In this study, the biological parameters of two B. atrolineatus strains originated from two different agro-ecological areas of Niger are examined. The analysis of the adult lifetime showed that B. atrolineatus strain of the Sahelo-Sudanese area lived longer (7.58 ± 2.19 days) than that of the Sahelian area (7.44 ± 1.39 days). Furthermore, males lived longer than females regardless of the strain origin. The egg laying activity showed that the eggs laid number was not statistically different according to the two areas. But it appeared that more than 94% of the eggs were laid in the first four days of cowpea seed infestation. The larvae survival rate and the rate of emergence also varied according to the geographical strain origin. There were few data recorded in Sahelian area where nearly 30% of the larvae did not reach adult stage. In the Sahelo-Sudanese area, less than 4% of the hatched larvae reached the adult stage. The sex-ratio also varied according to the geographic strain origins. It was in favor of males in the Sahelian area and was in favor of females in the Sahelo-Sudanese area.