Effects of habitat and body size on mortality rates of Poecilia latipinna
Effects of habitat and body size on mortality rates of Poecilia latipinna
复制标题
栖息地和体型对细孔雀鳀死亡率的影响
DOI：
10.2307/1941470
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发表时间：
1992
期刊：
影响因子：
4.8
通讯作者：
M. Mcmanus
中科院分区：
文献类型：
--
作者：
J. Trexler;J. Travis;M. Mcmanus
我们研究了体型和栖息地对在野外笼中饲养的成年和幼年帆鳍鲷（Poecilia latipinna）死亡率的影响，并排除了捕食者。幼鱼和成鱼的死亡率和大小依赖程度在不同年份和不同季节有所不同。当死亡率依赖于体型时，体型大的个体比体型小的个体死亡率低。在一些实验中，不同栖息地之间的死亡率存在差异，但在其他实验中没有。当冬季条件下存在栖息地影响时，幼鱼和成鱼在咸水栖息地的存活率都高于淡水栖息地。在我们所有的实验中，有些成年猩猩熬过了冬天。生长季节的成虫死亡率虽然较低，但也表现出生境影响的类似模式。幼鱼在生长季节的性成熟期存活率不受生境的影响。秋天出生的鱼比春天或夏天出生的鱼存活到性成熟的可能性要低得多，而且有一个阈值时间，超过这个阈值时间，新生的鱼几乎肯定会在冬天死亡，大概是因为它们无法达到能够承受冬季条件的最小体型。这些实验表明，任何一代molly体型的净选择方向取决于每年的随机事件，如冬季气候的严重性和捕食压力的强度。我们的研究结果说明了自然种群中不同选择性死亡来源的复杂相互作用，并强调了对不同死亡因素进行生态调查的重要性，以预测自然选择的运作。
We examined the effect of body size and habitat on mortality rates ofjuvenile and adult sailfin mollies (Poecilia latipinna) maintained in field cages that excluded pred- ators. Mortality rates and the extent of size dependence varied among years and among seasons within years for juvenile and adult fish. When mortality rates were size dependent, large individuals had lower mortality rates than small ones. Differences between habitats in mortality rates were present in some experiments but not others. When there were habitat effects under winter conditions, both juveniles and adults had higher survival rates in a saltwater habitat than in a freshwater one. Some adults survived through the winter in all of our experiments. Adult mortality during the growing season exhibited a similar pattern of habitat effects although at lower mortality rates. Juvenile survival to sexual maturity in the growing season showed no consistent effects of habitat. Fish born during the autumn had a much lower probability of survival to sexual maturity than those born in spring or summer, and there was a threshold time beyond which newborn fish were virtually assured of perishing over the winter, presumably due to the inability to achieve a minimum body size capable of withstanding winter conditions. These experiments illustrate that the net direction of selection on molly body size in any generation depends on events that are stochastic on a yearly scale, such as the climatic severity of the winter and the intensity of predation pressure. Our results illustrate the complex interplay of different sources of selective mortality that operate in natural pop- ulations, and highlight the importance of ecological investigations of the different agents of mortality for a predictive understanding of the operation of natural selection.
影响因子：
13.6
作者：
Diana H.S. Greene;D. Selivonchick
通讯作者：
Diana H.S. Greene;D. Selivonchick