Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).

<p>Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).</p

Variation of <i>S. robustus</i> abundance by host body mass.

<p>Relationship between <i>S. robustus</i> abundance and host body mass: observed values (blank circles) and values predicted by the model at different host densities (lines). Host body mass had a positive effect on <i>S. robustus</i> abundance (p = 0.0005; parameter estimate: 0.0059±0.0017 SE).</p

Variation of <i>C. sciurorum</i> abundance by season (A) and host density (B).

<p>Mean abundance of <i>C. sciurorum</i> (sample size above standard error bars) varied during different seasons (p<0.0001) and at different host densities (p<0.0001). Squirrels trapped in spring were more infested than in autumn and winter (both sequential Bonferroni adjusted p<0.0001) and animals living in high-density sites were more infested then those living in medium- and low-density populations (both adjusted p<0.008).</p

Most prevalent gastro-intestinal helminths and arthropods (excluding mites) parasitizing grey squirrels in North America.

<p>Only parasites that were recorded by more than one author and with maximum prevalence >5% are reported. Studies with sample size <50 hosts were excluded.</p

Helminth species infecting grey squirrels in Piedmont and Lombardy populations.

<p>N: number of host examined; n: number of infected hosts; p: prevalence; mI: mean intensity (no. parasites infected/hosts; when number of infected hosts <5, worm counts in italic).</p

Variation of <i>S. robustus</i> abundance by host density.

<p>Mean abundance of <i>S. robustus</i> (sample size above standard error bars) varied with density of hosts in the site (p<0.0001). Squirrels living in high-density sites were more infested than individuals living in medium- and low-density sites (both sequential Bonferroni adjusted p<0.0001) and squirrels living in medium-density sites were more infested than in low-density sites (adjusted p = 0.0008).</p