Rapid Targeted Assembly of the Proteome Reveals Evolutionary Variation of GC Content in Avian Lice.

Nucleotide base composition plays an influential role in the molecular mechanisms involved in gene function, phenotype, and amino acid composition. GC content (proportion of guanine and cytosine in DNA sequences) shows a high level of variation within and among species. Many studies measure GC content in a small number of genes, which may not be representative of genome-wide GC variation. One challenge when assembling extensive genomic data sets for these studies is the significant amount of resources (monetary and computational) associated with data processing, and many bioinformatic tools have not been optimized for resource efficiency. Using a high-performance computing (HPC) cluster, we manipulated resources provided to the targeted gene assembly program, automated target restricted assembly method (aTRAM), to determine an optimum way to run the program to maximize resource use. Using our optimum assembly approach, we assembled and measured GC content of all of the protein-coding genes of a diverse group of parasitic feather lice. Of the 499 426 genes assembled across 57 species, feather lice were GC-poor (mean GC = 42.96%) with a significant amount of variation within and between species (GC range = 19.57%-73.33%). We found a significant correlation between GC content and standard deviation per taxon for overall GC and GC3, which could indicate selection for G and C nucleotides in some species. Phylogenetic signal of GC content was detected in both GC and GC3. This research provides a large-scale investigation of GC content in parasitic lice laying the foundation for understanding the basis of variation in base composition across species.

Parasite escape mechanisms drive morphological diversification in avian lice.

Organisms that have repeatedly evolved similar morphologies owing to the same selective pressures provide excellent cases in which to examine specific morphological changes and their relevance to the ecology and evolution of taxa. Hosts of permanent parasites act as an independent evolutionary experiment, as parasites on these hosts are thought to be undergoing similar selective pressures. Parasitic feather lice have repeatedly diversified into convergent ecomorphs in different microhabitats on their avian hosts. We quantified specific morphological characters to determine (i) which traits are associated with each ecomorph, (ii) the quantitative differences between these ecomorphs, and (iii) if there is evidence of displacement among co-occurring lice as might be expected under louse-louse competition on the host. We used nano-computed tomography scan data of 89 specimens, belonging to four repeatedly evolved ecomorphs, to examine their mandibular muscle volume, limb length and three-dimensional head shape data. Here, we find evidence that lice repeatedly evolve similar morphologies as a mechanism to escape host defences, but also diverge into different ecomorphs related to the way they escape these defences. Lice that co-occur with other genera on a host exhibit greater morphological divergence, indicating a potential role of competition in evolutionary divergence.

Ticks, Fleas, and Harboured Pathogens from Dogs and Cats in Cyprus.

Ticks and fleas are blood-sucking ectoparasites that cause irritation and anaemia to their hosts and act as vectors of pathogens (vector-borne pathogens, VBPs) of relevance for animal and human health. In the present study, tick and flea species in dogs and cats from Cyprus were recorded and VBPs were detected in the collected specimens. Ectoparasites were collected from 220 animals (161 dogs and 59 cats), and a questionnaire including demographic, clinical, and other information was filled out for each animal. The ectoparasites were morphologically identified and the detection of VBPs was performed by PCR-coupled sequencing. Rhipicephalus sanguineus sensu lato was found on 108 dogs and 13 cats, and Ixodes gibbosus on 2 dogs. Ctenocephalides felis was the predominant flea species (on 62 dogs and 45 cats), while one dog and one cat were infested by Ctenocephalides canis and Echidnophaga gallinacea, respectively. The VBPs in ticks were Anaplasma platys, Rickettsia massiliae, Rickettsia conorii, Rickettsia felis, Hepatozoon felis and Hepatozoon canis, while Rickettsia felis, Rickettsia sp., Bartonella koehlerae, Bartonella clarridgeiae, and Bartonella henselae were recorded in fleas. Statistical analysis (chi-square test and multiple univariate generalized linear model) showed that animals up to 6 months of age were less likely to be infested with ticks than older animals, but more likely to be infested with fleas. Ticks were more prevalent in sheltered than in owned animals, while the odds ratio of flea presence was higher in owned animals than those living in shelters. The present study is the first investigation on the occurrence of ticks and fleas in dogs and cats from Cyprus, showing the presence of different VBPs in these important ectoparasites. The results point out the importance of systematic ectoparasite control in dogs and cats.

Molecular phylogenetics of the avian feather louse Philopterus-complex (Phthiraptera: Philopteridae).

The avian feather louse Philopterus-complex (Phthiraptera: Ischnocera: Philopteridae) currently contains 12 genera that have been grouped together because of shared morphological characteristics. Although previously lumped into a single genus (Philopterus), more recent morphological treatments have separated the group into several different genera. Here we evaluate the status of these genera using DNA sequence data from 118 ingroup specimens belonging to ten genera in the Philopterus-complex: Australophilopterus Mey, 2004, Cinclosomicola Mey 2004, Clayiella Eichler, 1940, Corcorides Mey, 2004, Mayriphilopterus Mey, 2004, Paraphilopterus Mey 2004, Philopteroides Mey 2004, Philopterus Nitzsch, 1818, Tyranniphilopterus Mey, 2004, and Vinceopterus Gustafsson, Lei, Chu, Zou, and Bush, 2019. Our sampling includes 97 new louse-host association records. Our analyses suggest that the genus Debeauxoecus Conci, 1941, parasitic on pittas (Aves: Pittidae), is outside of the Philopterus-complex, and that there is strong support for the monophyly of a group containing the remaining genera from the complex. Some diverse genera, such as Philopterus (sensu stricto) and Mayriphilopterus are supported as monophyletic, whereas the genera Australophilopterus, Philopteroides, and Tyranniphilopterus are not. The present study is the largest phylogenetic reconstruction of avian lice belonging to the Philopterus-complex to date and suggests that further generic revision is needed in the group to integrate molecular and morphological information.

The chiggers (Acari: Trombiculidae) on wild birds in Honduras.

The chiggers (Acari: Trombiculidae) Blankaartia sinnamaryi (Floch et Fauran, 1956), Parasecia soucouyanti (Brennan et Yunker, 1966), Eutrombicula lipovskyana (Wolfenbarger, 1952) and Neoschoengastia dalmati Brennan, 1951 were found in Honduras on a total of twelve bird species. Parasecia soucouyanti was recorded parasitising birds for the first time. All these mites are here reported from Honduras for the first time.

New species and additional data on the chewing louse genus Myrsidea (Phthiraptera: Menoponidae) from wild Neotropical Passeriformes (Aves).

Twenty-four species of chewing lice of the genus Myrsidea Waterston, 1915 (Phthiraptera: Menoponidae) from Neotropical Suboscines (Passeriformes: Formicariidae, Furnariidae, Pipridae, Thamnophilidae, Tityridae, Tyrannidae) are recorded and discussed. They include: eight new species which are described and illustrated (Myrsidea capeki new species ex Chiroxiphia caudata; Myrsidea leptopogoni new species ex Leptopogon superciliaris; Myrsidea leucophthalmi new species ex Automolus leucophthalmus; Myrsidea pachyramphi new species ex Pachyramphus polychopterus; Myrsidea philydori new species ex Philydor rufum; Myrsidea pyriglenae new species ex Pyriglena leucoptera; Myrsidea scleruri new species ex Sclerurus scansor and Myrsidea zuzanae new species ex Furnarius rufus), as well as nine previously known species with additional data on intraspecific morphological variability, host associations and geographical distribution (Myrsidea barbati Price, Hellenthal Dalgleish, 2005; Myrsidea dalgleishi Valim, Price Johnson, 2011; Myrsidea flaviventris Price, Hellenthal Dalgleish, 2005; Myrsidea klimesi Sychra, 2006; Myrsidea meyi Valim, Price Johnson, 2011; Myrsidea oleaginei Price, Hellenthal Dalgleish, 2005; Myrsidea olivacei Price, Hellenthal Dalgleish, 2005; Myrsidea pitangi Price, Hellenthal Dalgleish, 2005 and Myrsidea spellmani Price, Johnson Dalgleish, 2008b). Seven further species are recorded at genus level only due to lack of adequate material. A 379 bp portion of the mitochondrial cytochrome oxidase I (COI) gene was sequenced from seven species in order to assess relative genetic divergences among Myrsidea populations.

New data on the taxonomy and distribution of ten Neotropical chewing lice of the genus Myrsidea (Phthiraptera: Menoponidae), including the description of a new species.

The new species Myrsidea alexanderi is described and illustrated ex Pheugopedius maculipectus (Troglodytidae) from Honduras. Redescriptions and illustrations are given for both sexes of Myrsidea chiapensis ex Calocitta formosa from Costa Rica, and the male of M. dissimilis ex Progne chalybea from Brazil. Also, seven other previously known species or subspecies of the louse genus Myrsidea are recorded and discussed from passerine birds of the Neotropical Region, as follows: Myrsidea antiqua, Myrsidea balteri, Myrsidea diffusa, Myrsidea nesomimi borealis, Myrsidea paleno, Myrsidea psittaci and Myrsidea serini. Our data increase knowledge of intraspecific morphological variability within these species, and also of their host and geographical distribution. New host-louse associations are: Agelaioides badius for M. psittaci; Basileuterus culicivorus and Myiothlypis leucoblephara for M. paleno; Mimus saturninus for M. nesomimi borealis; and Icterus dominicensis and Molothrus rufoaxillaris for Myrsidea sp.

Three new species of Myrsidea (Phthiraptera: Menoponidae) from New Zealand passerines (Aves: Passeriformes).

Myrsidea ivanliteraki new species, M. novaeseelandiae new species, and M. hihi new species are described and illustrated from New Zealand birds, with Gymnorhina tibicen, Anthornis melanura and Notiomystis cincta as type hosts respectively. Also, Myrsidea vincula is redescribed and illustrated from one sample ex Strepera fuliginosa from Australia. Keys for the identification of females and males of the five species of Myrsidea recorded from New Zealand are also given.