简论《诗经》反映的周代自然科学知识

《诗经》是我国最早的一部诗歌总集 ,内容丰富多彩 ,其中所反映的周代丰富的自然科学知识 ,主要表现为 :有关土地整治、农田水利建设及农业耕作技术等方面的农学知识 ;有关天象星宿、天文历法及地文现象等方面的天文学知识 ;有关地震及不同的山川河流、地形地貌等方面的地学知识 ;有关物候现象及时令物候与人们生产生活的密切关系等方面的物候学知识 ;有关庙宇、家室建筑和多种建筑物及其形貌等方面的建筑学知识。从中可以看出《诗经》在我国历史及文学史上的重要地位和价值 ,以及我国古代劳动人民的勤奋、聪慧和才智。     

The phenology and intrinsic quality of wild crucifers that determine the community structure of their herbivorous insects

Summary This report examines the plant traits that effect the community structure of herbivorous insects on wild crucifers. Wild crucifers were classified into 4 types (A, B, C, D) according to their phenology. Type A and B plants had a pausing phenology, disappearing in the middle of the insects' active season, while type C and D plants had a continual phenology, existing all year long. The intrinsic quality of the plants as food, which was assessed by measuring the performance of herbivores, was superior in type A, B and D plants, while it was inferior in type C. The phenology and intrinsic quality were the alternative means of direct defense mechanisms against herbivorous insects: The plants with a pausing phenology were intrinsically superior (A, B), while the plants with a continual phenology were intrinsically inferior (C). However, there were a few plants with continual phenology and superior intrinsic quality (D, the type B plants that remained in the summer). Within the community of the herbivorous insects on the plants with direct defense mechanisms, the number of species and individuals was small and most of the community members were specialists of the plants. On the other hand, within the community on plants without direct defense mechanisms, the number of species was large and the proportion of generalists was high. In addition, the number of individuals was very large on the remaining type B plants, but it was small on type D plants, which were inferred to have indirect defense mechanisms.