在绵羊体内及草场上马歇尔线虫各发育阶段的季节动态研究

Seasonal Dynamic Research on Developmental Stages of Marshallagta in Sheep and on Grassland

本试验对典型的亚高山高寒草甸草原——巴音布鲁克草原绵羊寄生线虫的优势种马歇尔线虫进行了成虫寄生量、羊粪便中虫卵排出量和寄生虫体外发育育成率的逐月观察，结合气温、相对湿度、蒸发量和雨量的观察记录，得出了马歇尔线虫各发育阶段在绵羊体内及草场上的季节动态及与气温、湿度变化的关系。马歇尔线虫在体内的寄生量和草场上的体外育成量得出的成虫数量低谷在2006年7月～2006年8月，高峰在2006年11月第1次出现，到2007年2月出现1次明显的下降，而到2007年4月再次明显的升高。寄生性幼虫数量低谷于2006年7月～2006年8月，高峰在2006年9月第1次出现，到2007年2月再次升高。马歇尔线虫寄生性幼虫高峰与成虫高峰相对应。结果表明成虫高峰随体外幼虫高峰而来，粪便中虫卵的峰值则往往跟随成虫高峰而出现。体外育成率的高低又明显受气温及湿度影响，平均湿度低于50％时无峰出现，低于5．6℃时育成率为零，湿度在79％以下时育成率很低。本试验对羊体内及草场上寄生性马歇尔线虫季节消长规律进行了研究，为制定合理防制措施提供理论依据。

Through a monthly observation of the parasitic load of the imagoes, the output of parasite eggs from sheep＇s feces and the survival rate of ectogenetic parasites of Marshallagta, which was a typical dominant species among the parasitic nematodes parasitic on the sheep living on Bayanbulak grassland,which was a subalpinealpine meadow grassland, with the addition of the observing records of air temperature, relative humidity, evaporation capacity,the paper obtained the seasonal dynam- ics of Marshallagta in sheep and on grassland in different developmental stages as well as its relationship with the changes of air temperature and humidity. Both the parasitic load in sheep and the incubation amount in vitro on grassland were the lowest from July to August of 2006. But they reached their peak period in November of 2006 for the first time, and then an obvious decrease in February of 2007 before another peak period again in April of 2007. In addition, the amount of the parasitic larva was also the lowest from July to August of 2006, but its peak period appeared in September of 2006 for the first time, and afterwards an obvious rise came again in February of 2007. The peak period of the parasitic larva of Marshallagta corresponded to the peak period of the adult. It turned out that the peak period of the adult came with the peak period of larva, while the peak value of the parasite eggs in feces would often come along with the peak period of the adult. The in vitro survival rate was obviously affected by air temperature and humidity. When the average humidity was lower than 50 %, no peak would come. When the temperature was lower than 5.6℃, the survival rate was zero. When the humidity was lower than 79%, the survival rate was very low. The test made a study on the seasonal dynamic regularity of Marshallagta in sheep and on grassland, which supplied theoretical foundations for the formulation of proper prevention measures.