Butterflies that belong to the Heliconius genus, known colloquially as longwings, have discovered the secret to butterfly longevity. Like most members of the order Lepidoptera, longwings sip nectar from flowers using a straw-like organ called a proboscis. What distinguishes them from fellow butterflies — and moths — is that longwings can broaden their diet beyond these sweet liquids — which, in turn, is thought to extend their life.
That’s because Heliconius butterflies are able to ingest pollen by secreting enzymes onto their proboscides. When these enzymes mix with pollen grains, they create a protein-rich liquid that the butterfly can absorb. Longwings spend hours collecting and processing pollen grains and depositing them at other stops along the way. The plants pay them back, big time: the amino acids found in pollen are thought to increase egg production and lifespan up to eight months, making longwings one of the longest-living groups of butterflies in the world.
Their lifespan isn’t what gives these butterflies their name, however; their elongated wings do. Longwings are also sometimes called passion flower butterflies because they favor the passion vine both as a place to lay eggs and as a source of food. The leaves of the passion flower give the longwings their characteristic toxicity: longwing caterpillars feed on the plant, acquiring toxins that they retain through adulthood as protection from predators throughout their lives.
Cydno longwings can be distinguished from other Heliconius butterflies by their coloring: they are mainly black with white or yellowish markingson their forewings and blue on the hindwings. To make matters more confusing, different Heliconius species often exhibit similar color patterns. This defense mechanism, known as Müllerian mimicry, is a form of interspecies imitation used to ward off natural enemies.
See more than 500 live butterflies in The Butterfly Conservatory: Tropical Butterflies Alive in Winter, which runs through May 30.
Presenting Sponsor of The Butterfly Conservatory is Con Edison.
A version of this story originally appeared in the Winter issue of Rotunda, the magazine for Museum Members.