Host patch traits have scale‐dependent effects on diversity in a stickleback parasite metacommunity

Abstract

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

Scale‐dependent effects of host patch traits on species composition in a stickleback parasite metacommunity

“…Both trends are consistent with these parasites’ limnetic and benthic first hosts, respectively, and corroborate a prior study (Stutz et al 2014). Host sex affected infection rates for several parasites (Appendix : Table S2), typically with higher infection rates in females, who also had higher parasite richness (Bolnick et al 2020). Schistocephalus was the sole species that was significantly more common in males than in females, consistent with males’ tendency towards a more limnetic diet (Fig.…”

“…To quantify the effect of host genetic variation on parasite distributions, we used ddRADseq (Peterson et al 2012) to obtain single nucleotide polymorphism (SNP) genotypes from a subsample of 12 fish from each of 31 lakes (Table S1 in Bolnick et al 2020). Protocols, bioinformatics steps, and SNP filtering are exactly as described in Stuart et al (2017).…”

“…We identify scale‐independent and scale‐dependent factors influencing parasite community composition. A related paper (Bolnick et al 2020) uses these same data to examine scale dependence of factors regulating parasite species richness, an emergent property of the processes considered here.…”

What evolutionary processes maintain MHCIIβ diversity within and among populations of stickleback?

“…Details are provided in Bolnick & Ballare (2020). These samples were used to examine within- and between-population variation in diet (Bolnick & Ballare, 2020), parasite community composition (Bolnick, Resetarits, Ballare, Stuart, & Stutz, 2019), and parasite species richness (Bolnick, Resetarits, Ballare, Stuart, & Stutz, 2020). The parasite infection data for this study are archived at Dryad Digital Repository (Bolnick and Ballare, 2020).…”

What evolutionary processes maintain MHCIIβ diversity within and among populations of stickleback?

“…Details are provided in . These samples were used to examine within-and between-population variation in diet , parasite community composition (Bolnick, Resetarits, Ballare, Stuart, & Stutz, 2019), and parasite species richness (Bolnick, Resetarits, Ballare, Stuart, & Stutz, 2020). The parasite infection data for this study are archived at Dryad Digital Repository .…”