Fitness of the HI lineage on fresh and pre-infected cucumber
In the first-generation life table, net reproductive rate (R 0) of the HI lineage was only 8.92 on fresh cucumber versus 20.44 on pre-infected cucumber (p =0.003); the intrinsic rate (r ) was 0.15 on fresh cucumber versus 0.23 on pre-infected cucumber (p <0.001); the finite rate of increase (λ ) and the generation time (T ) were 1.16 and 14.20 on fresh cucumber, compared to 1.25 and 13.07 on pre-infected cucumber, respectively (p <0.001 and p =0.002, respectively) (Figure 1A). In life table of the third generation (F3),R 0, r , λ and T were 2.11, 0.09, 1.10 and 11.48 on fresh cucumber respectively, compared to 57.6, 0.42, 1.52 and 10.07 on pre-infected cucumber, and the differences between fresh and pre-infected cucumber were all significant (p <0.001) (Figure 1A). We transferred the nymphs produced by the HI lineage who was cultured on pre-infected cucumber for two generations to fresh cucumber, and we surprisingly found that they performed as well as the CU lineage did on fresh cucumber in the four parameters: R 0 (57.06 vs 65.38, p =0.342),r (0.38 vs 0.37, p =0.897) and λ (1.46 vs 1.45,p =0.879) (Figure 1A). The survival and fecundity curves clearly showed that the HI lineage performed much better on pre-infected cucumber than on fresh cucumber (Figure 1B), and the difference between pre-infected and fresh cucumber became more obvious in the third generation (Figure 1B). The survival and fecundity curves also showed that the HI lineage with feeding experience on pre-infected cucumber (HI adapted) performed as well as the CU lineage on fresh cucumber (Figure 1C).