DOI: 10.5061/dryad.wwpzgmssh
title: Data for: Local adaptation of a generalist hemiparasitic plant to one of its potential host plants

description: Coevolution is often found in parasite-host interactions but has not yet
 been described for hemiparasitic plants and their hosts. Root
 hemiparasites like Rhinanthus alectorolophus perform photosynthesis but
 also parasitize other plant species, some of which (e.g. Plantago
 lanceolata) may defend themselves against parasite attack by blocking the
 haustoria of the parasites. We grew seedlings of the hemiparasite
 Rhinanthus alectorolophus and the potential host Plantago lanceolata from
 seven grassland sites in a factorial design. To detect differences in host
 defence, we also included hosts from two ‘naïve’ populations from regions
 where the parasite does not occur. R. alectorolophus grew consistently
 larger and had higher fitness with sympatric than with allopatric hosts,
 suggesting parasite adaptation to local host populations. Moreover, R.
 alectorolophus remained smallest with allopatric hosts from the same
 region and reached intermediate sizes with allopatric hosts from other
 regions or naïve hosts, suggesting host adaptation to parasites at the
 regional scale. Parasite presence reduced the size of the host plants
 already after four weeks, but only that of hosts with ‘experience’ of the
 parasite, suggesting an early host response. Follow-up experiments
 confirmed that parasites attach to hosts already after four weeks and
 hosts respond by changing belowground allocation patterns. However,
 parasite roots did not preferentially grow towards sympatric hosts. Our
 results suggest that local adaptation to hosts can occur even in
 generalist parasites and does not require specialization on individual
 hosts. We discuss the role of potential mechanisms, including variation in
 chemical signalling (early) and in host defence (late effects).
description: # Data for: Local adaptation of a generalist hemiparasitic plant to one of
 its potential host plants
 [https://doi.org/10.5061/dryad.wwpzgmssh](https://doi.org/10.5061/dryad.wwpzgmssh) The publication describes three different experiments involving the hemiparasite *Rhinanthus alectorolophus* and its defended host *Plantago lanceolata*. ## Description of the data and file structure Four tables are provided as separate CSV files. Several of the variables contain missing data - these are either due to the experimental design (e.g., no parasite biomass in the host control treatment) or due to mortality (e.g., parasite died after planting). The abbreviations of the variables are: ### Table 1: Main Experiment (Rhi Pla Data) Variable - Explanation * ID - Number of Pot * HostPop - Host population * ParPop - Parasites population * Rep - Replicate * HostReg - Host region (KW = Kleinwalsertal; RH = Rhön; NH = Northern Hesse; Ne = neutral) * ParReg - Parasite region (KW = Kleinwalsertal; RH = Rhön; NH = Northern Hesse; Ne = neutral) * Host_Type - Host Type (-1 = naive; 0 = other region; 1 = same region; 2 = same site) * Par_yn - Parasite presence * naive_host - Naive host (1 = naive, 0 = experienced) * dead_or_repl - Parasite died or was replaced during the first week (1) or not (0) * Par_leaflength - Parasite leaf length after 4 weeks (mm) * Host_leaflength - Host leaf length after 4 weeks (cm) * Host_leafnumber - Number of host leaves after 4 weeks * log_Hostsize1 - Log early host size (length [cm] x number of leaves) * Mortality_final - final parasite mortality (1) or survival (0) * Mort_sinceM1 - Parasite died since the first measurement (1) or not (0) * Host_biomass - Host above-ground biomass at harvest (g) * Par_biomass - Parasite above-ground biomass at harvest (g) ### Table 2: Multiplicative fitness. Data aggregated from Table 1 Variable - Explanation * HostPop - (see Table 1) * ParPop - (see Table 1) * log_ParBiomass - log10(Parasite Biomass [g] * Mortality_final - mean parasite mortality (see Table 1) * Host_Type - (see Table 1) * Multifit_mg - calculated as (1-Mortality) * 10 ^ (log ParBiomass [g]) * 1000 * PopDist - Distance between Host and parasite population (km) * logPopdist - log10 of (PopDist [km] + 0.01) ### Table 3: Root allocation experiment Variable - Explanation * ID - Number of pot * Par_yn - *Plantago* grown with (1) or without (0) *Rhinanthus* * attached - Parasite attached to host root at harvest (1 = yes, 0 = no) * H_leaflength - Host: length of longest leaf after 4 weeks (cm) * H_leafwidth - Host: width of longest leaf after 4 weeks (cm) * H_leafno - Host: number of leaves after 4 weeks * P_leaflength - Parasite: length of longest leaf after 4 weeks (cm) * H_shootmass - Host: shoot mass (mg) * H_rootmass - Host: root mass (mg) * P_shootmass - Parasite: shoot mass (mg) * P_rootmass - Parasite: root mass (mg) * HPR_Length - Primary root length (cm) * HPR_Thickness - Primary root thickness (cm) * HLR_Length - Lateral root length (cm) * HLR_Thickness - Lateral root thickness (cm) * ParPop - Parasite population * HostPop - Host population * naive_host - Naive host (1 = naive, 0 = experienced) ### Table 4: Host choice experiment Variable - Explanation * ID - Petri Dish =&gt; use as a random factor * Direction - On which side of the parasite was the respective host planted (L=left, R=right) * Length1_mm - lateral extension of parasite root in the direction of this host after 7 days (mm) * ParPop - Parasite population * HostPop - Host Population * symp - Host is sympatric (1) or allopatric (0) * Host.length - Initial root length of host seedling (mm) * sterile - In two experiments, host seeds have been sterilized (1) or not (0) * sqrtLength - The response variable: square-root transformed Length1_mm ## Code/Software Data was analyzed in R using the code associated with this data download.