We studied biological characteristics and habitat requirements of Parnassius imperator in Yagou, Yongjing County. We also analyzed population trend and key factors responsible for its fluctuation. Our research methods included for example transect survey, observation at sample plots, indoor breeding, etc.
1)P. imperator is an endemic species to China. It is univoltine in Yongjing County, and overwinters in egg stage on rocks nearby host plants Corydalis adunca (also endemic to China). Eggs hatch in mid-March the following year. The larvae stage includes 4 instars and last for 52 days. Duration of the larva period is from late March to late June. The pupae stage lasts about 47 days, and larvae pupate in early May. Adults emerge at the beginning of May and can fly fast. Peak quantity of adults ranges from mid-July to mid-August, however adults can still be found in late September. The egg stage lasts about eight months.
2)P. imperator is a dominant species in Yagou, Yongjing County. Adults like to stay and fly in valley with bare rocks and shrubs, larvae are found on sunny and semi-sunny slopes. Geographic distribution of P. imperator and its host plant C. adunca overlaps in China. This explains their close co-evolutionary relationship.
3)Two subspecies of P. imperator. P. imperator gigas Kotsch, occured in Yongjing county and P. imperator regulus (Bryk et Eisner) in Hezuo city.
4)Extremely abnormal climate, for example, Strong cooling, frost or snow, is the main factor that affects the population decline of P. imperator. Human disturbance is afnother threat affecting survival of P. imperator. 5)Conversation measures should focus on conservation of habitats of Parnassius sp., and reduction of human disturbance to support survival of the population in Yagou. We also stress the need for long term population monitoring and research on impact of climate chang and habitat loss.