The silent adjuvant interaction on the predatory behavior and video tracking with computerized analysis on Marava...

The use of adjuvants in preparing insecticide solutions has become increasingly common in agriculture. These products ensure the potentiation and efficacy of chemical or biological products. Nevertheless, the effects of adjuvants are not limited to target insects; they can also affect beneficial insects. However, their risks to natural enemies have been poorly analyzed. Therefore, this study aimed to understand the influence of adjuvants recently introduced in the South American market, mainly in Brazil, on the functional response and behavioral ecology of the predator Marava arachidis (Yersin) (Dermaptera: Labiidae), using computerized analysis of the assay with the EthoVision software. The study was conducted in the laboratory to evaluate the sublethal effects of the adjuvants Redobro and Ranger on the predator M. arachidis. The study was divided into three bioassays: (1) survival, (2) predatory capacity, and (3) video tracking analysis. According to the results, M. arachidis exhibited a type II functional response, independent of adjuvant exposure. However, the predator's handling time (T_h) of the prey was prolonged up to 7.84 h in the insects exposed to the Ranger adjuvant compared to the others. The Ranger adjuvant reduced the survival of M. arachidis by 50 % during the 4-day interval, in addition to lowering the predator's resting frequency and continuous mobility. Our results showed that the survival pattern, functional response, and computerized behavioral ecology of M. arachidis were drastically reduced when females of this predator were exposed to the Ranger adjuvant. In contrast, the Redobro adjuvant had a small negative impact on the parameters of the functional response on M. arachidis. The present study is one of the few global reports to demonstrate the effects of adjuvants on the behavioral ecology of dermapterans.