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2
3
4
5
6
Appendix S1. The experimental design of the University of Kentucky Forage Climate Change Study where this project was
conducted. There are five replicate plots of four treatments. Elevated temperature plots (‘H’) received an increase in temperature of
3ºC, day and night, year-round. Precipitation (‘P’) plots received a 30% increase in long-term mean annual precipitation applied
during the growing season. Plots designated as ‘HP’ received both treatments. See Methods and Materials for more details.
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8
9
10
11
12
13
14
15
Appendix S2. Statistical Models
Table S2.1. Model comparisons with DIC values for models describing virus infection in 2009. Treatments include increased
temperature (‘H’), increased precipitation (‘P’), and increased temperature x precipitation (‘HP’). Elevated temperature plots (‘Heat’)
received an increase in temperature of 3ºC, day and night, year-round. Precipitation (‘Precip’) plots received a 30% increase in longterm mean annual precipitation applied during the growing season. Plots designated as ‘Heat x Precip’ received both treatments.
Species include “blue” (Kentucky Bluegrass, Poa pratensis), “dallis” (Dallisgrass, Paspalum dilatatum), “goose” (Goosegrass,
Eleusine indica) and “pos” (endophyte-infected Tall Fescue, Schedonorus arundinaceus).The posterior mean of the deviance minus
the deviance of the posterior means (pD) is an approximation of the true number of parameters and is used to calculate the Deviance
information criteria (DIC). DIC is an estimate of expected predictive error (lower deviance is better).
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2
3
4
5
6
7
16
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Model
P+ H+ HP + blue + dallis + goose + pos + blueH + dallisH + gooseH + posH + blueP + dallisP + gooseP + posP +
blueHP + dallisHP + gooseHP + posHP
P+ H+ HP + blue + dallis + goose + pos + blueH + dallisH + gooseH+ posH + blueP + dallisP + gooseP + posP
P+ H+ HP + blue + dallis + goose + pos + blueH + dallisH + gooseH + posH
P+ H+ HP + blue + dallis + goose + pos + blueP + dallisP + gooseP + posP
P+ H+ HP + blue + dallis + goose + pos
P+ H+ blue + dallis + goose + pos
P+H+HP
pD DIC
23.1 325.4
19.3
15.0
15.2
11.1
9.9
7
319.3
311.1
313.6
306.6
304.8
317.9
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20
21
22
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Table S2.2. Parameter estimates (marginal posterior means) from the binomial model for the
effects of temperature (‘H’), precipitation (‘P’), year, and endophyte infection (‘E+’) on the log
odds ratio of infection with B/CYDVs as a group (one or more viral species), relative to
endophyte-free tall fescue or to ambient heat and precipitation or to 2009. Parameter estimates
and 95% BCIs are shown for each treatment combination; bold font indicates those that do not
cover zero.
B/CYDVs
Treatment
P
H
E+
2010
2011
HP
P E+
H E+
2010P
2011P
2010H
2011H
2010 E+
2011 E+
HP E+
2010HP
2011HP
2010P E+
2011P E+
2010H E+
2011H E+
2010HP E+
2011HP E+
Parameter
Estimate
-0.302
-1.08
0.026
0.15
-0.489
0.857
0.061
0.731
-0.132
-13.2
0.813
2.173
-0.053
-1.1
-0.758
-1.23
11.6
-0.265
14.6
-1.33
0.344
2.01
-13.2
BCI
(-1.24 to 0.624)
(-2.11 to -0.096)
(-0.75 to 0.769)
(-0.671 to 0.966)
(-2.50 to 1.04)
(-0.558 to 2.33)
(-1.05 to 1.18)
(-0.424 to 1.96)
(-1.46 to 1.15)
(-33.5 to -0.549)
(-0.428 to 2.16)
(0.087 to 4.59)
(-1.27 to 1.13)
(-4.62 to 1.72)
(-2.40 to 0.941)
(-3.42 to 0.713)
(-1.61 to 32.2)
(-2.27 to 1.63)
(1.24 to 35.1)
(-3.48 to 0.674)
(-3.36 to 4.50)
(-1 to 4.98)
(-33.4 to 0.746)
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Table S2.3. Models of aphid presence in 2010 compared based on DIC values. Treatments
include increased temperature (‘H’), increased precipitation (‘P’), increased temperature and
precipitation (‘HP’), and endophyte infection (‘speciespos’). The posterior mean of the deviance
minus the deviance of the posterior means (pD) is an approximation of the true number of
parameters and is used to calculate the Deviance information criteria (DIC). DIC is an estimate
of expected predictive error (lower deviance is better).
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Model
1 P + H + speciespos + HP + speciesposP + speciesposH + speciesposHP
2 P + H + speciespos + HP + speciesposP + speciesposH
3 P + H + speciespos + HP + speciesposP
4 P + H + speciespos + HP + speciesposH
5 P + H + speciespos + HP
6 P + H + speciespos
7 P + H + HP
8 P+H
pD
10.3
9.8
9.1
8.9
8.3
7.2
7.2
6.0
DIC
84.4
87.3
86.2
85.3
84.5
83.2
82.9
81.3
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36
37
38
39
40
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Appendix S3. The proportion of plants infected by barley and cereal yellow dwarf viruses varied
among host species. Total counts of host plants tested are shown in white and infected plants are
shown in grey across all plots. (A) Virus infection rates for the 2009 data were: 26% for
Kentucky bluegrass (Poa pratensis, 26/99), 24% for dallisgrass (Paspalum dilatatum, 21/88),
16% for Indian goosegrass (Eleusine indica, 26/159), 11% for endophyte-free tall fescue
(Schedonorus arundinaceus; ‘E- S. arundinaceus’, 53/470) and 13% for endophyte-infected tall
fescue (‘E+ S. arundinaceus’, 53/396). (B) Virus infection rates for the 2009-2011 S.
arundinaceus data were: 12.2 % for endophyte-free S. arundinaceus (‘E-’, 93/762) and 13.4%
for endophyte-infected S. arundinaceus (‘E+’, 88/657).
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45
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47
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Appendix S4. The proportion infected (number infected / total number tested) for all plants with
each viral species (BYDV-PAV, BYDV-MAV, CYDV-RPV) for the 2009 data across host
species (A) and the 2009-2011data on tall fescue (Schedonorus arundinaceus) averaged across
endophyte status (B). Plants tested positive for BYDV-PAV most frequently and tested positive
for BYDV-MAV least frequently.
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54
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Appendix S5. The total number of aphids observed on plants, and total number of plants
searched of endophyte-free tall fescue (Schedonorus arundinaceus, ‘E- S. arundinaceus’) and
endophyte-infected tall fescue (‘E+ S. arundinaceus’) in each climate change treatment, in 2010.
Elevated temperature (‘H’) plots received an increase in temperature of 3ºC, day and night, yearround. Precipitation (‘P’) plots received a 30% increase in long-term mean annual precipitation
applied during the growing season. Plots designated as ‘HP’ received both treatments and control
(‘C’) plots were exposed to ambient temperatures and precipitation.
Treatment
C
H
HP
P
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Species
E- S. arundinaceus
E+ S. arundinaceus
Num.
Num.
Num.
Num.
Aphids
Plants
Aphids
Plants
3
36
2
26
11
48
6
30
4
48
4
30
4
41
0
24