Capacidade predatória e aspectos comportamentais de Stethorus tridens (Coleoptera: Coccinellidae) sobre o ácaro Tetranychus bastosi (Acari: Tetranychidae)

Abstract

At the moment, the concern with the consumption of pesticide-free foods has been increasing, which consequently increases the search for alternative methods of control that reduce the use of these harmful agents. In this context, biological control is inserted, which requires studies of the organisms involved, such as life cycle, capacity, and predation behavior, to become truly effective. Thus, the present study aimed to learn about the foraging process carried out by adult females of Stethorus tridens on the mite Tetranychus bastosi, determining their behavioral pattern. The time of greatest activity of this predator was also determined. The experiments were conducted in the laboratory under controlled conditions (27 ± 2ºC, RH of 70 ± 10% and photophase of 12 hours) in which the ladybugs were kept without food for 48 hours. Later, in jatropha leaf arenas, 20 individuals of T. bastosi and a ladybug were released. The entire predation process was filmed and analyzed to determine the behavioral steps, the average predation time, and the time that the ladybug takes in each of the behaviors performed. Also, it was determined the day when the ladybug has the highest predation activity. For this, leaf arenas of jatropha were also made, in which 50 mites and a ladybug were released, with 10 repetitions for each established period (morning, afternoon, and night). In foraging, the ladybug performs six behavioral steps: search, capture, consumption, disposal, cleaning, and rest. The average time of active predation is 4 minutes and 21 seconds. When taking into account the predatory activity of S. tridens, in the morning there is an average consumption of 29.8 mites, in the afternoon and at night, an average of 5.4 mites and 3.3 mites. It is concluded that the predator S. tridens is mostly diurnal and that it is more satiated after consuming adults of the mite. With this information, the foraging behavior of S. tridens on T. bastosi was elucidated, the results of which will assist in the evaluation of the potential of this predator for the management of this mite.