| The tick Haemaphysalis tibetensis Hoogstraal,1965 is only distributed in Qinghai-Tibet Plateau in Tibet and Gansu province of China,and regarded as potential vector of GRD spirochetes and orbivirus.In this paper,we studied the ultrastructure and biological characteristics of H.tibetensis,which laid the foundation for the identification,prevention and control of tick and tick borne diseases.The main results are as follows:1.At present,there are only the general morphological description of adults and presumed nymphs of H.tibetensis,but the morphological characteristics of the larva remained unknown.In this paper,the morphological characteristics of H.tibetensis especially the larval stage were observed by scanning electron microscope,and compared with other relative species.Larvae of H.tibetensis can be distinguished by the following characters:margins parallel anteriorly and blunt,protruding posteriorly;hind margin straight centrally with two anterior terminal arcs.Cornua absent.Basis captituli posterior margin wide and “U” shaped.Palpi stout,approximately twice as long as wide;segment I short and slender;segment II long,setae number one dorsointernally and ventrointernally;no obvious suture between segments II and III,ventral spur absent.Hypostome not as long as palpi;corona small,dental formula 2/2,denticles in files of 6–8.Scutum pyriform,widest at 1/3 length.Scapulae short and round,emargination broad but superficial.Cervical grooves almost parallel and terminating near center of scutum.Punctations few.Legs moderately robust.Coxa I,internal spur stout,terminally flat and wide;coxae II–III,internal spur short,terminally triangular on coxa II,rounded and blunt on coxa III.Trochanters I–III ventral spurs absent.Pulvilli moderately short,approximately 1/2 length of claws.Nymphs can be distinguished by: ventrointernal setae on palpal segment II number 2;denticles in each file about 8–10;internal spur on coxa I triangular,short and stout,ridged on II–IV.Males can be distinguished by: ventrointernal setae on palpal segment II number 4;dental formula 5/5;denticles in inner files 5,outer files10;terminally blunt on coxae I–III,terminally slender on coxa IV.Females can be distinguished by: infrainternal setae on palpal segment II number 5;suprainternal setae onpalpal segment II number 3;dental formula 4/4;denticles in files number 9,12,14,14 from inner to outer;internal spur on coxa I rounded and blunt,spurs on coxae II–III ridged,coxa IV sub-ridged.This is the first description on larval H.tibetensis,and key morphological characters of nymphs and adults by scanning electron microscopy.Differences with other relative species have also been evaluated,which will help further subgeneric classification and subsequent identifying this species.2.Results indicated that,the tick H.tibetensis required a mean duration of 166.7days to complete the whole cycle,and the average developmental periods of larvae and nymphs were34 days and 41.6 days,respectively.The summation of the prefeeding,feeding and preovipositon periods of females was 23.9 days,and oviposition lasted for 19.4 days.Egg incubation required 47.8 days,which was the longest period in the whole life cycle.Linear regression analysis revealed a positive correlation between the weight of the engorged female and the number of the egg mass laid(r=0.9096).The reproductive efficiency index and the reproductive fitness index were 5.2 and 4.5,respectively. |
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