DOI: 10.5061/dryad.zw3r228gk
title: Coinfection accelerates transmission to new hosts despite no effects on virulence and parasite growth

description: One of the fundamental aims of ecological, epidemiological and
 evolutionary studies of host-–parasite interactions is to unravel which
 factors affect parasite virulence. Theory predicts that virulence and
 transmission are correlated by a trade-off, as too much virulence is
 expected to hamper transmission dueowing to excessive host damage.
 Coinfections may affect each of these traits and/or their correlation.
 Here, we used inbred lines of the spider- mite Tetranychus urticae to test
 how coinfection with T. evansi, impacted virulence-transmission
 relationships, at different conspecific densities. The presence of T.
 evansi on a shared host did not change the relationship between virulence
 (leaf damage) and the number of transmitting stages (i.e., adult
 daughters). The relationship between these traits was hump-shaped across
 densities, both in single and coinfections, which corresponds to a
 trade-off. Moreover, transmission to adjacent hosts increased in
 coinfection, but only at low T. urticae densities. Finally, we tested
 whether virulence and the number of daughters were correlated with
 measures of transmission to adjacent hosts, in single and coinfections at
 different conspecific densities. Traits were mostly independent, meaning
 that interspecific competitors may increase transmission without affecting
 virulence. Thus, coinfections may impact epidemiology and parasite trait
 evolution, but not necessarily the virulence transmission trade-off.
description: # # Coinfection accelerates transmission to new hosts despite no effects
 on virulence and parasite growth
 \[[https://doi.org/10.5061/dryad.zw3r228gk\]’https://doi.org/10.5061/dryad.zw3r228gk’](https://doi.org/10.5061/dryad.zw3r228gk]’https://doi.org/10.5061/dryad.zw3r228gk’) ## Description of the data and file structure   The data were collected from 2 laboratory experiments in which different inbred lines of *T. urticae* were used to measure virulence ‘damage to 2cm2 bean leaf fragments’ and transmission, measured as movement between 3 bean leaf fragments linked by 3 cm Parafilm ‘plastic’ bridges. Missing data are denoted as n/a. ### Files and variables #### File: Godinho\_FINAL.xlsx \**Description:** There are 3 data sheets.   The data from the first experiment are in the sheet: ‘Experiment1_WithinHostMeasures’. The variables are: Column A ‘Block’, this is the temporal experimental block measures were taken. Column B ‘Line’, is the *T. urticae* inbred line. Column C ‘ID2’ is the identity for each individual patch. Column D ‘Density’ is the number of *T. urticae* adult females on each patch. Column E ‘Competition’ is whether T. urticae were in the presence of 10 *Tetranychus evansi* females (C = with interspecific competitors) or not (N = no *T. evansi*, no interspecific competition). Column F ‘Patch’ is the leaf patch number. Column G ‘Eggs’ is the total number of eggs on each patch counted 4 days after females were placed on a patch. Column H ‘Females’ is the total number of adult females on each patch. Column I ‘Real damage’ is the area leaf damage after the females had been on the leaf patch for 4 days. Column J ‘Eggs minus TE in competition treatments’ is the total number of eggs minus the mean number of eggs laid by 10 *T. evansi* females. Column K ‘Virulence ‘minus T.evansi for competition treatments’’ is the total area of damage minus the mean damage caused by 10 *T. evansi* females. Comumn L ‘Daughters per female’ is the per capita *T. urticae* number of adult daughters. The second sheet ‘Experiment2_DispersalScore’ is a data file from Experiment 2 with a single measure of transmission for inbred lines on across each 3 patch system. Column A ‘Block’, this is the temporal experimental block measures were taken. Column B ‘Patch’ is the number allocated to each 3 leaf patch system. Column C ‘Line’, is the *T. urticae* inbred line. Column D ‘Density’ is the number of *T. urticae* adult females on each patch. Column E ‘Competition’ is whether T. urticae were in the presence of 10 *Tetranychus evansi* females (C = with interspecific competitors) or not (NC = no *T. evansi*, no interspecific competition). Column F ‘DispersalScore’ is a score used for levels of transmission across the 3 patch system. It is calculated as the ‘number of mites on host patch 2 + the number of mites on host patch 3*2’/total number of mites’. Column G ‘Time’ is the day for each score. The third sheet ‘Experiment2_BetweenHost_measure’ is a data file from Experiment 2 with different measures for transmission for the inbred lines.   Column A ‘Block’, this is the temporal experimental block measures were taken. Column B ‘Box’ is the box each 3 patch system was placed. Colmun C ‘Position’ was the position each patch was within each box. Column D ‘Line’, is the *T. urticae* inbred line. Column E ‘Density’ is the number of *T. urticae* adult females on each patch. Column F ‘Competition’ is whether T. urticae were in the presence of 10 *Tetranychus evansi* females (C = with interspecific competitors) or not (NC = no *T. evansi*, no interspecific competition). Column G ‘d1 P1 tu’ is the number of *T. urticae* on the first patch on day 1. Column H ‘d1 P2 tu’ is the number of *T. urticae* on the second patch on day 1. Column I ‘d1 P3 tu’ is the number of *T. urticae* on the third patch on day 1. Column J ‘d2 P1 tu’ is the number of *T. urticae* on the first patch on day 2. Column K ‘d2 P2 tu’ is the number of *T. urticae* on the second patch on day 2. Column L ‘d2 P3 tu’ is the number of *T. urticae* on the third patch on day 2. Column M ‘d3 P1 tu’ is the number of *T. urticae* on the first patch on day 3. Column N ‘d3 P2 tu’ is the number of *T. urticae* on the second patch on day 3. Column O ‘d3 P3 tu’ is the number of *T. urticae* on the third patch on day 3. Column P ‘d6 P1 tu’ is the number of *T. urticae* on the first patch on day 6. Column Q ‘d6 P2 tu’ is the number of *T. urticae* on the second patch on day 6. Column R ‘d6 P3 tu’ is the number of *T. urticae* on the third patch on day 6. Column S ‘d9 P1 tu’ is the number of *T. urticae* on the first patch on day 9. Column T ‘d9 P2 tu’ is the number of *T. urticae* on the second patch on day 9. Column U ‘d9 P3 tu’ is the number of *T. urticae* on the third patch on day 9. Column V ‘Day on patch 2’ is the day a *T. urticae* female was observed on the second leaf patch. Column W ‘Day on patch 3’ is the day a *T. urticae* female was observed on the third leaf patch. Column X ‘Max number of Tu on patch 2’ is the maximum number of *T. urticae* observed on the second leaf patch. Column Y ‘Max number of Tu on patch 3’ is the maximum number of *T. urticae* observed on the third leaf patch. Column Z ‘Day patch 2 per female’ is the day *T. urticae* were observed on the second patch divided by the density of *T. urticae* females placed on the 3 patch system. Column AA ‘DayP3_perfemale’ is the day *T. urticae* were observed on the third patch divided by the density of *T. urticae* females placed on the 3 patch system. Column AB ‘MaxP2_perfemale’ is the maximum number of *T. urticae* observed on the second patch divided by the density of *T. urticae* females placed on the 3 patch system. Column AC ‘MaxP3_perFemale’ is the maximum number of *T. urticae* observed on the second patch divided by the density of *T. urticae* females placed on the 3 patch system.