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Abstract Avian feather lice (Phthiraptera: Ischnocera) have undergone morphological diversification into ecomorphs based on how they escape host preening defences. Parrot lice are one prominent example of this phenomenon, with wing, body, or head louse ecomorphs occurring on various groups of parrots. Currently defined genera of parrot lice typically correspond to this ecomorphological variation. Here we explore the phylogenetic relationships among parrot feather lice by sequencing whole genomes and assembling a target set of 2395 nuclear protein coding genes. Phylogenetic trees based on concatenated and coalescent analyses of these data reveal highly supported trees with strong agreement between methods of analysis. These trees reveal that parrot feather lice fall into two separate clades that form a grade with respect to the Brueelia-complex. All parrot louse genera sampled by more than one species were recovered as monophyletic. The evolutionary relationships among these lice showed evidence of strong biogeographic signal, which may also be related to the relationships among their hosts.
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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.
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- PAR ID:
- 10546517
- Publisher / Repository:
- The Royal Society Publishing
- Date Published:
- Journal Name:
- Proceedings of the Royal Society B: Biological Sciences
- Volume:
- 291
- Issue:
- 2019
- ISSN:
- 0962-8452
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1098/rspb.2023.2665
