DOI: 10.5061/dryad.95x69p8v5
title: Temporal host–symbiont dynamics in community contexts: Impact of host fitness and vertical transmission efficiency on symbiosis prevalence

description: Symbiotic associations play a role in plant ecology and evolution, but the
 outcome of the interaction depends on the life history traits of the
 partners and the environmental context. Although symbiosis with vertically
 transmitted microorganisms should result in mutualism, it is not clear how
 the transmission process aligns with the outcome of the context-dependent
 symbiosis. For three years, we sampled individuals of an annual
 plant species that forms symbiosis with a vertically transmitted fungal
 endophyte, in paired stands of two contrasting vegetation communities
 [Humid Mesophytic Meadows (HMM): productive / low stress, and Humid
 Prairies (HP): less productive / high stress]. We estimated the prevalence
 of symbiosis at the population level, and the fitness of the plant, the
 status of the symbiotic and the vertical transmission efficiency at the
 individual level. Over three years, the prevalence of symbiosis
 was ≈100% in HMM and ≈75% in HP. Plant fitness was very low and high in
 years with precipitation below and above the yearly mean, respectively.
 The higher fitness of endophyte-symbiotic plants was evident in the HMM
 and high precipitation years. Vertical transmission of endophytes was
 higher in HMM (≈96%) compared to HP (≈93%) and was not related to plant
 fitness. Despite transmission inefficiencies in HP, changes in prevalence
 within the growing season (from seeds to the final plant stand) suggest a
 fitness advantage for symbiotic plants. Vertical transmission is
 expected to promote mutualism as it aligns partners' fitness.
 Although symbiotic plants showed higher fitness and the probability of
 transmission failures was higher among low-fitness plants, the variation
 in transmission efficiency between plants and vegetation communities was
 not related to the fitness of the individual host. Our study provides
 evidence that context-dependent vertical transmission efficiency and
 endophyte-mediated fitness advantages interact complexly to determine the
 prevalence of symbiosis in populations that occur in contrasting
 vegetation communities.
description: # Temporal host–symbiont dynamics in community contexts: Impact of host
 fitness and vertical transmission efficiency on symbiosis prevalence DOI:
 [https://doi.org/10.5061/dryad.95x69p8v5](https://doi.org/10.5061/dryad.95x69p8v5) We have submitted our raw data (see "File list" and "Information of the dataset" sections) regarding a three-year study focusing on an annual plant species (*Lolium multiflorum* L.) that forms symbiosis with a vertically transmitted fungal endophyte (*Epichloë occultans*). The study was conducted in stands situated in two different vegetation communities: Humid Mesophytic Meadows (HMM), characterized by productivity and low-stress conditions, and Humid Prairies (HP), exhibiting less productivity and high-stress conditions. ## Description of the data and file structure \############################# **File list:** "endophyte_vt.xlsx" "pop_endo_prevalance.xlsx" "plant_fitness.xlsx" "pop_endo_incidence.xlsx" "genetic_structure.xlsx" "NDVI.xlsx" "Bioclimatic information.xlsx" \############################# **Information of the dataset** "endophyte_vt.xlsx": the dataset of endophyte transmission. "pop_endo_prevalance.xlsx": the dataset of population endophyte prevalence. "plant_fitness.xlsx": the dataset of plant fitness. "pop_endo_incidence.xlsx": the dataset of population endophyte incidence that includes two sheets for the growing seasons 2009 and 2010. "genetic_structure.xlsx": the dataset for analysis of genetic structure. "Bioclimatic information.xlsx": the dataset of monthly values of climatic conditions (mean precipitation, and mean minimum and maximum temperatures). \############################ List of variables in "endophyte_vt.xlsx": -*year*: year of sample collection (2008, 2009 and 2010) -*site*: each location where pairs of stand were sampled (1 to 10) -*stand*: every of the two plant communities sampled in each site (HMM stands for Humid Mesophytic Meadow or HP stands for Humid Prairies)\ -*plant*: ID of each sampled individual plant -*transmission*: the proportion of seeds (unitless) hosting endophyte per plant (only valid for endophyte-symbiotic plants) -*transmission_perc*: the proportion of seeds, expressed as percentage, hosting endophyte per plant (only valid for endophyte-symbiotic plants) List of variables in "pop_endo_prevalance.xlsx": -*community*: HMM for Humid Mesophytic Meadow or HP for Humid Prairies -*year*: year of sample collection (2008, 2009 and 2010) -*site*: each location where pairs of stand were sampled (1 to 10) -*stand*: every of the two plant communities sampled in each site (HMM stands for Humid Mesophytic Meadow or HP stands for Humid Prairies)\ -*pop_endo_prevalence*: the proportion of plants hosting endophyte per population, expressed as percentage List of variables in "plant_fitness.xlsx": -*community*: HMM for Humid Mesophytic Meadow or HP for Humid Prairies -*year*: year of sample collection (2008, 2009 and 2010) -*site*: each location where pairs of stand were sampled (1 to 10) -*stand*: every of the two plant communities sampled in each site (HMM stands for Humid Mesophytic Meadow or HP stands for Humid Prairies)\ -*symbiosis*: symbiotic status of plant in each stand (E+: simbiotic plants or E-: non-symbiotic plants) -*fitness*: seed production (number) per plant in each stand List of variables in "pop_endo_incidence.xlsx": -*community*: HMM for Humid Mesophytic Meadow or HP for Humid Prairies -*site*: each location where pairs of stand were sampled (1 to 10) -*stand*: every of the two plant communities sampled in each site (HMM stands for Humid Mesophytic Meadow or HP stands for Humid Prairies)\ -*season*: initial (Autumn) and final (Summer) stages (seed and mature plant, respectively) of the life cycle of the annual plant *Lolium multiflorum* -*Yt*: the prevalence of *Epichl*oë fungal endophytes in populations of the annual plant Lolium multiflorum List of variables in "genetic_structure.xlsx": -*indiv*: identification of each individual plant -*community*: HMM for Humid Mesophytic Meadow or HP for Humid Prairies -*site*: each location where pairs of stand were sampled (1 to 10) -*stand*: every of the two plant communities sampled in each site (HMM stands for Humid Mesophytic Meadow or HP stands for Humid Prairies)\ -columns "E" to "AL": identification of each nuclear microsatellite DNA where a value of '0' indicates absence while a value of '1' indicates presence. List of variables in "Bioclimatic_information.xlsx": -*year_month*: the years (2008, 2009, and 2010) and the months (1 to 12, representing January to December) of the study -*precipitation*: monthly values of precipitation, recorded in millimeters (mm), for each of the three years of the study -*tmin*: monthly values of minimum temperature, recorded in degrees Celsius, for each of the three years of the study -*tmax*: monthly values of maximum temperature, recorded in degrees Celsius, for each of the three years of the study