Extinction of innate floral preferences in the pollinator Eristalis tenax

Abstract

Innate behaviors 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. The hoverfly Eristalis tenax, a solitary generalist pollinator, is an ideal model for studying innate behavior in a naturalistic context because its survival depends on the innate ability to identify flowers. Innate behavior in E. tenax has previously been considered inalterable, but we hypothesized that E. tenax can modulate their innate behavior after training in a multimodal sensory context, in contrast to the prior work that employed unimodal sensory cues. To test this, we examined if E. tenax can extinguish an innate proboscis extension response (PER) to a multimodal floral object after undergoing aversive 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. Here, we report a complete extinction of the proboscis extension response (PER) to an innately attractive floral object following aversive training. E. 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. Our results contrast with literature stating that innate preferences cannot be extinguished in E. tenax. This could be because our study uses multimodal objects instead of the unimodal stimuli used in previous work. Ultimately, these findings improve our understanding of how animals navigate the uncertainties of dynamic objects in the natural world.