Shifting balances in the weighting of sensory modalities are predicted by divergence in brain morphology in incipient species of Heliconius butterflies

Denise Dell'Aglio*, Owen McMillan, Stephen H Montgomery

*Corresponding author for this work

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

8 Citations (Scopus)
111 Downloads (Pure)

Abstract

Integrating and weighting sensory perception across modalities is crucial to how animals adapt to their environment. Divergence in brain structure is often in sensory processing regions, suggesting investment reflects the needs of species specific ecologies. Here, we use two parapatric, closely related species, Heliconius erato cyrbia and H. himera, to test the hypothesis that divergence in sensory brain regions affects foraging decisions. These butterflies are isolated across an ecological gradient, which is linked to differences in brain morphology, with H. e. cyrbia investing more in visual centres, and H. himera investing in olfactory centres. Here, we demonstrate that these two species vary in how they associate visual and olfactory cues with positive food rewards. We show that when individuals are trained on paired olfactory and visual stimuli, and are then presented with these stimuli in conflict, they show distinct behavioural responses. H. himera is more likely to favour positive olfactory cues than H. e. cyrbia, which favours visual cues regardless of the paired stimulus. This suggests that these species have diverged in the emphasis placed on these different sensory domains during foraging, in a way which is consistent with observed differences in brain morphology. This result strengthens evidence that speciation initiated by local adaptation is partly facilitated by changes in the neural basis of key behavioural functions.
Original languageEnglish
Pages (from-to)83-90
Number of pages8
JournalAnimal Behaviour
Volume185
Early online date4 Feb 2022
DOIs
Publication statusPublished - 1 Mar 2022

Bibliographical note

Funding Information:
We are very grateful to anonymous referees for manuscript feedback. We thank the Butterfly Ecology and Evolution Research (BEER) and Oscar Paneso for assistance in the insectaries. We also thank the Smithsonian Tropical Research Institute for support in Panama and Richard Merril for thoughtful discussions at the onset of this work. This work was carried out under permission from Ministerio del Ambiente, Panama (permit SE/A-82-19) and Instituto Nacional de Biodiversidad, Ecuador (permit MAE-DNB-CM-2016-0045). This research was supported by a Smithsonian Institution Postdoctoral Fellowship to D.D.D. and a Natural Environment Research Council (NERC) Independent Research Fellowship (IRF) ( NE/N014936/1 ) and a European Research Council (ERC) Starter Grant ( 758508 ) to S.H.M.

Funding Information:
We are very grateful to anonymous referees for manuscript feedback. We thank the Butterfly Ecology and Evolution Research (BEER) and Oscar Paneso for assistance in the insectaries. We also thank the Smithsonian Tropical Research Institute for support in Panama and Richard Merril for thoughtful discussions at the onset of this work. This work was carried out under permission from Ministerio del Ambiente, Panama (permit SE/A-82-19) and Instituto Nacional de Biodiversidad, Ecuador (permit MAE-DNB-CM-2016-0045). This research was supported by a Smithsonian Institution Postdoctoral Fellowship to D.D.D. and a Natural Environment Research Council (NERC) Independent Research Fellowship (IRF) (NE/N014936/1) and a European Research Council (ERC) Starter Grant (758508) to S.H.M.

Publisher Copyright:
© 2022 The Association for the Study of Animal Behaviour

Keywords

  • Heliconius
  • olfactory cues
  • visual cues
  • learning
  • conflicting stimuli

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