Reproductive development and seasonal activity of two Korean native Coprini species (Coleoptera: Scarabaeidae)

Seasonal activity of the native dung beetles, Copris ochus (Motschulsky) and Copris tripartitus Waterhouse, was studied in Jeju Island, Korea. Reproductive condition and breeding cycles of adult females were determined using physiological age-grading techniques to assess the proportions of newly emerged, nulliparous and parous beetles, and those resorbing oocytes. C. ochus appears to be univoltine. Its main period of adult emergence occurs in summer rather than in spring (March–May), as was previously thought. The female population consisted of the complete range of reproductive age classes in August–September. C. tripartitus also appears to be univoltine. However, this species has two adult activity periods: a peak activity in spring when most oviposition occurs, and another in autumn when the new generation emerges. With the onset of winter, C. tripartitus adults cease reproductive development and females over winter in a nulliparous stage.