title: Body size evolution of oxyurid (Nematoda) parasites: the role of hosts.
abstract: Studying the diversification of body size in a taxon of parasites allows comparison of patterns of variation observed in the parasites with patterns found in free-living organisms. The distributions of body size of oxyurid nematodes (obligate parasites of vertebrates and invertebrates) are lognormally right-skewed, except for male oxyurids in invertebrates which show left-skewed distributions. In these parasitic forms, speciose genera do not have the smallest body sizes. Parasite body size is positively correlated with host body size, the largest hosts possessing the largest parasites. This trend is shown to occur within one monophyletic group of oxyurids, those of Old World primates. Comparative methods are used to take account of the effects of phylogeny. The use of multiple linear regression on distance matrices allows measurements of the contribution of phylogeny to the evolution of body size of parasites. Evolution of body size in female pinworms of Old World primates appears to be dependent only on the body size of their hosts. The tendency of parasite body size to increase with host body size is discussed in the light of the evolution of life-history traits.
authors.affiliation: Centre de Biologie et d'Écologie tropicale et méditerranéenne, Laboratoire de Biologie Animale (Unité de Recherche Associée au CNRS 698), Université de Perpignan, Avenue Villeneuve, 66860, Perpignan, France.
authors.forename: Serge
authors.initials: S
authors.lastname: Morand
authors.affiliation: Department de sciences biologiques, Université de Montréal, Succ. A, C.P. 6128, H3C 3J7, Montréal, Québec, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Legendre
authors.affiliation: Laboratory of Parasitology, University of Nebraska State Museum, University of Lincoln, 68588-0514, Nebraska, USA.
authors.forename: Scott Lyell
authors.initials: SL
authors.lastname: Gardner
authors.affiliation: Laboratoire de Biologie parasitaire (Unité de Recherche Associée au CNRS 114b0), Muséum National d'Histoire Naturelle, 75231, Paris Cedex 05, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Hugot
keywords: Body size; Host-parasite relationship; Independent comparisons; Lognormally skewed distribution; Nematodes