Transition from a random to an ideal free to an ideal despotic distribution: the effect of individual difference in growth
Transition from a random to an ideal free to an ideal despotic distribution: the effect of individual difference in growth
复制标题
从随机到理想自由再到理想专制分布的转变：个体差异对增长的影响
DOI：
10.1007/s101640170009
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发表时间：
2001
影响因子：
0.9
通讯作者：
K. Iguchi
中科院分区：
文献类型：
--
作者：
H. Hakoyama;K. Iguchi
个体生长差异可能导致食品竞争的垄断形式。我们在实验室研究了克隆鲑鱼Oncorhynchus Masou ishikwae食物块之间竞争模式和个体分布的长期转换。这一转变伴随着生长补偿，即由于个体生长速度的差异，个体之间的大小差异随着时间的推移而增加。120厘米的实验水箱被分成两个隔间(补丁)，其间放置了不透明的隔板。鱼能够在斑块之间自由移动，因此能够使用长期记忆来评估斑块的质量，但它们不能直接看到另一块斑块中的食物输入。在4周的时间里，观察了两个食物块之间的分布，摄食量，以及4组6只个体的生长和竞争行为。我们发现：(1)群体内体重的变异随着时间的推移而增加；(2)平均而言，使用较好斑块的个体比随机分布的个体多，但比理想自由分布预测的个体少；(3)在为期4周的实验期间，鱼类资源利用的分布和模式从随机分布到理想自由分布再到理想专制分布。我们认为，增长去补偿导致竞争对手的空间分布和资源利用模式的长期变化。
Individual differences in growth can lead to a monopolistic form of food competition. We studied the long-term transition in the mode of competition and the distribution of individuals between food patches of the cloned salmonid fish,Oncorhynchus masou ishikawae, in the laboratory. This transition was accompanied by growth depensation, i.e., the increase over time in the variance of size between individuals resulting from the differences in individual growth rates. The 120-cm experimental tanks were divided into two compartments (patches) between which an opaque partition was placed. Fish were able to move freely between the patches and therefore were able to assess the patch quality using long-term memory, but they were not able to see the food input in the other patch directly. The distribution between the two food patches, the amount of food gained, and the growth and the agonistic behavior of four groups of six individuals were observed over 4 weeks. We found that (1) within-group variation in body weight increased with time; (2) on average, the better patch was used by more individuals than predicted by a random distribution but fewer individuals than predicted by an ideal free distribution, and (3) the distribution and pattern of resource use by the fish changed over the 4-week experimental period from a random distribution to an ideal free distribution and finally to an ideal despotic distribution. We suggest that growth depensation causes the long-term change in the spatial distribution and pattern of resource use by competitors.