Heliconiini butterflies display flight behaviours reminiscent of orientation flights when using new floral sources

Despite their small brains, many insects form long-term memories of the spatial distribution of resources. To support this, some species display 'orientation' flights to increase the capture of landscape cues around novel resources. The role of orientation behaviour in spatial learning has been broadly explored in Hymenoptera, which are well known to navigate between their nests and floral resources. Here, we describe exaggerated flight behaviours expressed in a foraging context in Heliconiini butterflies, resembling orientation behaviours in Hymenoptera. Heliconiini butterflies are of particular interest as they include the genus Heliconius, which is reported to have a greater capacity for spatial memory in association with a novel dietary strategy of pollen feeding, including formation of stable foraging routes. We hypothesised that these flight behaviours may provide a strategy to memorise the location of floral resources. We compared Heliconius and non-Heliconius butterflies to evaluate this ability in pollen- and non-pollen-feeding Heliconiini species. We characterized three behavioural patterns that are directed towards a new floral resource: circle flights, hovering and feeding bouts. Although all Heliconiini studied displayed these patterns, Heliconius spent more time performing these flight patterns, in particular hovering before landing. We suggest that these behaviours could provide the context in which individuals acquired sensory information to guide future foraging events, and our data indicate greater emphasis of this process during memory formation. Our findings of behaviours reminiscent of orientation flights in Heliconiini butterflies provide new avenues of research on how spatial learning and memory have converged between Lepidoptera and Hymenoptera.