Spatial variation in helminth community structure in the red-legged partridge (Alectoris rufaL.): effects of definitive host density

Abstract

Parasite community ecology has recently focused on understanding the forces structuring these communities. There are few surveys, however, designed to study the spatial repeatability and predictability of parasite communities at the local scale in one host. The purpose of our study was to address the relationship between infracommunity and component community richness, and to describe spatial variations on the local scale, of helminth parasite communities in an avian host, the red-legged partridge (Alectoris rufta). We sampled 235 wild partridges from 8 separate localities, with different partridge population densities, in the Ciudad Real and Toledo provinces of central Spain, and we determined their overall and intestinal helminth species. We found that habitat variables (mean temperature and land use) were not significantly associated with any component community. The partridge population abundance index was directly correlated with the prevalence and mean intensity of infection but not with component community species richness. There was a curvilinear relationship between infracommunity and component community species richness, as well as negative interspecific associations, for the helminth species assemblage parasitizing the intestine. A nestedness/anti-nestedness pattern, considered as part of a continuum, was associated with prevalence, mean intensity and partridge population abundance index, but not with component community richness. Increases in the partridge population abundance index and the prevalence and mean intensity of infection were associated with increases in helminth community nestedness. Although negative interactions between helminth species could not be ruled out as forces structuring helminth communities, our results suggest that parasite community structure in the red-legged partridge was primarily determined by the extrinsic influence of parasite habitat heterogeneity and its amplification of the differing probabilities of colonization of parasite species.

Temporal and between-site variation in helminth communities of bank voles (Myodes glareolus) from N.E. Poland. 2. The infracommunity level

“…This finding is consistent with earlier studies, which have generally shown that the greatest source of variation in quantitative data (abundance) fitted to statistical models derives from differences among sites Montgomery, 1989, 1990 ;Eira et al 2006) rather than to changes in time (Kisielewska, 1970 a ;Keymer and Dobson, 1987 ;Bajer et al 2005 ;Bugmyrin et al 2005). Therefore, at the level of infracommunity structure, there seems to be considerable medium-term stability in these communities and, as in other helminth and protozoan infections, the site from which animals are taken is critically important (Mollhagan, 1978 ;Thul et al 1985 ;Calvete et al 2004 ;Booth, 2006). The haplodiploid oxyurid nematodes can be singled out as the most problematic in studies of helminth communities and this is really because the tools we have to analyse communities cannot deal with their highly aggregated distributions.…”

Seasonal and habitat dependence of fleas parasitic on small mammals in Tanzania

“…The latter component is especially important for ectoparasites, which, in contrast to endoparasites, are strongly affected by the off-host environment. The diversity of the host's biotic and abiotic environment seems to be the main cause of the variation of parasite communities across host individuals, populations, species and communities (Calvete et al 2004). Therefore, some part of a parasite community encountered in a host is due to host identity, whereas another part is due to the host's environment (Kennedy & Bush 1994).…”

Relationships between local and regional species richness in flea communities of small mammalian hosts: saturation and spatial scale

“…The criticism was mainly related to statistical issues (Srivastava 1999), the definition of two spatial scales (Loreau 2000;Shurin et al 2000;Hillebrand and Blenckner 2002), and the effects of different types of interactions (Shurin and Allen 2001). Nevertheless, the use of regional to local diversity regressions remains common (Valone and Hoffman 2002;Heino et al 2003;Calvete et al 2004;Karlson et al 2004). The reason for this can be the methodological problems that arise when using some of recently suggested "unorthodox" approaches to compare between "local" and "regional" species richness.…”

“…This is the infracommunity, which includes all parasitic individuals of all species within an individual host. The measure of local parasite species richness is thus mean (e.g., Morand et al 1999) or maximum (e.g., Calvete et al 2004) infracommunity parasite species richness. The next hierarchical level is the component community of parasites, which is defined as all infracommunities within a give host population.…”

“…However, analyses of local-versus-regional species richness in parasites have revealed that saturated and unsaturated communities are equally common (e.g., Poulin 1996;Morand et al 1999;Kennedy and Guégan 1996;Calvete et al 2004). Guégan et al (2005) suggested that these contrasting results arise due to the fact that studies reporting linear relationships between the infracommunity and component community species richness tested this relationship among host species (e.g., Poulin 1996), whereas studies reporting curvilinear relationships between the two parameters compared different populations of the same host species (e.g., Calvete et al 2004).…”