Sleeping with the ‘enemy’ raises extinction risk

Sleeping with the ‘enemy’ raises extinction risk

Weta might be saying no to interspecies ardour, but human-induced environmental change is looming as a matchmaker.

New research has been looking at a paradox animals at risk of extinction face - breeding themselves out of existence.

Sleeping with the ‘enemy’: hybridization of an endangered tree weta, carries a message that at-risk animals’ habitats, and populations, need to be maintained.

Lincoln University Senior Ecology Tutor Mike Bowie, along with University of Canterbury colleagues, examines whether rare weta species are mating with more common species in the study.

The rare species can become genetically swamped by the genes from the more common one, rendering the former effectively extinct.

They examined if the Banks Peninsula tree weta was breeding and producing hybrids with the more prolific Canterbury tree weta, with which it shares some habitats. They collected and tested 466 DNA samples from the insects for the study.

Natural hybridization is an important part of the evolutionary process and can enable the exchange of adaptive traits between species, or lead to the evolution of new species.

However, these outcomes are rare, especially when hybridization results from human induced changes such as the introduction of exotic species, habitat modification and climate change, which may increase the rates of hybridization beyond natural levels, Mr Bowie said.

While the result show the weta appear to be generally keeping their distance, and they remain distinct species, there are still risks, Mr Bowie said.

Extreme loss of habitat can cause changes to population densities, which increases the risks of hybridization.

“Landowners should be encouraged to conserve native habitat including kanuka and old totara logs and fence posts where these weta reside,” he said.

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