The responses of the meal-worm larvae (tenebrio molitor) to the presence of tobacco leaves in their diets as the only source of proteins, are directly related to the concentrations of alkaloids. Thus, the "Tenebrio test" makes it possible to classify tobacco varieties according to their alkaloid content. On the other hand, tobacco nicotine-free varieties offer, for the insect, protein sources as valuable as some varieties of alfalfa with low level of saponins. Since the "Tenebrio test" gives generally the same results as the tests on rats and chickens for evaluating the nutritional value of proteins, the test shows the possibilities to use the nicotine-free tobacco leaves in animal diets.