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Abstracts - Ranna H. S. Bezerra

INDUCTION OF VOLATILE ORGANIC COMPOUNDS BY HERBIVOROUS MITES (ACARI: TETRANYCHIDAE) IN CASSAVA AND THEIR ROLE IN THE ATTRACTION OF A NATURAL ENEMY

Ranna H. S. Bezerra1*, Delia M. Pinto-Zevallos1, Silvia R. Souza2 and Bianca G. Ambrogi1

1 Laboratório de Ecologia Química, Departamento de Ecologia, Universidade Federal de Sergipe, Marechal Rondon, s/n - Jardim Rosa Elze, CEP 49100-000, São Cristóvão-SE, Brasil; rannaheidy@hotmail.com; delia.pintozevallos@gmail.com; bianca.ambrogi@gmail.com

2 Instituto de Botânica, Centro de Pesquisa em Ecologia e Fisiologia, Av. Miguel Estefano Água Funda, CEP 09560-500, São Paulo, SP – Brasil; souzasrd@gmail.com

* Correspondence: rannaheidy@hotmail.com

Under natural conditions, plants release volatile organic compounds (VOCs) that can differ either qualitative or quantitatively from those induced by herbivory. Induced VOCs are specific, varying with the attacked plant species, with the herbivore, and the developmental stages and conditions from both species. These compounds mediate important ecological interactions involving the communication with organisms of second and third trophic levels. Cassava (Manihot esculenta) is a native plant from Brazil cultivated in all regions, but mainly in the northeast region. Several studies have been conducted to identify the volatile compounds induced by herbivory and observe their influence in the behavior of herbivores and their natural enemies, however, to date little is known about the VOCs emissions of cassava plants and their role in arthropod-plant interactions. This study aimed at identifying the volatiles induced by herbivory from with 200 or 400 herbivorous mites Mononychellus tanjoa, Tetranychus urticae and T. gloveri in cassava plants, and how the predatory mite Neoseiulus idaeus (Phytoseiidae) respond to induced VOCs blends. Dual choice experiments were conducted to assess the preference of inexperienced (reared on prey-infested bean plants) and experienced (adapted on prey-infested cassava plants) predatory mites, N. idaeus, between odors of uninfested plants or plants infested with either M. tanajoa, T. urticae or T. gloveri. Two hundred individuals significantly increasedthe emissions of caryophyllene and alloaromadendrene from T. urticae-infested plants, and methyl salicylate (MeSA) from T. gloveri-infested plants. Four hundred individuals significantly increased the emissions of MeSA from M. tanajoa-infested plants. In addition, T. urticae induced eight compounds that were not detected in other treatments. Regardless of the infesting species, inexperienced N. idaeus did not discriminate between uninfested or infested plants. Upon experience, they discriminated between the odors of uninfested and T. urticae-damaged plants. Our findings suggest that infestation by mites results in density-dependent and species-specific emission of VOCs, and that N. idaeus relies on associative learning to forage for its prey.