Data from: Herbivory-induced volatiles function as defenses increasing fitness of the native plant Nicotiana attenuata in nature

From an herbivore’s first bite, plants release herbivory-induced plant volatiles (HIPVs) which can attract enemies of herbivores. However, other animals and competing plants can intercept HIPVs for their own use, and it remains unclear whether HIPVs serve as an indirect defense by increasing fitness for the emitting plant. In a two-year field study, HIPV-emitting N. attenuata plants produced twice as many buds and flowers as HIPV-silenced plants, but only when native Geocoris spp. predators reduced herbivore loads (by 50%) on HIPV-emitters. In concert with HIPVs, plants also employ antidigestive trypsin protease inhibitors (TPIs), but TPI-producing plants were not fitter than TPI-silenced plants. TPIs weakened a specialist herbivore’s behavioral evasive responses to simulated Geocoris spp. attack, indicating that TPIs function against specialists by enhancing indirect defense.

从植食性昆虫首次取食开始，植物便会释放植食性昆虫诱导植物挥发物（herbivory-induced plant volatiles，HIPVs），这类物质可吸引植食性昆虫的天敌。然而，其他动物以及竞争植物可截获HIPVs以供自身利用，目前仍不清楚HIPVs是否通过提升释放植物的适合度，从而发挥间接防御作用。在一项为期两年的野外研究中，释放HIPVs的野生烟草（Nicotiana attenuata，N. attenuata）植株所产生的芽与花数量，是HIPVs沉默植株的两倍，但该现象仅发生在当本地大眼长蝽属（Geocoris spp.）天敌使HIPVs释放植株上的植食昆虫负载量降低50%的情况下。与HIPVs协同作用的是，植物还会分泌抗消化胰蛋白酶抑制剂（antidigestive trypsin protease inhibitors，TPIs），但产生TPIs的植株并未比TPIs沉默植株拥有更高的适合度。TPIs会削弱专食性植食昆虫对模拟大眼长蝽属天敌攻击的行为逃避反应，这表明TPIs可通过增强间接防御，实现对专食性植食昆虫的防御功能。