Heisenberg M, Heusipp M, Wanke C
Theodor-Boveri-Institut für Biowissenschaften (Biozentrum), Lehrstuhl für Genetik, Würzburg, Germany.
J Neurosci. 1995 Mar;15(3 Pt 1):1951-60. doi: 10.1523/JNEUROSCI.15-03-01951.1995.
The Drosophila brain is highly variable in size. Female flies grown in densely populated larval cultures have up to 20% more Kenyon cell fibers in their mushroom bodies than flies from low-density cultures. These differences in the number of Kenyon cell fibers are accompanied by differences in the volume of the calyx. During imaginal life, volume changes are observed in the calyces, all parts of the optic lobes, the central brain, and central complex. They occur not only in the first week of adulthood but also between days 8 and 16. Factors causing these changes are little understood. In flies kept in pairs for 1 week, the size of the calyx but not of the lobula is influenced by the sex of the partner. Females have larger calyces if the partner is female than if it is male. Males seem to be affected in the same way. Females living solitarily in little food vials for the first week of their imaginal life have smaller lobulae than females having spent the week in a populated flight cage. Males and females of heterosexual groups of 40 animals have still smaller lobulae, medullae, and calyces than their siblings kept in isolation. In addition, brain size is influenced by yet unidentified factors causing long and short trends. The data suggest that in Drosophila, most neuropil regions of the brain are continuously reorganized throughout life in response to specific living conditions.
果蝇的大脑大小差异很大。在高密度幼虫培养环境中生长的雌性果蝇，其蘑菇体中的肯扬细胞纤维比低密度培养环境中的果蝇多20%。肯扬细胞纤维数量的这些差异伴随着萼体积的差异。在成虫期，萼、视叶的所有部分、中枢脑和中央复合体都会出现体积变化。这些变化不仅发生在成年后的第一周，也发生在第8天至第16天之间。导致这些变化的因素鲜为人知。成对饲养1周的果蝇中，萼的大小受伴侣性别的影响，但小叶不受影响。如果伴侣是雌性，雌性果蝇的萼比伴侣是雄性时更大。雄性果蝇似乎也受到同样的影响。在成虫期第一周单独生活在小食物瓶中的雌性果蝇，其小叶比在群居飞行笼中度过这一周的雌性果蝇更小。40只动物组成的异性群体中的雄性和雌性果蝇，其小叶、髓质和萼比单独饲养的同胞果蝇还要小。此外，大脑大小还受到尚未确定的导致长期和短期趋势的因素的影响。数据表明，在果蝇中，大脑的大多数神经纤维网区域在整个生命过程中会根据特定的生活条件持续重组。
