Learning can be detrimental for a parasitic wasp: R scripts and Telenomus podisi data

Animals have evolved the capacity to learn, and the conventional view is that learning allows individuals to improve foraging decisions. We describe a first case of maladaptive learning where a parasitoid learns to associate chemical cues from an unsuitable host, thereby re-enforcing a reproductive cul-de-sac (evolutionary trap). Telenomus podisi parasitizes eggs of the exotic stink bug Halyomorpha halys at the same rate as eggs of its coevolved host, Podisus maculiventris, but the parasitoid cannot complete its development in the exotic species. We hypothesized that T. podisi learns to exploit cues from this non-coevolved species, thereby increasing unsuccessful parasitism rates. We conducted bioassays to compare the responses of naïve vs. experienced parasitoids on chemical footprints left by one of the two host species. Both naïve and experienced females showed a higher response to footprints of P. maculiventris than of H. halys. Furthermore, parasitoids that gained an experience on ...动物已演化出学习能力，学界传统观点认为，学习可帮助个体优化觅食决策。我们首次报道了一例拟寄生者（parasitoid）的适应不良学习现象：该类群会将环境化学信号与不适宜寄主建立关联，进而使其陷入生殖死胡同的进化陷阱（evolutionary trap）。本研究中的豆荚短缘腹细蜂（Telenomus podisi），对外来臭蝽（Halyomorpha halys）卵的寄生率与其对协同进化寄主斑腹刺益蝽（Podisus maculiventris）卵的寄生率相当，但该拟寄生者无法在该外来物种体内完成发育。我们提出假说：豆荚短缘腹细蜂会学习利用该非协同进化物种的信号，从而提升无效寄生的发生率。我们开展了生物测定（bioassay）实验，对比未接触过寄主的（naïve）与已获得学习经验的拟寄生者，对两种寄主遗留的化学足迹（chemical footprints）的行为反应。无论是未接触过寄主的还是已获得学习经验的雌性拟寄生者，对斑腹刺益蝽（Podisus maculiventris）化学足迹的反应强度均高于对褐边蝽（Halyomorpha halys）的反应。此外，曾获得过某一寄主物种经历的拟寄生者……