Queen Alexandra’s Birdwing

Queen Alexandra’s Birdwing (Ornithoptera alexandrae), is the largest butterfly in the world. The species was named by Lord Walter Rothschild in 1907, in honor of Queen Alexandra, wife of King Edward VII of the United Kingdom. The first European to discover the species was Albert Stewart Meek in 1906, a collector employed by Lord Walter Rothschild to collect natural history specimens from Papua New Guinea. Although the first specimen was taken with the aid of a small shotgun, Meek soon discovered the early stages and bred out most of the first specimens.

Female Queen Alexandra’s Birdwings are larger than males with markedly rounder, broader wings. This sex can reach a wingspan of 14 inches, a body length of 3.2 inches and a body mass of up to 0.42 ounces, all enormous measurements for a butterfly. The female has brown wings with white markings and a cream-colored body with a small section of red fur on its thorax. Males are smaller than females with brown wings that have iridescent blue and green markings and a bright yellow abdomen.

The female Queen Alexandra’s Birdwing lays about 27 eggs during its entire lifespan. Newly emerged larvae eat their own eggshells before feeding on fresh foliage. The larva is black with red tubercles and has a cream-colored band or saddle in the middle of its body. Male pupae may be distinguished by a faint charcoal patch on the wing cases; this becomes a band of special scales in the adult butterfly called a sex brand. The time taken for this species to develop from egg to pupa is approximately six weeks, with the pupal stage taking a month or more. Adults emerge from the pupae early in the morning while humidity is still high, as the enormous wings may dry out before they have fully expanded if the humidity drops. The adults may live for three months or more and have few predators.

The adults are powerful fliers most active in the early morning and again at dusk when they actively feed on flowers. Males also patrol areas of the host plants for newly emerged females early in the morning. Females may be seen searching for host plants for most of the day. Courtship is brief but spectacular; males hover above a potential mate, dousing them with a pheromone to induce mating. Receptive females will allow the male to land and pair, while unreceptive females will fly off or otherwise discourage mating.

Males are strongly territorial and will see off potential rivals, sometimes chasing small birds as well as other birdwing species. Flight is usually high in the rainforest canopy, but both sexes descend to within a few meters of the ground while feeding or laying blue eggs.

Photo Credit: Robert Nash, Curator of entomology, Ulster Museum