Scientists have identified a brand-new species of butterfly in Waterton Lakes National Park, a region of high peaks and glacial lakes in Canada's Rocky Mountains.
Long thought to be half-moon hairstreaks, the population of small, brown butterflies is actually an incredibly isolated new species.
Studying its genome, researchers found that this population – which lives around 400km away from its closest relative – may have been isolated for 40,000 years. The species has been named the 'curiously isolated hairstreak’ (Satyrium curiosolus).
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A curious discovery
"Understanding exactly how this population was isolated is a difficult question,” Dr Dupuis, an author of the study, tells BBC Wildlife. However, the species likely managed to survive in a glacial ‘refuge’, a pocket of land that did not freeze over during the last ice age.
The curiously isolated hairstreak is not only geographically and genetically isolated from its relatives, it also occupies a very different niche. “It receives nearly twice as much rainfall, feeds on a distinct larval plant, and forms associations with unique ant species during its larval stage,” Dr MacDonald, lead author of the study, says.
"The species likely managed to survive in a glacial ‘refuge’, a pocket of land that did not freeze over during the last ice age."
Due to their isolation and small population size, the curiously isolated hairstreak is very inbred. High levels of inbreeding often spell disaster for a population, which usually dwindle to extinction.
The curiously isolated hairstreak, though, seems to have gone through a process known as ‘genetic purging’, an unusual case where inbreeding actually leads to bad genes being lost from the population. This means that high inbreeding levels have not spelt disaster for this species.
The species is still at risk, though. With so few individuals, low levels of genetic diversity, and extreme ecological specialisation, the butterfly is probably unlikely to be able to cope with change – but a changing climate is coming.
Usually, conservationists can do something called ‘genetic rescue’ in such cases. This is where a closely related species breeds with the population, mixing in new versions of genes and increasing genetic diversity. But this is unlikely to work in the curiously isolated hairstreak.
“Given the genetic differentiation and the ecological uniqueness of the population… bringing in butterflies from other areas, with differently adapted genomes, could actually decrease the health of the population,” Dr Dupuis says.
For now, the species will be managed without genetic rescue, although this method is not being ruled out as a last-ditch method of species recovery.
While finding such an isolated new species is unusual, 'cryptic’ species (new species that look like already-known species) are common. "In almost every genomic study we conduct on insects, cryptic species abound!” Dr Macdonald says. "There is much more diversity that initially meets our eye.”
Find out more about the study: Genomic and ecological divergence support recognition of a new species of endangered Satyrium butterfly (Lepidoptera, Lycaenidae)
Main image: mountain views in Waterton Lakes National Park in Alberta, Canada. Credit: Getty
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