Sex Differentiation, Behavior Of Gonad Chromosomes And The Morphology Of Salivary Gland Chromosomes Of Bradysia Odoriphaga

Bradysia odoriphaga is a critical agricultural pest. At present, the studies on Bradysia odoriphaga are focused on its occurrence rule, selecting effective insecticides, and biological and ecological characteristics. But the study on chromosomes is scanty.Employing air-dry preparation, the morphological characteristics and behavior of chromosomes in the mitosis and meiosis of Bradysia odoriphaga were studied. The development of teste and salivary gland, and salivary gland chromosome DNA puff were also studied. The purpose for the study was to make clear the sex determination mechanisms of Bradysia odoriphaga, and to find functional genes on salivary gland chromosomes. The results are as follows.1. Bradysia odoriphaga showed both monogenic and digenic reproduction. Progenies were mostly single sex or predominated by one sex, and bisexual progenies were few. When females and males from bisexual progeny were crossed, the proportion of females producing bisexual progenies increased.2. In Bradysia odoriphaga, the number of metaphase chromosomes of meiosis was n=4.3. It was difficult to identify chromosomes in mitosis prophase, for they were intertwisted together. At metaphase, chromosomes turned shorter and aligned at the metaphase plate. The chromatids segregated to opposite poles at anaphase.4. In male meiosis I, the chromosomes didn't align in a metaphase-like array. Indeed, they proceeded directly from prometaphase to an anaphase-like stage.By meiosis II, while maternal autosomes aligned at the metaphase plate, the undivided X chromosome was seen at one pole of the spindle. At anaphase II, the autosomal chromatids segregated to opposite poles in the conventional manner. While the X-chromosome-containing chromatid set reaching the pole...