Balog Adalbert
School of Forestry and Environmental Studies, Yale University, 370 Prospect Street, New Haven, CT, USA.
Bull Entomol Res. 2013 Oct;103(5):578-83. doi: 10.1017/S0007485313000217. Epub 2013 Apr 22.
The interplay between the host plant of an insect herbivore and an insect predator (here two-spot ladybird beetles; Adalia bipunctata (L).; Coleoptera: Coccinellidae), feeding upon such a herbivore was examined in the laboratory as factors possibly determining the differential abundance and success of green and red host races of pea aphid, Acyrthosiphon pisum Harris. The experiment comprised three treatments: two host plants (bean and clover), two treatment levels (control and predation) and three colour morph levels (green alone, red alone and green and red in mixture). Green morphs had higher fitness on the general host plant, bean Vicia faba, than on the derived host, clover (Trifolium pratense), in the absence of predation. Although green morph fitness was reduced by predation when infesting bean together with reds, there was no observable net fitness loss due to predation on clover in mixed colonies with red morphs. Red morphs exhibited fitness loss alone on both bean and clover, while clover plants seemingly prevented fitness loss in the presence of predation when red morphs were mixed with green ones. According to this scenario, when colour morphs existed as a mixed colony, the net fitness of either pea aphid morph was not influenced by predation on clover. Predators had significant effects only on red morphs on broad bean either when alone or were mixed together with green morphs. Thus, only red morphs experienced the benefits of switching from the general to the derived host red clover in the presence of predation. For green morphs, there was no apparent cost of switching host plants when they faced predation. Hence, the co-existence of green-red colour polymorphism of pea aphids on single host plants appears to be maintained by the morph gaining fitness on the derived host due to a host plant– and predation–reduction effect. These findings have important implications for understanding the ecology and evolution of host switching by different colour-plant host adapted races of pea aphids
在实验室中研究了植食性昆虫的寄主植物与以该植食性昆虫为食的捕食性昆虫（这里是二斑瓢虫；Adalia bipunctata (L).；鞘翅目：瓢虫科）之间的相互作用，这些因素可能决定了豌豆蚜（Acyrthosiphon pisum Harris）绿色和红色寄主型的不同丰度和生存情况。实验包括三种处理：两种寄主植物（豆类和三叶草）、两个处理水平（对照和捕食）以及三个体色形态水平（仅绿色、仅红色和绿色与红色混合）。在没有捕食的情况下，绿色形态在一般寄主植物蚕豆（Vicia faba）上的适合度高于在衍生寄主三叶草（Trifolium pratense）上的适合度。虽然绿色形态在与红色形态一起侵染豆类时因捕食而适合度降低，但在与红色形态混合的群体中，在三叶草上因捕食并未观察到明显的净适合度损失。红色形态在豆类和三叶草上单独存在时适合度都会降低，而当红色形态与绿色形态混合时，三叶草植物似乎能防止其在有捕食情况下适合度降低。根据这种情况，当体色形态以混合群体存在时，豌豆蚜任何一种体色形态的净适合度都不受在三叶草上捕食的影响。捕食者仅对蚕豆上单独的红色形态或与绿色形态混合时的红色形态有显著影响。因此，只有红色形态在有捕食的情况下体验到了从一般寄主转换到衍生寄主红三叶草的益处。对于绿色形态来说，当它们面临捕食时，转换寄主植物没有明显代价。因此，豌豆蚜在单一寄主植物上绿色 - 红色体色多态性的共存似乎是由于一种体色形态在衍生寄主上因寄主植物和捕食减少效应而获得适合度得以维持。这些发现对于理解不同颜色植物寄主适应型豌豆蚜寄主转换的生态学和进化具有重要意义。
