Megachile pluto

Females can reach 38 mm in body length, with a wingspan of 63.5 mm.

Researchers describe it as the largest known living bee species on Earth.

Females have extraordinarily long mandibles (jaws) and an enlarged upper lip.

It is known only from three islands in the North Moluccas of Indonesia: Bacan, Halmahera and Tidore.

Researchers think it nests communally inside termite nests in trees.

Females nest inside the nests of a tree-dwelling termite, Microcerotermes amboinensis.

Nesting females gather resin from nearby trees and use it as their main building material.

The females appear to use their big jaws to collect tree resin, rolling it into neat balls that they carry in flight.

Alfred Russel Wallace collected the bee on Bacan Island in the late 1850s, and the British entomologist Frederick Smith described it as a new species in 1860.

After going unrecorded for many decades, the bee was found again in 1981 by the entomologist Adam C. Messer, who reported the first known males.

A specimen offered on an international online auction site sold to a private collector for US$9,100.

In January 2019 a search team found a single female living in a termite nest in a tree, about 2.5 metres off the ground, in the North Moluccas.

The IUCN Red List assesses Wallace's giant bee as Vulnerable (assessment by Michael Kuhlmann, published 2014).

Its forest habitat faces extensive clearing for agriculture, which researchers see as a concern for the species.