DOI: 10.5061/dryad.mv332
title: Data from: A hyperparasite affects the population dynamics of a wild plant pathogen

description: Assessing the impact of natural enemies of plant and animal pathogens on
 their host's population dynamics is needed to determine the role of
 hyperparasites in affecting disease dynamics, and their potential for use
 in efficient control strategies of pathogens. Here we focus on the
 long-term study describing metapopulation dynamics of an obligate
 pathogen, the powdery mildew (Podosphaera plantaginis) naturally infecting
 its wild host plant (Plantago lanceolata) in the fragmented landscape of
 the Åland archipelago (southwest Finland). Regionally, the pathogen
 persists through a balance of extinctions and colonizations, yet factors
 affecting extinction rates remain poorly understood. Mycoparasites of the
 genus Ampelomyces appear as good candidates for testing the role of a
 hyperparasite, i.e. a parasite of other parasites, in the regulation of
 their fungal hosts’ population dynamics. For this purpose, we first
 designed a quantitative PCR assay for detection of Ampelomyces spp. in
 field-collected samples. This newly developed molecular test was then
 applied to a large-scale sampling within the Åland archipelago, revealing
 that Ampelomyces is a widespread hyperparasite in this system, with high
 variability in prevalence among populations. We found that the
 hyperparasite was more common on leaves where multiple powdery mildew
 strains coexist, a pattern that may be attributed to differential
 exposure. Moreover, the prevalence of Ampelomyces at the plant level
 negatively affected the overwinter survival of its fungal host. We
 conclude that this hyperparasite may likely impact on its host population
 dynamics and argue for increased focus on the role of hyperparasites in
 disease dynamics.
description: Population level
 datasetThe excel file contains
 for each population: the name (Patch_ID), informations on the location
 (commune, village and geographic coordinates), the fraction of leaves
 bearing chamsothecia averaged over the analyzed plants (prop_chasmos), the
 powdery mildew abundance in July 2012 (PM_AA_july12), the total number of
 samples analyzed, the number of samples positive for
 Ampelomyces.Hyperparasite_patch_level_data.xlsxSample level datasetThe excel file contains for each sample: the name (Sample_ID), the population of origin (Patch), the plant name (Plant_Code), the fraction of leaves bearing chasmothecia (estimated at the plant level, Prop_chasmo_Plant), the presence/absence of multiple strains of powdery mildew within the sample (Mult_PM_strains) and the presence/absence of Ampelomyces based on the molecular detection test (Aq_PA)Hyperparasite_sample_level_data.xlsxQuadrat level datasetFor each quadrat, the excel sheet contains: the quadrat name (Quadrat_ID), population (Patch), the prevalence of Ampelomyces within the quadrat in autumn 2011 (Aq_prev), the proportion of plants found to be infected by the powdery mildew in july 2012 (Prop_PM_infect_plants_2012) and the proportion of leaves bearing chasmothecia in autumn 2011 (Prop_chasmos_2011)Hyperparasite_quadrat_level_dataset.xlsx