Pistas quimiossensoriais de predadores e concorrentes influenciando na busca por refúgio no fruto pelo ácaro do coqueiro Aceria guerreronis Keifer (Acari: Eriophyidae)

Abstract

Organisms are adapted to recognize environmental cues that can provide information about predation risk or competition. Non-vagrant eriophyoid mites mainly avoid predation by using habitats that are difficult for predators to access (galls or confined spaces in plants) such as the meristematic region of the coconut fruit, which is inhabited by the phytophagous mites Aceria guerreronis and Steneotarsonemus concavuscutum. The objective of this study was to investigate the response of A. guerreronis to cues from the predators Neoseiulus baraki and Amblyseius largoensis in coconut fruits, cues from conspecifics (A. guerreronis injured) and cues from the phytophage S. concavuscutum. The test was carried out throught the release about 300 A. guerreronis on coconut fruits previously treated with cues from predators, conspecific or heterospecific phytophagous. We also observed the walking behaviour of A. guerreronis exposed to the same chemical cues using a video tracking system. The infestation of fruits by A. guerreronis was greater in the presence of predator cues and reduced in the presence of S. concavuscutum cues, but cues from injured conspecifics did not interfere in the infestation process. In addition, the cues tests also altered the walking parameters of A. guerreronis; it walked more in response to cues from predators and the heterospecific phytophage. Aceria guerreronis had more time in activity in the treatments with clues in comparison with the control treatment. These results suggest that A. guerreronis recognizes cues from predators and competitors cues and modifies its behaviour to increase its fitness.