The recovery programme for the Lord Howe Island Phasmid (Dryococelus australis) following its rediscovery


  • Nicholas Carlile,

  • David Priddel,

  • Patrick Honan

  • Nicholas Carlile and David Priddel are research scientists with the New South Wales Department of Environment and Climate Change (PO Box 1967, Hurstville BC, NSW 1481, Australia; Tel. 02 95856504; Fax: 02 95856606; Email: The main focus of their work is the restoration of island ecosystems and the recovery of threatened seabirds, although other insular species such as the Lord Howe Island Phasmid also benefit. Patrick Honan is Head Keeper of invertebrates at Melbourne Zoo (PO Box 74, Parkville, Vic. 3052, Australia; Tel. 03 92859457; Fax: 02 95856606; Email:


Summary  Until its rediscovery on Balls Pyramid in February 2001, the Lord Howe Island Phasmid or Stick Insect (Dryococelus australis) was thought to be extinct. It disappeared from Lord Howe Island soon after the accidental introduction of the Ship Rat (Rattus rattus) in 1918. In this paper, we report on the recovery actions undertaken for this critically endangered species since its rediscovery. Monitoring of the small surviving population on Balls Pyramid has shown it to fluctuate between about 9 and 35 adult individuals. As a safeguard against extinction, two adult pairs were removed from Balls Pyramid in February 2003 to establish captive populations in Melbourne and Sydney. Although all four founders bred readily in captivity, one pair died only a month after capture. The second female would have also died soon after capture had it not been for veterinary intervention using novel untested techniques. The single surviving pair bred successfully but the hatch rate of eggs was poor. For the next generation, both fecundity and hatch rates were low. The lack of knowledge regarding the specific husbandry requirements of this particular species undoubtedly contributed to these problems. Careful management, together with a cautious scientific approach, eventually led to all problems being resolved. Presently, there are more than 700 individuals and 14 000 eggs in captivity. Approximately 80% of incubated eggs are expected to hatch. To establish additional captive colonies, adults and eggs have been sent to other institutions, both within Australia and overseas. Now that the species is reasonably secure in captivity, the opportunity exists to reintroduce this iconic insect back onto Lord Howe Island, but this can occur only after the introduced rodents have been removed. A programme to eradicate both the Ship Rat and the House Mouse (Mus musculus) from Lord Howe Island is currently being developed.