Studies On Postembryonic Development Of The Brain And Expression Of Gonadotropin-releasing Hormone Receptor Orthologoue In The Honey Bee (Apis Cerana Cerana)

Apis cerana cerana (Hymenoptera: Apidae) belong to a subspecies of Apis cerana. With possesse a long history of breeding, as a specia species of China, it plays a very important role in the ecology balance keeping of nature. During its long evolutionary process, it has set up a firm relationship of mutural-adaptation with the local vegetable life, and has become a great part of beekeeping occupation in China, because of its characteristics of resistance of heat, cold and varroa, swift-flying, sensitive-smelling and effective use of local forage.The author of this thesis carries out a systematic comparative research into the process of develop of mushroom bodies in the central nervous system, visual and olfactory system, and the presentation of GnRHR orthologoue in its body, based on the techniques of anatomy, immunohistochemistry and in situ hybridization etc. And the author discusses the characteristics of the proliferation and programmed cell death of its brain cells, the pattern of cell divisions and its visual and olfactory system adapt with the social environment during its growing process. Also the author compares the developmental process of Apis cerana cerana with other species, supply a gaps in the fields of developmental biology on the specie, and offers theoretic evidences to the neurobiology, developmental biology, social behaviorism, and the evolution of animals, as well as to the effectively protection and use of this precious resource. The results of investigation are offered as follows:1. The brain structure of Apis cerana cerana were composed of protocerebrum, deutocerebrum, and tritocerebrum. The protocerebrum composed of mushroom bodies,central body complex,lateral protocerebrum and optic lobes. The deutocerebrum composed of olfactory lobes. The tritocerebrum composed of subesophageal ganglion. The result suggest that: (1)A gigantic mushroom body in anterior showed that the honey bee has transcendent capability in learning and memory. (2)The function of the queen bee and drone brain in looking for food, learing, memory and other behavior is inferior to worker bee. (3)The vision system of drone is prominence. 2. The mushroom bodies are paired neuropils in the insect brain that act as multimodal sensory integration centers and are involved in learning and memory. In the Honey bee, the mushroom bodies are created in their entirety by several neuroblasts per hemisphere. Asymmetric divisions that produce a smaller ganglion mother cell (GMC) while regenerating the neuroblast, later, symmetric neuroblast divisions product is two nerve cell. The only indications of the mushroom bodies in the first and second larval instars were two clusters of neuroblasts per hemisphere: medial cluster and lateral cluster. These neuroblasts divide continuously from early embryogenesis until late in the pupal stage. Based on position with respect to the calyx and cell size, Kenyon cells clearly distinguished three subpopulations: inner compact, outer compact and noncompact. Peduncular neuropil was first visible in the third instar. The presence of a a-lobe andβ-lobe in the protocerebral neuropil of late 4 instar larvae. The calycal neuropil rapidly increased in size during the pupal stage. Distinct lip and collar regions were first identifiable on pupal day 3, and the basal ring is distinguishable around during the prepupal stage. The first signs of apoptosis are detected during days 3 of pupal development, when proliferation is still massive. The result suggest that: (1)he neuroblasts that located in the dorsal anterior protocerebrum is stem cells. (2)Development of Kenyon cells of Apis cerana cerana keep to "out-inside" pattern of development. (3)The clear coincidence in time and space of both PCD and the cessation of proliferation supports the hypothesis that MB neuroblasts are eliminated by switching from proliferation to apoptosis.3. We have examined the temporal patterns of neuronal proliferation and cell death during genesis of the OOA and IOA. The medulla and the lamina are generated by distinct populations of neuroblasts in the outer optic anlage; the neuroblasts divide asymmetrically to generate ganglion mother cells. Ganglion mother cells later divide symmetrically to generate immature neurons. Generation of the medulla cortex starts with the onset of the final larval instar, and cell death within the medulla cortex begins after the end of the final larval instar. Generation of the lamina cortex is initiated with the arrival of retinal afferents at the optic lobes, and cell death in the lamina cortex begins 1 day later. Generation of the outer optic ganglia terminates with the abrupt cessation of mitotic activity followed by degeneration of the outer optic anlage. The lobula neurons are generated by neuroblasts in a second structure, the inner optic anlage. The clear coincidence in time and space of both PCD and proliferation. The adult retina is generated from a group of epithelial cells lying within the larval head capsule between the larval ocelli and antenna. Proliferation of these cells begins during the feeding larval stage but accelerates at the end of the final larval instar. Proliferation occurs in one zones of mitotic activity; these zones flank a furrow in the presumptive retinal epithelium. The furrow and flanking mitotic zones migrate from posterior to anterior across the presumptive retinal epithelium. Posterior to the furrow, presumptive retinal cells form clusters and extend axons into the larval optic nerve. The result suggest that: (1)The optic lobes are generated by OOA and IOA. (2)The retina is generated from a morphogenetic furrow. (3)Generation of the lamina cortex is initiated with the arrival of retinal afferents at the optic lobes. (4)the findings on structure and development of the visual system may be seen to argue in favor of a close phylogenetic relationship of insects and crustaceans.4. The adult olfactory lobe of Apis cerana cerana emerges from a precursor, the larval antennal lobe. Some of the interneurons of the adult antennal lobe derive from a lateral neuroblast which starts to divide early in the first larval instar, the multilayered LAL cortex becomes gradually thinner and ultimately forms a unicellular flattened rind in front of the lobe neuropil. Most of its cells move to their adult locations dorsolateral and ventrolateral. The arrival of antennal afferents at the antennal lobe during 3 instar larvae; The glomeruli were first identifiable on pupal day 3; During antennal lobe development, number of apoptosis is a few, subsequently, the number of apoptotic nuclei increased. Apoptotic nuclei disappear during days 4 of pupal development. The result suggest that: (1)The adult olfactory lobe of Apis cerana cerana emerges from a the larval olfactory lobe. (2)The arrival of antennal afferents at the antennal lobe lead to cells differentiation. (3)The olfactory lobes of Apis cerana cerana are sexually dimorphic.5. Glial cells are involved in several functions during the development of the nervous system. In order to understand potential glial contributions to neuropile formation, we examined the cellular pattern of glia during the development of the mushroom body, antennal lobe and central complex in the brain of the honeybee. In the early larva, a continuous layer of glial cell bodies defines the boundaries of all growing neuropiles. Initially, the neuropiles develop in the absence of any intrinsic glial somata. In a secondary process, glial cells migrate into defined locations in the neuropiles. The result suggest that: (1)The combined data from the three brain regions suggest that glial cells can prepattern the neuropilar boundaries and guidance structures for migrating neurons or outgrowing axons. (2)The corresponding increase in the number of neuropile-associated glial cells is most likely due to massive immigrations of glial cells from the cell body rind using neuronal fibres as guidance cues.6. GnRH (gonadotropin-releasing hormone) plays a pivotal role in the regulation of reproduction in vertebrates through interaction with a specific receptor. In situ hybridization showed that GnRHR orthologoue mRNA was expressed in some regions involved in autonomic functions, feeding, memory and movement. GnRHR orthologoue are central components of the reproductive endocrine system, bee-GnRHR staining was specifically localized to the germline, intestine, ovary and testis, suggesting a functional role for bee-GnRHR signaling in the coupling of food intake with reproduction.