Interação adjuvantes e ecologia comportamental computadorizada de Marava Arachidis (Dermaptera: Labiidae)

Abstract

Biological control has been a highly demanded method by the rural producer community in Latin America for the management of pests of great economic importance. The use of adjuvant compounds is essential for optimizing the application of pesticides. Bearing in mind that the essential principle of integrated management is the use of compatible strategies, it is essential to conduct studies that demonstrate the compatibility of chemical molecules such as adjuvants with biological control, although such knowledge is still considered incipient. For cotton cultivation, among the natural enemies for the control of Anthonomus grandis Boheman, 1843 (Coleoptera: Curculionidae), the species Marava arachidis (Yersin, 1860) (Dermaptera: Labiidae) has a prominent status due to its voracity. Therefore, the present study had the following objectives (i) characterization of the predatory capacity of M. arachidis using 3º instar larvae of A. grandis as prey; (ii) highlight the impact of Redobro® and Ranger® adjuvants on the functional response of M. arachidis using A. grandis larvae and (iii) analyze the computerized behavioral ecology of this predator. The experiment was conducted under laboratory conditions. To characterize the functional response, predators were exposed to the following densities of prey per predator: 1, 2, 4, 6 and 8 larvae per 90x15mm Petri dish, with 10 replications at each density. To evaluate the impact of adjuvants and functional response, the treatments used were: distilled H₂O and the adjuvants Redobro® (commercial dose= 3ml/L) and Ranger® (commercial dose= 3ml/L), adopting the same densities as in the previous study. Computerized behavioral variables were quantified to verify sublethal effects of the products on the ethology of M. arachidis. The data were modeled with nonlinear regression and survival analysis. The results showed that M. arachidis is an excellent predator of A. grandis larvae, with a type II functional response; however, when exposed to the Ranger® adjuvant, the survival and predatory behavior of M. arachidis was altered. Furthermore, the locomotion pattern of M. arachidis females was altered, expressing a lower frequency of rest and continuous mobility. Therefore, the results of the present study highlight the high predatory capacity of M. arachidis. On the other hand, the use of the Ranger® adjuvant must be adopted in a considered manner due to its impact on the survival and pattern of predation behavior of M. arachidis.