Papua New Guinea is home to diverse fauna, and this includes the largest species of butterfly known in the world.

Females of this species reach a wingspan of up to 28 centimetres.

O. alexandrae is one of three butterflies that are listed under CITES Appendix I, so commercial international trade is illegal.

Sexual dimorphism tells males from females, through size difference (females being larger) and differences in colouration. Females are brown with white chevrons and cream, brown and red thorax. Males are much more vibrant, being iridescent blues and greens with black markings, and a bright yellow abdomen. You can determine the sex of the individual at the pupa stage as a charcoal patch is visible in that of males. They emerge after approximately a month, during humid mornings that allow their large wings to unfold correctly.

The imago or adult stage of its life persists for about three months on average and has few predators owing to its size. Large Nephila orb-weaving spiders and some birds may eat this butterfly.

The adults will feed from large flowers and are usually crepuscular in their activity.

The males are highly territorial and will actively chase off competitors, even going so far as to ward off other species of birdwing and birds.

Unfortunately, this species is restricted now to only around 40 square miles of coastal rainforest habitat in the Oro Province of Papua New Guinea. Its main threat is habitat destruction for oil palm plantation; it needs old growth/primary rainforest to thrive.

Additionally, the eruption of Mount Lamington in the 1950s also contributed significantly to its habitat reduction and population decline.

Collectors have also attempted to smuggle the species due to their black-market pricing of up to $10,000 USD. Several were caught and fined much more than this for the act.

While no hobbyist entomologists will be hatching these at home any time soon, the chance to see them in their natural habitat in the post-pandemic world would undoubtedly be a wonderful experience.