Brueelia lice

Brewer, Paige J. & Sweet, Andrew D., 2023, Prevalence and diversity of parasitic bird lice (Insecta: Psocodea) in northeast Arkansas, International Journal for Parasitology: Parasites and Wildlife 22, pp. 205-215 : 213

4.5. Phylogenetic patterns of lice reflect host taxonomy and ecology

Based on the concatenated gene phylogenies of Myrsidea and Brueelia , these lice typically have close evolutionary relationships to lice from similar host taxonomic groups or shared habitats. Lice often rely on specific host morphology, such as feather and body size, for survival ( Johnson et al., 2005). These host traits are often shared among species in the same taxonomic family or order. For example, our samples of Brueelia and Myrsidea lice from Turdidae were in monophyletic groups with other Turdidae lice. This is possibly due to similar host body sizes and habitats which allow lice to disperse and survive on multiple thrush species. Lice primarily rely on direct contact between hosts for dispersal ( Rothschild and Clay 1952; Clayton and Tompkins, 1994; Brooke, 2010). Because interactions are often higher among individuals in shared habitats, those could increase opportunity for distantly related hosts to share parasites ( Brooke, 2010). For example, a Brueelia louse from D. carolinensis was grouped together with lice from several species of Passerellidae and S. aurocapilla . Although D. carolinensis is not closely related or morphologically similar to Passerellidae or Parulidae , this relationship could have occurred because of the shared understory habitat between these hosts. Similarly, Brueelia lice from Passerellidae and S. aurocapilla were clustered together. Although these two hosts are not closely related, the relationships among their lice might occur from utilizing similar habitats, which could increase the likelihood of lice dispersing between the two hosts. Furthermore, Myrsidea lice from S. aurocapilla , C. cardinalis and S. ruticilla were sorted together despite their distantly related hosts. This mixed group of hosts could also be related to the shared habitat of these species ( Burke and Nol, 1998; Leston and Rodewald, 2006; Donajkowski, 2009).

Although host taxonomy and habitat as drivers of louse evolutionary relationships were supported by several examples, there were some notable exceptions. For example, in the Myrsidea phylogeny two lice from S. aurocapilla , including a louse from a previous study, were distantly related to the other S. aurocapilla lice. The genetic separation of these lice could reflect morphologically ambiguous yet reproductively isolated cryptic species. We found a similar pattern in some Brueelia lice from M. ater . Our two samples of M. ater lice were grouped together but were distantly related to M. ater lice from a previous study. This relationship could be related to the brood parasitism strategy of M. ater . Brood parasites rely on non-related individuals, usually of different species, to raise offspring of the brood parasite ( Servedio and Hauber, 2006). This type of interaction could allow lice from the host parent to transfer lice to M. ater . Furthermore, the decrease in louse transfers among familial M. ater could decrease gene flow among lice and allow species divergence of the lice. Although M. ater have particular species of lice that are acquired from interactions with other M. ater , our results indicate a possible unrecorded association or cryptic diversity from either a parasitized or M. ater louse species ( Clayton and Johnson, 2001). Future work should rely on morphological characters to rigorously assess the taxonomy of potentially cryptic species identified in our phylogeny.