Research into the genetics of Bermuda’s population of leafcutter bees has sparked more questions about their possible origin.

Jenn Rose, who studied the insects as part of her masters of science thesis at the University of Copenhagen, Denmark, sought to use their genetic make-up to determine where they came from.

In the summer edition of the Envirotalk newsletter, published by the Department of Environment and Natural Resources, Ms Rose said Bermuda’s leafcutter bees, Megachile pruina pruina, may represent a “unique lineage” no longer found in the United States.

“Despite over 20,000 bee species globally, our understanding of their natural history and diversity remains largely unexplored and unknown,” she said.

“This knowledge gap presents a significant challenge as many species may vanish without a trace.”

Bermuda’s population of leafcutter bees is found in the Castle Harbour Islands Nature Reserve and, while the insects are considered a vulnerable species under the Bermuda Protected Species Act, Ms Rose said little research had been carried out on them.

She said an analysis of their DNA revealed a “strong separation” between Bermuda’s leafcutter bees and those found in the United States, while there was relatively little separation between different populations in the US.

“Bermuda’s M pruina samples were more closely related to an unidentified species collected in Mexico as well as two species collected in three locations in the Caribbean,” Ms Rose said.

“Unfortunately, the inability to identify the Mexican species has left a mystery surrounding this relationship.

“The origins of Bermuda’s leafcutter bee become particularly intriguing when considering the island’s isolation and considerable distance from the mainland.

“Further analysis estimating divergence could provide insights into the bee’s arrival in Bermuda, while previous studies indicate that M pruina in the United States evolved around four to nine million years ago.”

Ms Smith said it was possible that leafcutter bees reached the island through the Gulf Stream and was able to survive because of its foraging strategies, along with the prevalence of plants found in the US and Caribbean.

“While the leafcutter bee population in Bermuda did not originate from the populations analysed, it is plausible that the source population either was not sampled or became extinct,” she said.

“Considering its close relationship to Caribbean and Latin American species, it is also possible that M pruina might have historically existed or still exists in these regions, as the true distribution of the species in North America has not been extensively studied.

“If the source population no longer exists, the bee population in Bermuda could potentially represent a unique and isolated evolutionary lineage, echoing the familiar narrative of the Bermuda skink.”

Ms Rose also noted that Bermuda’s leafcutter bee population has lower genetic diversity than populations in the US, which increased the likelihood of inbreeding and the creation of sterile “diploid” drones.

“Although the male Bermuda leafcutter bees examined in this study were not diploid, the limited sample size warrants further analysis and investigation,” she said.

Ms Rose said more work was needed to determine if Bermuda’s leafcutter bees were an endemic subspecies found no where else in the world and to help develop conservation strategies to safeguard the population.

“Given that only 3.7 per cent of Bermuda’s insect species are considered endemic, it is vital to conserve and protect this unique bee exclusive to the island,” she added.