We collected four species of Osmia spp. consisting of O. cornifrons, O. pedicornis, O. taurus and O. satoi in Yeongwol, Bonghwa and Yechon locations. O. pedicornis was the dominant species, which accounts for 59.6% to 76.4% in the three locations. The sex ratio of Osmia spp. were from 1:1 to 1: 2.8 in O. cornifrons and from 1:2.8 to 1: 5.5 in O. pedicornis. The sex ratio of O. cornifrons and O. pedicornis was different in 3 locations. The female and male cocoons of O. cornifrons were the long elliptical-shaped and grey-brown color. The female and male cocoons of O. pedicornis were the long elliptical-shaped and polished dark-brown color. In both species of O. cornifrons and O. pedicornis, the cocoon size of the females was significantly larger than that of the male. Between those two species, the latter had a relatively bigger size than the former.

In the age of sexual maturity of queen, mating occurred at 6.7% immediately after eclosion and it was the highest as 85.0% at 10 days after emergence. However, a remarkable decrease was occurred at 20 days after the emergence. With regard to oviposition rate, the highest rate was observed as 81.3-81.8% at 6 to 10 days of eclosion. The rate of colony foundation and progeny-queen production were the highest as 43.8% and 37.5%, respectively, at 8 days of eclosion. In the age of sexual maturity of male, mating rate was as high as 38.3% immediately after the eclosion, the highest as 80.0% at 25 days of eclosion, and 76.6% at 8 days of eclosion. The oviposition rate was the highest as 76.9% at 6 days of eclosion, and decreased to 75.0% at 8 days and 72.7% at 10 days of eclosion. Summarized, our results indicate that sexual maturity for mating of B. terrestris is most favorable 6-8 days after eclosion for queen and 6-10 days after for male.