A living individual of a bee species feared to be extinct has been found in the Indonesian islands known as the North Moluccas.
The Wallace’s giant bee (Megachile pluto) belongs to Megachilidae, a family of mostly solitary bees.
This species is the largest bee on Earth. Females may reach a length of 1.5 inches (3.8 cm), with a wingspan of 2.5 inches (6.35 cm), but males only grow to about 0.9 inches (2.3 cm) long. Females are also remarkable for their enormous, stag beetle-like mandibles.
Wallace’s giant bees nest communally, apparently always within the inhabited nests of the tree-dwelling termite Microcerotermes amboinensis. Females harvest tree resin to build compartments inside the termite nest, which protects the galleries.
The species was originally discovered in 1859 by the British explorer and naturalist Alfred Russel Wallace, a co-discoverer of evolution by natural selection.
During his stay on the Bacan Island of the Moluccas, Wallace observed and collected a giant female bee. He described it as ‘a large black wasp-like insect, with immense jaws like a stag-beetle.’ The specimen was scientifically described a year later by the British entomologist Frederick Smith as a new species of wild bee.
The Wallace’s giant bee was believed extinct until it was rediscovered in 1981 by the American researcher Adam Catton Messer. He observed several males and females of the giant bee and confirmed that it was a narrow endemic species found only on three islands of the North Moluccas: Bacan, Halmahera and Tidore.
After 1981, the Wallace’s giant bee was not observed in the wild for almost four decades.
A honeybee (Apis mellifera) worker (left) compared to the Wallace’s giant bee (Megachile pluto). Image credit: J.W. Porter / A.C. Messer.
In January 2019, a live female was found and filmed by a team of American, Canadian and Australian biologists who set out to search for the species in the North Moluccas.
“As we walked into the dense forests for the first time, rich with the scent of clove and nutmeg hanging densely in the air, I had a hard time believing that I was actually following in Wallace’s footsteps, in an area that at times seemed little changed from his travels not much more than 150 years in the past,” said team member Clay Bolt, a photographer specializing in documenting North American bees.
“We were excited to see a few different Megachile species, and several large bees or wasps flying past well out of reach in the canopy.”
“We also observed many other unusual species, including Polyrhachis ants, jumping spiders with extended mandibles, and gorgeous jewel beetles.”
“Each day, we stared at termite mounds for 20 minutes at a time, then moved on to the next mound. It was invigorating but tiring work,” he said.
“On the last day of searching, we found a bee nest. The structure was just too perfect and similar to what we expected to find.”
“I climbed up next and my headlamp glinted on the most remarkable thing I’d ever laid my eyes on. I simply couldn’t believe it: we had rediscovered the Wallace’s giant bee.”
