Electronic supplemental material: Enemy-free space promotes maintenance of host races in an aphid species

Ilka Vosteen*, Jonathan Gershenzon, Grit Kunert

Max-Planck Institute for Chemical Ecology

Hans-Knöll-Straße 8

07749 Jena

Germany

* corresponding author:

Phone 0049 (0)3641 57 1314

Fax 0049 (0)3641 57 1302

Tab. S1: Statistical values for the analysis of proportion of V. faba-plants with parasitized aphids in 2013: glmm with binomial error structure. Plants were aphid infested for one or six days and had either open or wax-covered extrafloral nectaries.

factor / χ² / p-value
aphid race / 4.212 / 0.122
extrafloral nectaries / 0.451 / 0.502
infestation time / 0.043 / 0.836
aphid race x extrafloral nectaries / 1.143 / 0.565
infestation time x extrafloral nectaries / 0.220 / 0.639
aphid race x infestation time / 0.514 / 0.774

Tab. S2: Statistical values for the analysis of proportion of plants with parasitized aphids in 2013: glmm with binomial error structure. Trifolium, Pisum and Medicago race aphids had infested their native and universal host plants for one or six days.

factor / χ² / p-value
aphid race - plant species combination / 3.645 / 0.602
infestation time / 0.025 / 0.875
aphid race - plant species combination x / 2.615 / 0.759
infestation time

Tab. S3: Statistical values for the analysis of aphid survival on V. faba-plants in 2013: glmm with negative binomial error structure. Plants were aphid infested for one or six days and had either open or wax-covered extrafloral nectaries.

factor / χ² / p-value
aphid race / 12.266 / 0.002
infestation time / 3.700 / 0.054
extrafloral nectaries / 0.021 / 0.886
infestation time x extrafloral nectaries / 1.834 / 0.176
aphid race x infestation time / 0.260 / 0.878
aphid race x extrafloral nectaries / 0.982 / 0.612

Tab. S4: Statistical values for the analysis of aphid survival in 2013: glmm with negative binomial error structure. Trifolium, Pisum and Medicago race aphids had infested their native and universal host plants for one or six days.

factor / χ² / p-value
aphid race - plant species combination / 54.729 / < 0.001
infestation time / 6.044 / 0.014
aphid race - plant species combination x / 7.603 / 0.180
infestation time

Tab. S5: Statistical values for the analysis of aphid survival in 2014: glmm with negative binomial error structure. Trifolium, Pisum and Medicago race aphids had infested their native and universal host plants for one or six days.

factor / χ² / p-value
aphid race - plant species combination / 33.538 / < 0.001
infestation time / 2.838 / 0.092
aphid race - plant species combination x / 0.340 / 0.997
infestation time

Fig. S1: Proportion of host plants infested with different pea aphid races (clones T, P1 and M1) that carried hoverfly eggs during a field experiments in July 2014. The native hosts are Trifolium race- T. pratense, Pisum race- P. sativum, and Medicago race- M. sativa, and the universal host is V. faba. Bars represent means ± standard error; different letters indicate significant differences (p ≤ 0.05).

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