Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
Institute of Biology, Freie Universität Berlin, Berlin, Germany.
Sci Rep. 2017 Aug 4;7(1):7316. doi: 10.1038/s41598-017-06704-z.
Plants employ various defences killing the insect attacker in an early stage. Oviposition by cabbage white butterflies (Pieris spp.) on brassicaceous plants, including Brassica nigra, induces a hypersensitive response (HR) - like leaf necrosis promoting desiccation of eggs. To gain a deeper insight into the arms race between butterflies and plants, we conducted field and greenhouse experiments using different B. nigra genotypes. We investigated variation in HR and consequent survival of P. brassicae egg clusters. Impact of egg density, distribution type and humidity on HR formation and egg survival was tested. HR differed among plant genotypes as well as plant individuals. Egg density per plant did not affect HR formation. Remarkably, egg survival did not depend on the formation of HR, unless butterflies were forced to lay single eggs. Larval hatching success from single eggs was lower on plants expressing HR. This may be due to increased vulnerability of single eggs to low humidity conditions at necrotic leaf sites. We conclude that effectiveness of HR-like necrosis in B. nigra varies with plant genotype, plant individual and the type of egg laying behaviour (singly or clustered). By clustering eggs, cabbage white butterflies can escape the egg-killing, direct plant defence trait.
植物采用各种防御机制，在早期杀死昆虫攻击者。甘蓝夜蛾（Pieris spp.）在十字花科植物（包括黑芥）上产卵，会引发类似于过敏反应（HR）的叶片坏死，促进卵的干燥。为了更深入地了解蝴蝶和植物之间的军备竞赛，我们使用不同的黑芥基因型进行了田间和温室实验。我们研究了 HR 及其对甘蓝夜蛾卵群存活率的影响。我们还测试了卵密度、分布类型和湿度对 HR 形成和卵存活的影响。植物基因型和个体之间存在 HR 差异。每个植物上的卵密度并不影响 HR 的形成。值得注意的是，除非蝴蝶被迫产下单个卵，否则卵的存活率并不取决于 HR 的形成。从单个卵中孵化的幼虫成功率在表达 HR 的植物上较低。这可能是由于在坏死叶片部位，单个卵对低湿度条件的脆弱性增加所致。我们的结论是，黑芥中类似过敏反应的坏死有效性因植物基因型、个体和产卵行为类型（单独或成群）而异。通过将卵成群产卵，甘蓝夜蛾可以逃避卵杀直接的植物防御特性。
