This study was carried out to investigate the inhabitation features of cockroaches in Jejusi, Korea. For sampling, fourteen sites were selected from every two sites of seven different habitat categories, including dwelling house, Korean restaurant, Japanese restaurant, Chinese restaurant, tea-room, hotel-inn and hospital. The cockroaches were weekly captured using sticky-traps from March, 2005 to February, 2006. Studies were focused on the temporal fluctuations of the total sample and two developmental stages (nymph and adult), the sex ratio, the positive trap percentage, and the comparative population sizes of the habitats. The positive trap percentage was 16.64%. Three species, Blatella germanica, Periplaneta americana, and Periplaneta fuliginosa, were confirmed to inhabit in Jejusi. The predominant species was P. fuliginosa (89.16%). Meanwhile, P. americana and B. germanica were shown to be much lower population size (6.44 and 4.40%, respectively). The mean sex ratio was 0.75% (males/females): B. germanica, 0.62%, P. americana, 0.29% and P. fuliginosa, 0.87%. The nymphs (82.19%) surpassed the adults (17.81%) in the individual number. Periplaneta fuliginosa also exceeded much more the other two species (P. americana and B. germanica, 5.37% and 1.67%, respectively) in the nymph number/the collected cockroaches. Both curves of the nymph and adult in the seasonal population change of P. fuliginosa made the peaks at September. This result suggested that the life cycle of this species is univoltine. The positive trap percentage and population size in the Japanese restaurant where was shown to be the most heavily polluted habitats by cockroaches were 20.67% and 0.79 (individuals/trap/week), respectively. Also, Chinese restaurant and dwelling house where were shown to be comparatively high polluted were 31.67% and 23.75% in positive trap percentage and 0.76 and 0.40 in population size, respectively. In contrast, hotel-inn, tea-room, hospital and korean restaurant were shown to be quite or very low numbers as 16.50%, 16.00%, 6.20%, and 6.00% in positive trap percentage, and 0.37, 0.18, 0.10, 0.06 in population size, respectively. It was concluded that there were differences in the species composition and the actual living conditions of the cockroach between Jejusi and other cities of Korea.

• Seong-yoon Kim(Division of Medical Entomology, National Institute of Health)
• Won-Taek Kim(Division of Medical Entomology, National Institute of Health)
• Kyu-sik Chang(Division of Medical Entomology, National Institute of Health)