三种蚤生殖系统的细微结构:雌性外生殖器的发育

FINE STRUCTURES OF THE REPRODUCTIVE SYSTEM OF THREE FLEA SPECIES: DEVELOPMENT OF FEMALE GENITALIA

本文研究了缓慢细蚤 Leptopsylla segnis(Schōnherr),不等单蚤 Monopsyllus anisus(Rothschild)和猫栉首蚤指名亚种Ctenocephalides felis felis(Bouché)雌性外生殖器的结构,观察了从幼虫、前蛹、蛹至成虫各发育时期的雌性外生殖器的内部结构变化。对一直悬而未决的雌蚤中输卵管等的起源问题,进行了详细的观察和探讨。认为从晚期3龄幼虫开始出现的雌性外生殖器芽,在前蛹期成为四个部分:1.第7腹板后缘腹壁内陷形成的一对外胚层囊;2.紧接外胚层囊后并延伸至第8腹板的外胚层增厚;3.在第8腹板后部,外胚层增厚两侧的产卵器芽;4.第8腹板后缘腹壁内陷形成的受精囊芽。并认为,这三种蚤的中输卵管由一对外胚层囊和其后的外胚层增厚前端的一小部分内陷形成,阴道由外胚层增厚的大部分和第8、9腹板腹壁内陷形成,受精囊由受精囊芽内陷形成。

Microscopical studies on the internal structures during the development of female geni-talia from the first instar larvae up to mature adults of Leptopsylla segnis (Schoherr, 1811), Monopsyllus anisus (Rothschild, 1907) and Ctenocephalides felis felis (Bouche, 1835) were carried out and the results show that the development of the female genitalia of these fleas is essentially the same. The rudiments of the female genitalia start to appear at the late third larval instar. In the prepupa they are fully formed and composed of the following four parts: 1. A pair of pyriform ectodermal pouches is formed as ectodermal invaginations on the venter of the the seventh abdominal segment. 2. Immediately behind the ectodermal pouches there is a median thickening, which is formed by the ectodermal proliferation on the venter of the eighth abdominal segment. 3. The rudiments of the ovipositor which only appear in the prepupa and are present in the pupa but disappear in the adult are formed as a fold of the thickening body wall on the venter of the eighth abdominal segment. 4. The rudiment of the sperma-theca is formed as an ectodermal invagination on the posterior margin of the venter of the eighth abdominal segment. In the pupa the median oviduct is formed by the ectodermal pouches and the anterior small section of the ectodermal proliferation, the vagina is formed by the large section of the ectodermal proliferation and the invagination of the ventral body wall of the eighth and ninth abdominal segments, and the spermatheca is formed by the spermatheca rudiment.