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While mitochondrial genome content and organization is quite diverse across all Eukaryotes, most bilaterian animal mitochondrial genomes (mitogenomes) exhibit highly conserved gene content and organisation, with genes typically encoded on a single circular chromosome. However, many species of parasitic lice (Insecta: Phthiraptera) are among the notable exceptions, having mitogenomes fragmented into multiple circular chromosomes. To better understand the process of mitogenome fragmentation, we conducted a large-scale genomic study of a major group of lice, Amblycera, with extensive taxon sampling. Analyses of the evolution of mitogenome structure across a phylogenomic tree of 90 samples from 53 genera revealed evidence for multiple independent origins of mitogenome fragmentation, some inferred to have occurred less than five million years ago. We leveraged these many independent origins of fragmentation to compare the rates of DNA substitution and gene rearrangement, specifically contrasting branches with fragmented and non-fragmented mitogenomes. We found that lineages with fragmented mitochondrial genomes had significantly higher rates of mitochondrial sequence evolution. In addition, lineages with fragmented mitochondrial genomes were more likely to have mitogenome gene rearrangements than those with single-chromosome mitochondrial genomes. By combining phylogenomics and mitochondrial genomics we provide a detailed portrait of mitogenome evolution across this group of insects with a remarkably unstable mitogenome structure, identifying processes of molecular evolution that are correlated with mitogenome fragmentation.

The sucking louse Haematopinus tuberculatus (Burmeister 1839) is an ectoparasite of buffaloes, cattle, camels, and American bison. Alphacypermethrin (ACYP) is a pyrethroid insecticide commonly used to control arthropods of veterinary and public health interest. Therapeutics, such as antiparasitic compounds, is often administered to buffaloes based on dosage and intervals recommended for cattle because very few drugs have buffalo-specific label indications. A trial was conducted on 20 louse-infested buffaloes at a farm to assess the efficacy and safety of ACYP pour-on, at the manufacturer’s recommended dose for cattle, on buffaloes naturally infested by H. tuberculatus. Ten animals were assigned to ACYP-treated group (ACYP-group) and ten to untreated control group (C-group). On day 0, all ACYP-group buffaloes received alphacypermethrin pour-on. Louse counts were performed on days −1, 7, 14, 21, 28, 35, 42, 49, and 56 at eight predilection sites on the skin of each buffalo. ACYP was completely effective (100 %) at day 7, highly effective (99.8 %) at day 14, and completely effective (100 %) from day 21 until the end of the study (day 56 post-treatment). During the trial, ACYP was well tolerated by all animals as there were no observed clinically adverse reactions. The results of this trial suggest that ACYP is an effective, safe, and user-friendly compound suitable for treatment of buffaloes with natural louse infestations.

Parasitic “wing lice” (Phthiraptera: Columbicola) and their dove and pigeon hosts are a well-recognized model system for coevolutionary studies at the intersection of micro- and macroevolution. Selection on lice in microevolutionary time occurs as pigeons and doves defend themselves against lice by preening. In turn, behavioral and morphological adaptations of the lice improve their ability to evade host defense. Over macroevolutionary time wing lice tend to cospeciate with their hosts; yet, some species of Columbicola have switched to new host species. Understanding the ecological and evolutionary factors that influence coadaptation and codiversification in this system will substantially improve our understanding of coevolution in general. However, further work is hampered by the lack of a robust phylogenetic framework for Columbicola spp. and their hosts. Previous attempts to resolve the phylogeny of Columbicola based on sequences from a few genes provided limited support. Here, we apply a new approach, target restricted assembly, to assemble 977 orthologous gene sequences from whole-genome sequence data generated from very small, ethanol-preserved specimens, representing up to 61 species of wing lice. Both concatenation and coalescent methods were used to estimate the species tree. These two approaches yielded consistent and well-supported trees with 90% of all relationships receiving 100% support, which is a substantial improvement over previous studies. We used this new phylogeny to show that biogeographic ranges are generally conserved within clades of Columbicola wing lice. Limited inconsistencies are probably attributable to intercontinental dispersal of hosts, and host switching by some of the lice.

Chewing lice (Phthiraptera) are obligate and permanent ectoparasites commonly found on birds. The life cycle of these insects is completed on the body of the host and therefore many are host specific. This is the first report of chewing lice on a wild Golden eagle ( Aquila chrysaetos ) and a zoo-kept Eurasian griffon vulture ( Gyps fulvus ) in Tyrol, Austria. Three different species of chewing lice were identified: Craspedorrhynchus aquilinus was found on Aquila chrysaetos and Colpocephalum turbinatum and Falcolipeurus quadripustulatus were found on Gyps fulvus . The lice were identified morphologically and by barcoding. Chewing lice (Phthiraptera) of eagles, vultures, and other Accipitriformes are understudied, and further research is needed.

Lice (Phthiraptera) are obligate ectoparasites of birds and mammals found worldwide. Chewing lice, belonging to the families Menoponidae and Philopteridae, are particularly diverse in Brazil, although their distribution is unevenly documented across states. This study focused on recent collections from protected areas in Maranhão and Piauí, the sampling involved mist netting and comprehensive ectoparasite examination, with specimens identified using both light microscopy and Scanning Electron Microscopy. A total of 239 birds were collected, 63 (26.35%) of which were infested with chewing lice. Seventeen distinct species were identified, including seven that had not been previously recorded in Brazil. Our findings contribute to the growing knowledge of chewing lice diversity in Brazil, with particular emphasis on the underrepresented states of Maranhão and Piauí.

Unlike most bird species, individual kingfisher species (Aves: Alcedinidae) are typically parasitized by only a single genus of louse (Alcedoffula, Alcedoecus, or Emersoniella). These louse genera are typically specific to a particular kingfisher subfamily. Specifically, Alcedoecus and Emersoniella parasitize Halcyoninae, whereas Alcedoffula parasitizes Alcedininae and Cerylinae. Although Emersoniella is geographically restricted to the Indo-Pacific region, Alcedoecus and Alcedoffula are geographically widespread. We used DNA sequences from two genes, the mitochondrial COI and nuclear EF-1α genes, to infer phylogenies for the two geographically widespread genera of kingfisher lice, Alcedoffula and Alcedoecus. These phylogenies included 47 kingfisher lice sampled from 11 of the 19 currently recognized genera of kingfishers. We compared louse phylogenies to host phylogenies to reconstruct their cophylogenetic history. Two distinct clades occur within Alcedoffula, one that infests Alcedininae and a second that infests Cerylinae. All species of Alcedoecus were found only on host species of the subfamily Halcyoninae. Cophylogenetic analysis indicated that Alcedoecus, as well as the clade of Alcedoffula occurring on Alcedininae, do not show evidence of cospeciation. In contrast, the clade of Alcedoffula occurring on Cerylinae showed strong evidence of cospeciation.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now routinely used for the rapid identification of microorganisms isolated from clinical samples and has been recently successfully applied to the identification of arthropods. In the present study, this proteomics tool was used to identify lice collected from livestock and poultry in Algeria. The MALDI-TOF MS spectra of 408 adult specimens were measured for 14 species, including Bovicola bovis, B. ovis, B. caprae, Haematopinus eurysternus, Linognathus africanus, L. vituli, Solenopotes capillatus , Menacanthus stramineus , Menopon gallinae, Chelopistes meleagridis , Goniocotes gallinae , Goniodes gigas, Lipeurus caponis and laboratory reared Pediculus humanus corporis . Good quality spectra were obtained for 305 samples. Spectral analysis revealed intra-species reproducibility and inter-species specificity that were consistent with the morphological classification. A blind test of 248 specimens was performed against the in-lab database upgraded with new spectra and validated using molecular tools. With identification percentages ranging from 76% to 100% alongside high identification scores (mean = 2.115), this study proposes MALDI-TOF MS as an effective tool for discriminating lice species. La Spectrométrie de Masse à Temps de Vol par Désorption/Ionisation Laser Assistée après Matrice est maintenant utilisée pour l’identification rapide des microorganismes isolés à partir d’échantillons cliniques et a récemment été appliquée avec succès pour l’identification des arthropodes. Dans cette étude, cet outil protéomique a été utilisé pour identifier les poux prélevés sur le bétail et la volaille en Algérie. Les spectres MALDI-TOF MS de 408 spécimens adultes ont été mesurés pour 14 espèces, dont Bovicola bovis , B. ovis , B. caprae , Haematopinus eurysternus, Linognathus africanus , L. vituli , Solenopotes capillatus , Menacanthus stramineus , Menopon gallinae , Chelopistes meleagridis , Goniocotes gallinae , Goniodes gigas , Lipeurus caponis et Pediculus humanus corporis élevé en laboratoire. Des spectres de bonne qualité ont été obtenus pour 305 échantillons. L’analyse spectrale a révélé une reproductibilité intra-espèce et une spécificité inter-espèces qui concordaient avec la classification morphologique. Un test à l’aveugle de 248 échantillons a été effectué par rapport à la base de données de notre laboratoire mise à niveau avec de nouveaux spectres et validée à l’aide d’outils moléculaires. Avec des pourcentages d’identification allant de 76 à 100 % et des scores d’identification élevés (moyenne : 2,115), cette étude propose MALDI-TOF MS comme un outil efficace pour distinguer les espèces de poux.

Rensch’s rule (RR) postulates that in comparisons across closely related species, male body size relative to female size increases with the average size of the species. This holds true in several vertebrate and also in certain free-living invertebrate taxa. Here, we document the validity of RR in avian lice using three families (Philopteridae, Menoponidae, and Ricinidae). Using published data on the body length of 989 louse species, subspecies, or distinct intraspecific lineages, we applied phylogenetic reduced major axis regression to analyse the body size of females vs. males while accounting for phylogenetic non-independence. Our results indicate that philopterid and menoponid lice follow RR, while ricinids exhibit the opposite pattern. In the case of philopterids and menoponids, we argue that larger-bodied bird species tend to host lice that are both larger in size and more abundant. Thus, sexual selection acting on males makes them relatively larger, and this is stronger than fecundity selection acting on females. Ricinids exhibit converse RR, likely because fecundity selection is stronger in their case.

The study of the structure of ectoparasite communities in wild mammals is fundamental, as it contributes to comprehend the ecological and health dynamics of these systems. This study analyzed the structure of ectoparasite communities in wild carnivores and rodents in central Chihuahua, Mexico, considering biological variables of the hosts (species and sex) and environmental factors such as temperature in one year cycle. A total of 745 ectoparasites were collected, including 738 fleas (seven species, two families), four lice (two species), and one tick species. Seasonal variation and host family significantly influenced the presence and frequency of ectoparasites. Flea species clustered by host group: Pulicidae predominated in carnivores, with Pulex simulans being the most abundant species during winter, while Ceratophyllidae dominated in rodents, with Malaraeus eremicus as the most abundant flea in autumn-winter and Jellisonia sp. nva. in spring-summer. No significant interspecific interactions were observed among flea species. In rodents, no significant relationship was found between the rodent’s sex and the presence of fleas. In northern Mexico, studies on the composition and interactions of ectoparasite communities in wild mammals and their seasonal structuring are scarce. This research provides new records of ectoparasite-host interactions in the state of Chihuahua, Mexico, and updates current knowledge on how biological and climatic factors influence ectoparasite community behavior. These findings offer valuable insights for biology, public health, and species conservation.

Parasitic lice (order Phthiraptera) infest birds and mammals. The typical animal mitochondrial (mt) genome organization, which consists of a single chromosome with 37 genes, was found in chewing lice in the suborders Amblycera and Ischnocera. The sucking lice (suborder Anoplura) known, however, have fragmented mt genomes with 9–20 minichromosomes. We sequenced the mt genome of the elephant louse, Haematomyzus elephantis – the first species of chewing lice investigated from the suborder Rhynchophthirina. We identified 33 mt genes in the elephant louse, which were on 10 minichromosomes. Each minichromosome is 3.5–4.2 kb in size and has 2–6 genes. Phylogenetic analyses of mt genome sequences confirm that the elephant louse is more closely related to sucking lice than to the chewing lice in the Amblycera and Ischnocera. Our results indicate that mt genome fragmentation is shared by the suborders Anoplura and Rhynchophthirina. Nine of the 10 mt minichromosomes of the elephant louse differ from those of the sucking lice (Anoplura) known in gene content and gene arrangement, indicating that distinct mt karyotypes have evolved in Anoplura and Rhynchophthirina since they diverged ~92 million years ago.