Document Type : Research Paper
Authors
1
Ph. D. Candidate, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
2
Professor, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
3
Associate Professor, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Abstract
Induced defense responses of a plant to herbivory can influence interactions of that plant with subsequent organisms that use it as a food source. In this study, we conducted several experiments in order to understand whether preference and performance of Trialeurodes vaporariorum, Tetranychus urticae, and Aphis gossypii are affected by the previous herbivory of conspecific on the cucumber plant; and whether these effects are local or systemic. Longevity, fecundity, and pre-imaginal development period were measured as performance criteria. About A. gossypii; longevity andfecundity, about of T. urticae; fecundity and pre-imaginal development period, and about T. vaporariorum fecundity negatively affected by the previous herbivory of conspecifics. Results indicated that herbivory of these pests can induce resistance in cucumber, and can affect preference and performance of conspecifics. Results of performance experiments variedfrom negative to neutral depending on the performance criteria and the studied level (local or systemic). No positive effect was observed in studied interactions. According to results, all three herbivores tested here were able to induce resistance in cucumber and affect the preference of conspecifics. However, whitefly was unable to detect the previous herbivory of conspecifics, although these plants negatively affected whiteflies. According to results of preference experiments, it can be concluded that T. urticae was much more accurate than others at detection of the induced plants. Effect of induced defense on herbivore performance is not always aligned with the preference of the herbivore. Conducting both performance and preference experiments not only revealed the effect of induction of plant defense, but also showed the sensitivity of the herbivore at detection of changes in plant and ability to choose the appropriate host.
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