七星瓢虫雌成虫卵巢发育不同阶段体内保幼激素的含量

本文以大蜡螟Galleria mellonella(L.)为生测昆虫,应用蜡测定法(Wax test)测定了取食天然食物及人工饲料的七星瓢虫雌成虫在不同卵巢发育阶段体内保幼激素(JH)的含量。取食蚜虫者羽化后8日左右(卵巢管内出现第三卵母细胞,卵黄大量沉积即将排卵),雅虫JH含量达到高峰(593.3G.U.),但一经开始排卵(羽化后约10日左右)保幼激素的含量猛然下降。直至持续产卵达10次的雌虫(羽化后约25日)JH含量仍保持在比较平稳的状态。取食人工饲料者卵巢发育缓慢,羽化30日后不产卵个体的JH水平仍很低,仅及取食蚜虫组高峰的1/6。这一结果证实了JH对七星瓢虫雌成虫卵巢发育及排卵的调控,也指出了取食人工饲料的雌虫产卵率及产卵量明显偏低的重要原因。 在应用蜡测法的过程中肯定了JH浓度与大蜡螟蛾中胸背板保持的部分蛹皮面积之部的关系。

THE CONCENTRATION OF JUVENILE HORMONE IN FEMALE ADULTS OF COCCINELLA SEPTEMPUNCTATA DURING OVARIAN DEVELOPMENT

The concentration of juvenile hormone (JH) in the female adults of the lady beetle Coccinella septempunctata during ovarian development has been studied with the bioassay method using the greater wax moth. The results are as follows:1.The body of female lady beetle reared with aphids had the highest JH concentration (593.3 G. U.) on the 8th day after emergence. At this time, large amount of yolk protein was deposited in the first two ooeytes and the third one appeared. Two days later oviposition started, the JH content declined sharply (204.7 G. U.) and then it was maintained at a more or less constant level during the egg-laying period.2.The JH concentration in the body of the female beetle fed with artificial diet (liver homogenate and cane sugar in 5 :2 w/w) was much lower and the ooeytes remained immature and on the 30th day after emergence the JH in the body was 90.7 G, U. This is the major cause of the low oviposition rate and less eggs laid in the female lady beetles reared on artificial diet.3.In the wax test, the area of pupal cuticle regenerated on the mesothoracic tergite of adult is related to the JH content.