Longwing Butterflies: Care & Information (Heliconius Species)

Longwing butterflies, belonging to the Heliconiinae subfamily of Nymphalidae, are a fascinating and unique group of butterflies often known as Passionvine Butterflies due to their close evolutionary relationship with Passiflora plants. Their characteristic wing shape—long in wingspan but short vertically—makes them instantly recognisable.

This guide covers the biology and care of Longwings, including their eggs, caterpillars, pupae and adults, as well as their extraordinary behaviours. These species are popular with hobbyists, educators and butterfly houses due to their remarkable natural history.

Background: What Makes Longwing Butterflies Unique?

Heliconius butterflies are widely studied in evolutionary biology because of:

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Mimicry & Sympatric Species

With around 100 species and numerous subspecies across Central and South America, many Heliconius share overlapping ranges.

For example, Heliconius cydno and H. melpomene occur together almost everywhere. Although they differ in colour (blue/black vs red), research suggests cydno diverged from melpomene millions of years ago. Their contrasting wing patterns act as a mating barrier, helping maintain distinct species despite close proximity.

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Pollen-Feeding — Unique Among Butterflies

Longwings are the only butterflies known to feed on pollen in addition to nectar. When drinking nectar, pollen sticks to their proboscis, then they secrete enzymes that digest it into amino acids. This nutrient-rich diet is believed to contribute to their unusually long lifespans—up to six months, compared with weeks for many other butterflies.

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Advanced Memory & Learning

A region of the Heliconius brain responsible for learning and memory is 3–4 times larger than in other butterflies. This adaptation allows them to remember the exact locations of specific flowers, visiting them daily along established traplines.

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Zebra Longwing laying eggs

This female Zebra Longwing, Heliconius charithonia, is laying eggs on the fresh growth tips of Passiflora caerulea, Blue Passionvine.

Egg Care

Longwing eggs are humidity-sensitive and should be kept in a closed plastic container away from direct sunlight to prevent overheating or drying out. Eggs typically hatch within a few days.

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How to Care for Eggs

  • Keep in a closed container to retain humidity.
  • Avoid direct light or heat sources.
  • Eggs hatch quickly; once they darken from yellow to orange, hatching is imminent.
  • Place a small sprig of Passiflora in the container once eggs begin hatching.
  • Heliconius larvae are extremely small and benefit from moisture provided by live foliage.

In nature, eggs are laid on fresh growth in shaded, humid microhabitats, so recreating this environment improves hatch rates.

Caterpillar Care

Heliconius caterpillars develop rapidly—usually reaching pupation in around 3 weeks.

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Conditions

  • Room temperature is generally ideal as this species does not enjoy extreme temperatures.
  • Provide slightly elevated humidity (80%+); lightly mist if conditions are dry.
  • Warm locations (22-26℃) encourage faster growth but avoid excessive heat.

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Host Plants

Different species specialise on different Passiflora, but all species included in our Passionvine/Longwing mix reliably feed on:

  • Passiflora caerulea (Blue Passionvine) — ideal and widely available
  • Other cultivated Passiflora species
  • Living vines are best, though fresh-cut stems work if replaced frequently

Passiflora caerulea is incredibly easy to grow both outdoors and indoors. Ours grow outdoors year-round in Scotland, showing their suitability for UK keepers.

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Larval Development

Caterpillars:

  • Feed on tender new growth when young and small, before moving onto mature foliage as they grow, and even consuming stems when in L5
  • Pupate by suspending themselves from stems using a silk pad
  • Adopt the classic J-shape shortly before shedding into the chrysalis
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Heliconius charithonia chrysalis

The pupa is adorned with small spines which give it the appearance of dead foliage when hanging from host plant stems - an excellent camoflague.

Pupae (Chrysalis) Care

Longwing pupae are distinctive, often adorned with small spines that resemble dead foliage — an excellent natural camouflage.

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Conditions for Successful Hatching

  • Room temperature (20-24℃)
  • High humidity (85% minimum)
  • Can be achieved using the polystyrene box method described in our pupae care guide.
  • Minimal disturbance, especially as emergence approaches

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Development

  • Pupae darken and wing patterns become visible shortly before emergence (shown in the image below)
  • Development takes roughly 10-14 days, depending on temperature.

Adult Longwing Butterfly Care

Adult Heliconius butterflies are extremely variable in colour and pattern, even within a single species. Our examples below of Heliconius melpomene subspecies from Ecuador are a perfect illustration of this diversity.

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Housing & Behaviour

Longwings enjoy:

  • Dappled sunlight
  • Moderate warmth
  • High humidity
  • Shaded areas for egg-laying

They exhibit remarkable behaviour, especially in larger enclosures such as greenhouses, but can also be kept successfully in smaller setups indoors.

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Diet

Offer both nectar and fruit for the butterflies to feed from. Heliconius butterflies require both nectar and amino acids to live their full natural lifespan. They obtain:

  • Pollen from flowers, if available
  • Amino acid supplements added to nectar solution if flowers are not present

This is essential: without amino acids, adults live only a few weeks instead of several months.

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Breeding Considerations

  • Provide shaded Passiflora foliage for egg-laying
  • Avoid direct sun on eggs and young larvae
  • Maintain humidity and warmth to mimic natural conditions
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    Heliconius melpomene subspecies ecuatorialis

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    Heliconius melpomene subspecies plesseni

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    Heliconius melpomene subspecies cythera

Variability

A key feature of Longwing butterflies is the massive diversity in pattern and colouration. Here are a few photos from our butterfly farm:

Larvae

Dryas julia & Heliconius larvae

This handful of caterpillars exhibits the variation between and among larvae of the same and different species

Assorted Longwing Larvae

Gulf Fritillary

Agraulis vanillae

This butterfly is the only species in its genus, a sub-family of the Longwing butterflies.

Agraulis vanillae Pupae

Small Postman Butterfly

Heliconius erato

Although this subspecies or erato resembles the larger Postman melpomene, it is in fact more closely related to the Zebra Longwing charithonia - this is a remarkable example of adaptive mimicry!

Heliconius erato Pupae

Small Postman Butterfly

Heliconius erato

Almost unbelievably, this butterfly is the same species as the one pictured above, however it belongs to a different geographical race or subspecies and mimics a different subspecies of the larger Postman melpomene.

Heliconius erato pupae

Postman Butterfly

Heliconius melpomene rosina

This is yet another subspecies of the Postman butterfly, this particular subspecies being native to Costa Rica, yet it is the same species as the examples of melpomene from Ecuador (above).

Heliconius melpomene Pupae
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Zebra Longwing

Heliconius charithonia

Incredibly, the Small Postman (erato) is more closely related to this butterfly than it is to the large Postman (melpomene).

Heliconius charithonia Pupae
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Cydno Longwing

Heliconius cydno

This butterfly, in rich shades of metallic black/blue, is a sister species of the Postman (melpomene), having separated from it millions of years ago but remaining closely related in genetic terms

Heliconius cydno Pupae
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Tiger Longwing

Heliconius hecale

This is another striking Longwing with multiple regional colour forms which are co-mimetic with other Heliconius.

Heliconius hecale Pupae
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Tiger Longwing

Heliconius hecale

A different regional subspecies to the one above. These subspecies can interbreed to produce beautiful mixed specimens which show traits of both parents.

Heliconius hecale Pupae
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Numata Longwing

Heliconius numata

This butterfly also has a multitude of adult forms which occur across different regions and are co-mimetic with the species Heliconius ismenius or hecale.

Heliconius numata Pupae
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Numata Longwing

Heliconius numata

A different numata subspecies with light cream patches, distinct to the subspecies shown above.

Heliconius numata Pupae
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Sara Longwing

Heliconius sara

This little butterfly is in the same clade as the Small Postman erato despite having very different colouration.

Heliconius sara Pupae