Tanopicobia gen. nov., a new genus of quill mites, its phylogenetic placement in the subfamily Picobiinae (Acariformes: Syringophilidae) and picobiine relationships with avian hosts

Enigmatic host-mite relationships: Unraveling the distribution of quill mites on Birds-of-Paradise

Mites of the family Syringophilidae (Acariformes: Prostigmata: Cheyletoidea) are permanent and obligatory parasites of birds. This study presents an analysis of mite material collected from 22 avian species belonging to the family Paradisaeidae (Passeriformes), revealing the presence of four mite species belonging to four genera: Syringophiloidus attenboroughi n. sp., Peristerophila regiusi n. comb., Picobia frankei, and Gunabopicobia garylarsoni. In the present work, the genus Neoperisterophila is synonymized with the genus Peristerophila. While the genera Syringophiloidus and Picobia were expectedly found on paradisaeid birds, given their prevalence in passerines, the presence of Peristerophila and Gunabopicobia was intriguing, suggesting potential host-switching events. The specificity of these mites varies, with some showing occurrence on hosts of closely related genera and others infesting phylogenetically distant hosts. Notably, the distribution of specific mite species on the Birds-of-Paradise appears to be influenced by both long coevolutionary histories and incidental contacts between often unrelated or intergeneric hybrid species of paradisaeid birds. Furthermore, our research of 104 specimens from 22 Birds-of-Paradise species shows generally low infestation rates across the studied species, suggesting a nuanced interaction between these mites and their avian hosts. Additionally, our network analysis provides a deeper understanding of these host-parasite interactions, revealing a high level of specialization and complexity in these ecological relationships.

Species Composition of Parasitic Mites of the Subfamily Picobiinae (Acariformes: Syringophilidae) Associated with African Barbets (Piciformes: Lybiidae)

In this study, we conducted a parasitological investigation of the quill mite fauna of the subfamily Picobiinae (Acariformes: Prostigmata: Syringophilidae) associated with African barbets (Aves: Piciformes: Lybiidae). We examined twenty-seven host species, representing 57% of the forty-seven known host species in the family Lybiidae, belonging to seven genera (70% of the ten genera in the family). Our research revealed that ten host species were infested by three species of picobiine mites belonging to the genus Tanopicobia: (1) Tanopicobia hallae Sikora and Skoracki, sp. n., from three species of the genus Lybius and two species of the genus Tricholaema, (2) Tanopicobia stactolaema Sikora and Skoracki, sp. n., from two species of the genus Stactolaema, and (3) Tanopicobia trachyphoni Skoracki et al., 2020, collected from three host species of the genus Trachyphonus. Our findings demonstrate that birds belonging to the family Lybiidae have a specific parasite fauna consisting exclusively of mites of the genus Tanopicobia; this mite genus is apparently restricted to African barbets.

First Records of Picobiine Mites Associated with Birds-of-Paradise: Can Interspecific Sexual Behaviour of Hosts Play a Role in the Distribution of Quill Mite Parasites?

While birds-of-paradise (Passeriformes: Paradisaeidae) are a well-known group of birds, our understanding of their parasites is still limited. This study reports on parasitic quill mites of the subfamily Picobiinae (Acariformes: Syringophilidae), which have never before been recorded on this group of birds. The mite specimens presented in this paper were collected from birds-of-paradise that had been captured in Papua New Guinea and Indonesia in the years 1910-1911 and are now deposited in the Bavarian State Collection of Zoology, Munich, Germany. Two syringophilid species are described as new to science: (i) Picobia frankei sp. n. from the magnificent riflebird Lophorina magnifica, the glossy-mantled manucode Manucodia ater, and the crinkle-collared manucode Manucodia chalybatus, and (ii) Gunabopicobia garylarsoni sp. n. from the twelve-wired bird-of-paradise Seleucidis melanoleucus and the lesser bird-of-paradise Paradisaea minor. We hypothesise that the presence of both picobiine species on phylogenetically unrelated paradisaeids may be caused by the sexual behaviour of these birds, where interspecific copulations may play a role in the switching of parasites between non-closely related host species.

Host-Parasite Relationships of Quill Mites (Syringophilidae) and Parrots (Psittaciformes)

The family Syringophilidae (Acari: Prostigmata) includes obligatory ectoparasites, which occupy feather quills from various parts of avian plumage, where they feed and reproduce. Our study was concerned with the global fauna of syringophilid mites associated with Psittaciformes, as well as host-parasite specificity and evolution. We assumed that the system composed of quill mites and parrots represents a model group that can be used in a broader study of the relationships between parasites and hosts. In total, we examined 1524 host individuals of parrots belonging to 195 species, 73 genera, and 4 families (which constitute ca. 50% of global parrot fauna) from all zoogeographical regions where Psittaciformes occur. Among them, 89 individuals representing 81 species have been infested by quill mites belonging to 45 species and 8 genera. The prevalence of host infestations by syringophilid mites varied from 2.8% to 100% (95% confidence interval (CI Sterne method) = 0.1–100). We applied a bipartite analysis to determine the parasite-host interaction, network indices, and host specificity at the species and whole network levels. The Syringophilidae-Psittaciformes network was composed of 24 mite species and 47 host species. The bipartite network was characterized by a high network level specialization H2′ = 0.98, connectance C = 0.89, and high modularity Q = 0.90, with 23 modules, but low nestedness N = 0.0333. Moreover, we reconstructed the phylogeny of the quill mites on the generic level, and this analysis shows two distinct clades: Psittaciphilus (Peristerophila + Terratosyringophilus) (among Syringophilinae subfamily) and Lawrencipicobia (Pipicobia + Rafapicobia) (among Picobiinae). Finally, the distributions and host-parasite relationships in the system composed of syringophilid mites and parrots are discussed.

The Occurrence of Quill Mites (Arachnida: Acariformes: Syringophilidae) on Bee-Eaters (Aves: Coraciiformes: Meropidae: Merops) of Two Sister Clades

We studied the quill mite fauna of the family Syringophilidae, associated with bee-eaters. We examined 273 bird specimens belonging to nine closely related species of the genus Merops, representing two phylogenetic sister clades of a monophyletic group. Our examination reveals the presence of two species of the genus Peristerophila, as follows: (1) a new species Peristerophila mayri sp. n. from Merops viridis in the Philippines, M. leschenaulti in Nepal and Sri Lanka, and M. orientalis in Sri Lanka; and (2) P. meropis from M. superciliosus in Tanzania and Egypt, M. persicus in Sudan, Tanzania, Liberia, Senegal, Kenya, and D.R. Congo, M. ornatus in Papua New Guinea, M. philippinus in Thailand, Indonesia and Sri Lanka, and M. americanus in the Philippines. The prevalence of host infestations by syringophilid mites varied from 3.1 to 38.2%. The distribution of syringophilid mites corresponds with the sister clade phylogenetic relationships of the hosts, except for P. meropis associated with Merops americanus. Possible hypotheses for the host lineage shift are proposed.

K. VP, Vijay N, Sharma VK. Genomic Insights Into the Molecular Basis of Sexual Selection in Birds

Sexual selection is a well-known biological process, yet the genomic basis and patterns of sexual selection are not fully understood. The extravagant ornamental plumage of peacock (Pavo cristatus) was instrumental in shaping Charles Darwin's theory of sexual selection and is considered to be an honest signal of its immunocompetence. Here, we used the recently generated draft genome sequence of peafowl (Pavo cristatus) and carried out a comparative analysis across 11 bird genomes that encompass a range of sexual selection and also had high-quality genomic and phenotypic data publically available to study the genomic basis of sexual selection. We found that varying degree of purifying selection was the predominant mechanism of action for sexual selection at the genome-wide scale and observed that sexual selection mostly influences genes regulating gene expression and protein processing. Specifically, the genome-wide phylogenetically corrected regression analysis supported the continuous or ongoing model of sexual selection. Genes involved in nucleic acid binding and gene expression regulation, including a specific regulator of sex-determination known as TRA2A to be under positive selection in the species with high post-copulatory sexual selection manifested as high sperm competition. We also detected specific feather-related and immune-related gene-pairs evolving under similar selection pressures across the 11 species, including peacock (Pavo cristatus), which is consistent with the Hamilton-Zuk hypothesis. The comparative genomics analysis of 11 avian taxa has provided new insights on the molecular underpinnings of sexual selection and identifies specific genomic regions for future in-depth analysis.