The Southern green stink bug (Nezara viridula) is a cosmopolitan pest that affects crops like soybean (Glycine max), reducing grain yield and quality. Its feeding behavior involves phases such as locating, accepting, and consuming food, which are influenced by nutritional stimuli. This study aimed to optimize bioassays to evaluate soybean damage and the behavior of N. viridula by developing a starvation protocol to standardize experimental conditions. This study also examines how the insect’s nutritional status impacts soybean crops, providing tools for applied ecology and entomology in agroecosystems.

Experiments were conducted in the Biochemistry Laboratory of the Faculty of Agronomy at the University of Buenos Aires (UBA) using adult N. viridula differentiated by sex that were fed with fresh soybean pods (Glycine max, cv Williams 82, R6 stage). Different stink bug starvation periods (0, 24, 48, 72 h) were evaluated, and the insects were allowed to feed on pods with different treatments (control, damaged by stink bug and MeJA). In “no-choice” experiments, feeding behaviors were recorded using BORIS software. The digestive protease activity of insect guts was analyzed in pools comprising one male and one female (N=72) with 4–6 replicates per treatment.

Our results suggested that N. viridula at 24 h of starvation increased selectivity among pod treatments. To evaluate plant damage, 48–72 h starvation periods are more suitable, as the response time of the stink bugs remains consistent regardless of their initial state. In general, the insects become less selective after prolonged periods without food, aligning with findings by Matthews and Matthews (2009). These insights help to optimize experimental protocols for behavior and damage studies in crops.