荒川库蠓雌雄成虫形态和超微结构

Morphology and ultrastructure of female and male adults of Culicoides arakawai ( Arakawa) ( Diptera: Ceratopogonidae)

【目的】为了更加准确地进行蠓科(Ceratopogonidae)昆虫的分类鉴定,获得更全面、细致的荒川库蠓Culicoides arakawai(Arakawa)雌雄成虫形态和超微结构特征。【方法】利用扫描电子显微镜对荒川库蠓雌雄成虫形态和超微结构特征进行观察研究。【结果】获得荒川库蠓雌雄成虫复眼、触角、口器、翅、盾板、足和生殖器等性状特征扫描电镜图共计31幅,其中包括精确的体躯量度值,如雌虫触角鞭节各节长度比值为4.80∶3.22∶3.56∶3.54∶3.44∶3.56∶3.56∶3.86∶7.32∶6.96∶7.02∶7.40∶9.78,雌虫触须各节长度比值为2.90∶7.47∶8.07∶2.58∶3.92;雌雄虫翅大小分别为1.34~1.36 mm×0.56~0.66 mm和1.22~1.32 mm×0.40~0.48 mm;受精囊大小为71.87μm×48.07μm。观察到已知特征未被描述的细节,如雌虫小颚齿19枚,分两排排列,雄虫小颚具12~13枚细长小颚齿;雌虫小盾片梯形,具4根粗鬃和6~8根细鬃;雌虫后足距的表面具排列成扇状细毛;雌虫爪端部分叉,爪间突具4对毛状分支;雌虫受精囊表面具刻点,基孔与受精囊宽度比值约为1/9;雄虫尾叶内表面具微毛和大毛及特殊结构。发现新特征——爪毛。通过对比发现荒川库蠓性二型现象明显,如雌雄成虫在触角形态、触角感器的类型及其分布、大颚和小颚的形态及齿的数量和形状、舌的形态及翅形等性状特点上均存在明显差异。【结论】本研究为荒川库蠓的准确鉴定及蠓科昆虫分类学和系统学研究提供参考依据,并具有重要的经济学及医学意义。

【Aim 】 This study aims to get more ultrastructure details of female and male adults of Culicoides arakawai（ Arakawa） for accurate identification of biting midges. 【Methods 】 The ultrastructure of female and male adults of C. arakawai was observed by scanning electronic microscope.【Results】A total of 31 electron micrographs of female and male adults of C. arakawai,including the features of compound eyes, antennae, mouthparts, wings, scutellum and postscutellum, legs and genitalia were obtained successfully. More accurate data of some features were obtained. For example,the length ratios of various segments of antennal flagella and palpi of female adults are 4. 80∶ 3. 22∶ 3. 56∶3. 54∶ 3. 44∶ 3. 56 ∶ 3. 56 ∶ 3. 86 ∶ 7. 32 ∶ 6. 96 ∶ 7. 02 ∶ 7. 40 ∶ 9. 78 and 2. 90 ∶ 7. 47 ∶ 8. 07 ∶ 2. 58 ∶ 3. 92,respectively; the sizes of wings of female and male adults are 1. 34-1. 36 mm × 0. 56-0. 66 mm and 1. 22-1. 32 mm × 0. 40-0. 48 mm,respectively,and the size of spermatheca is 71. 87 μm × 48. 07 μm. The poorly known features were observed,including female with 19 teeth of maxil arranged in 2 lines,malewith 12-13 slender teeth of maxil,female trapeziform scutellum with 4 thick bristles and 6-8 thin bristles,female spur with hairs arranged fan-shaped on the surface,the terminal branch of claw,empodium of female with 4 pairs of hairy branches,spermatheca with punctations on surface,the width ratio of datum hole to spermatheca about 1/9,and hypopygium of male with microtrichia and macrochaeta and special structure in the inner surface. The ungual digitule was newly discovered. The sexual dimorphism was notable in antennal characteristics,type of sensilla,pattern,teeth,number and shape of mandible,and shape of tongue and wing between female and male adults. 【Conclusion 】The results provide useful information for the accurate identification of C. arakawai and for studying the taxonomy and phylogeny of Ceratopogouidae,and have significant economic and medical value.