Tucić Nikola, Stojković Oliver, Gliksman Ivana, Milanović Agana, Šešlija Darka
Institute of Zoology,Faculty of Science, University of Belgrade, Serbia, Yugoslavia.
Department of Evolutionary Biology, Institute for Biological Research, University of Belgrade, Serbia, Yugoslavia.
Evolution. 1997 Dec;51(6):1896-1909. doi: 10.1111/j.1558-5646.1997.tb05112.x.
Four types of laboratory populations of the bean weevil (Acanthoscelides obtectus) have been developed to study the effects of density-dependent and age-specific selection. These populations have been selected at high (K) and low larval densities (r) as well as for reproduction early (Y) and late (O) in life. The results presented here suggest that the r- and K-populations (density-dependent selection regimes) have differentiated from each other with respect to the following life-history traits: egg-to-adult viability at high larval density (K > r), preadult developmental time (r > K), body weight (r > K), late fecundity (K > r), total realized fecundity (r > K), and longevity of males (r > K). It was also found that the following traits responded in statistically significant manner in populations subjected to different age-specific selection regimes: egg-to-adult viability (O > Y), body weight (O > Y), early fecundity (Y > O), late fecundity (O > Y), and longevity of females and males (O > Y). Although several life-history traits (viability, body weight, late fecundity) responded in similar manner to both density-dependent and age-specific selection regimes, it appears that underlying genetic and physiological mechanisms responsible for differentiation of the r/K and Y/O populations are different. We have also tested quantitative genetic basis of the bean weevil life-history traits in the populations experiencing density-dependent and age-specific selection. Among the traits traded-off within age-specific selection regimes, only early fecundity showed directional dominance, whereas late fecundity and longevity data indicated additive inheritance. In contrast to age-specific selecton regimes, three life-history traits (developmental time, body size, total fecundity) in the density-sependent regimes exhibited significant dominance effects. Lastly, we have tested the congruence between short-term and long-term effects of larval densities. The comparisons of the outcomes of the r/K selection regimes and those obtained from the low- and high-larval densities revealed that there is no congruence between the selection results and phenotypic plasticity for the analyzed life-history traits in the bean weevil.
已培育出四种菜豆象（Acanthoscelides obtectus）实验室种群，用于研究密度依赖型和年龄特异性选择的影响。这些种群在高（K）和低幼虫密度（r）下进行选择，同时也在生命早期（Y）和晚期（O）进行繁殖选择。此处呈现的结果表明，r种群和K种群（密度依赖型选择模式）在以下生活史特征方面彼此分化：高幼虫密度下的卵到成虫存活率（K > r）、成虫前发育时间（r > K）、体重（r > K）、后期繁殖力（K > r）、总实际繁殖力（r > K）以及雄性寿命（r > K）。还发现，在经历不同年龄特异性选择模式的种群中，以下特征有统计学上的显著反应：卵到成虫存活率（O > Y）、体重（O > Y）、早期繁殖力（Y > O）、后期繁殖力（O > Y）以及雌性和雄性寿命（O > Y）。尽管几个生活史特征（存活率、体重、后期繁殖力）对密度依赖型和年龄特异性选择模式的反应相似，但似乎导致r/K和Y/O种群分化的潜在遗传和生理机制不同。我们还测试了经历密度依赖型和年龄特异性选择的种群中菜豆象生活史特征的数量遗传基础。在年龄特异性选择模式下权衡的特征中，只有早期繁殖力表现出定向显性，而后期繁殖力和寿命数据表明是加性遗传。与年龄特异性选择模式相反，密度依赖型模式下的三个生活史特征（发育时间、体型、总繁殖力）表现出显著的显性效应。最后，我们测试了幼虫密度短期和长期影响之间的一致性。r/K选择模式的结果与低幼虫密度和高幼虫密度下获得的结果比较表明，菜豆象分析的生活史特征的选择结果和表型可塑性之间不存在一致性。
