caa a22 4500 469098074 CHVBK 20180323133037.0 cr unu---uuuuu 170328e19920801xx s 000 0 eng 10.1007/BF00317796 doi (NATIONALLICENCE)springer-10.1007/BF00317796 Stadler Bernhard Department of Animal Ecology, University of Bayreuth, P.O. Box 10 12 51, W-8580, Bayreuth, Federal Republic of Germany aut Physiological responses of Uroleucon jaceae (L.) to seasonal changes in the quality of its host plant Centaurea jacea L.: multilevel control of adaptations to the life cycle of the host [Elektronische Daten] [Bernhard Stadler] Summary: 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. Springer-Verlag, 1992 Uroleucon jaceae nationallicence Aphids nationallicence Plant quality nationallicence Host adaptation nationallicence Reproductive investment nationallicence Oecologia Springer-Verlag 91/2(1992-08-01), 273-280 0029-8549 91:2<273 1992 91 442 https://doi.org/10.1007/BF00317796 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00317796 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Stadler Bernhard Department of Animal Ecology, University of Bayreuth, P.O. Box 10 12 51, W-8580, Bayreuth, Federal Republic of Germany aut NATIONALLICENCE 773 0- Oecologia Springer-Verlag 91/2(1992-08-01), 273-280 0029-8549 91:2<273 1992 91 442 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer