Groeters Francis R
Department of Zoology, University of California at Davis, 95616, Davis, CA, USA.
Oecologia. 1993 Mar;93(3):406-411. doi: 10.1007/BF00317885.
The milkweed-oleander aphid, Aphis nerii (Boyer de Fonscolombe) (Homoptera: Aphididae), feeds on different milkweed species in northern California than in Puerto Rico. The hosts vary, primarily between regions, for both identity and quantity of cardenolides that the aphid sequesters for its own defense. In tests for hostassociated fitness trade-offs only one case was found in which host plant and fitness corresponded, but the effect was not significant. However, power to detect fitness trade-offs was limited and the possibility of considerable differences in fitness on a particular host for aphids from different hosts cannot be excluded. On Californian host species, among which migration is common, generalized host use could result from selection for general-purpose genotypes. However, this explanation cannot apply to generalized host use of Californian and Puerto Rican milkweeds because the regions are isolated by distance. A cardenolide sequestration mechanism that is free of substantial energy costs could provide the basis for fitness homeostasis on variable host plants that makes trade-offs unlikely even on hosts from different regions.
马利筋-夹竹桃蚜，即 Nerii 蚜（Boyer de Fonscolombe）（同翅目：蚜科），在加利福尼亚北部和波多黎各取食不同的马利筋物种。寄主因地区而异，主要体现在蚜虫为自我防御而积累的强心甾类的种类和数量上。在关于寄主相关适合度权衡的测试中，仅发现一个寄主植物与适合度相对应的案例，但该效应并不显著。然而，检测适合度权衡的能力有限，且不能排除来自不同寄主的蚜虫在特定寄主上适合度存在显著差异的可能性。在加利福尼亚的寄主物种中，迁徙很常见，通用寄主利用可能是对通用基因型选择的结果。然而，这种解释不适用于加利福尼亚和波多黎各马利筋的通用寄主利用情况，因为这两个地区距离遥远相互隔离。一种无大量能量消耗的强心甾类积累机制可为在可变寄主植物上的适合度稳态提供基础，这使得即使在来自不同地区的寄主上也不太可能出现权衡。
