The Cairns Birdwing Butterfly

The Cairns Birdwing Butterfly is Australia's largest butterfly.

The wingspan of the female can measure 180mm. The smaller male butterfly has green wings with black markings, while the female has black wings with yellow and white markings. The abdomen of both the male and the female is yellow and the thorax is red.

The caterpillar or ‘larva’, is black and features short spines along the upper surface of the thorax and abdomen. The spines are red or pink in the intermediate sections. The head of the larva has a white mark. A full-grown caterpillar may have a purple tinge in its colouring and can grow to a length of 90mm.The pupa or ‘chrysalis’, is typically grey-yellow or golden.

The Cairns Birdwing Butterfly is one of 14 subspecies of Birdwing. Birdwing Butterflies are found in north-east Australia, the Moluccas Islands, New Guinea and the Solomon Islands. New Guinea is home to the largest known butterfly on Earth, the Queen Alexandra's Birdwing (Troides alexandrae) whose wingspan can reach 280 mm.

After mating the female Cairns Birdwing seeks a suitable plant on which to lay her eggs. Hatching may occur within 5 -10 days, depending on the temperature. As the caterpillar grows it passes through a series of moults in which the outer skin or ‘cuticula’, is shed. Before commencing the final moult (usually the fifth) the caterpillar uses saliva to form a silk pad on the underside of a branch, and a 'girdle' that supports its head as it hangs below the branch. The lower portion of the abdomen is fixed to the silk pad by a network of tiny hooks called the 'cremaster'. The final moult commences the pupal stage.The butterfly emerges from the chrysalis approximately one month after pupation has commenced, although this period is quite variable.The adult Cairns Birdwing Butterfly lives for 4-5 weeks, during which mating may occur. The coupling of the male and female can last for up to 36 hours.
Habitat and distribution.

The destruction of tropical rain forest has led to a decline in the population of the Cairns Birdwing Butterfly and it is now a protected species.

Click here to listen to the interview with Norman Dowsett of Melbourne Zoo about ht eBirdwing Butterfly as well as how to attract more butterflies to your garden.

For more information, please visit http://www.zoo.org.au/

Lord Howe Island Stick Insect

Lord Howe Island Stick Insects were once very common – their large size and unusual appearance prompted the name ‘land lobster’.

But these insects and 15 bird species were defenseless against rats that invaded their native island when the ship Mokambo ran aground in 1918.

In 2001 the NSW Department of Environment and Climate Change surveyed the precipitous sea stack and found three insects living on a small group of Melaleucas on the side of a cliff.
With almost no soil and no water, the bushes were growing on top of the only known water soak, where a severe storm could have blown the entire world’s population off the cliff into the sea.

In February 2003 Lord Howe Island Rangers revisited Balls Pyramid and found 17 individuals. (A later survey estimated the total population there as no more than 40 individuals.)
Patrick Honan brought two adults back to Melbourne Zoo in February 2003 and the breeding program has been so wildly successful that there are now more than 700 insects and 15,000 eggs! The plan is to reintroduce them back to their natural habitat one they have eradicated the rats.

There was very little knowledge of the species: their age at breeding, their lifespan, the incubation period for their eggs, or their habits. Over the past five years, the Zoo’s invertebrate team has discovered many unusual features of this species:

· unlike other species, these stick insects move around actively and are very aware of their surroundings,
· young stick insects are green and feed openly on plants during daylight,
· the large, black adults hide in tree hollows during daylight and are active only at night,
· adults mate up to three times a night and form pairs, with the male sitting protectively over the female when at rest during the day,
· females of this species lay about 250 eggs during their lifetime, in batches of 9 or 10, and they bury the eggs underground, which is unusual for stick insects,
· eggs take between six and nine months to hatch,
· they live for up to 18 months, compared to a 12 to 14-month average for other stick insect species

Click here to here the interview with keeper Patrick Honan from Melbourne Zoo.

For more information about Melbourne Zoo see http://www.zoo.org.au/