finally, we applied our DNA metabarcoding pipeline to a total of 6501 unidentified and unsorted feather mite individuals sampled from 380 European passerine birds belonging to 10 bird species (field test). Our results show that this proposed pipeline is suitable for correct identification and quantitative estimation of the relative abundance of feather mite species in complex samples, especially when dealing with a moderate number (> 30) of individuals per sample.

Global associations between birds and vane-dwelling feather mites.

Understanding host-symbiont networks is a major question in evolutionary ecology. Birds host a great diversity of endo- and ectosymbiotic organisms, with feather mites (Arachnida: Acariformes: Analgoidea, Pterolichoidea) being among the most diverse of avian symbionts. A global approach to the ecology and evolution of bird-feather-mite associations has been hampered because of the absence of a centralized data repository. Here we present the most extensive data set of associations between feather mites and birds. Data include 12 036 records of 1887 feather mite species located on the flight feathers of 2234 bird species from 147 countries. Feather mites typically located inside quills, on the skin, or on downy body feathers are not included. Data were extracted from 493 published sources dating from 1882 to 2015. Data exploration shows that although most continents and bird families are represented, most bird species remain unexplored for feather mites. Nevertheless, this is the most comprehensive data set available for enabling global macroecological analyses of feather mites and their hosts, such as ecological network analyses. This metadata file outlines the structure of these data and provides primary references for all records used.

Population Genomics of Pooled Samples: Unveiling Symbiont Infrapopulation Diversity and Host-Symbiont Coevolution.

Microscopic symbionts represent crucial links in biological communities. However, they present technical challenges in high-throughput sequencing (HTS) studies due to their small size and minimal high-quality DNA yields, hindering our understanding of host-symbiont coevolution at microevolutionary and macroevolutionary scales. One approach to overcome those barriers is to pool multiple individuals from the same infrapopulation (i.e., individual host) and sequence them together (Pool-Seq), but individual-level information is then compromised. To simultaneously address both issues (i.e., minimal DNA yields and loss of individual-level information), we implemented a strategic Pool-Seq approach to assess variation in sequencing performance and categorize genetic diversity (single nucleotide polymorphisms (SNPs)) at both the individual-level and infrapopulation-level for microscopic feather mites. To do so, we collected feathers harboring mites (Proctophyllodidae: Amerodectes protonotaria) from four individual Prothonotary Warblers (Parulidae: Protonotaria citrea). From each of the four hosts (i.e., four mite infrapopulations), we conducted whole-genome sequencing on three extraction pools consisting of different numbers of mites (1 mite, 5 mites, and 20 mites). We found that samples containing pools of multiple mites had more sequencing reads map to the feather mite reference genome than did the samples containing only a single mite. Mite infrapopulations were primarily genetically structured by their associated individual hosts (not pool size) and the majority of SNPs were shared by all pools within an infrapopulation. Together, these results suggest that the patterns observed are driven by evolutionary processes occurring at the infrapopulation level and are not technical signals due to pool size. In total, despite the challenges presented by microscopic symbionts in HTS studies, this work highlights the value of both individual-level and infrapopulation-level sequencing toward our understanding of host-symbiont coevolution at multiple evolutionary scales.

Feather mites (Acariformes, Astigmata) from marine birds of the Barton Peninsula (King George Island, Antarctica), with descriptions of two new species.

We report on the first investigation of feather mites associated with birds living on the Barton Peninsula (King George Island, Antarctica). We found seven feather mite species of the superfamily Analgoidea from four host species. Two new species are described from two charadriiform hosts: Alloptes (Sternalloptes) antarcticussp. nov. (Alloptidae) from Stercorariusmaccormicki Saunders (Stercorariidae), and Ingrassiachionis sp. nov. (Xolalgidae) from Chionisalbus (Gmelin) (Chionidae). Additionally, we provide partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI), which was utilized as a DNA barcode, for all seven feather mite species.

Feather mites of the genus Trouessartia (Acariformes: Trouessartiidae) from passerines (Aves: Passeriformes) in Georgia, USA.

Ten new species of the feather mite genus Trouessartia Canestrini, 1899 (Analgoidea: Trouessartiidae) are described from various passerines of the superfamily Passeroidea in Georgia: Trouessartia americana sp. n. from Setophaga americana (Linnaeus), T. helmitheros sp. n. from Helmitheros vermivorum (Gmelin, JF), T. mniotilta sp. n. from Mniotilta varia (Linnaeus), T. pensylvanica sp. n. from Setophaga pensylvanica (Linnaeus) (type host) and S. palmarum (Gmelin, JF), T. ruticilla sp. n. from S. ruticilla (Linnaeus), T. seiurus sp. n. from Seiurus aurocapilla (Linnaeus), T. tigrina sp. n. from Setophaga tigrina (Gmelin, JF) (Parulidae), T. passerinae sp. n. from Passerina caerulea (Linnaeus) (type host) and P. cyanea (Linnaeus), T. ciris sp. n. from P. ciris (Linnaeus) (Cardinalidae), and T. spizellae sp. n. from Spizella passerina (Bechstein) (Passerellidae). Based on a specific combination of morphological characters, all new species and six previously known species are arranged into a new species group capensis in the genus Trouessartia. The most important diagnostic characters of this species group include: in both sexes, the dorsal hysterosomal apertures are absent; in males, the postgenital plaque is well developed and genital setae g have cylindrical articulation rings; in females, the external copulatory tube is straight, stylet- or finger-like, and situated on the margin of the interlobar membrane, and the head of spermatheca has a semi-ovate extension without indentations. A key to all species referred to the capensis group is provided and host associations of this group with passerines are summarized and briefly discussed. It is hypothesized that this species group originated on the ancestors of New World nine-primaried oscines (Emberizoidea) and diverged in close relation with this group of hosts.

Feather mites of the genus Trouessartia Canestrini (Acariformes: Trouessartiidae) from swallows (Passeriformes: Hirundinidae) in Canada.

Seven species of the feather mite genus Trouessartia Canestrini, 1899 (Astigmata: Trouessartiidae) have been recorded on swallows and martins (Passeriformes: Hirundinidae) in Manitoba (Canada). Of them, five are described as new species: Trouessartia ampulicaudata sp. n. and T. petrochelidon sp. n. from the American cliff swallow Petrochelidon pyrrhonota (Vieillot), T. bochkovi sp. n. from the tree swallow Tachycineta bicolor (Vieillot), and T. cryptocaudata sp. n. and T. progne sp. n. from the purple martin Progne subis (Linnaeus). A new species group stelgidopteryx, incorporating Trouessartia species living on hirundinids of the genera Progne, Tachycineta and Stelgidopteryx, is established. Renewed diagnoses of four Trouessartia species groups (appendiculata, crucifera, minutipes, and stelgidopteryx) restricted to hirundinids and a key to species recorded so far and potentially expected on swallows of North America are proposed. Host associations of Trouessartia species with swallows in North America are briefly discussed.

Redescription of six feather mite species of the genus Proterothrix Gaud, 1968 (Analgoidea: Proctophyllodidae: Pterodectinae) from the "Édouard Louis Trouessart" Collection.

Six feather mite species presently referred to the genus Proterothrix Gaud, 1968 (Proctophyllodidae: Pterodectinae) were briefly described without being drawn by a French zoologist Édouard Louis Trouessart in the end of the 19th century. The type material used for description of these species is still preserved in the Muséum National d'Histoire Naturelle (Paris, France). Based on this material, we provide detailed redescriptions, according to the modern format used for pterodectine mites, for the following species: Proterothrix diminuta (Trouessart, 1899), P. modesta (Trouessart, 1899), and P. phyllura (Trouessart, 1899) from Manucodia ater (Lesson) (Corvida: Paradisaeidae); P. emarginata (Trouessart, 1899) from M. chalybatus (J. R. Forster) (Corvida: Paradisaeidae); P. paradisiaca (Trouessart, 1885) from Paradisaea minor Shaw (Corvida: Paradisaeidae) and Sericulus chrysocephalus (Lewin) (Corvida: Ptilonorhynchidae); and P. xiphiura (Trouessart, 1885) from Psarisomus dalhousiae (Jameson) (Tyranni: Eurylaimidae). The lectotypes and paralectotypes have been designated herein for all examined species.

Feather mite abundance varies but symbiotic nature of mite-host relationship does not differ between two ecologically dissimilar warblers.

Feather mites are obligatory ectosymbionts of birds that primarily feed on the oily secretions from the uropygial gland. Feather mite abundance varies within and among host species and has various effects on host condition and fitness, but there is little consensus on factors that drive variation of this symbiotic system. We tested hypotheses regarding how within-species and among-species traits explain variation in both (1) mite abundance and (2) relationships between mite abundance and host body condition and components of host fitness (reproductive performance and apparent annual survival). We focused on two closely related (Parulidae), but ecologically distinct, species: Setophaga cerulea (Cerulean Warbler), a canopy dwelling open-cup nester, and Protonotaria citrea (Prothonotary Warbler), an understory dwelling, cavity nester. We predicted that feather mites would be more abundant on and have a more parasitic relationship with P. citrea, and within P. citrea, females and older individuals would harbor greater mite abundances. We captured, took body measurements, quantified feather mite abundance on individuals' primaries and rectrices, and monitored individuals and their nests to estimate fitness. Feather mite abundance differed by species, but in the opposite direction of our prediction. There was no relationship between mite abundance and any measure of body condition or fitness for either species or sex (also contrary to our predictions). Our results suggest that species biology and ecological context may influence mite abundance on hosts. However, this pattern does not extend to differential effects of mites on measures of host body condition or fitness.

Captive individuals of endangered Philippine raptors maintain native feather mites (Acariformes: Pterolichoidea) species.

Endangered species of hosts are coupled with endangered species of parasites, which share the risk of co-extinction. Conservation efforts sometimes include breeding of rare species in captivity. Data on parasites of captive populations of endangered species is scarce and the ability of small numbers of captive host individuals to support the biodiversity of native parasites is limited. Examination of ectosymbionts of the critically endangered Philippine eagles and the endangered Mindanao Hawk-Eagle kept at the Philippine Eagle Center, Philippines, revealed three feather mite species despite regular treatment with insecticide powder. No other ectosymbiont taxa were detected. Studies in morphology and molecular phylogeny of these feather mites based on mitochondrial and nuclear DNA markers indicate that species found were typical for Accipitridae. Three new pterolichoid feather mite species (Acari: Pterolichoidea) were described from two species of eagles (Accipitriformes: Accipitridae) endemic to the Philippines: Hieracolichus philippinensis sp. n. (Gabuciniidae) and Pseudalloptinus pithecophagae sp. n. (Pterolichidae) from the Great Philippine Eagle Pithecophaga jefferyi Ogilvie-Grant, 1896, and Pseudogabucinia nisaeti sp. n. (Kramerellidae) from the Mindanao Hawk-Eagle Nisaetus pinskeri Gould, 1863. The presence of H. philippinensis on P. jefferyi supports the recent finding that the Great Philippine Eagle belongs to the lineage of serpent eagles (Circaetinae) rather than to the Harpy and other eagles.

Out of Africa: the mite community (Arachnida: Acariformes) of the common waxbill, Estrilda astrild (Linnaeus, 1758) (Passeriformes: Estrildidae) in Brazil.

BACKGROUND: The common waxbill, Estrilda astrild (L., 1758) (Passeriformes: Estrildidae) is a small passerine bird native to Sub-Saharan Africa that has been introduced into several regions of the world. RESULTS: In the present paper, eight mite species (Acariformes) are reported from this host from Brazil, including three species new to science: Montesauria caravela n. sp., M. conquistador n. sp. (Proctophyllodidae), Trouessartia transatlantica n. sp., T. minuscula Gaud & Mouchet, 1958, T. estrildae Gaud & Mouchet, 1958 (Trouessartiidae), Onychalges pachyspathus Gaud, 1968 (Pyroglyphidae), Paddacoptes paddae (Fain, 1964) (Dermationidae) and Neocheyletiella megaphallos (Lawrence, 1959) (Cheyletidae). Comparative material from Africa was also studied. CONCLUSIONS: These mites represent at least three morpho-ecological groups regarding their microhabitats occupied on the bird: (i) vane mites (Montesauria and Trouessartia on the large wing and tail feathers); (ii) down mites (Onychalges); and (iii) skin mites (Paddacoptes and Neocheyletiella). On one bird individual we found representatives of all eight mite species. Although the common waxbill was introduced to the Neotropical region almost two centuries ago, we demonstrate that it still retains its Old World acarofauna and has not yet acquired any representatives of typical Neotropical mite taxa.

New feather mites of the genus Amerodectes Valim and Hernandes (Acariformes: Proctophyllodidae) from passerines (Aves: Passeriformes) in Georgia, USA.

Eight new species of the feather mite genus Amerodectes Valim and Hernandes, 2010 (Proctophyllodidae: Pterodectinae) are described from passerines (Aves: Passeriformes) in Georgia, USA: Amerodectes cathari sp. n. from Catharus ustulatus (Nuttall) (Turdidae), A. haemorhous sp. n. from Haemorhous mexicanus (Muller, PLS) (Fringillidae), A. helmitheros sp. n. from Helmitheros vermivorum (Gmelin) (Parulidae), A. hribari sp. n. from Geothlypis trichas (Linnaeus) (Parulidae), A. hylocichlae sp. n. from Hylocichla mustelina (Gmelin) (Turdidae), A. passerinae sp. n. from Passerina ciris (Linnaeus) (Cardinalidae), A. seiurus sp. n. from Seiurus aurocapilla (Linnaeus) (Parulidae), and A. spizellae sp. n. from Spizella passerina (Bechstein) (Emberizidae). An updated world checklist of Amerodectes species and a key to species recorded and potentially expected in North America (USA and Canada) are proposed.

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.

Microhabitat selection and coexistence in feather mites (Acari: Analgoidea) on Alaskan seabirds.

Two species of feather mites, Alloptes (A.) sp. and Laronyssus martini, coexisted on the flight feathers of kittiwakes, while Alloptes (C.) sp. occurred alone on murres. All three species were found mostly on the ventral surface of mid-wing regions. On individual feathers, the mites were attached to the distal sides of barbs on the trailing vanes. The two species coexisted on kittiwakes but occupied different portions of feathers. The results suggest that the two species compete for the attachment site on the feather and Alloptes (A.) sp. is excluded by L. martini from the preferred microhabitat.

Feather mites of Calidris fuscicollis (Aves: Scolopacidae) in Brazil / Ácaros plumícolas de Calidris fuscicollis (Aves: Scolopacidae) no Brasil

Abstract During the period 2010-2012, eighty individuals of Calidris fuscicollis (Vieillot, 1819) were collected on the southern coast of Rio Grande do Sul, Brazil, with the objective of determining the presence of feather mites. Of the 80 birds examined, 32.5% were infested by mites, identified as Avenzoaria calidridis (Oudemans, 1904) (Avenzoariidae) (31.25%), Montchadskiana securicata (Megnin & Trouessart 1884) (Pterolichidae) (22.5%) and Alloptes limosae (Dubinin, 1951) (Alloptidae) (6.25%). This is the first report of feather mites on Calidris fuscicollis in Brazil.

Resumo Durante o período de 2010-2012, oitenta espécimes de Calidris fuscicollis (Vieillot, 1819) foram coletados na costa sul do Estado do Rio Grande do Sul, com o objetivo de determinar a presença de ácaros de pena. Das 80 aves examinadas, 32,5% estavam infestadas por ácaros, os quais foram identificados como Avenzoaria calidridis (Oudemans, 1904) (Avenzoariidae) (31,25%), Montchadskiana securicata (Megnin & Trouessart 1884) (Pterolichidae) (22,5%) e Alloptes limosae (Dubinin, 1951) (Alloptidae) (6,25%). Este é o primeiro relato de ácaros de pena em Calidris fuscicollis no Brasil.

Gastrointestinal and external parasites of the white-crested elaenia Elaenia albiceps chilensis (Aves, Tyrannidae) in Chile / Parasitas gastrointestinais e externos de guaracava de crista branca Elaenia albiceps chilensis (Aves, Tyrannidae) de Chile

The objective of this study is to evaluate the ectoparasites and helminths of the white-crested elaenia, Elaenia albiceps chilensis. Feather mites Anisophyllodes elaeniae, Trouessartia elaeniae, and Analges sp. were detected in 51% of birds (n=106), whereas 24% were infected with lice (Tyranniphilopterus delicatulus, Menacanthus cfr. distinctus, and Ricinus cfr. invadens). Helminths Viguiera sp. and Capillaria sp. were found in five of the birds that were necropsied (n=20). With the exception of A. elaeniae, T. elaeniae, and T. delicatulus, all parasites represented new records found for the white-crested elaenia, and therefore for the Chilean repertoire of biodiversity.

O objetivo deste estudo foi avaliar a fauna de ectoparasitas e helmintos do guaracava de crista branca Elaenia albiceps chilensis. Em 51% das aves (n=106), foram detectados os ácaros de pena Anisophyllodes elaeniae, Trouessartia elaeniae e Analges sp. enquanto 24% foram infectadas por piolhos (Tyranniphilopterus delicatulus, Menacanthus cfr. distinctus e Ricinus cfr. invadens. Em contrapartida, em cinco aves necropsiadas foram encontrados os helmintos Viguiera sp. e Capillaria sp. Com exceção de A. elaeniae, T. elaeniae e T. delicatulus, todos os parasitas representam novos registros para a guaracava de crista branca e, portanto, para a diversidade da fauna parasitária do Chile.

Epidemiology of Megninia spp. in laying flocks from the State of Minas Gerais, Brazil / Epidemiologia de Megninia spp. em estabelecimentos de postura no Estado de Minas Gerais, Brasil

Aspects related to the epidemiology of Megninia ginglymura were studied, in order to determine predisposing factors for the ocurrence in layer chicken houses of commercial farms in the State of Minas Gerais, Brazil. An observational, cross-sectional, analytical survey was conducted for identifying major risks or protection factors for infestations. Four hundred thirty-one houses located in forty-three farms were visited in 2012. Regarding the farms, 17 (39.53%) had chickens infested by M. ginglymura and 1 (2.32%) presented Megninia cubitalis. The epidemiological aspects of the occurrence of M. ginglymura were investigated using multiple logistic regression models. The chicken house organization was an important protection factor involved in the occurrence of M. ginglymura (odds ratio [OR] = 0.85). The presence of subsistence breedings of poultry within the premises or at the proximity of a farm was characterized as a risk factor for the occurrence of infestations (OR = 3.92). The use of mineral oil (OR = 0.16) was considered protective against new infestations. Some regions of the state were characterized by a higher risk for mite infestation than others.

Aspectos relacionados à epidemiologia de infestações pelo ácaro Megninia ginglymura foram estudados com o objetivo de determinar os principais fatores para a ocorrência desse ectoparasito em galinhas poedeiras de granjas comerciais no Estado de Minas Gerais, Brasil. Um estudo observacional, analítico e seccional foi realizado para verificar os principais fatores de risco ou proteção para as infestações. Quatrocentos e trinta e um galpões distribuídos em quarenta e três granjas foram visitados, no ano de 2012. Em relação às granjas, 17 (39,53%) possuíam aves infestadas por M. ginglymura e uma (2,32%) apresentou galinhas infestadas por Megninia cubitalis. Os aspectos epidemiológicos para a ocorrência de M. ginglymura foram investigados, utilizando-se modelos de regressão logística múltipla. A organização dos galpões nas granjas foi verificada como um importante fator de proteção envolvido na epidemiologia dessa espécie (Razão de Chances=0,85). A presença de criações de galinhas de subsistência dentro das instalações das granjas ou nas proximidades (Razão de Chances =3,92) foi caracterizada como um fator de risco para a ocorrência de infestações. O uso de óleo mineral foi considerado um fator de proteção contra infestações por M. ginglymura. Algumas regiões do Estado de Minas Gerais foram caracterizadas como de maior risco do que outras para infestações por esse ácaro.