Feb 21, 2019 9:00 AM

The Triumphant Rediscovery of the Biggest Bee on Earth

Despite the astonishing size of Wallace's giant bee, the species was lost to science for 40 years. This is the story of its dramatic rediscovery.

Wallace giant bee 4 times bigger than European honeybee it's pictured next to

For security reasons, I can’t tell you exactly where Clay Bolt rediscovered Wallace’s giant bee. But I can tell you this. With a wingspan of two and a half inches, the goliath is four times bigger than a European honeybee. Very much unlike its honey-manufacturing cousin, it’s got enormous jaws, more like those of the famous stag beetle. And it lives not in nests with thousands of family members but largely alone in burrows in termite mounds, a tubular home it coats with waterproof resin.

Last month, Bolt and his colleagues were on a miserable slog through the rain on an Indonesian Island That Shall Not Be Named, searching for termite mounds in trees, the last place a scientist spotted the superlative species of bee nearly 40 years ago. Sometimes they’d sit under a tree with a pair of binoculars for 20 minutes, watching for the distinctive movements that would reveal a bee in a mound way up high. For mounds closer to the ground, they’d scramble up for a closer look.

After six days of searching perhaps 40 mounds on two different islands—movement. “Our guide shimmied up the tree and looked inside with his cell phone flashlight and noticed something move,” Bolt says. “He jumped down because he was terrified of snakes.”

Heart aflutter, Bolt went up himself and came face to face with the biggest bee in the world, what locals call the “king of bees.” (Despite the name, it’s the females who are the giants, measuring almost twice as long as the males, who also lack the impressive mandibles.) Neither aggressive nor alarmed, the female was hard at work using her curious mouth to rework the resin that lines her chamber. Bolt placed a test tube over the entrance and delicately coaxed the bee out with gentle flicks of grass blades, capturing a creature no scientist has seen alive in four decades.

Clay Bolt

This is a scientific saga that began in the early days of modern biology, with a character nearly as curious as the giant bee that would take his name: Alfred Russel Wallace. A tall, skinny, reserved young explorer, he spent the 1850s traipsing through tropical forests collecting specimens to be sold back in England. One of them was a specimen a local brought to him, “a large black wasp-like insect, with immense jaws like a stag-beetle.”

It was during these travels that Wallace—wracked with some kind of tropical disease, perhaps malaria—fever-dreamed the idea of evolution by natural selection at the same time that Charles Darwin was independently mulling his famous theory. Unfortunately for Wallace’s legacy, he scribbled the idea down and sent it to Darwin, who then rushed to publish On the Origin of Species. (To be fair, Darwin’s friends presented both biologists’ findings to the scientific community first.)

Bolt had read Wallace’s journals, and knew the legend of the giant bee well. So when entomologist Eli Wyman was showing him around the collections of the American Museum of Natural History in 2015 and offered to get out a specimen, Bolt didn’t hesitate. “I was immediately enamored of it,” he says. “From that moment, we really began to hatch a plan to see if we could be the ones to find it and rediscover it, because it's just so rare and beautiful.”

That would make them an extreme rarity: a scientific team catching sight of the giant bee alive. After Wallace, the second to study the species in the field was an entomologist named Adam Messer. In 1981, he observed the bizarre resin-gathering excursions of Wallace’s giant bee, which in addition to its huge mandibles uses a part of the mouth called a labrum to harvest the stuff from a tree.

“Facing upward,” Messer writes, “a female loosened resin with the mandibles, then scraped it up using the elongate labrum in the manner of a bulldozer blade. The ball of resin which formed was held in place between the tree and the labrum while being progressively enlarged.” The female would then take it back to her nest, along with wood fibers, to waterproof the tunnel walls.

The resin may also help explain why Wallace’s giant bee evolved to be so giant. In addition to waterproofing the tunnels, the sticky resin may help keep the termites out. “She's strong enough to actually power through that without getting stuck,” says Bolt, “whereas the little termites would definitely get stuck if they tried to penetrate.”

The evolutionary story of this mysterious species, though, is far from resolved, as is the question of the bee’s sociality. Messer found several females living in one termite nest, but the species has nowhere near the sophisticated society of a honeybee. Which is fine, really: The majority of bee species are solitary, so honeybees are the outliers here.

Out of concern for the state of the species’ population, Bolt left his specimen in the wild. Poachers would not be so sensitive, which is why he’s keeping the bee’s location a secret. “I felt an incredible responsibility because by saying that this creature does exist, it means that people could try to go in search for it,” Bolt says. “So that's why I immediately began talking to authorities and locals in Indonesia to try to figure out a way to help protect it.”

News of the rediscovery comes just a week after an alarming report cataloged huge declines in insect populations. The simultaneously horrible and reassuring truth is that while insects won’t altogether vanish from the face of the Earth, some are suffering more than others. Pollinating species are falling victim to pesticides, but other species will inevitably adapt to a warmer and generally less hospitable planet.

“In a time of biodiversity declines, including for insects, this rediscovery gives us hope that not all is lost and that we have managed to protect not only an amazing bee, but importantly also the unique habitat that is its, and likely many other rare species', home,” says Cornell University entomologist Corrie Moreau, who wasn’t involved in this new work.

The challenge is that protecting species like Wallace’s giant bee requires understanding them. It means sending people like Bolt into inhospitable spots for days on end, and it means using what we’ve learned to inform how we protect vulnerable species. It entails identifying vulnerable habitats and protecting them at all costs.

This is particularly urgent for large species like Wallace’s giant bee, because large species are more vulnerable. The bigger you are, the fewer of your kind can fit in an ecosystem. “It's just like lemurs,” says Brian Fisher, curator of entomology at the California Academy of Sciences, who wasn’t involved in this work. “You can predict exactly the next extinction of lemurs based on body size. It's the same thing for insects.”

Complicating matters is the fact that fewer than half of insect species have been discovered. “Over and over again, in the news it’s Elon Musk putting people on Mars, SpaceX. But there's no exploration happening on Earth,” Fisher says. “There's nobody launching an EarthX, which we're running out of time to do if we want to actually document who we share this planet with.”

In the meantime, Wallace’s giant bee stands as both a triumph of survival and of the scientific endeavor. “Now's not the time to wave your hands in despair,” Bolt says. “Now's the time to get to work and try to do what we can to protect bees.”