A Harrison-szabály és Poulin növekvő variancia elméletének tesztelése a Ricinidae és a Philopteridae tetűcsaládokban

A century ago Lancelot Harrison (1915) concluded that in host-parasite relationships a bigger host has bigger parasites than the small ones. This positive correlation, known as Harrison’s rule, was tested in many studies and seems to be true in many different parasite taxa. This hypothesis was supplemented by Robert Poulin. He proposed that not only the mean, but also the variance of parasite body size should increase with the increasing host body size, because small parasites species can live in both small- and large-bodied hosts. This latter hypothesis has never been tested. The aim of this study was to test Harrison’s rule and Puolin’s hypothesis across the louse families Ricinidae and Philoteridae (Insecta: Phthiraptera)

Size matters for lice on birds: Coevolutionary allometry of host and parasite body size

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Data from: Size matters for lice on birds: coevolutionary allometry of host and parasite body size

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 methods to account for phylogenetic non-independence 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

Louse and host bird body sizes by louse families

Louse species (families), louse female total body length (obtained from taxonomic descriptions, see Supplements of our paper), host birds name and body mass (obtained from Dunning, 2008). Families are coded as: M: Menoponidae; R: Ricinidae; P: Philopteridae

Louse and host bird body sizes by Philopterid guilds

Louse species, female total body length, host species, host body mass, and louse guilds. Guilds are coded as: H: 'head lice'; W: wing lice; B: 'body lice'; G: generalists