Figure 1.

Performance of Tetranychus evansi. Mean (± SEM, four plants, 10 mites per plant) oviposition of T. evansi on tomato leaves that were previously damaged by conspecific mites (a, closed circles, solid line) or Tetranychus urticae (b, closed triangles, solid line), on non-infested leaves of infested plants (systemic, open circles and triangles and interrupted line) and leaves from non-damaged control plants (eight plants, 10 mites per plant, closed squares and dotted line). The effect of treatment was significant (linear mixed effects model; a: F_2,13 = 9.85, P = 0.0025; b: F_2,13 = 44.6, P < 0.0001). Curves with different letters within each panel differ significantly. The experiments with T. urticae and T. evansi were not carried out at the same time for logistical reasons. As it was impossible to maintain constant greenhouse conditions, plant quality will have varied with time. Treatments can therefore only be compared with their controls within the same experiment (i.e. within the same panel). (c) Developmental rate and juvenile survival of T. evansi (in h, from egg to adult) on tomato leaves treated as in a and b. The curves show the fraction of mites of the initial cohort of 40 eggs per treatment that developed into adults. Error bars are left out for reasons of clarity.