Phylogenetic analysis of beak and feather disease virus across a host ring-species complex

Abstract

Pathogens have been hypothesized to play a major role in host diversity and speciation. Susceptibility of hybrid hosts to pathogens is thought to be a common phenomenon that could promote host population divergence and subsequently speciation. However, few studies have tested for pathogen infection across animal hybrid zones while testing for codivergence of the pathogens in the hybridizing host complex. Over 8 y, we studied natural infection by a rapidly evolving single-strand DNA virus, beak and feather diseases virus (BFDV), which infects parrots, exploiting a host-ring species complex (Platycercus elegans) in Australia. We found that host subspecies and their hybrids varied strikingly in both BFDV prevalence and load: both hybrid and phenotypically intermediate subspecies had lower prevalence and load compared with parental subspecies, while controlling for host age, sex, longitude and latitude, as well as temporal effects. We sequenced viral isolates throughout the range, which revealed patterns of genomic variation analogous to Mayr's ring-species hypothesis, to our knowledge for the first time in any host-pathogen system. Viral phylogeny, geographic location, intraspecific host density, and parrot community diversity and composition did not explain the differences in BFDV prevalence or load between subpopulations. Overall, our analyses suggest that functional host responses to infection, or force of infection, differ between subspecies and hybrids. Our findings highlight the role of host hybridization and clines in altering host-pathogen interactions, dynamics that can have important implications for models of speciation with gene flow, and offer insights into how pathogens may adapt to diverging host populations.psittacine circovirus | host-pathogen coevolution | heterosis | sympatric speciation | crimson rosella

Spectral sensitivity of cone photoreceptors and opsin expression in two colour-divergent lineages of the lizardCtenophorus decresii

“…The carotenoid-rich oil droplets found in the retinas of all birds, lungfish and many reptiles (Goldsmith et al, 1984;Vorobyev, 2003;Walls, 1942) are also a potential source of intraspecific variation in visual sensitivity, because the density of pigments in these droplets is known to be affected by external variables such as diet (Bowmaker et al, 1993;Knott et al, 2010) and ambient light intensity (Hart et al, 2006). However, comparisons of morphs and subspecies of varying plumage coloration (Eastwood et al, 2014) have so far not revealed systematic differences in visual sensitivity (Knott et al, 2012(Knott et al, , 2013, even when the species has intraspecific variation in acoustic and visual signals Ribot et al, 2009Ribot et al, , 2012.…”

Nest box design for a changing climate: The value of improved insulation

“…The nest boxes used in this study are of a typical design, construction and placement for nest boxes in Australia and elsewhere and are commonly occupied by small‐ to medium‐sized birds such as rosellas (Berg & Ribot ; Eastwood et al . ; Mihailova et al . ; Larson et al .…”

Olfactory eavesdropping: The odor of feathers is detectable to mammalian predators and competitors

“…During this period, CRP were by far the most common mammal to occupy nest boxes at this site, but CBPs also occurred. This timing was chosen to avoid interference with rosella reproduction in the nest boxes, which is monitored as part of other studies (Eastwood et al., , ; Knott et al., ; Larson et al., ; Mihailova et al., ; Ribot et al., ).…”