Field Ecology Researches On Haemaphysalis Longicornis

Ticks are very important vectors,transmitting a great variety of infectious pathogens and causing serious damage to human and livestock.What is more important,all kinds of pathogens not only develop in ticks but also preserve infestion for a long time.In the course of the spread of pathogens,the ecology and biology of ticks characterize the tick-borne diseases,and it is also the scientific basis for the development of integrated strategies of controlling ticks and prevention tick-borne diseases.So the study of its ecology has important medical and epidemiological significance.This study was carried out in Xiaowutai National Natural Conservation Area of Hebei province,and a series of researches were conducted on the habitat,seasonal dynamic of non-parasitic stage,seasonal dynamics of parasitic stages and the biological characteristics under the natural environment of Haemaphysalis longicornis which has a wide distribution in China.In this study,flagging,investigation of hosts,controlled environment,biogeography, statistics etc.,such as cross-disciplinary approach were used.The results for clarifying the ecological adaptation measures of H.longicornis,and researching the controlling of ticks and tick-borne measures in epidemiological studies have important values of theory and practical application,as well as to lay the foundation for more in-depth follow-up study.The main findings are as follows:1.In this study,grass,shrub,broad-leaved forest and coniferous forest habitat types were selected to investigate the habitats of various periods of H.longicornis.Statistical data showed that,the major habitats of H.longicornis was the shrub.In grass and broad-leaved forest habitat,there is also a distribution,but a low proportion in four kinds of habitat types was observed.The tick species has not be found in coniferous forest.So our statistics analysis of the seasonal dynamics of H.longicornis was focused on shrub.2.The statistical analysis of seasonal dynamics of non-parasitic stage of H.longicornis based on the survey data of shrub habitat.The results showed that H.longicornis activitied in early March,and disappeared in mid-October on vegetation,and there was an overlap among three stages.Larvae activitied in late June,reached the season peak in early September,and disappeared in mid-October.Nymphs activitied in early April,achieved the activity peak in early May,and disappeared in mid-September.Adults are active from early March to late September,its seasonal peak in early July,late September adults disappeared.Collected adult sex ratio of females and males was 0.85:1.3.Using the method of investigating hosts research the seasonal dynamics of the parasitic phase of H.longicornis.The results showed this species that can be found on sheep through the year.Larvae appeared in early July on sheep,disappeared in mid-October,the number peak in September.Nymphs appeared in mid-March,the peak in late April, disappeared in early September.Throughout the investigation,adults can be found on sheep, and the season peak in mid-July,females was found from early April to early October.In the entire period of the survey,the sex ratio of females and males was 0.43:1.4.The results in investigation of the biting parts and the proportion of the number on different parts of H.longicornis showed that the main sites of parasitic was ear,abdomen, mandible,eyelid,groin and oxter,and ear has the largest proportion.Various stages in different parts have different proportion of the number of bites.5.Under field condition,H.longicornis take to complete the life cycle was on average 155.7 days.The mean time for the different stages of its cycle were as follows:minimum incubation period of the eggs,41.5 days;prefeeding,feeding and premoulting periods of larvae and nymphs,2.9,4.1 and 27.6 days,1.9,3.6 and 39.5days,respectively;prefeeding, feeding,preoviposition and oviposition period of female adults,3.3,5.7,10.0 and 15.6days, respectively.The weight ratio of larvae,nymphs and adults before and after feeding was 17.0,12.1 and 102.6,respectively.The mortality rate of the engorged larvae,nymphs and were 5.3%, 52.3%and 20.0%,respectively.The oviposition pattern included a positive relationship between weights of engorged females and the number of eggs laid(r=0.6641 p＜0.05).REI and RFI in females were 9.44 and 9.11,respectively.The engorgement weight of nymphs produced females was heavier than nymphs produced males(r=0.5991,p＜0.05).