Department of Zoology, Oregon State University, Corvallis, OR, USA.
J Evol Biol. 2010 Apr;23(4):724-37. doi: 10.1111/j.1420-9101.2010.01938.x. Epub 2010 Feb 9.
Although body size can affect individual fitness, ontogenetic and spatial variation in the ecology of an organism may determine the relative advantages of size and growth. During an 8-year field study in the Bahamas, we examined selective mortality on size and growth throughout the entire reef-associated life phase of a common coral-reef fish, Stegastes partitus (the bicolour damselfish). On average, faster-growing juveniles experienced greater mortality, though as adults, larger individuals had higher survival. Comparing patterns of selection observed at four separate populations revealed that greater population density was associated with stronger selection for larger adult size. Large adults may be favoured because they are superior competitors and less susceptible to gape-limited predators. Laboratory experiments suggested that selective mortality of fast-growing juveniles was likely because of risk-prone foraging behaviour. These patterns suggest that variation in ecological interactions may lead to complex patterns of lifetime selection on body size.
尽管体型大小会影响个体的适应能力，但生物体的个体发育和空间变化可能会决定体型和生长的相对优势。在巴哈马进行的一项为期 8 年的实地研究中，我们研究了一种常见的珊瑚礁鱼类——双色雀鲷（Stegastes partitus）在整个与珊瑚礁相关的生命阶段的体型和生长的选择性死亡。平均而言，生长较快的幼鱼死亡率更高，而成年后，体型较大的个体存活率更高。比较四个不同种群观察到的选择模式表明，种群密度越大，对成年体型较大的选择就越强。体型较大的成年个体可能更有优势，因为它们是更优秀的竞争者，并且不易受到口器限制的捕食者的影响。实验室实验表明，生长迅速的幼鱼的选择性死亡可能是由于冒险觅食行为。这些模式表明，生态相互作用的变化可能导致对体型的终生选择出现复杂的模式。
