World’s biggest bee found

Published:22 February 2019

Wallace bee compared to a bumble bee One of the first images of a living Wallace’s giant bee, Megachile plutois, the world’s largest bee, which is approximately four times larger than a European honeybee. © Clay Bolt: claybolt.com

Search team produces first live photos and video of Indonesia’s extraordinary lost bee

An international team of scientists and conservationists has announced the finding of what many consider to be the ‘holy grail’ of bee discoveries – Wallace’s giant bee.

The bee (Megachile pluto) is the world’s largest, with a wingspan more than six centimetres (2.5 inches). Despite its conspicuous size, the bee has been lost to science since 1981.

In January, a search team that set out to find and photograph Wallace's giant bee successfully rediscovered the species in the North Moluccas, an island group in Indonesia. The find resurrects hope that more of the region’s forests still harbour this very rare species.

A member of the team, biologist and CQUniversity adjunct Professor Environmental Sciences Simon Robson said amid such a well-documented global decline in insect diversity it was wonderful to discover that this iconic species was still hanging on.

“Unfortunately, we know that a lot of insect and animal diversity is declining all over the world so it’s nice to know that this iconic bee still exists out there – it gives you some hope for it,” Prof. Robson said.

“Plus, as biologists we’re always interested in things that are the largest, the smallest, the fastest, the slowest and its gives us some idea of some of the limits of the biological world and how that might adapt to change and we’re certainly living in a world where the environment is changing a lot.”

Prof. Robson, who is also an honorary professor at the University of Sydney, said very little was currently known about the giant bee.

“All that we know at the moment is that it makes nests inside termite mounds, it has incredibly large mandibles which collects resin from trees and it lines the nest with that resin which probably acts as an antifungal device. There is a lot to be learnt about that antiseptic.”

Prof. Robson was with a team organised by Global Wildlife Conservation, a Texas-based organisation that runs a Search for Lost Species program, when the bee was found.

“It was absolutely breathtaking to see this ‘flying bulldog’ of an insect that we weren’t sure existed anymore,” said Clay Bolt, a natural history photographer specialising in bees, who took the first photos and video of the species alive after spending years researching the right habitat with collaborator and team member, Eli Wyman from Princeton University.

“To see how beautiful and big the species is in real life, to hear the sound of its giant wings thrumming as it flew past my head, was just incredible. My dream is to now use this rediscovery to elevate this bee to a symbol of conservation in this part of Indonesia.”

The female giant bee makes her nest in active arboreal termite mounds, using her large mandibles to collect sticky tree resin to line the nest and protect it from invading termites. In hot and humid conditions, and sometimes during torrential downpours, the team observed dozens of termite mounds over the course of the search.

It wasn’t until the last day of a five-day stop in an area of interest that the team, which included Prof. Robson and Dr Glen Chilton, an honorary professor at Saint Mary’s University in Canada, found a single female Wallace’s giant bee living in an arboreal termites’ nest in a tree about 2.5 metres off the ground.

The bee is named after Alfred Russell Wallace, the co-discoverer alongside Charles Darwin of the theory of evolution through natural selection. Wallace, an English entomologist, discovered the giant bee exploring the Indonesian island of Bacan. He described the female bee, which is about the length a human thumb, as “a large black wasp-like insect, with immense jaws like a stag-beetle”.

The bee wasn’t seen again until 1981, when entomologist Adam Messer rediscovered it on three Indonesian islands and was able to observe some of its behaviour, including how it uses its mandibles to gather resin and wood for its nests. Since then, other teams have looked for the bee, with no luck.

In Indonesia, forest destruction for agriculture threatens the habitat for this species and many others. Between 2001 and 2017, Indonesia lost 15 percent of its tree cover, according to Global Forest Watch.

The team has already started conversations with Indonesian collaborators to look for Wallace’s giant bee in other locations—with the hope of eventually working together to develop a plan to strengthen conservation measures for the bee.

A documentary film, In Search of the Giant Bee is now being produced by Vanessa Dylyn of Matter of Fact Media, in association with Townsville-based scientist Glen Chilton.