日本沼虾第一触角感受器的形态和分布

Morphology and distribution of antennular sensilla in Macrobrachium nipponense

应用扫描电子显微镜对日本沼虾第一触角触鞭上各种感受器的分布情况和形态结构进行了观察。结果表明，雌性和雄性日本沼虾触角感受器在种类、形态和分布上均相似。第一触角分为内、外两鞭，外鞭上具有附鞭。触角上共有四种感受器，分别为化感刚毛（或称嗅毛）、Ⅰ型简单刚毛、Ⅱ型简单刚毛和有齿刚毛。化感刚毛上端柔软，顶端无孔，仅着生于附鞭的凹槽内。其它三种感受器在内外两鞭上均有分布。Ⅰ型简单刚毛通体光滑，顶端逐渐变细，具一顶孔，常伴生Ⅱ型简单刚毛和有齿刚毛，但长度比后两种的短；Ⅱ型简单刚毛基部光滑，顶端被鳞片覆盖，且具复杂的孔结构；有齿刚毛有大小两种类型，表面长有许多齿状突起，齿状突起主要分布于刚毛近顶端1／2--1／3区域内，近基部光滑无齿状突起。有齿刚毛的顶端也被鳞片覆盖，也具复杂的孔结构，结构与Ⅱ型简单刚毛十分相似。

Scanning electron microscopy and light microscopy were used to examine the morphology and distribution of antennular sensilla of the Macrobrachium nipponense. The results showed that there is no sexual dimorphism in the morphology and distribution of the antennular sensilla. Each antennule consisted of two flagella, the medial flagellum and the lateral flagellum on which there is an appendage flagellum. There are four types of sensilla on the flagella of antennules of M. nipponense： aesthetascs, two types of simple setae and denticulated setae. Aesthetascs are located on the appendage flagella of the antennules. The distal part of the aesthetasc is very soft and there is no pore on the tip of the aesthetascs. Other types of setae are located on both the lateral and medial flagella. Type Ⅰ simple setae are smooth with a pore on the tip. They usually appear in groups with type Ⅱ or denticulated setae and they are shorter than the type Ⅱ and the denticulated setae. Type Ⅱ setae are smooth with scales around tip, with complicated pore structure. There are two different sizes of denticulated setae. The 1/2--1/3 distal portion of the denticulated setae is studded with numerous denticles. Their tips and pore structures are similar to those of type Ⅱ setae.