Structure and Succession in a Beetle Community Inhabiting Cow Dung
Structure and Succession in a Beetle Community Inhabiting Cow Dung
复制标题
牛粪中甲虫群落的结构和演替
作者：
H. Koskela;I. Hanski
材料包括62 500个个体的179甲虫物种收集在整个演替过程中（30天）暴露在三个大的栖息地（现场，松树和云杉林）在夏季的三个月（6月，7月和8月）的粪便。将采集的标本分为食粪类（50种）和食肉类（129种），并给出了所有标本的体长和干重的平均值。食粪动物被指定为微生境和食物专家，食肉动物被指定为微生境通才。对于食粪动物来说，物种最丰富的大型栖息地是田野，而对于食肉动物来说，则是松树林。可能的原因是合适的小生境的分布，以及大生境的小气候和结构。对于平均值每下降在继承的第一个10天，食肉动物（16种和191个人）数量超过食粪动物（11和126，分别），但在总生物量的情况是相反的（129和443毫克重，分别）。在物种和个体的数量，个体粪便之间的多样性的变化有一个最小的约第2至第7天的汇总数据，包括那些大生境和季节梯度。据推测，这反映了演替速度的下降和天气的影响，因为粪便的表面干燥成坚硬的覆盖物。食粪动物体现了一个典型的异养演替：在一个短暂的高峰（物种，个体和多样性）的第二天从一开始，有一个激进的减少。在食肉动物的高峰是广泛的，并发生在第3和第8天，可能是因为猎物（主要是双翅目卵和幼虫）的食肉动物没有减少在第1周的演替。群落的结构和演替在很大程度上取决于非生物因素，特别是气候条件。
The material included 62 500 individuals of 179 beetle species collected during the whole course of succession (30 days) from droppings exposed in three macro habitats (field, pine and spruce forest) in three summer months (June, July and August). The collection was divided into coprophages (50 species) and carnivores (129 species), and mean values are given for the lengths and dry weights of all species found. The trophic status of dung-inhabiting beetles is briefly discussed. Coprophages are designated as microhabitat and food specialists, and carni vores as microhabitat generalists. For coprophages the macrohabitat richest in species was the field, and for carnivores the pine forest. Probable reasons are the distribution of suitable microhabitats, and the microclimate and structure of the macrohabitat. For average values per dropping during the first 10 days of succession, carnivores (with 16 species and 191 individuals) outnumbered coprophages (with 11 and 126, respectively) but in total biomass the situation was the opposite (129 and 443 mg weight, respectively). Variation in the numbers of species and individuals, and diversity among individual droppings had a minimum from about the 2nd to the 7th day in the pooled data, including those for the macrohabitat and seasonal gradients. Presumably this reflected a decreased rate of succession and decreased influence of the weather as the surface of the dung dried into a hard cover. Coprophages exemplified a typical heterotrophic succession: after a brief peak (in species, individuals, and diversity) on the 2nd day from the beginning, there was a radical decrease. In the carnivores the peak was broader, and occurred between the 3rd and 8th days, probably because the prey (mainly dipterous eggs and larvae) available to the carnivores does not decrease during the 1st week of the succession. The structure of the community and the succession depended largely on abiotic factors, especially on weather conditions.