Plants can protect themselves by damaging the digestion of insects. However, some insects can activate responses in their digestive system, more specifically in the insect midgut, to deal with plant defense compounds. This is of ecological relevance as a reflection of adaptive capability of insects. This work focused on digestive proteinases of Pterophylla beltrani Bolivar and Bolivar to evaluate if there were differences in expression profiles depending on sex and sensitivity to cations. Intestinal proteolytic activity in P. beltrani adults was determined by a colorimetric assay. Results were related to sex and 2 years of collection (2018 and 2019). Sensitivity was determined using different cations such as Ca, Mg, Mn, and Zn at 100 mM in the reaction mixture of proteolytic activity. Proteolytic activity was stable between years. Most activity was in males in 2019 (256,325 PAU/g) and to a lesser extent in females in 2018 (207,333.33 PAU/g) and 2019 (205,708.3 PAU/g). Proteolytic activity in the presence of Ca, Mg, and Mn was affected to a lesser percentage of 12% of remnant activity but diminished in the presence of Zn (53.7 to 73.5%). Results showed diversity regarding the presence and sensitivity of digestive proteinases in P. beltrani, which is of ecological importance because it could reflect ability to adapt to defenses of plants associated with diet.