Scale-dependent effects of geography, host ecology, and host genetics on diversity of a stickleback parasite metacommunity

Abstract

18Many metacommunities are distributed across habitat patches that are themselves aggregated 19 into groups. Perhaps the clearest example of this nested metacommunity structure comes from 20 multi-species parasite assemblages, which occupy individual hosts that are aggregated into host 21 populations. At both spatial scales, we expect parasite community diversity in a given patch 22 (either individual host or population) to depend on patch characteristics that affect colonization 23 rates and species sorting. But, are these patch effects consistent across spatial scales? Or, do 24 different processes govern the distribution of parasite community diversity among individual 25 hosts, versus among host patches? To answer these questions, we document the distribution of 26 parasite richness among host individuals and among populations in a metapopulation of 27 threespine stickleback (Gasterosteus aculeatus). We find some host traits (host size, gape width) 28 are associated with increased parasite richness at both spatial scales. Other patch characteristics 29 affect parasite richness only among individuals (sex), or among populations (lake size, lake area, 30 elevation, and population mean heterozygosity). These results demonstrate that some rules 31 governing parasite richness in this metacommunity are shared across scales, while others are 32 scale-specific. 33

Resource diversity promotes among‐individual diet variation, but not genomic diversity, in lake stickleback

“…As described in Bolnick et al . (preprint), this effect of lake size is independent of variation in lake elevation or distance from the ocean. However, this among‐lake variation in heterozygosity had no detectable effect on among‐individual diet variation, E ( r = −0.174; P = 0.425; Fig.…”

“…This variation in lake size is uncorrelated with other biogeographic features such as elevation, distance up‐river from the ocean, or proximity to other lakes, that also contribute to variation in population genetic diversity (Bolnick et al . preprint). Lake sizes were obtained from the British Columbia Ministry of the Environment HabitatWizard (http://maps.gov.bc.ca/ess/hm/habwiz/), supplemented by surface area analysis of GoogleEarth satellite images for the smallest lakes that were not listed on HabitatWizard.…”