Tiny eggs have started hatching this week at the San Diego Zoo, and scientists there are celebrating the arrival of baby tree lobsters.
It’s all part of a conservation effort for the Lord Howe Island stick insect. The huge, black, shiny creature, also known as a tree lobster, is a superstar of the entomological world, because its history is such a strange saga of passion and commitment.
“It’s a very emotional story about an animal that most people don’t get emotional about,” says Paige Howorth, the San Diego Zoo’s curator of entomology.
The Lord Howe Island stick insect once thrived in only one place — Lord Howe Island, near Australia. But in 1918, a ship ran aground and the island got overrun by hungry rats. Soon, the island’s famous insect was extinct. Or so everyone thought.
Decades later, in the 1960s, a few dead ones turned up on Ball’s Pyramid, a jagged mountain of rock that sticks straight up out of the South Pacific Ocean, about a dozen miles from Lord Howe Island.
“Ball’s Pyramid is a very inhospitable place,” says Howorth. “There’s no free water on the rock. Really, not much grows there.”
It seemed like an unlikely refuge for a plant-eating insect. But in 2001, a few guys went out there to find out once and for all if this really was the creature’s last redoubt.
High above the shoreline, they spotted insect droppings beneath a shrub growing in a rocky crevice. They went back that night and, lo and behold — there were a couple dozen of the giant bugs.
The rediscovery made headlines around the world. “It was a massive, massive P.R. event for insects,” Howarth says, “especially an insect like this, which is not one you would deem charismatic, you know, for the most part.”
Two years later, on Valentine’s Day in 2003, climbers went back to Ball’s Pyramid and retrieved two male tree lobsters and two females. The Melbourne Zoo now has a breeding program and hundreds of the insects.
Zookeeper Rohan Cleave takes care of them there, and thinks it’s amazing how this species really, sort of, came back from the dead.
“It’s a very romantic story,” he says, “in that there’s always that hope that one day, they may go home.”
But before the insects ever could be released back into the wild on Lord Howe Island, the island would have to get rid of the rats — which the residents are now trying to do.
In the meantime, there are some living on the island in captivity, at a museum and a school. And Melbourne Zoo wants to establish other colonies, says Howorth, “so that if something catastrophic happened to the population at Melbourne, there would be something to fall back on for this species.”
The San Diego Zoo tried to breed this insect a few years ago, but it was a failure. Howorth says they decided that if they were going to try again, they’d need to get ahold of the two main plants that the insects feed on in Melbourne. “And they aren’t available in the States,” she notes.
The zoo had to get clippings from Australia and grow a bunch of these bushes. Finally, they were ready. Howorth flew to Melbourne last month and brought back 300 eggs, which have just started hatching.
“The nymphs seem to emerge from the egg overnight or in the very early morning hours,” Howarth says. “Most mornings since Saturday have included one or two little green surprises. We couldn’t be happier!”
She says the little ones appear to be munching on the plants.
“The nymph that comes out of the egg is about three times the size of the egg itself,” says Howorth. “It’s just folded up in there like an origami piece or something — it’s amazing.”
More eggs should keep hatching over the next few months, she says, since they are of staggered ages.
“Zoos have an opportunity to conserve the broad, cross section of biodiversity, not just the pandas and the polar bears and the tigers. And it’s exciting to see this actually happening with the Lord Howe Island stick insect,” says Scott Hoffman Black, executive director of the Xerces Society for Invertebrate Conservation.
He says other insects, like the American burying beetle, have been reintroduced to other locations.
“But these island systems are uniquely difficult when you end up with a rat on the island,” he notes. “And you really have to control it before you put these animals back in.”
The huge, black tree lobster may look intimidating, but temperamentally it is fairly docile, Howorth says. And its mouthparts can’t bite people.
It has been claimed that the males and females snooze together, cuddled up in pairs, with the male wrapping his six legs protectively around the female. But Howorth says assuming that the sleep position connotes affection would be premature.
“I don’t know if it means he loves her,” she says, laughing. “I’m not willing to say that.”