One of the main obstacles of classical biological control is that biological control organisms cannot be recalled once they are released in nature. It is particularly true for the flowerhead weevil, Rhinocyllus conicus Frölich, which was released as a biological control organism for the invasive musk thistle, Carduus nutans L. (MT). While weevils successfully suppressed introduced populations of musk thistles and other invasive thistle species, non-target attacks have been reported on multiple native thistles including federally listed threatened and endangered (T&E) thistle species. To investigate the foraging behavior of female weevils on invasive and native thistles, we examined volatile organic compounds (VOCs) emitted from MT and a T&E plant species, Sacramento Mountains thistle, Cirsium vinaceum Wooton & Standley (SMT) in the Lincoln National Forest, New Mexico. We used a dynamic headspace volatile collection system and gas chromatography-mass spectrometry to compare volatile profiles between MT and SMT. Female weevils reacted to 7 electrophysiologically active chemical compounds in the blends based on gas chromatography-electroantennography. The behavioral response of female weevils was indifferent when VOCs from both thistles were offered in y-tube olfactometry experiments. Yet, they preferred VOCs collected from MT to purified air. The searching time of female weevils was longer to VOCs collected from SMT over controls. Investigating signals during the initial host recognition of released biological control organisms may open new opportunities to reduce non-target attacks on T&E plant species.

经典生物防治的主要障碍之一是一旦生物防治生物在自然界释放后便无法召回。花头象鼻虫Rhinocyllus conicusFrölich尤其如此，它作为入侵性麝香蓟（Carduus nutans）的生物防治生物被释放。L.（MT）。尽管象鼻虫成功地抑制了麝香蓟类和其他入侵蓟类物种的外来种群，但据报道，对多种本土蓟类进行了非目标攻击，包括联邦政府列出的濒危和濒危（T＆E）蓟类物种。为了调查雌性象鼻虫对入侵和天然蓟马的觅食行为，我们研究了从MT和T＆E植物物种，萨克拉曼多山蓟，西西里斯油菜（Cirsium v​​inaceum）排放的挥发性有机化合物（VOC）。Wooton＆Standley（SMT）位于新墨西哥州林肯国家森林。我们使用动态顶空挥发物收集系统和气相色谱-质谱法比较了MT和SMT之间的挥发物分布。根据气相色谱-电血管造影，雌性象鼻虫对共混物中的7种电生理活性化合物起反应。当在y型管嗅觉测量实验中提供两种蓟的VOC时，雌性象鼻虫的行为反应都不会改变。但是，他们更喜欢从MT收集的VOC而不是纯净的空气。雌性象鼻虫的搜寻时间比从SMT收集到的VOC更长。在最初宿主识别释放的生物控制生物期间调查信号可能为减少对T＆E植物物种的非目标攻击提供新的机会。