海南省血红扇头蜱不同发育阶段形态电镜观察

Scanning electron microscopic observation of morphology of Rhipicephalus sanguineus at different developmental stages in Hainan Province

目的 了解海南地区优势种血红扇头蜱(Rhipicephalus sanguineus)不同发育阶段的外部形态特征及超微结构,为海南省血红扇头蜱谱系的识别及防控提供理论基础。方法 借助扫描电子显微镜观察海南省优势种血红扇头蜱幼蜱、若蜱和成蜱不同发育阶段的外部形态。结果 幼蜱须肢各节之间分界不明显,刚毛数少且呈锯齿状,口下板齿式为2|2,有3对肢节,肛门瓣上有1对肛毛,无肛后沟、气门板、多孔区和生殖孔;若蜱须肢各节开始有明显分界,口下板齿式为2|2,有4对肢节,有肛后沟,肛门瓣上有3对肛毛,无生殖孔和双孔区;雄成蜱须肢覆盖鳌肢鞘,刚毛整体为圆锥形,口下板齿式为齿式3|3,有4对肢节,有肛后沟和肛侧板,肛门瓣上有7根肛毛,生殖孔呈卵圆形;雌成蜱口下板齿式为3|3,有4对肢节,有1对孔区,共有3根刚毛,有肛后沟,肛门瓣上有4对肛毛和2个气孔样小孔,生殖孔呈宽U型。此外,雄成蜱盾板几乎占据整个背面,幼蜱、若蜱和成蜱的假头基均呈六角形,并且第1对足上均发现哈氏器的存在。结论 对血红扇头蜱不同发育阶段进行扫描电子显微镜观察,根据其形态结构特点初步认为海南省血红扇头蜱为血红扇头蜱热带谱系(Rhipicephalus linnaei),为后续血红扇头蜱的鉴别和地方蜱传疾病综合防控提供一定的参考意义。

Objective To understand the morphological characteristics and ultrastructure of the dominant species of Rhipicephalus sanguineus in Hainan at different developmental stages,and provide theoretical basis for the identification of the lineage and control of Rhipicephalus sanguineus.Methods The external morphology of different developmental stages of the dominant species of Rhipicephalus sanguineus,including larva,nymph and adult tick in Hainan were observed by scanning electron microscope.Results The division between each segment of larva pedipalps was not obvious,and setae was serrated;dental formula type 2|2;3 pairs of podomere;a pair of setae on the anal valve;none of anal groove,spiracular plate,porous area and genital aperture.There was a clear boundary at the beginning of each segment of nymph pedipalps;dental formula type 2|2;4 pairs of podomere;3 pairs of setae on the anal valve;anal groove;none of porous area and genital aperture.The male adult tick′s trichotheca are covered by the pedipalps,and the whole bristles are conical;dental formula type 3|3;4 pairs of podomere;anal groove and paraprocts;7 setae on the anal valve;genital aperture was oval.The female of adult tick can be distinguished by dental formula 3|3;pairs of podomere;porous areas with 3 short setae;anal groove;4 pairs of setae and 2 pores on the anal valve;genital pore was broadly U-shaped.In addition,the male adult′s scutum occupies almost the entire dorsal surface,the basis capituli of larva,nymph and adult tick all were hexagonal,and the existence of Haller′s organ was found on the first pair of legs.Conclusions Scanning electron microscopy observation of the different developmental stages of R.sanguineus revealed clear morphological features,preliminarily suggesting that R.sanguineus in Hainan Province may belong to the tropical lineage,which provide a certain experimental basis for the identification of the tick and the comprehensive prevention and control of local tick-borne diseases.