Heliconius butterflies live longer and age more slowly than close relatives, with experiments suggesting that pollen alone cannot explain their longevity.
Some Heliconius butterflies, found in tropical rainforests across South and Central America, can survive for almost a year while most butterflies live only a few weeks. Their unusual diet has been one possible explanation for this longevity. Unlike most butterflies, which primarily rely on flower nectar, Heliconius adults also eat pollen.
Yet removing pollen from their diet did not erase their advantage. In experiments comparing the pollen-feeding Heliconius hecale with its shorter-lived relative Dryas iulia, which does not eat pollen, researchers found that H. hecale still lived substantially longer without it. The result suggests that nutrition and evolved differences both contribute to its extended lifespan.
The difference also showed up in how well the butterflies maintained their bodies. H. hecale retained its body mass for longer than D. iulia. To assess muscle function and physical performance, the researchers tested the butterflies’ grip strength. They detected no apparent deterioration in older H. hecale individuals, while D. iulia weakened with age. At least in the measures tested, H. hecale appeared to experience little or no physiological decline as it grew older.
Close relatives, sharply different lifespans
The diet experiments were part of a University of Bristol-led study conducted with researchers at the Smithsonian Tropical Research Institute in Panama. Published in Nature Communications, the work examined lifespan and aging across the wider Heliconiini butterfly tribe. The team combined records from butterfly houses, studies in which butterflies were marked, released, and recaptured, and controlled experiments in insectaries, facilities where insects are raised.
Across those comparisons, Heliconius butterflies aged more slowly and had lower baseline mortality, or underlying risk of death, than relatives that do not feed on pollen. Their advantage appeared in both maximum lifespan and median lifespan, the age by which half the butterflies in a group had died.
Some Heliconius species lived about three times as long as their close relatives on average. The largest contrast in maximum lifespan was much greater. Heliconius hewitsoni, the longest-lived species in the comparison, reached 348 days, while the short-lived relative Dione juno reached just 14 days. That represents a roughly 25-fold difference.
Butterfly evolution offers clues to longevity
Dr. Jessica Foley, the study’s lead author from the University of Bristol’s School of Biological Sciences, said, “As the most species-rich animal class, insects are renowned for their extraordinary morphological and ecological diversity. They also exhibit extreme variation in longevity, with maximum lifespans ranging from just a few days in adult mayflies to several decades in the reproductive castes of some ants and termites. This represents a roughly 5,000-fold difference within the class, compared with around a 100-fold difference in lifespan observed in mammals.
“Heliconius butterflies are among the longest-lived butterflies, but what makes them particularly remarkable is that they appear to have evolved not only longer lifespans, but also slower aging. This allows them to live significantly longer than closely related species from which they diverged relatively recently in evolutionary time.
“The exciting implication of this lifespan extension is that it provides a powerful opportunity to identify the mechanisms that underpin longevity. By comparing long-lived Heliconius butterflies with their short-lived relatives, we have a natural evolutionary experiment that can help reveal how lifespan is extended, making them a highly promising new model for research into the biology of aging and longevity.”
Reference: “Evolution of increased longevity and slowed ageing in a genus of tropical butterfly” by Jessica Foley, Josie McPherson, Made Roger, Cruz Batista, Rémi Mauxion, Greta Hernández, Richard Kelson, Fletcher J. Young, W. Owen McMillan and Stephen H. Montgomery, 16 June 2026, Nature Communications.
DOI: 10.1038/s41467-026-73635-7
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