A GENETICALLY-BASED LATITUDINAL CLINE IN THE EMISSION OF

HERBIVORE-INDUCTED PLANT VOLATILE ORGANIC COMPOUNDS

Journal of Chemical Ecology

ELIZABETH L. WASON*, ANURAG A. AGRAWAL, and MARK D. HUNTER

* Corresponding author: E. L. Wason ().

Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Kraus Natural Science Building, Ann Arbor, MI 48109.

phone (281) 224-0099. fax (734) 763-0544.

Online Resource 1 CONCENTRATION OF 16 VOLATILE ORGANIC CHEMICALS (VOCs) EMITTED BY PLANTS FROM 20 POPULATIONS ACROSS 10o OF LATITUDE

Data represent VOC emissions from undamaged (–) and monarch-damaged (+) milkweed plants. VOC concentrations are presented as the means across replicates  SE, normalized by internal standard, plant biomass, and total sampled air volume (ng/g dry mass/L). Indicated (.) are instances in which the VOC was not detected. Chemicals in bold were verified by authentic standards. Chemicals not in bold were tentatively identified by the mass spectrometer, with reference to the NIST (National Institute of Standards and Technology) library. Most chemicals are monoterpenes, except where indicated with superscripts † (green leafy volatile) and ‡ (sesquiterpene) and * (chemical class is ambiguous).

Online Resource 1

Volatile / 46.8o / 45.92o / 45.38o / 44.52o
Chemical / – / + / – / + / – / + / – / +
1 / -phellandrene / . / . / 0.47660.477 / . / 0.03810.038 / 0.09270.093 / . / 0.37900.379
2 / -myrcene / . / . / 0.70680.707 / . / 0.02880.029 / 0.05340.053 / . / 0.81740.817
3 / D-limonene / . / . / 0.69630.399 / . / 0.02930.029 / 0.10340.103 / . / 4.18604.186
4 / Cineole / . / . / . / . / . / . / . / 0.24980.250
5 / Ocimene / 0.16880.169 / 0.32230.322 / 0.07910.079 / 0.22060.061 / 0.83680.837 / 0.52390.038 / 0.11580.084 / 1.34911.018
6 / Unknown pk15 / . / 0.09820.051 / . / 0.01810.018 / 0.03280.033 / 0.64660.213 / 0.03050.031 / .
7 / Unknown pk16 † / . / 0.15340.153 / . / 0.14650.084 / . / 0.28360.179 / . / 0.09840.098
8 / (Z)-3-Hexen-1-ol† / . / 1.85121.851 / . / 0.04340.043 / 0.03160.032 / 0.11960.026 / 0.02290.023 / 0.22120.142
9 / Unknown pk33 / . / 0.23850.029 / . / 0.03790.038 / 0.05000.050 / 0.09830.011 / 0.09340.093 / 0.06220.062
10 / Caryophyllene ‡ / 0.09830.098 / 0.05500.055 / . / 0.04010.021 / 0.26930.269 / 0.37340.087 / 0.25270.070 / 0.12270.062
11 / Unknown pk38* / . / 0.81680.261 / 0.30180.302 / . / 0.04640.046 / . / . / .
12 / Unknown pk39‡ / . / 0.10700.107 / . / 0.07440.059 / 0.13320.133 / 0.12140.121 / 0.01820.018 / 0.05880.059
13 / Unknown pk42 / 0.05400.054 / 3.25593.256 / 0.08000.080 / . / 0.01670.017 / 0.02940.029 / . / .
14 / Unknown pk43‡ / 0.06580.066 / . / . / 0.06410.064 / 0.19220.192 / 0.40690.016 / . / .
15 / 2,6-Dimethyl-3,5,7-octatriene-2-ol / . / 0.51130.080 / 0.23070.231 / 0.02540.025 / 0.60300.603 / 0.26100.011 / . / .
16 / Eugenol / . / 1.51011.272 / . / . / 0.57000.570 / . / . / .

Online Resource 1 continued

Volatile / 42.67o / 42.45o / 42.38o / 41.65o
Chemical / – / + / – / + / – / + / – / +
1 / -phellandrene / . / . / 0.0639±0.064 / . / 0.0147±0.015 / . / . / 0.1260±0.126
2 / -myrcene / . / . / . / . / . / . / . / .
3 / D-limonene / . / . / . / . / . / . / . / .
4 / Cineole / . / . / 0.0672±0.067 / . / . / . / . / .
5 / Ocimene / 0.0817±0.082 / 0.1934±0.118 / 0.3271±0.327 / 0.6710±0.129 / 0.0834±0.083 / 0.0719±0.072 / . / 0.4510±0.356
6 / Unknown pk15 / . / 0.0409±0.025 / 0.2790±0.279 / . / . / 0.0661±0.066 / 0.1724±0.076 / 0.0544±0.054
7 / Unknown pk16 † / . / 0.5474±0.547 / . / 0.4222±0.422 / . / . / . / .
8 / (Z)-3-Hexen-1-ol† / 0.0263±0.026 / . / . / 0.1293±0.129 / 0.3874±0.387 / 0.2196±0.122 / . / .
9 / Unknown pk33 / . / . / 0.1298±0.130 / 0.0999±0.100 / 0.0566±0.041 / 0.2802±0.160 / . / .
10 / Caryophyllene ‡ / 0.0951±0.033 / 0.1721±0.028 / 0.3519±0.352 / 0.0970±0.097 / 0.0538±0.054 / 0.0974±0.097 / . / .
11 / Unknown pk38* / . / . / . / . / . / . / . / .
12 / Unknown pk39‡ / . / . / 0.1498±0.150 / . / 0.0374±0.037 / 0.0377±0.038 / . / .
13 / Unknown pk42 / . / . / . / . / . / . / . / .
14 / Unknown pk43‡ / . / 0.0866±0.087 / 0.1778±0.178 / 0.0886±0.089 / . / . / . / .
15 / 2,6-Dimethyl-3,5,7-octatriene-2-ol / 0.0241±0.024 / 0.0899±0.049 / 0.1419±0.142 / . / 0.0512±0.051 / 0.0860±0.086 / . / .
16 / Eugenol / . / . / . / . / 0.3076±0.308 / . / . / .

Online Resource 1 continued

Volatile / 40.9o / 40.12o / 40.1o / 40.08o
Chemical / – / + / – / + / – / + / – / +
1 / -phellandrene / . / 0.6088±0.609 / . / . / . / . / . / .
2 / -myrcene / . / 0.2948±0.295 / . / . / 0.1841±0.184 / . / . / .
3 / D-limonene / . / 0.3933±0.393 / . / . / . / . / . / .
4 / Cineole / . / 0.7089±0.709 / . / . / . / . / . / .
5 / Ocimene / . / 0.1717±0.172 / 0.1432±0.143 / 0.1162±0.078 / 0.2742±0.274 / 0.0852 / 0.0385±0.038 / 0.0569±0.057
6 / Unknown pk15 / . / . / 0.0995±0.099 / . / 0.0998±0.100 / 0.1862 / 0.1368±0.038 / 0.1229±0.014
7 / Unknown pk16 † / . / 0.1248±0.084 / . / 0.2401±0.240 / 0.1403±0.140 / . / . / .
8 / (Z)-3-Hexen-1-ol† / . / 0.0247±0.025 / . / . / 0.1085±0.108 / . / . / .
9 / Unknown pk33 / . / . / . / . / . / . / . / .
10 / Caryophyllene ‡ / . / 0.0438±0.044 / 0.0606±0.030 / 0.0471±0.047 / 0.1266±0.127 / 0.1233 / 0.3226±0.323 / 0.0826±0.083
11 / Unknown pk38* / . / . / . / . / . / . / . / .
12 / Unknown pk39‡ / . / . / . / 0.0243±0.024 / . / . / 0.0243±0.024 / .
13 / Unknown pk42 / . / . / . / . / . / . / . / .
14 / Unknown pk43‡ / . / . / . / 0.0321±0.032 / 7.7981±7.798 / . / 0.0391±0.039 / .
15 / 2,6-Dimethyl-3,5,7-octatriene-2-ol / . / . / . / 0.0513±0.051 / . / 0.0725 / . / .
16 / Eugenol / . / . / . / 0.0362±0.036 / 2.5149±2.515 / . / . / .

Online Resource 1 continued

Volatile / 39.55o / 39.18o / 38.87o / 38.67o
Chemical / – / + / – / + / – / + / – / +
1 / -phellandrene / . / . / . / 0.0585±0.059 / 0.0091±0.009 / . / 0.2955 / .
2 / -myrcene / . / . / . / . / . / . / . / .
3 / D-limonene / . / . / . / . / . / . / . / .
4 / Cineole / . / . / . / . / . / . / . / .
5 / Ocimene / 0.0858±0.086 / 0.1521±0.039 / . / 0.5323±0.019 / 0.0876±0.088 / 0.5932±0.482 / 0.3691 / 0.3296±0.035
6 / Unknown pk15 / . / . / . / 0.0528±0.053 / 0.0619±0.062 / . / 0.3726 / 0.0351±0.035
7 / Unknown pk16 † / . / 0.0555±0.055 / . / . / . / 0.4187±0.212 / . / .
8 / (Z)-3-Hexen-1-ol† / . / . / . / . / 0.0715±0.072 / 0.1019±0.102 / . / .
9 / Unknown pk33 / . / . / . / 0.1017±0.102 / 0.1167±0.117 / . / . / 0.1079±0.054
10 / Caryophyllene ‡ / 0.1011±0.101 / 0.2807±0.118 / . / 0.1140±0.033 / 0.0808±0.043 / 0.2619±0.262 / 0.8837 / 0.0483±0.048
11 / Unknown pk38* / . / . / . / . / . / . / . / .
12 / Unknown pk39‡ / . / . / . / . / . / 0.0671±0.067 / . / 0.0874±0.087
13 / Unknown pk42 / . / . / . / . / . / . / . / .
14 / Unknown pk43‡ / . / . / . / . / . / 0.4989±0.499 / . / 0.0713±0.071
15 / 2,6-Dimethyl-3,5,7-octatriene-2-ol / . / . / . / . / 0.0093±0.009 / 0.1857±0.186 / . / .
16 / Eugenol / 0.0520±0.052 / . / . / . / . / . / . / .

Online Resource 1 continued

Volatile / 37.35o / 36.67o / 35.92o / 35.88o
Chemical / – / + / – / + / – / + / – / +
1 / -phellandrene / . / . / . / . / . / . / . / .
2 / -myrcene / . / . / . / . / . / . / . / .
3 / D-limonene / . / . / . / . / . / . / . / .
4 / Cineole / . / . / . / . / . / . / . / .
5 / Ocimene / . / 0.5035±0.362 / 0.2642 / . / . / 0.1556 / . / 0.2422±0.038
6 / Unknown pk15 / . / 0.2060±0.206 / . / . / . / . / . / 0.0573±0.020
7 / Unknown pk16 † / . / 0.0566±0.057 / . / . / . / . / . / 0.0422±0.042
8 / (Z)-3-Hexen-1-ol† / . / . / . / . / . / . / . / .
9 / Unknown pk33 / 0.0751±0.075 / 0.0867±0.044 / 0.2033 / . / . / . / . / 0.0752±0.002
10 / Caryophyllene ‡ / 0.1322±0.073 / 0.2086±0.086 / 0.2554 / . / 0.0331 / . / . / 0.1184±0.060
11 / Unknown pk38* / . / . / . / . / . / . / . / 0.3126±0.313
12 / Unknown pk39‡ / . / . / . / . / . / . / . / 0.0533±0.053
13 / Unknown pk42 / . / . / . / . / . / . / . / 7.8869±7.887
14 / Unknown pk43‡ / 0.1370±0.137 / . / . / . / . / . / . / .
15 / 2,6-Dimethyl-3,5,7-octatriene-2-ol / . / 0.2665±0.158 / . / . / . / . / . / 0.1454±0.010
16 / Eugenol / . / 0.0946±0.095 / . / . / . / . / . / .