Courtship behavior induced by appetitive olfactory memory

Abstract

Reinforcement signals such as food reward and noxious punishment can change diverse behaviors. This holds true in fruit flies, Drosophila melanogaster, which can be conditioned by an odor and sugar reward or electric shock punishment. Despite a wide variety of behavior modulated by learning, conditioned responses have been traditionally measured by altered odor preference in a choice, and other memory-guided behaviors have been only scarcely investigated. Here, we analyzed detailed conditioned odor responses of flies after sugar associative learning by employing a video recording and semi-automated processing pipeline. Trajectory analyses revealed that multiple behavioral components were altered along with conditioned approach to the rewarded odor. Notably, we found that lateral wing extension, a hallmark of courtship behavior of D. melanogaster, was robustly increased specifically in the presence of the rewarded odor. Strikingly, genetic disruption of the mushroom body output did not impair conditioned courtship increase, while markedly weakening conditioned odor approach. Our results highlight the complexity of conditioned responses and their distinct regulatory mechanisms that may underlie coordinated yet complex memory-guided behaviors in flies.

Keywords:

• Learning and memory
• appetitive memory
• conditioned behavior
• courtship
• Drosophila

Acknowledgments

We deeply appreciate Dr Daisuke Yamamoto (Tohoku University, now at NICT Akashi, Japan) for supporting the launch of our lab at Tohoku University, and sharing lab equipment with us. This study would not have been achieved without the support. We also thank Dr Masayuki Koganezawa (Tohoku University) for comments on the article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by MEXT/JSPS KAKENHI [17H04765 to NY; 17H01378, 16H01496 and 17H0554 to HT], Naito Foundation (HT) and Uehara Memorial Foundation (HT).