Belfast now home to mysterious new species of beetle that may have come from Australia

The little beetle may have come from Australia
The little beetle may have come from Australia -Credit:Joshua Clarke/Buglife

A mysterious new species of beetle has been discovered by a conservationist in Northern Ireland.

Joshua Clarke was carrying out a night time survey for Buglife NI when he came across the colourful creature now named Xenosacalles irlandikos, which loosely translates as the Irish stranger weevil.

The bug's new name stems from the fact it is believed to have arrived here from somewhere else but it also goes by the nickname the 'fence-climber twiglet weevil' due to its prevalence on wooden fences.

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Following its discovery in Co Down in September 2022, Joshua teamed up with Stewart Rosell, a PhD student based at Agri-Food and Biosciences Institute, to search other sites with similar habitat for the weevil.

That led to finds in other areas, including Belfast, before it was discovered leading Irish entomologist, Dr Roy Anderson, had independently collected specimens as early as 2011 which remained undetermined.

They were later confirmed to be the same species after efforts to evaluate and describe the new species with the help of leading weevil researcher, Dr Peter Stüben, at the Curculio Institute in Germany.

The colourful weevil from above
The colourful weevil from above -Credit:Joshua Clarke/Buglife

Dr Stüben said: "The distinct features, like the raised reddish-brown structure on its back called the scutellum, along with genetic analysis of its mitochondrial DNA, revealed this weevil was not closely related to any known Western Palearctic species."

The weevil expert described the new species' morphology and provided its DNA barcode in the journal Weevil News and was later contacted by Tasmanian entomologist and weevil enthusiast, Otto Bell, who recognised the species as a possible undescribed weevil specimen he and his twin brother Bruno Bell had collected in Victoria, Australia.

"We only know of several specimens of this previously undetermined species," said Mr Bell.

Two of those specimens are available in the Tasmanian Museum & Art Gallery collections. Senior curator Dr Simon Grove said: "These specimens were collected by Dick Bashford in 2010 on King Island as by-catch during panel traps for monitoring Ips bark beetles and remained undescribed until now" adding, "we agreed Xenosacalles irlandikos is our weevil".

AFBI's Stewart Rosell said the discovery of the new beetle on the island of Ireland "highlights our incomplete understanding of global invertebrate biodiversity and the challenges this creates for entomologists identifying and understanding non-native invertebrates".

The Irish stranger weevil having a sit down
The Irish stranger weevil having a sit down -Credit:Joshua Clarke/Buglife

Joshua, whose discovery sparked the chain of events that have now given the beetle a name, said: "The influx of non-native species to Ireland shows no signs of slowing down. Introductions frequently occur through the importation of plants and wood products and factors like climate change may enable introduced species to gain a foothold and proliferate in new regions.

"This includes non-native species being described outside of their native range, such as the flatworm Marionfyfea adventor with probable introduction from New Zealand, and Anasaitis milesae , a jumping spider with speculative origins from the Caribbean."

Research is ongoing to confirm the Irish stranger weevil's origins, phylogeny, and ecology.

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