A mother Lord Howe Island stick insect has left behind an "incredible" gift for Melbourne Zoo that could protect future generations of the species, once thought extinct.
The rare adult specimen, dubbed Vanessa after the climber who found her, was discovered as part of an April expedition to the NSW rocky outpost, Balls Pyramid.
Stick insect Vanessa laid 135 eggs before her death on October 10 and her offspring started emerging a week later, with the latest hatching on Thursday taking the tally to six.
It's "incredibly important" for Vanessa's genetic line to be incorporated into the zoo's existing population, invertebrate coordinator Kate Pearce told AAP.
"We'll never be able to release these insects back into their natural environment unless they're capable of withstanding diseases and the rat infestation is reduced," Ms Pearce said.
For 80 years, people thought rats had eaten the insect to extinction until researchers found three around a sea stack near their island home in 2001.
Two years later scientists decided to send two of these insects to Melbourne and two to a private breeder in Sydney in a bid to bring the species back from the brink of extinction.
Melbourne Zoo's original couple, Adam and Eve, arrived in 2003 and despite their short two-year life span the pair's ancestry has grown to 14,500 nymphs over 14 years.
A Lord Howe Island rat eradication project is due to begin in mid-2018.