Futuyma Douglas J, Philippi Thomas E
Department of Ecology and Evolution, State University of New York, Stony Brook, NY, 11794.
Evolution. 1987 Mar;41(2):269-279. doi: 10.1111/j.1558-5646.1987.tb05796.x.
Progeny of uncommon parthenogenetic genotypes of the polyphagous geometric Alsophila pometaria were reared on four host plant species representing the same genus, different confamilial genera, and different families. On the supposition that uncommon asexual genotypes have arisen recently from the sympatric sexual population, they may be viewed as a representation of variation in the sexual population that has been captured by parthenogenesis. In both the laboratory and the field, significant effects of genotype, host, and their interaction were found for survival. Live weight displayed significant effects of genotype, host, and genotype x host interaction in the laboratory, and significant main effects in the field. The broad heritability of live weight within hosts was significantly greater than zero in all cases, ranging from 0.18 to 0.33. Heritability values in the field were similar to those in the laboratory. Genetic correlations between weight attained on pairs of host plants, calculated from uncorrected family means, were all positive and many were statistically significant. When the data were corrected for differences in generalized vigor by taking the deviations from genotype means on a standard host plant, one of nine genetic correlations was significant and positive, and one was significant and negative. Within their limits of precision, these data suggest that genetic factors enhancing performance on one host do not generally have strong antagonistic pleiotropic effects on performance on the other hosts in this population. The relevance of these observations to the evolution of resource specialization in general and host specialization by phytophagous insects in particular is discussed. The common assumption that trade-offs in efficiency of utilization cause the evolution of specialized resource use requires more empirical evidence than seems to exist.
多食性尺蛾（Alsophila pometaria）罕见孤雌生殖基因型的后代在代表同一属、不同同科属以及不同科的四种寄主植物上饲养。假设罕见的无性基因型最近源自同域有性种群，那么它们可被视为已被孤雌生殖捕获的有性种群变异的一种表现形式。在实验室和田间，均发现基因型、寄主及其相互作用对存活率有显著影响。在实验室中，活体重表现出基因型、寄主以及基因型×寄主相互作用的显著影响，在田间则表现出显著的主效应。在所有情况下，寄主内活体重的广义遗传力均显著大于零，范围为0.18至0.33。田间的遗传力值与实验室中的相似。根据未校正的家系均值计算，成对寄主植物上所达到的体重之间的遗传相关性均为正，且许多具有统计学意义。当通过取与标准寄主植物上基因型均值的偏差来校正广义活力差异的数据时，九个遗传相关性中有一个显著为正，一个显著为负。在其精度范围内，这些数据表明，在该种群中，增强在一种寄主上表现的遗传因素通常不会对在其他寄主上的表现产生强烈的拮抗多效性影响。本文讨论了这些观察结果与一般资源专业化进化，特别是植食性昆虫寄主专业化进化的相关性。关于利用效率的权衡导致专门资源利用进化的普遍假设，需要比现有更多的实证证据。
