... new and surprising result is observed : in controls, the regression lines of blocks II and III of D. melanogaster, and II of D. simulans, pass over the origin 0,0 (intercept,« ... operating causing in each block the appearance of different values of mating, fecundity, productivity and competitive ability, and notably, with a very distinct effect in D. ... generationtimes and larger population sizes in spring and summer than in winter and autumn.The fecundity values of controls and competition cultures (no data were obtained in block...