Romanovskiĭ Iu E
Department of General Ecology, M.V. Lomonosov Moscow State University, Moscow 119899, Russia.
Zh Obshch Biol. 2001 Jan-Feb;62(1):25-33.
Although the life history evolution of small- and large-bodied mammals seems to be governed by different factors, the both shows relative neonate size and juvenile survival to be slightly dependent on body mass. I propose a hypothesis that natural selection simultaneously maximizes a time to maturity (minimizes somatic growth rate) and a number of newborn survived to reproduction. In this case optimal juvenile survival of large-bodied mammals must be close to e-beta and that of small-bodied approximately e-(1 + beta), where beta is the slope of the regression of log annual fecundity on log annual juvenile mortality. Analysis of vital characters for 71 mammal species revealed the slope to be close to unity. As a result frequency distribution of log juvenile survival shows bimodality which coincides well with predicted optimal survival for large- and small-bodies species. It is shown that the relative neonate size can be directly proportional to the juvenile survival and inversely proportional to the lifetime offspring production irrespective of mortality factors.
尽管小型和大型哺乳动物的生活史进化似乎受不同因素支配，但两者都显示出相对新生儿大小和幼体存活率与体重略有相关。我提出一个假说，即自然选择同时使成熟时间（使体细胞生长速率最小化）和存活至繁殖的新生个体数量最大化。在这种情况下，大型哺乳动物的最佳幼体存活率必须接近e-β，而小型哺乳动物的最佳幼体存活率约为e-(1 + β)，其中β是年生育力对数对年幼体死亡率对数回归的斜率。对71种哺乳动物生命特征的分析表明，该斜率接近1。结果，幼体存活率对数的频率分布呈现双峰性，这与大型和小型物种预测的最佳存活率非常吻合。研究表明，无论死亡率因素如何，相对新生儿大小都可能与幼体存活率成正比，与终生后代产量成反比。
