【摘要】 <正> 一.引言 东亚飞蝗在卵階段的发育过程有许多地方是和其他种类的昆虫相类似的,但是也有许多地方可作为飞蝗种的特徵。蝗虫是陸棲的昆虫,它们的卵经常在土中孵育,因此在卵的生理和构造上有许多与此种生活习性相适应的特点。和其他昆虫的卵一样,蝗卵是一种有壳卵(cleidoic egg),但含有更为充分的营养物质。它外面的卵包膜更多还原

【Abstract】 When incubated at a constant temperature of 30℃, the eggs of the oriental migratory locust, Locusta mgratoria manilensis Meyen, were observed to absorb a maximum amount of water from their surrounding environment on the 5th day or thereabout since they were laid. The water content of the newly-laid eggs was about 50% of their total weight, and it rose to 74% on the 6th day when the embryos were going to start revolution or blastokinesis. During katatrepsis additional water may be absorbed, so that before hatching the water content of the eggs is about 80%. Hence there is no great difference between the mode of water absorption in this species and that of the African migratory Iocust, L. migratoria migratorioides R. & F., but it is quite different from that of Melanoplus differentialis Thos., as revealed by the data of Bodine and Slifer.The absorption of water led to conspicuous changes in volumes and densities of the developing eggs. Eggs incubated in moistened soil were observed to double or triple their volumes when the maximum amount of water had been absorbed and their densities were correspondingly decreased. Though the true cause of absorbing such a large amount of water in a relatively short period is not clear, these changes may be regarded as indications for alteration in the nature of the "morphogenetic substratum" and are pre-requisite for the normal development of the embryo.The reduction of dry materials in the egg during development was estimated to be roughly 15—20% of the original; and the utilization of lipids and the increase in respiratory rate were determined. It was found that 40% of the lipids contained in the newly-laid egg was used up when the embryo had fully developed. Since egg diapause is lacking in this species, the course of change in the rate of respiratory metabolism is quite different from that of Melanoplus differentialis.The growth of the embryo and the changes in the physical and chemical properties of the developing egg may alter to a certain extent the eapacity to resist the act of unfavourable environment,but the changes in the egg membranes seem to be especially important in this respect. The chorion and the serosal cuticles are the essential protective structures; they protect the egg from mechanical injuries and serve as the barriers to Water loss. Newly-laid eggs are protected by the chorion, and its protective function seems to be taken over afterwards by the serosal Cuticles which are secreted by the serosa. The secretion of the serosal cuticles in the developing eggs started on the 4th day(some at the end of the 3rd day)when incubatde at 30℃,and the maximum thickness was observed to have been reached from the 6th day to the 8th day.At that time the chitin content of the cuticle is about 2% of the dry weight of the egg. It was found that most of the eggs overwintering in the field contained embryos of the same developmental stages as those incubated at 30℃ for 6 days; therefore they must possess fully developed protective structures.It is seen that the chorion is secreted by the mother follicular cells but the serosal curicles are formed by the egg itself; therefore the former is proposed to be called the primary protective structure and the latter the secondary one. Regarding their functions the latter is more effective than then former. After the 10th day of incubation at 30℃ the inner part of the serosal cuticles was observed to start dissolation and the embryo would secrete a layer of cuticle on its own outer surface. It is assumed that the protective function of the chorion and serosal cuticles is partly taken over by this embryonic cuticle.更多还原