The effect of different diets [Tenebrio molitor L. (Coleoptera: Tenebrionidae) pupae; T. molitor pupae and Eucalyptus cloeziana plant; T. molitor and Eucalyptus urophylla plant and T. molitor pupae and guava plant (Psidium guajava)] on the morpho-physiological features of the fat body of Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) females was studied in the field. Adult females of B. tabidus have trophocytes about twofold larger (966.32mum(2)) when fed on E. urophylla and T. molitor than those fed on other diets. The trophocytes of B. tabidus showed similar morphological aspects with the different diets and age of this predator. The histochemical tests indicated a reduced quantity of proteins and carbohydrates in the fat body of B. tabidus females with all diets and age of this predator.