The Reproductive Endocrine Rhythm Of City Sparrows And Its Environmental Factors

The the reproductive endocine has a great influence on the avian reproductive behaviors and population dynamic. For most temperate birds, photo period is the key environment factor relates to the initiation and termination of reproductive endocrine, while the extension of day length can act on the hypothalamus-pituitary-gonadal axis (HPG) to stimulate breeding activities and the shortening of day length stimulate hypothalamus to release GnIH to inhibit reproduction. In some habitats with special climatics, the key environment factors affect the reproductive endocrine can be temperature and so on. Factors such as artificial light, temperature, food supply and social signal may result in the difference of bird gonadal development status between city and forest.This research aims to survey the differences of the reproductive endocine of sparrows among various habitat types. The main results were:1. The environment between cities and suburbs has a significant difference that the light at night and temperature in cities are higher than suburbs. There are no significant differences of the weight of sparrows among various habitats.2. The luteinizing hormone increasing and decreasing of the city sparrows were earlier than sparrows living in suburbs; to the city sparrows, the highest luteinizing hormone concentration was lower than suburbs, he highest LH concentration was1.25±0.24ng/ml in Minzu university,1.21±0.09ng/ml in Zhongshan Park,1.47±0.26ng/ml in Beilangzhong,1.29±0.18ng/ml in Zhaoquanying (F=4.24, df=3, P=0.036). Long period of light at night could cause the endocrine of luteinizing hormone earlier,but it could also reduced the its sensitivity to photoperiod thus the highest luteinizing hormone concentration could be lower, and higher temperature in spring could also reduce it. 3. The testosterone increasing and decreasing of the city sparrows were later than sparrows living in suburbs;to the city sparrows, the highest testosterone concentration was lower than suburbs, he highest testosterone concentration was1.93±0.52ng/ml in Minzu university,1.73±0.6ng/ml in Zhongshan Park,2.25±0.67ng/ml in Beilangzhong,2.17±0.02ng/ml in Zhaoquanying,(F=2.59, df=3, P=0.015). The estradiol increasing and decreasing of the city sparrows were later than sparrows living in suburbs;to the city sparrows, the highest estradiol concentration was lower than suburbs, he highest estradiol concentration was0.75±0.14ng/ml in Minzu university,0.69±0.18ng/ml in Zhongshan Park,1.09±0.04ng/ml in Beilangzhong,0.95±0.25ng/ml in Zhaoquanying,(F=2.59, df=3, P=0.015). The time rhythm of luteinizing hormone didn't affect the time rhythm of gonadal hormone, but the secretoryvolume did. The environmental influence to luteinizing hormone could affect endocrine of gonadal hormone.This study will be helpful to understand the influence of urban environment to wild birds.