title: Szidat's rule re-tested: relationships between flea and host phylogenetic clade ranks in four biogeographic realms.
abstract: We tested Szidat's rule (the more primitive the host, the more primitive the parasites it harbours) by analysing the relationships between phylogenetic clade ranks of fleas and their small mammalian hosts in four biogeographic realms (Afrotropics, Neotropics, Nearctic and Palearctic). From the host perspective, we tested the association between host clade rank and the mean clade rank of all fleas collected from this host. From the flea perspective, we tested the relationships between flea clade rank and the mean clade rank of hosts on which this flea was recorded. First, we tested whether the analysis of the relationships between host and flea clade ranks should be controlled for phylogenetic dependence among either host or flea species. Then, we tested for the associations between host and flea clade ranks separately for each realm using either a phylogenetic general least-squares analysis or an ordinary least-squares analysis. In all realms, the mean clade rank of fleas parasitic on a given host increased with an increase of this host's clade rank, and the mean clade rank of hosts recorded on a given flea increased with an increase of this flea's clade rank, suggesting that Szidat's rule, at least to some extent, holds for fleas.
authors.affiliation: Mitrani Department of Desert Ecology,Swiss Institute for Dryland Environmental and Energy Research,Jacob Blaustein Institutes for Desert Research,Ben-Gurion University of the Negev,Sede Boqer Campus,8499000 Midreshet Ben-Gurion,Israel.
authors.forename: Boris R
authors.initials: BR
authors.lastname: Krasnov
authors.affiliation: Mitrani Department of Desert Ecology,Swiss Institute for Dryland Environmental and Energy Research,Jacob Blaustein Institutes for Desert Research,Ben-Gurion University of the Negev,Sede Boqer Campus,8499000 Midreshet Ben-Gurion,Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Kiefer
authors.affiliation: Mitrani Department of Desert Ecology,Swiss Institute for Dryland Environmental and Energy Research,Jacob Blaustein Institutes for Desert Research,Ben-Gurion University of the Negev,Sede Boqer Campus,8499000 Midreshet Ben-Gurion,Israel.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Warburton
authors.affiliation: Wyler Department of Dryland Agriculture,French Associates Institute for Agriculture and Biotechnology of Drylands,Jacob Blaustein Institutes for Desert Research,Ben-Gurion University of the Negev,Sede Boqer Campus,8499000 Midreshet Ben-Gurion,Israel.
authors.forename: Irina S
authors.initials: IS
authors.lastname: Khokhlova
mesh_terms: D000818:Animals; D058267:Flea Infestations / Q000469:parasitology*; D006790:Host-Parasite Interactions; D016018:Least-Squares Analysis; D008322:Mammals / Q000145:classification* / Q000469:parasitology*; D010802:Phylogeny; D005423:Siphonaptera / Q000145:classification* / Q000502:physiology
keywords: Clade rank; fleas; mammals; phylogeny