Predação intraguilda e atração de inimigos naturais por voláteis induzidos pela herbivoria múltipla em roseiras

Abstract

Knowledge about the interactions that occur in rose-herbivore-natural enemy systems have a great importance in the application of biological control programs in protected crops. In this work I tested under laboratory conditions the following hypotheses: (1): combination of two potencial predators Orius insidiosus and Neoseiulus californicus increases the predation of Tetranychus urticae; (2) there is no intraguild predation among N. californicus and O. insidiosus; (3) O. insidiosus can distinguish volatile compounds emitted from infested plants submitted to simple and multiple herbivory by T. urticae and Frankliniella insularis; (4) O. insidiosus preference for volatiles from infested-rose plants by T. urticae and F. insularis is reflected in its feeding preference as well as the prey quality. To test the first hypothesis, was studied the predation behavior of O. insidiosus and N. californicus alone or in combination, in the presence of T. urticae during 60 minutes. For the second hypothesis was evaluated the occurrence of intraguild predation and the prey consumption by both predators by counting the number of prey consumed and number of predators killed. For the third hypothesis olfactometer studies were carried out to evaluate the attraction of O. insidiosus to different treatments non-infested rose plants, infested rose plants with T. urticae or F. insularis and under multiple infestation by T. urticae and F. insularis. Also were collected and identified the volatile compounds of the treatments describe above. For the last hypothesis was tested the preference and biology of O. insidiosus with T. urticae and F. insularis. I observed that the survival rate of O. insidiosus when combined with N. californicus in the presence of T. urticae was 100%. However, the survival rate of N. californicus increased according to the development of T. urticae. O. insidiosus spent more time than N. californicus feeding of T. urticae when alone or in combination. O. insidiosus showed a high consumption of eggs, larvae, protoninfas, deutoninfas, and adult of T. urticae when alone. When these predators were combined, there was an additive response in the consumption of nymphs and adults of T. urticae, but there was a negative effect in egg consumption. O. insidiosus was attracted for the volatiles emitted by plants under simple and multiple herbivory, however, they cannot distinguish odors between plants under single and multiple herbivory. Both T. urticae and F. insularis are suitable for the development of O. insidiosus. In addition, O. insidiosus showed no preference among the prey. These results have implications in biological control programs of rose plant pests.