关键词: 藏羚, 可可西里卓乃湖, 产羔地, 温、湿度, 寄生虫卵发育, 感染风险回避

Abstract:

Herbivores aggregation is beneficial to reduce the predation risk but it can also increase the transmission and infection risk of parasites. Zhuonai Lake, located in Hoh Xil, Qinghai Province, an important calving ground of Tibetan antelope (Pantholops hodgsonii). The aggregating time of Tibetan antelope in Zhuonai Lake area is mainly concentrated from early June to July (less than 30 days).Climate factors such as temperature and humidity in this region might have an important impact on the development of parasite eggs/oocysts in the host’s feces. In this study, a microclimate observer was constructed in the calving ground of Zhuonai Lake to collect local meteorological data on June 9th, 2018. In this area, fresh feces of Tibetan antelope were collected and placed outdoors for 0, 10, 15, 20, 25, 30, 35 days, and nearly one year (300 days). We used the flotation technique to detect the development status of eggs/oocysts in different periods within 35 days and the species of surviving larvae in the feces placed outdoors for nearly one year. Our aim was to preliminarily test the development, hatching, and overwintering survival of the dominant parasite eggs/oocysts in the feces of aggregated Tibetan antelope in the Zhuonai Lake area and evaluate whether the calving ground increases the risk of gastrointestinal parasite transmission and infection in Tibetan antelope. The results showed that: (1) between June 9 and July 16, the 35 days average temperature was 5℃ and the average relative humidity was 81%. (2) During the aggregating period of Tibetan antelope in Zhuonai Lake area (less than 30 days), the dominant parasite eggs/oocysts in the feces did not develop to the infective stage (Third larvae stage). For example, dominant nematode eggs, including Trichostrongylus sp., Marshallagia sp., and Nematodirus sp., only developed to the first larvae stage within 30 days. Additionally, the sporulation rates of dominant coccidian species Eimeria pantholopensis and E. wudaoliangensis were 0, 18.9 %, 54.0 % and 0, 13.5 %, 30.4 % on the 25th days, 30th days, and 35th days, respectively. (3) Few parasite eggs survived over the winter until the next year. Only a few larvae of the Marshallagia sp. and Nematodirus sp. were found in feces which were placed for nearly one year to survive over the winter in the calving ground of Zhuonai Lake. This study suggests that the risk of gastrointestinal parasite transmission and infection was low during the aggregating period of Tibetan antelope in Zhuonai Lake area. Short-term utilization of calving ground and rapid back-migration were important behavioral strategies for Tibetan antelope to avoid increasing the risk of gastrointestinal parasitic infection. Furthermore, the climate environment such as low temperature was beneficial to the natural purification of parasites.

Key words: Tibetan antelope (Pantholops hodgsonii), Zhuonai Lake, Calving ground, Temperature and humidity, Development of parasite eggs/occysts, Infection risk