Two species of flour beetles, Tribolium castaneum and Tribolium freemani, are competing according to the Lotka‒Volterra equations. If the α of T. freemani on T. castaneum is 1.5, the addition of 150 T. freemani individuals would depress the T. castaneum population growth rate by the same amount as the addition of _______ T. castaneum individuals would.