Table 1. Percentage of root mycorrhizal colonization in ‘donor' and CMN-connected ‘receiver' tomato plants, and weight gain of Spodoptera litura fed on the leaves of these plants.

			Mycorrhizal cononization (%)		Larval weight gain (mg)
Treatment	Inoculation on ‘donor'	CMN	‘Donor'	‘Receiver'	‘Donor'	‘Receiver'
A	Fm + SL	Yes	59.7 ± 0.8 a	38.1 ± 3.5 a	43.6 ± 4.9 b	48.5 ± 4.9 c
B	SL	No	0 c	0 b	72.2 ± 7.2 a	95.7 ± 7.7 a
C	Fm + SL	No	55.4 ± 1.3 a	41.5 ± 1.6 a	55.6 ± 5.8 ab	61.3 ± 5.2 bc
D	Fm	Yes	46.4 ± 1.7 b	38.2 ± 1.4 a	Un-infested	73.0 ± 5.7 b

Funneliformis mosseae was used to establish common mycorrhizal networks (CMNs) between ‘donor' and ‘receiver' tomato plants. Third instar larvae of S. litura (SL) were used to attack tomato plants. In bioassays the ‘receiver' plants were inoculated with larvae 24 h later than ‘donor' plants. Four treatments included: A) a ‘receiver' plant was connected with a S. litura attacked ‘donor' plant through CMNs; B) a ‘receiver' plant was grown near a SL-attacked ‘donor' plant without mycorrhizal inoculation; C) a mycorrhizal ‘receiver' plant was grown near a SL-attacked mycorrhizal ‘donor' plant but the two tomato plants were separated by water proof membrane; D) a ‘receiver' plant was connected with a neighboring plant by CMNs without insect infestation. Four sets of bioassays were independently carried out and three pots per treatment were set up for each set of bioassays. Values are means ± standard error. Significant differences (P < 0.05 using Tukey post-hoc test) among treatments in the same column are indicated by different letters. Results of ANOVA analyses are presented in the Supporting Information (Table S2).