Proportion of seeds (seed number/total female flower number) as a function of the proportion of wasp offspring (galled flower number/total female flower number) in F. racemosa with different treatments. (a,b) Collected from crop field. (a) Foundresses introduced simultaneously; the foundress numbers were two, three, five, seven and nine with sample size 21, 20, 20, 20 and 20, respectively (linear: n = 101, r = 0.67, p < 0.001). (b) Foundresses sequentially introduced; foundress numbers were one, two, five, seven and nine with sample size 21, 20, 20, 23 and 65, respectively (quadratic: F test = 201.87, p < 0.001). (c,d) Collected from locally fragmented forest. (c) Foundresses introduced simultaneously; foundress numbers were two, three, five, seven and nine with sample size 20 for each treatment (linear: n = 100, r = 0.52, p < 0.001). (d) Foundresses sequentially introduced; foundress numbers were one, two, three, five, seven and nine with sample size 20 samples for each treatment (quadratic: F test = 23.14, p < 0.001).