Lineage sorting in multihost parasites: Eidmanniella albescens and Fregatiella aurifasciata on seabirds from the Galapagos Islands

Abstract

Parasites comprise a significant percentage of the biodiversity of the planet and are useful systems to test evolutionary and ecological hypotheses. In this study, we analyze the effect of host species identity and the immediate local species assemblage within mixed species colonies of nesting seabirds on patterns of genetic clustering within two species of multihost ectoparasitic lice. We use three genetic markers (one mitochondrial, COI, and two nuclear, EF1-α and wingless) and maximum likelihood phylogenetic trees to test whether (1) parasites show lineage sorting based on their host species; and (2) switching of lineages to the alternate host species depends on the immediate local species assemblage of individual hosts within a colony. Specifically, we examine the genetic structure of two louse species: Eidmanniella albescens, infecting both Nazca (Sula granti) and blue-footed boobies (Sula nebouxii), and Fregatiella aurifasciata, infecting both great (Fregata minor) and magnificent frigatebirds (Fregata magnificens). We found that host species identity was the only factor explaining the patterns of genetic structure in both parasites. In both cases, there is evident genetic differentiation depending on the host species. Thus, a revision of the taxonomy of these louse species is needed. One possible explanation of this pattern is extremely low louse migration rates between host species, perhaps influenced by fine-scale spatial separation of host species within mixed colonies, and low parasite infrapopulation numbers.

“More Than Meets the Eye”: Cryptic Diversity and Contrasting Patterns of Host-Specificity in Feather Mites Inhabiting Seabirds

“…This scenario also offers the opportunity to test parasite/symbiont structure at hierarchical spatial scales (among host individuals, populations and communities), and make predictions on selection and adaptation processes (McCoy et al, 2001). Not surprisingly, few studies have used this multispecies and multi-scale approach (but see Johnson et al, 2002;Rivera-Parra et al, 2015).…”

Colonization of Parasites and Vectors

“…Parasites that colonized the Galapagos with their vertebrate hosts share patterns of distribution and evolutionary history with their hosts. Rivera-Parra et al (2015) showed that the species identity of the host was more important than sampling location for determining the phylogenetic relationships within each species of louse parasitizing two related seabird species, despite the fact that the hosts breed together in dense mixed-species colonies. However, these lice have different prevalence on different islands, demonstrating that the relationships among parasites, hosts, and islands are idiosyncratic (Rivera-Parra et al 2014).…”

WiSPA: A new approach for dealing with widespread parasitism

“…Cophylogeny mapping algorithms aim to map P into H, where the number of codivergence events is maximised and the map cost E is minimised (Charleston and Libeskind-Hadas 2014). Although such cost schemes may not evaluate coevolutionary scenarios exactly, particularly modelling preferential host switching (Charleston and Robertson 2002), this technique has been used to evaluate a large number of coevolutionary systems (Page 2002;Page et al 2004;Jackson and Charleston 2004;Cruaud et al 2012;Rivera-Parra et al 2015).…”