Plant breeding has improved traits such as fruit flavor and yield but may have compromised direct and indirect defenses to herbivores compared to their wild ancestors. This has been termed the plant domestication-reduced defense hypothesis. We present evidence that domestication of Capsicum annuum (the chili pepper) from its wild progenitor, Capsicum annuum var. glabriusculum, has not affected resistance to the insect herbivore, Manduca sexta (the tobacco hornworm). Caterpillars performed equally well on the domesticated and wild pepper. Subsequent behavioral choice assays with one of the main natural enemies of M. sexta, the parasitoid wasp Cotesia congregata, showed that parasitoids preferentially chose herbivore-damaged domesticated pepper plants over their wild relative. To investigate this tri-trophic interaction further, we then assessed the efficiency of C. congregata to parasitize M. sexta on numerous wild pepper accessions and domesticated pepper cultivars in a large foraging enclosure. We found that herbivores feeding on domesticated plants were parasitized at more than twice the rate of those on wild genotypes. These results imply that pepper domestication has not changed resistance to herbivorous insects (i.e., leaf palatability as a direct defense), but rather has improved volatile attraction to recruit natural enemies.

植物育种改善了果实的风味和产量，但与野生祖先相比，可能损害了对草食动物的直接和间接防御。这被称为植物驯化降低防御假设。我们目前的证据表明，驯化辣椒从它的野生祖先，（将辣椒）辣椒变种。glabriusculum，没有影响对昆虫食草动物，Manduca sexta（烟草天蛾）的抗性。毛毛虫在驯化和野生胡椒上的表现同样出色。随后的行为选择测定法，是M. sexta的主要天敌之一，寄生寄生的黄蜂Cotesia congregata，表明寄生虫比野生近缘种更优先选择受草食动物危害的驯化辣椒植物。为了进一步研究这种三营养交互作用，我们然后评估了在大量觅食圈中大量聚集的野生胡椒和驯化的胡椒品种上的C. congregata寄生化M. sexta的效率。我们发现以家养植物为食的草食动物被寄生的可能性是野生基因型的两倍。这些结果表明，胡椒驯化并没有改变对草食性昆虫的抗性（即，叶适口性作为直接防御），而是改善了挥发性吸引以招募天敌。