摘 要：
黄柄黑蜂是稻瘿蚊的群居内寄生天敌,常产卵二、三堆在寄主卵或初孵幼虫体内,每堆卵10多粒,每粒卵发育为一个体,是属单胚繁殖。卵梭状,长15微米,宽6微米。卵母细胞两次成熟。在日平均温度29.5℃下,卵核第一次分裂形成纺锤体大约在产卵后10—12小时,第二次分裂形成纺锤体约在产卵后24小时。在产卵后48小时,两个极体在卵的前端合并为极核,雌性原核和雄性原核在卵的后端合并为分裂核。产卵后2.5天,卵粒长大,此时称为寄生体,胚区及包围它的滋养羊膜形成。当寄生体发育至第4天,副核团分裂一大一小两块占据卵的前端。寄生体发育至5—6天,就变为圆形,胚核由一个分裂为2个、4个。卵产后8天,囊胚层形成。产后10—13天,寄生体长达300微米,宽192微米。卵期13—14天。幼虫期仅3天。蛹期8—10天。在一寄主内能发育9—61头黄柄黑蜂。雌蜂具有避免在同一寄主上重复产卵的本能。雌雄性比为8:1。每年发生8代,以早期胚在稻瘿蚊1龄幼虫体内越冬。
译 名：
ONTOGENY AND BIOLOGY OF PLATYGASTER ORYZAE, A GREGARIOUS ENDOPARASITE OF THE RICE GALL MIDGE
作 者：
LIU SIU-KING (South-China Agricultural College)Gu SIU-WEI LIANG YE-MIN(Institute of Entomology, Guangdong Province)
摘 要：
Platygaster oryzae Cameron is a gregarious endoparasite of the rice gall midge Orseolia oryzae in South China. The female adult deposits a group of eggs at one ovipositional action on the egg or into the body of the first instar larva of the host. Each egg develops into a single parasite through a monembryonic process similar to that described for other Platygasteridae.The newly deposited egg is spindle-shaped, 15×6 μ in size. At 10 to 12 hours after oviposition the oocyte nucleus swells and elongates slightly, starting to form spindle. At the close of the first maturation division the first polar body is at the anterior pole, and the oocyte nucleus of second order is found near the center of the egg. The second meiotic spindle appears about 24 hours after oviposition and the nucleus undergoes changes similar to that in the first maturation division. The anterior part of the spindle becomes the second polar body while the posterior part becomes the female pro-nucleus. After the second maturation division the first and second polar bodies unite to form a single polar nucleus in the anterior region of the egg which is known as the polar region; and the female and male nuclei are close to each other in the posterior region. About 48 hours after oviposition the female and male nuclei fuse to form the cleavage nucleus.About 2.5 days after oviposition the egg begin to grow, measuring 20×8 μ in size. An embryonal cell together with its surrounding membrane forms the trophamnion. About 4 days after oviposition the paranuclear mass formed by polar nucleus grows and divides to form two masses of unequal size. At that time the egg body still retains the spindle shape. It measures 25×15μ in size one or two days later and on the 6th day after oviposition it becomes spherical and contains two embryonic nuclei which soon divide to form four embryonic nuclei. One day later the embryo is in the early blastula stage containing 16 to 32 nuclei, with two paranuclear masses in the trophamnion. On about 8th day after oviposition the embryo is at the germ layer stage; and two to four days later it is typically U-shaped within its trophamnion, with one para-nuclear mass at its side. From this time on, the embryo grrows noticeably, measuring 300×192 μ in size, Finally the young larva breaks the trophamniotic membrane and begins to feed on the host. The egg stage lasts 13 to 14 days while the larvel stage is only 3 days.The fully developed larva is white and ovoid, 705×372 μ in size, and possesses three thoracic and seven abdominal segments, with spiracles on the second and third thoracic segments and the first and second abdominal segments. The mouth is a simple transverse orifice. The mandibles are long and nearly straight. Before pupation each larva forms an ovoid cocoon which is included within the host skin.The female adult oviposit a group of 10 to 15 eggs at each oviposition and usually it can deposit 2 to 3 egg groups in one host. It can discriminate the parasitized host eggs.From each parasitized puparium would emerge from 9 to 61 parasites (21 in average). The sex ratio is eight to one in favor of the female. In most cases both sexes develop in the same host; only 1% will be in parthenogenesis. The life span of the adult is about 3 to 5 days.Most of Platygaster oryzae hibernate in the early embryonic stages in the first in-star larvae of the host; they breed eight generations per year. The duration of each generation is about 25 to 30 days except the overwintering generation.
