For the first time scientists have successfully bred Australia’s longest stick insect Ctenomorpha gargantua in a breeding program at Museum Victoria.
When the museum’s live exhibits coordinator Maik Fiedel came across an incredibly rare 50-centimetre long specimen in 2014, it broke Australia’s record for largest stick insect ever found.
Nicknamed Lady Gaga-ntuan (now Lady Gaga in short), the female found in the tropics near Cairns was close the end of her lifespan, and died shortly after being collected. However, scientists were in luck, as the stick insect laid 12 eggs. These were carefully maintained in hopes for the best.
“I set them up in a take-away container on a 50-50 mixture of coco-peat and sand, and sprayed them with water once or twice a week,” explains Fiedel, who says he never gives up on any stick insect eggs.
Keeping them at the right conditions made for an arduous wait, but after six months the first eggs started hatching, and yielded a total of seven nymphs - four females and three males.
Now, 18 months later, all seven of stick-Lady Gaga’s babies have reached adulthood and laid eggs in a world-first captivity breeding program for Ctenomorpha gargantua. All the females have actually outgrown their mother, and the longest of them measures a record-breaking length of 56.5 centimetres, making her Australia’s longest insect.
Furthermore, Lady Gaga will soon be a grandmother, as the offspring were successfully cross-bred, and have laid several dozen eggs of their own.
Record-breaker might be in the works
Currently the longest insect in the world is a 56.7 cm-long specimen of Phobaeticus chani stick insect from Borneo, part of the collection at Natural History Museum in London. But Maik Fiedel thinks that Lady Gaga and her children actually represent the largest stick insect species in the world.
“In nature there are always some that turn out bigger than others, so we can’t really base a record on one freak that was found,” says Fiedel. “But if we can prove that these animals always turn out quite large, it has really good potential to be confirmed as the longest insect ever.”
To continue the breeding program, researchers hope to collect more wild specimens, too. Males are easier to find than females, and they could provide a useful genetic diversity boost to the museum’s collection. And there’s always the potential of finding other exciting bugs, too.
“Who knows what else is out there,” says Fiedel. “I don’t know if there are longer and bigger things, but there are definitely more species to be found.”
Caring for rare species no easy task
A lot of trial and error was involved in figuring out how to make the gargantuan stick insects happy in captivity.
“Because nothing is known about the biology and ecology of these animals in the wild, we don’t know what their food plant is in the wild, how long it lives for, it was all based on assumptions,” explains Fiedel.
The rearing process involved some stressful times, when three months in the insects rejected the assigned diet of eucalyptus leaves and went lethargic in their climate-controlled chamber. Maik Fiedel tried many solutions, and eventually hand-fed them tiny slices of apple to provide some fructose for energy, which seemed to do the trick.
Now the insects are on a temporary display at Museum Victoria and are once again happy eating locally-sourced eucalyptus.
Maik Fiedel is hopeful that Australia might have a world record insect on its hands soon.
“If we get enough eggs, we could try to rear them under conditions really beneficial for the species, and hopefully document the whole way from egg-hatching to adulthood, and maybe even have a world record within nine months.”