The cabbage beetle, Colaphellus bowringi Baly undergoes an imaginal summer and winter diapause in the soil; adult emergence is spread over several months to more than 2 years, with prolonged diapause occurring in certain adults under natural conditions. The relationship between natural duration of diapause and postdiapause reproduction was investigated at 25°C under 12L: 12D photoperiod. The mean body weight of postdiapause adults with the long diapause duration of 21 months was significantly greater than with the shorter diapause duration of 5, 11 and 17 months. The longevity and mean total egg production of the postdiapause adult females with the long diapause duration of 21 months was significantly greater than that of postdiapause females with shorter diapause duration of 5, 11 and 17 months. All results demonstrate that extended diapause is associated with a high level of postdiapause reproductive performance. There is no negative trade off between diapause duration and the post-diapause reproductive traits that we measured in C. bowringi.