Life history and population dynamics of Korean woodroach (Cryptocercus kyebangensis) populations

Ecological aspects of Cryptocercus kyebangensis life history were investigated via laboratory rearing and field observations. The number of antennal segments and head width were used to classify the first four instars. The results, which combine both the field collection and the laboratory rearing, indicate that eleven instars occur in C. kyebangensis. It supports the proposal on the number of instars of Park and Choe (2003c) based on field collections. A total of 388 nymphs from 13 colonies were collected prior to winter to investigate overwintering stages. Of them, 4% (n = 17) were the second instars, 57% (n = 220) were the third instars, and 39% (n = 151) were the fourth instars, respectively. Thus, most of them overwinter in the third or fourth instars. The results indicate that young nymphs of C. kyebangensis have to reach at least 3rd or 4th instar to survive low temperature environment of winter. According to seasonal dynamics of populations, C. kyebangensis reaches adulthood in the summer of the fourth or fifth year (4–5 yr span) after their birth.