萝卜蚜种群的空间格局及其时序动态

对杭州郊区结球甘蓝和小白菜上萝卜蚜种群的空间格局及其时序动态做了定量分析．两类蔬菜上萝卜蚜种群终年呈聚集分布，但聚集强度变化有明显的季节规律，一年中１１月前后有一个明显的扩散高峰．在一季作物上的聚集强度随时间的变化过程因季节而异，春夏季为高→低→高，夏秋季一直较高。秋冬季又为高→低→高，冬春季从低向高持续上升，最后对萝卜蚜种群空间图式及其时序动态特征的成因，尤其是气温和植株营养条件变化的影响进行了讨论．

Spatial pattern and its time series dynamics in a population of Lipophis erysimi

Systematic samplings of Lipaphis erysimi on crucifer vegetables were carried out dur-ing 1990 1992 in the suburbs of Hangzhou to study its spatial pattern on the crops.The value ofK of negative binomial distribution was chosen to describe the spatial pattern and its time series dy-namics in the aphid population.The results revealed that the population was aggregated throughoutthe year on all crops. However, the intensity of aggregation changed seasonally.Each year,therewas one obvious peak of dispersal around Novernber.The change pattern of aggregation intensitythroughout the growth of a crop differed between seasons.During spring to summer,the populationchanged from highly aggregated to loosely aggregated and then to highly aggregated again.Duringsummer to autumn,the intensity of aggregation always was very high.During autumn to winter,the population changed gradually from highly aggregated to loosely aggregated and then to highlyaggregated again. During winter to spring,the intensity of aggregation increased gradually until theend of the crop.Factors which could be related to the spatial pattern and its dynamics in the aphidpopulation,especially the possible influence of temperature and plant nutrition,were discussed.