Butterfly of the Month - June 2023

The Richmond Birdwing Butterfly (Ornithoptera richmondia) is the largest of our Swallowtails in South-East Queensland with a wingspan of 105mm for the male and 115mm for the female, sometimes exceeding that with reports of substantially larger sizes.

The butterfly is certainly one of our most spectacular ones by colour alone and independent of size. The male’s wing colour on the underside are astounding with the black base being outdone by green, blue-green and yellow markings with added black spots. The upper side of the forewing is predominantly black with a wide iridescent green band along the outer leading margin and a much smaller one along the inner margin of the wing. The female’s upper and underside are very similar, brown with white and yellow markings and the obligatory black spots on the hindwing

The Richmond Birdwing butterfly is smaller than the Cairns Birdwing which only occurs in North Queensland. However, both butterflies are similar in appearance and could easily be mistaken for each other.

Like all swallowtail species (Papilionidae) the butterfly starts its life cycle with a globular egg, usually laid singly or in very small numbers on the underside of a larval host plant leaf. Regionally the Richmond Bird is the largest butterfly. It doesn’t come as a surprise that its eggs are larger than those of other butterflies and reach up to 2.3mm in diameter.

After hatching the larva devours the egg shell and then proceeds to feed on the foliage of the host plant through all five instar stages. Before pupating it can reach a length of 58mm. Larvae vary in colour which can range from black to a pale grey brown. They come equipped with a multitude of spines. Examples of differently coloured larvae are shown in our image. The pupa (chrysalis) is green, but the colour may slightly vary from the one depicted here.

In Brisbane the butterfly feeds on the native Pararistolochia praevenosa which is listed as Near threatened under the Nature Conservation Act 1992. P. laheyana is an alternative host plant in higher altitudes above 600m.

The Richmond Birdwing butterfly used to once be common roughly between Sunshine Coast and Gold Coast and their hinterlands, and the butterfly could be considered abundant in Brisbane until the early 1900s. The expansion of Brisbane has led to immense land clearing and loss of the butterfly’s rainforest habitat which has shrunk to 1% of its original size. Unlike Gold Coast and Sunshine Coast areas, no permanent Richmond Birdwing populations exist anymore in Brisbane. With habitat loss came fragmentation, and the populations north and south from us became isolated, which in turn led to in-breeding furthering the decline of the butterfly even more. Additionally, the introduction of the exotic Dutchman’s Pipe (Aristolochia elegans) caused further problems as the Richmond birdwing is attracted to it and lays eggs on its leaves confusing it with the available native hosts. The plant is toxic to the butterfly, and no larva surives after hatching.

The Richmond Birdwing butterfly (Ornithoptera richmondia) is now among Queensland’s threatened species with the conservation status being ‘vulnerable’. It needs all the help it can get. The Richmond Birdwing Conservation Network (RCBN) actively supports and promotes the butterfly’s recovery with participation in a breeding program which allows for mating of Richmond birdwings from different geographic areas and releasing the genetically more diverse offspring and by engaging the community in planting programs..

It continues to be of high importance to create movement corridors for the butterflies between the beforementioned permanent populations. Brisbane and surrounding administrative areas have a big role to play in the recovery. RCBN work closely together with community groups, local governments, other organisations and institutions in the recreation of those corridors by raising and planting native host vines and by building stepping stone consisting of those larval food plants, by building biomass. There is plenty of work to do before we see more than the very occasional butterfly arrive back in Brisbane. All rehabilitators and home gardeners are invited to support the Richmond Birdwing Butterfly. What an opportunity for all of us to participate in the recovery of a magnificent butterfly.