Data from: Evolution of the olfactory system during the radiation of Heliconiini butterflies

Sensory system evolution plays a crucial role in shaping species’
interactions with their environment, yet the extent to which olfactory
system diversity reflects ecological and evolutionary pressures at a
macroevolutionary scale remains unclear. Here, we investigate the
evolution of the olfactory system across the Heliconiini butterfly tribe,
an ecologically diverse but closely related group. Using a comparative
approach, we examined variation in antennal lobe morphology and its
constituent structures, the glomeruli and antennal lobe hub, as well as
odourant receptor repertoires across species. We found that antennal lobe
size variation is driven by independent shifts in glomerular and antennal
lobe hub volumes, with species-specific differences occurring against a
backdrop of broader phylogenetic stability. While no direct associations
with ecological traits were observed, certain species showed large
expansions in total glomerular volume and odourant receptor numbers,
warranting further investigation into unmeasured ecological or behavioural
factors. Additionally, comparisons between wild-caught and
insectary-reared individuals revealed a surprising pattern of
developmental plasticity, with antennal lobe hub volumes increasing and
glomeruli volumes decreasing in captivity, highlighting the influence of
environmental conditions on neural development. These findings suggest
that olfactory evolution in Heliconiini is shaped by both evolutionary
divergence and developmental plasticity, emphasizing the need to integrate
phylogenetic, ecological, and developmental perspectives to fully
understand sensory system adaptation.