Butterfly, Queen Alexandra's birdwing

Ornithoptera alexandrae (or Troides alexandrae)

phylum: Arthropoda

class: Insecta

order: Lepidoptera

family: Papilionidae

status: Endangered, IUCN Endangered, ESA

range: Papua New Guinea

Description and biology

Many biologists (people who study living organisms) believe the Queen Alexandra's birdwing butterfly is the world's largest butterfly. It has an average head and body length of 3 inches (7.6 centimeters). Females of the species have wingspans measuring more than 10 inches (25.4 centimeters). Males, which are smaller, have wingspans of about 7 inches (17.8 centimeters). Females and males also differ in color. In females, the upper surfaces of the wings have cream markings on a dark, chocolate-brown background. In males, the upper surfaces have iridescent yellow, pale blue, and pale green markings on a black background. In both sexes, the abdomen is yellow and the lower surface of the wings where they attach to the butterfly's body are bright red.

The Queen Alexandra's birdwing butterfly has a seven- month life span. Females lay large eggs, which measure about

0.16 inch (0.41 centimeter) in diameter, on the leaves of a particular vine. The eggs hatch quickly, and the larvae or caterpillars emerge to begin feeding on these leaves. The caterpillars exist for four months before entering the pupal, or cocoon, stage to transform into an adult butterfly. After it has metamorphosed (pronounced met-a-MORE-fozed) or changed into an adult, the butterfly may live for another three months.

The adult butterfly has few predators, but its eggs are often eaten by ants. Caterpillars are preyed on by snakes, lizards, toads, and birds such as cuckoos and crow pheasants.

Habitat and current distribution

This butterfly species is found in a few sites in Papua New Guinea, but mainly on the Popondetta Plain in the northern part of the island. Because the Queen Alexandra's birdwing butterfly flies high and is rarely seen, biologists have been unable to determine any population totals.

Queen Alexandra's birdwing butterflies inhabit primary and secondary lowland rain forests at elevations up to 1,300 feet (396 meters). Biologists have reported seeing male butterflies swarm around large Kwila trees when they are bearing flowers. Those males that do not visit these flowers are not accepted by females to mate. Biologists cannot explain the reason for this.

History and conservation measures

The Queen Alexandra's birdwing butterfly was identified in 1906, when a female specimen was first collected. During the twentieth century, the butterfly's habitat was broken up by logging operations and farming. In 1951, the Mt. Lamington volcano erupted, destroying about 100 square miles (259 square kilometers) of prime butterfly habitat.

Large tracts of butterfly habitat in the Popondetta region have been converted into cocoa and rubber plantations. Currently, the Queen Alexandra's birdwing butterfly is threatened by the area's expanding oil palm industry. Growing human populations in the region pose a further threat as forests are cleared to create urban areas.

The Queen Alexandra's birdwing butterfly is protected by international treaties, but illegal capture remains a threat. Collectors around the world will pay large amounts of money to own a specimen of the world's largest butterfly.

The Papua New Guinea government has passed legislation safeguarding this and other butterfly species on the island. These laws are strictly enforced. A Wildlife Management Area, covering approximately 27,000 acres (10,800 hectares) of grassland and forest, has been established north of the Popondetta region. Plans to establish more reserves for the Queen Alexandra's birdwing butterfly are in progress.

DID YOU KNOW?

The 1951 eruption of Mt. Lamington in Oro Province was the worst natural disaster ever to hit Papua New Guinea. Over 2,940 people were killed by lava flows. One dome of the volcano grew 1,600 feet (488 meters) above the crater before it collapsed. The volcano was active for six days before it finally erupted, covering most of Oro Province in ash and producing mudflows that continued until 1956. Some biologists believe the volcano's destruction of a large amount of prime habitat was the beginning of the decline of the Queen Alexandra's birdwing butterfly.