Nature Communications (Jul 2023)

Rapid expansion and visual specialisation of learning and memory centres in the brains of Heliconiini butterflies

  • Antoine Couto,
  • Fletcher J. Young,
  • Daniele Atzeni,
  • Simon Marty,
  • Lina Melo‐Flórez,
  • Laura Hebberecht,
  • Monica Monllor,
  • Chris Neal,
  • Francesco Cicconardi,
  • W. Owen McMillan,
  • Stephen H. Montgomery

DOI
https://doi.org/10.1038/s41467-023-39618-8
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 11

Abstract

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Abstract Changes in the abundance and diversity of neural cell types, and their connectivity, shape brain composition and provide the substrate for behavioral evolution. Although investment in sensory brain regions is understood to be largely driven by the relative ecological importance of particular sensory modalities, how selective pressures impact the elaboration of integrative brain centers has been more difficult to pinpoint. Here, we provide evidence of extensive, mosaic expansion of an integration brain center among closely related species, which is not explained by changes in sites of primary sensory input. By building new datasets of neural traits among a tribe of diverse Neotropical butterflies, the Heliconiini, we detected several major evolutionary expansions of the mushroom bodies, central brain structures pivotal for insect learning and memory. The genus Heliconius, which exhibits a unique dietary innovation, pollen-feeding, and derived foraging behaviors reliant on spatial memory, shows the most extreme enlargement. This expansion is primarily associated with increased visual processing areas and coincides with increased precision of visual processing, and enhanced long term memory. These results demonstrate that selection for behavioral innovation and enhanced cognitive ability occurred through expansion and localized specialization in integrative brain centers.