Approximately 4x larger than a European honey bee, Wallace’s giant bee is the world’s largest bee. Composite image by Clay Bolt.With no sightings for the past 38 years, it was feared that Wallace’s Giant Bee Megachile pluto may have become extinct. That was until January this year when a team of North American and Australian researchers rediscovered, and filmed, the bee alive in the North Moluccas, a group of islands in Indonesia.
Wallace’s Giant Bee is named after the British explorer and naturalist Alfred Russel Wallace, who, together with Charles Darwin, is credited with developing the theory of evolution through natural selection. Wallace first discovered the species for science in 1858 on the Indonesian island of Bacan. He described the creature as “a large, black wasp-like insect, with immense jaws like a stag beetle”. In 1860, a British entomologist determined that the insect was a bee, describing it as a ‘giant of the genus to which it belongs’, that genus being Megachile.
At around four times the size of a honeybee, and with a wingspan of 2.5 inches, it certainly is large. Despite its size, the bee remained elusive after Wallace’s initial discovery, and almost nothing was known about its life history. That was until 1981, when Adam Messer, an American entomologist, rediscovered it on three islands in an archipelago known as the North Moluccas in Indonesia. Messer discovered that the females nest inside arboreal termite mounds, using their giant mandibles to collect resin and wood with which line their nests in order to make them termite-proof. Like other bees, it feeds on nectar and pollen gathered from flowers. Writing about his expedition in 1984 he noted that “it remains rare in its range, and as this solitary bee lives only in aerial termite mounds, isn’t exactly easy to find”.
The next specimen was collected in 1991 by French researcher Roch Desmier de Chenon, but later expedition teams failed to find the bee again. This lack of sightings led the charity Global Wildlife Conservation to include it in its list of “25 most wanted” lost species in 2017. Fortunately, in January this year a team of North American and Australian researchers observed a single female Megachile pluto nesting inside a termites’ nest in a tree 2 metres above the ground.
Nature photographer Clay Bolt, who was part of the expedition team, is the first person to have to have photographed and filmed Megachile pluto alive in the wild. Bolt, along with biologists Eli Wyman and Simon Robson and writer Glen Chilton, travelled to Indonesia in January. After five days of fruitless searching, the team had begun to feel a bit discouraged. They were about to give up when they noticed a resiny hole in an arboreal termite nest. They climbed up to the hole and placed a collection tube over it and watched as a large female Wallace’s Giant Bee appeared.
“We yelled and screamed and hugged each other,” commented Simon Robson.
“It was absolutely breathtaking to see this ‘flying bulldog’ of an insect that we weren’t sure existed anymore,” said Clay Bolt. “To actually see how beautiful and big the species is in life, to hear the sound of its giant wings thrumming as it flew past my head, was just incredible.”
Eli Wyman, a biologist at Princeton, says he could feel the displacement of air as she flew by. “Such an incredible, tangible experience from an animal that had only lived in my imagination for years”.
After photographing and filming the bee, it was returned to the nest. According to Bolt the bee seemed “very relaxed” and non-aggressive, unlike some of its close relatives.
The bee’s forest habitat is threatened by large-scale deforestation for agriculture, and its size and rarity make it a sought after collectors item, and therefore a target for collectors. Last year two Megachile pluto specimens were listed on the online marketplace eBay, one of which sold for over US $9000. This has raised fears among conservationists that the publicity surrounding its rediscovery could put the species at risk.
Megachile pluto has no legal protection at present, and it is legal for this species to be bought and sold across borders. This species is currently only considered “vulnerable” by the International Union for Conservation of Nature (IUCN), but, considering its rarity and that its range is almost certainly smaller than previously believed, many entomologists and conservationists believe that it should be reclassified as endangered.
French researcher Roch Desmier de Chenon, who observed 20 or 30 Megachile pluto on the island of Halmahera in 1991, says that, despite being aware that it was a big discovery, he didn’t publish his work because he feared that the information might aid collectors in capturing specimens for the international trade.
Robin Moore, a conservation biologist with Global Wildlife Conservation, which runs a programme called The Search for Lost Species, which funded the expedition, commented “We know that putting the news out about this rediscovery could seem like a big risk given the demand, but the reality is that unscrupulous collectors already know that the bee is out there.”
Moore thinks it is vital that the Indonesian government are made aware of Wallace’s Giant Bee and take steps to protect the species and its habitat. “By making the bee a world-famous flagship for conservation we are confident that the species has a brighter future than if we just let it quietly be collected into oblivion,” he said. Indeed, Roch Desmier de Chenon now regrets not publishing his rediscovery in 1991.
In addition to over-collection, Megachile pluto is also threatened by habitat destruction through deforestation.
The report of the rediscovery of Wallace’s Giant Bee Megachile pluto comes in the wake of a global review of long-term insect abundance research that highlighted dramatic declines that the authors warn could lead to the extinction of 40% of the world’s insect species over the next few decades.
Clay Bolt has published his account of the expedition here:
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