title: Size matters for lice on birds: Coevolutionary allometry of host and parasite body size.
abstract: Body size is one of the most fundamental characteristics of all organisms. It influences physiology, morphology, behavior, and even interspecific interactions such as those between parasites and their hosts. Host body size influences the magnitude and variability of parasite size according to Harrison's rule (HR: positive relationship between host and parasite body sizes) and Poulin's Increasing Variance Hypothesis (PIVH: positive relationship between host body size and the variability of parasite body size). We analyzed parasite-host body size allometry for 581 species of avian lice (∼15% of known diversity) and their hosts. We applied phylogenetic generalized least squares (PGLS) methods to account for phylogenetic nonindependence controlling for host and parasite phylogenies separately and variance heterogeneity. We tested HR and PIVH for the major families of avian lice (Ricinidae, Menoponidae, Philopteridae), and for distinct ecological guilds within Philopteridae. Our data indicate that most families and guilds of avian lice follow both HR and PIVH; however, ricinids did not follow PIVH and the "body lice" guild of philopterid lice did not follow HR or PIVH. We discuss mathematical and ecological factors that may be responsible for these patterns, and we discuss the potential pervasiveness of these relationships among all parasites on Earth.
authors.affiliation: Department of Biomathematics and Informatics, University of Veterinary Medicine Budapest, István u. 2, H-1078, Budapest, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Harnos
authors.affiliation: Department of Biomathematics and Informatics, University of Veterinary Medicine Budapest, István u. 2, H-1078, Budapest, Hungary.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lang
authors.affiliation: Department of Biomathematics and Informatics, University of Veterinary Medicine Budapest, István u. 2, H-1078, Budapest, Hungary.
authors.forename: Dóra
authors.initials: D
authors.lastname: Petrás
authors.affiliation: Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah, 84112.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Bush
authors.affiliation: Department of Ecology, University of Veterinary Medicine Budapest, Rottenbiller u. 50, H-1077, Budapest, Hungary.
authors.forename: Krisztián
authors.initials: K
authors.lastname: Szabó
authors.affiliation: MTA-ELTE-MTM Ecology Research Group, Hungarian Academy of Sciences, Pázmány s. 1/C, H-1117, Budapest, Hungary.
authors.forename: Lajos
authors.initials: L
authors.lastname: Rózsa
mesh_terms: D058325:Amblycera / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D001715:Bird Diseases / Q000469:parasitology; D001717:Birds / Q000469:parasitology*; D049628:Body Size; D005260:Female; D006790:Host-Parasite Interactions; D058326:Ischnocera / Q000502:physiology*; D010373:Lice Infestations / Q000469:parasitology / Q000662:veterinary; D008297:Male
keywords: Harrison's rule; Phthiraptera; Poulin's increasing variance hypothesis; phylogenetic generalized least squares models