Evolutionarily speaking, extinction is like the massive hidden part of an iceberg. More than 99% of nature’s experiments have failed but the successful 1% that is remaining is stunning us as we continue to learn. Not all extinction is natural however. As we are more and more certain Anthropocene, Human caused extinction rate is becoming much higher than the natural background extinction rate. Scientists are rushing to assess the on going rate of the extinction in different parts of the World.
The story of the Lord Howe Island stick insect (Dryococelus australis) is fascinating. These flightless, nocturnal, prehistoric looking insects also called as land lobsters are quite big sizing up to 12cm long, and weigh 8-9g. Before Humans unintentionally introduced rodents to the island in 1918 they were so abundant that fishermen were using them as fish bait. Rodents finished them off. In 1960s they were thought to be extinct but it turned out a few individuals survived in a rather unexpected place. They literally clung onto life under a Melaleuca howeana bush located on the World’s tallest vertical sea wall (550m high) on Ball’s Pyramid for 80 years until they became rediscovered by scientists.
In 2001, David Priddel and Nicholas Carlile from the NSW Government’s Office of Environment and Heritage sailed to Ball’s Pyramid to prove, to officially confirm that the species was extinct. They climbed and checked out Melaleuca howeana bushes growing from on the steep wall. To their suprise they found a population – between 24 and 40 individuals under the canopy of a single bush. How they got there nobody exactly knows. They might have been carried over as nesting material by common noddy birds.
Eggs were brought to Melbourne Zoo as a part of a breeding and recovery program for the insect. The long-term plan is to eradicate rodents from Lord Howe Island and repopulate the island with stick insects. After a few ups and downs the breeding program is now a success. In a world first, zookeeper Rohan Cleave captured the amazing hatching process of a critically endangered Lord Howe Island Stick Insect at Melbourne Zoo. The eggs incubate for over 6 months and until now the hatching process has never been witnessed.