Rajan Deepa, Mishra Aditi, Sharan Maansi, Gharpure Gauri, Olsson Shannon
Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India.
J Chem Ecol. 2025 Aug 27;51(5):87. doi: 10.1007/s10886-025-01626-x.
Innate behaviours allow solitary animals to complete essential tasks in the absence of social learning. However, we know little about the degree to which ecologically relevant innate preferences can change, and a complete extinction of innate preferences has rarely been shown. The hoverfly Eristalis tenax, a solitary generalist pollinator, is an ideal model for studying innate behaviour in a naturalistic context because its survival depends on the innate ability to identify flowers across many habitats, which could necessitate both learning and unlearning floral objects. Innate behaviour in E. tenax has previously been considered inalterable, but we hypothesised that E. tenax could modulate their innate behaviour after training to a multimodal object derived from chemical and visual cues previously shown to be attractive to hoverflies in field and laboratory assays. To test this, we examined whether E. tenax can extinguish an innate proboscis extension response (PER) to a floral object after undergoing aversive absolute conditioning with quinine, and if flies can acquire PER to an innately unattractive object using sucrose as reinforcement. Finally, we assessed long-term memory retention of these learned behaviours. Here, we report a complete extinction of the PER to an innately attractive floral object following aversive training. Eristalis tenax can also acquire PER to an innately unattractive object after appetitive training. Flies can retain these memories for days after training, and aversive memories last longer than appetitive memories. Ultimately, these findings improve our understanding of how animals integrate innate and learned behaviours to navigate the uncertainties of dynamic objects found in their natural environment.
先天行为使独居动物能够在没有社会学习的情况下完成基本任务。然而，我们对与生态相关的先天偏好能够改变的程度知之甚少，而且很少有研究表明先天偏好会完全消失。食蚜蝇Eristalis tenax是一种独居的广食性传粉者，是在自然环境中研究先天行为的理想模型，因为它的生存依赖于在许多栖息地识别花朵的先天能力，这可能需要学习和忘却花朵目标。此前，人们认为E. tenax的先天行为是不可改变的，但我们推测，在训练到一个由化学和视觉线索组成的多模态目标后，E. tenax可以调节它们的先天行为，此前在野外和实验室试验中已证明这些线索对食蚜蝇有吸引力。为了验证这一点，我们研究了E. tenax在用奎宁进行厌恶绝对条件反射后，是否能够消除对花朵目标的先天伸吻反应（PER），以及苍蝇是否可以使用蔗糖作为强化物，对先天无吸引力的目标获得PER。最后，我们评估了这些习得行为的长期记忆保持情况。在这里，我们报告了在厌恶训练后，对先天有吸引力的花朵目标的PER完全消失。食蚜蝇在进行了偏好训练后，也可以对先天无吸引力的目标获得PER。苍蝇在训练后可以将这些记忆保持数天，而且厌恶记忆比偏好记忆持续的时间更长。最终，这些发现增进了我们对动物如何整合先天和习得行为以应对自然环境中动态物体的不确定性的理解。
