The decay of parasite community similarity in ring‐billed gulls Larus delawarensis and other hosts

Abstract

The similarity of parasite communities often decays with increasing geographic distance. Here, geographic distance decay is evaluated in parasite communities of 145 ring‐billed gulls from six localities in Quebec, Canada, among both individual gulls and gull populations. Spatial decay in similarity is compared to temporal decay, using host age differences as a distance measure. The similarity of parasite communities of individual gulls from localities spanning 300 km within Quebec is more strongly associated with host age differences than with geographic distance. Among gull populations in Quebec, only geographic distance is significantly related to parasite community similarity. The explanatory power of geographic distance is higher still when data from Quebec are combined with those from a study conducted 3000 km away, indicating an effect of spatial scale on geographic distance decay. The rate at which parasite community similarity decays with distance in gulls is compared with that of 17 other host species using data from published studies. Spatial scale explains two thirds of the variance in distance decay rates, and some of the remaining variance is explained by latitude. The rate of decay in parasite community similarity with distance is greater in larger scale studies and further away from the equator. Traits of host species traits such as vagility, body weight and trophic level have little or no effect on distance decay rates.

Effect of habitat use and diet on the gastrointestinal parasite community of an avian omnivore from an urbanized environment

“…In Ring-billed Gulls nesting on a single island adjacent to Montréal, we isolated 20 parasite genera, a diversity similar to the 23 genera recorded in 145 gulls of multiple age classes sampled in a broader range of Montréal-area habitats in 1994 and 1995 (Locke et al 2012). The most prevalent and abundant genera were Wardium and Diplostomum, which are acquired from freshwater prey.…”

“…Although this approach underestimates parasite richness, it was assumed to have negligible effect on the relationship between parasites and foraging habitat utilization and diet. Moreover, taxonomic and identification difficulties make species-level diagnosis in the most diverse genera (Diplostomum (Trematoda: Digenea) and Wardium (Cestoda)) unachievable, and other genera previously found in this Ring-billed Gull population were represented by single species (Locke et al 2012). Prevalence is defined as the percentage of hosts infected with a particular parasite taxon and mean abundance is defined as the mean number of parasites of a given taxon per host, including uninfected birds (Bush et al 1997).…”

“…In a recently published survey from our study area, gastrointestinal (GI) parasites were examined in migratory Ring-billed Gulls breeding in various colonies in the St. Lawrence River close to Montréal and eastwards in 1994-1995(Locke et al 2012. The majority of the helminth species recovered were transmitted through intermediate aquatic hosts (e.g., fish and arthropods), but some birds were infected by species with terrestrial life cycles.…”

Parasite communities of two three-spined stickleback populations in subarctic Norway—effects of a small spatial-scale host introduction

“…Changes in these factors through space may contribute to the widely observed tendency for parasite community similarity to decrease with increasing geographical distance (Poulin and Morand 1999;Poulin 2003;Pérez-del-Olmo et al 2009;Locke et al 2012). Accordingly, we expect that sites separated by small geographical distances would have similar biotic and abiotic factors, important for the successful colonization of parasites, leading to high similarity between parasite communities on a small spatial scale.…”

Mite‐y bees: bumble bees (Bombus spp., Hymenoptera: Apidae) host a relatively homogeneous mite (Acari) community, shaped by bee species identity but not by geographic proximity

“…E-mail: shaas014@yorku.ca * Current address: York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3 Canada host generally determines the identities of these symbionts (Hechinger & Lafferty, 2005). Poulin & Morand, 1999;Davies & Pedersen, 2008;Jaatinen et al, 2009;Locke et al, 2012). For symbionts, the host and/or its nest represent their main resource reservoir; therefore, the availability and heterogeneity of hosts ought to shape the communities of symbionts.…”