Enhanced long-term memory and increased mushroom body plasticity in Heliconius butterflies

Fletcher J Young, Amaia Alcalde Antón, Lina Melo-Flórez, Antoine Couto, Jessica R Foley, Monica Monllor, W. Owen McMillan, Stephen H Montgomery

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Heliconius butterflies exhibit expanded mushroom bodies, a key brain region for learning and memory in insects, and a novel foraging strategy unique among Lepidoptera – traplining for pollen. We tested visual long-term memory across six Heliconius and outgroup Heliconiini species. Heliconius species exhibited greater fidelity to learned colours after eight days without reinforcement, with further evidence of recall at 13 days. We also measured the plastic response of the mushroom body calyces over this time period, finding substantial post-eclosion expansion and synaptic pruning in the calyx of Heliconius erato, but not in the outgroup Heliconiini Dryas iulia. In Heliconius erato, visual associative learning experience specifically was associated with a greater retention of synapses and recall accuracy was positively correlated with synapse number. These results suggest that increases in the size of specific brain regions and changes in their plastic response to experience may coevolve to support novel behaviours.
Original languageEnglish
Article number108949
JournaliScience
Volume27
Issue number2
DOIs
Publication statusPublished - 18 Jan 2024

Bibliographical note

Funding Information:
We thank the Ministerio del Ambiente, Panama, and the science support, administrative, and facilities staff at the Smithsonian Tropical Research Institute in Panama for making this research possible. In particular, we thank Oscar Paneso and Cruz Batista for help in butterfly stock and host plant care. We also gratefully acknowledge the Wolfson Bioimaging Facility for their support and assistance in this work. This work was supported by a NERC Independent Research Fellowship ( NE/N014936/1 ) and an ERC Starter Grant ( 758508 ) to SHM, and a PhD Studentship from Trinity College, Cambridge to FJY.

Funding Information:
We thank the Ministerio del Ambiente, Panama, and the science support, administrative, and facilities staff at the Smithsonian Tropical Research Institute in Panama for making this research possible. In particular, we thank Oscar Paneso and Cruz Batista for help in butterfly stock and host plant care. We also gratefully acknowledge the Wolfson Bioimaging Facility for their support and assistance in this work. This work was supported by a NERC Independent Research Fellowship (NE/N014936/1) and an ERC Starter Grant (758508) to SHM, and a PhD Studentship from Trinity College, Cambridge to FJY. Conceptualization: S.H.M. Methodology: F.J.Y. A.A. A.C. and S.H.M. Investigation: F.J.Y. A.A. L.M.F. J.F. and M.M. Formal analysis: F.J.Y. Resources: W.O.M. and S.H.M. Visualization: F.J.Y. Supervision: W.O.M. and S.H.M. Funding acquisition: S.H.M. Writing – original draft: F.J.Y. and S.H.M. Writing – review and editing: All authors. The authors declare no competing interest.

Publisher Copyright:
© 2024 The Authors

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