骆驼斯氏副柔线虫病传播媒介西方角蝇和截脉角蝇的幼虫龄期划分

【目的】本研究旨在找出区分西方角蝇Haematobia irritans和截脉角蝇H.titillans幼虫龄期划分标准,为准确鉴定两种角蝇各龄幼虫,研究斯氏副柔线虫在角蝇体内的发育过程,以及制定防控骆驼斯氏副柔线虫病的有效措施等奠定基础。【方法】采用实验室人工孵育两种角蝇幼虫的方法,分别测量不同发育阶段幼虫的虫体长、咽骨体长和咽骨体宽3项指标,利用SPSS Statistics 19.0统计软件对数据进行处理,结合Crosby生长法则和线性回归的方法进行分析,比较两种角蝇幼虫之间差异,以确定两种角蝇幼虫最佳龄期划分标准。【结果】结果表明,两种角蝇的幼虫均分为3龄,咽骨体是两种角蝇幼虫龄期划分的特征性结构,两种角蝇各龄幼虫相同指标的测量值随龄期的增长呈现出相同的增长规律。咽骨体长是划分两种角蝇幼虫龄期的最佳测量指标,咽骨体宽可作为分龄的辅助指标;两种角蝇相邻龄期幼虫的体长变化范围存在相互重叠,不能准确划分角蝇幼虫龄期。【结论】研究表明通过西方角蝇和截脉角蝇幼虫咽骨体的形态特征可简便、快速和准确地鉴定两种角蝇幼虫的龄期。

Determination of larval instars of horn flies Haematobia irritans and H. titillans (Diptera: Muscidae), the vectors of camel parabronemosis

【Aim】 This study aims to investigate the criteria for dividing the larval instars of horn flies Haematobia irritans and H. titillans, which will be fundamental for the determination of larval instars of the two horn flies, the development of nematode Parabronema skrjabini in its vectors, and the development of efficient control measures of camel parabronemosis. 【Methods】 The larvae of the two horn flies at different developmental stages were obtained by laboratory artificial rearing. Three morphological variables, i.e., the body length, and the length and width of pharyngeal sclerite of the larvae, were measured, and the data were analyzed by SPSS Statistics19.0. Combined with the Crosby growth rule, the difference in the three morphological variables between the larvae of the two horn flies was compared, and the best criteria of instar division were determined. 【Results】 The results indicate that the larvae of the two horn flies can be divided into three instars. Pharyngeal sclerite is the characteristic structure of the larvae of the two horn flies, and the variables of the larvae of the two species in different ages show the same growth pattern with the increase of larval instars. The length of pharyngeal sclerite is the best morphological variable for separating the larvae of the two horn flies, while the width of pharyngeal sclerite can be used as an assistant variable for the division of the larval instars. However, there is an overlap in the variation range of body length between the adjacent larval instars of the two horn flies, so body length can not be used to separate the instars accurately. 【Conclusion】 Our study indicates that the morphological characteristics of larval pharyngeal sclerite can be used to identify the larval instars of  H. irritans  and H. titillans  conveniently, rapidly and correctly.