Co-phylogeny of a hyper-symbiotic system: Endosymbiotic bacteria (Gammaproteobacteria), chewing lice (Insecta: Phthiraptera) and birds (Passeriformes).

Chewing lice are hosts to endosymbiotic bacteria as well as themselves being permanent parasites. This offers a unique opportunity to examine the cophylogenetic relationships between three ecologically interconnected organismal groups: birds, chewing lice, and bacteria. Here, we examine the cophylogenetic relationships between lice in the genus Guimaraesiella Eichler, 1949, their endosymbiotic Sodalis-allied bacteria, and a range of bird species from across South China. Both event and distance-based cophylogenetic analyses were explored to compare phylogenies of the three organismal groups. Pair-wise comparisons between lice-endosymbionts and bird-endosymbionts indicated that their evolutionary histories are not independent. However, comparisons between lice and birds, showed mixed results; the distance-based method of ParaFit indicated that their evolutionary histories are not independent, while the event-based method of Jane indicated that their phylogenies were no more congruent than expected by chance. Notably, louse host-switching does not seem to have affected bacterial strains, as conspecific lice sampled from distantly related hosts share bacteria belonging to the same clade.

The Distribution of Quill Mites (Betasyringophiloidus seiuri) Among Flight Feathers of the Ovenbird (Seiurus aurocapilla).

Quill mites of the family Syringophilidae (Acariformes: Prostigmata) are permanent ectoparasites that live inside the hollow quills of feathers and use their long chelicerae to pierce the quill wall to feed on living tissue of the quill follicle. Ovenbirds (Parulidae: Seiurus aurocapilla (Linnaeus)) are host to the quill mite Betasyringophiloidus seiuri (Clark), which has been previously reported to infest only 5.1% of this host's tail feathers; however, this species has also been reported to inhabit the wing feathers of ovenbirds, but without any data on prevalence or intensity. We examined all 1,008 flight feathers from 21 dead ovenbirds from Canada for quill mites and calculated infestation parameters per feather location. Nine of the 21 birds were infested with mites (prevalence of 42.9%). Feathers with the highest prevalence were Primaries 1 and 2 and Secondaries 1, 2, and 5. Only 2 of the 9 infested birds had mites in their tail feathers; in each case, only a single feather was infested. Mean intensity was 28.4 mites/feather with a range of 2-135.6, and ∼88% of the adult mites were female. To determine if quill volume and quill wall thickness correlated with mite presence and abundance, we took quill measurements from the flight feathers of 3 additional ovenbirds. There was a strong positive correlation between quill volume and mean mite intensity. Feathers that had quill walls thicker in some areas than the mites' extended chelicerae had lower prevalences than did feathers with walls consistently thinner than the length of the chelicerae. We conclude that B. seiuri is much more likely to be found in wing than in tail feathers and that it has greater reproductive success in quills with both large volumes and thin walls; however, whether foundress mites preferentially choose to colonize these feathers requires more study.

Phylogeography of a migratory songbird across its Canadian breeding range: Implications for conservation units.

The objectives of this study were to describe and evaluate potential drivers of genetic structure in Canadian breeding populations of the Ovenbird, Seiurus aurocapilla. We performed genetic analyses on feather samples of individuals from six study sites using nuclear microsatellites. We also assessed species identity and population genetic structure of quill mites (Acariformes, Syringophilidae). For male Ovenbirds breeding in three study sites, we collected light-level geolocator data to document migratory paths and identify the wintering grounds. We also generated paleohindcast projections from bioclimatic models of Ovenbird distribution to identify potential refugia during the last glacial maximum (LGM, 21,000 years before present) as a factor explaining population genetic structure. Birds breeding in the Cypress Hills (Alberta/Saskatchewan) may be considered a distinct genetic unit, but there was no evidence for genetic differentiation among any other populations. We found relatively strong migratory connectivity in both western and eastern populations, but some evidence of mixing among populations on the wintering grounds. There was also little genetic variation among syringophilid mites from the different Ovenbird populations. These results are consistent with paleohindcast distribution predictions derived from two different global climate models indicating a continuous single LGM refugium, with the possibility of two refugia. Our results suggest that Ovenbird populations breeding in boreal and hemiboreal regions are panmictic, whereas the population breeding in Cypress Hills should be considered a distinct management unit.