Taxonomists who closely examined a very damaged, unassuming, small white micro-moth (Topiris candidella) held in the collections of the Natural History Museum (NHM) in London have unveiled a previously unknown history linking it to the famous naturalist and explorer Alfred Russel Wallace.
In addition, the analysis of the moth has proven key to discovering 13 other species in its genus – 11 of these are new to science, and one has been named T. thunbergella, to honour the climate activist Greta Thunberg.
The new paper, published in ZooKeys, describes how a hidden label beneath the pinned moth bore the handwritten letters 'SAR', revealing that it had actually been collected in Borneo by the naturalist Alfred Russel Wallace in late 1855. Just months later, he published his ‘Sarawak Law’ paper, where he wrote about new species evolving from existing ones.
The species was later described by Francis Walker in 1863, but the specimen was dismissed by the eminent entomologist Edward Meyrick in 1927 as “better neglected” due to its poor state.
At some point prior to 1929, the specimen became badly damaged, and all that remains now are the pin which held the moth in place, part of its thorax and legs, the forewings, and the hindwings – the lattermost having become detached at some point and now mounted and labelled separately.
When this project first began in 2017, the available technology wasn’t suitable for analysing the DNA. However, a pilot study using cutting-edge genome skimming techniques looked promising. In November 2022, the scientists removed a small fragment from one of the specimen’s remaining legs, and sent it to be analysed.
The results revealed a connection of a small groups of moths in south-east Asia, and 11 species new to science, which are described in the paper.
“This discovery highlights the incredible potential of modern DNA analysis to reveal the evolutionary history of species, even from fragmented and long-forgotten specimens,” says Dr David Lees, Senior Curator for Microlepidoptera at the Natural History Museum.
“By applying this innovative sequencing technique, we have not only revived Francis Walker’s species Topiris candidella, from 1863, but also expanded our understanding of an entire group of small white moths.”
The study and the new genome skinning technique means that scientists are now hoping to more thoroughly examine the other Microlepidotera collected by Alfred Russel Wallace and held at the NHM, which have been “neglected by taxonomists”.
Main image: Topiris candidella, the modern specimen used for the reference sequence/Mark Sterling, Trustees of NHMUK
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