Stadler Bernhard
Department of Animal Ecology, University of Bayreuth, P.O. Box 10 12 51, W-8580, Bayreuth, Federal Republic of Germany.
Oecologia. 1992 Aug;91(2):273-280. doi: 10.1007/BF00317796.
Exploiters of short-lived plants have evolved strategies in response to physiological changes that occur during the development of their hosts. The ability to adapt to host quality changes is necessary particularly if the mobility of an animal is poor or risk-constrained. In the plant-aphid system Centaurea jaceae-Uroleucon jaceae, the responses of the aphid to the seasonal changes in its host plant grown in poor and good quality soil were investigated. Coarse- and fine-tuned physiological reactions were observed in discrete aphid generations which were reared on plants grown either in a growth chamber or in a greenhouse. The number of ovarioles and developmental time depended on extrinsic factors (length of photoperiod) not directly related to plant quality. The reproductive investment of the aphids was also independent of their total dry weight. However, within the gonadal system high correlations were found at the embryonic level (e.g. the number of sclerotized embryos or the length of the oldest embryos per ovariole were highly correlated with gonadal dry weight). Aphids which were living on the 4-leaf stage of high-quality host plants showed a significantly higher investment in their gonads than aphids feeding on senescenting hosts. Factor analysis corroborated that aphids reared on poor-quality hosts revealed no grouping of variables measured, whereas those which were reared on high-quality plants showed clustering in respect of somatic (tibia length, dry weight of soma) and gonadal (number of sclerotized and unsclerotized embryos, length of the oldest embryos, ovariole number, gonad dry weight) factors. Three different levels of adaptive response to plant quality are distinguished: individual response to host quality, maternal influences on offspring and response to changes not specific to habitat (photoperiod). These different levels of regulation are thought to enable the aphids to adapt to a host of a given nutritional quality and anticipate deteriorating habitat quality simultaneously. It is concluded that physiological constraints in aphids are only revealed when aphids are exposed to severe nutritional stress for several generations.
一年生植物的寄生者已经进化出应对宿主发育过程中发生的生理变化的策略。适应宿主质量变化的能力尤为必要，特别是当动物的移动性较差或受到风险限制时。在植物 - 蚜虫系统矢车菊 - 菊长管蚜中，研究了蚜虫对生长在质量差和质量好的土壤中的宿主植物季节性变化的反应。在生长室或温室中种植的植物上饲养的不同蚜虫世代中观察到了粗略和精细调节的生理反应。卵巢小管数量和发育时间取决于与植物质量无直接关系的外部因素（光周期长度）。蚜虫的生殖投资也与它们的总干重无关。然而，在性腺系统内，在胚胎水平上发现了高度相关性（例如，硬化胚胎的数量或每个卵巢小管中最老胚胎的长度与性腺干重高度相关）。生活在高质量宿主植物四叶期的蚜虫对性腺的投资明显高于以衰老宿主为食的蚜虫。因子分析证实，在质量差的宿主上饲养的蚜虫所测量的变量没有分组，而在高质量植物上饲养的蚜虫在体细胞（胫节长度、躯体干重）和性腺（硬化和未硬化胚胎的数量、最老胚胎的长度、卵巢小管数量、性腺干重）因素方面表现出聚类。区分了对植物质量的三种不同水平的适应性反应：对宿主质量的个体反应、母体对后代的影响以及对非特定于栖息地的变化（光周期）的反应。这些不同水平的调节被认为使蚜虫能够适应给定营养质量的宿主，并同时预测栖息地质量的恶化。得出的结论是，只有当蚜虫几代都面临严重的营养压力时，其生理限制才会显现出来。
