New tick species facing extinction

By AG Staff 8 March 2017
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Researchers believe a newly discovered species of Australian tick is at risk of extinction due to its preference for one critically endangered marsupial.

SCIENTISTS HAVE DISCOVERED a new species of Australian tick, but believe it may already be facing extinction due to its preference for critically endangered woylies.

The researchers, from Murdoch University in Western Australia, collected ticks from the two remaining woylie populations in south western Australia and found 42 per cent of woylies with ticks hosted the new species, which has been named Ixodes woyliei

The researchers also looked at ticks on268 other marsupials in the same areas, including brushtail possums, western quolls and southern brown bandicoots, but only found the new tick species on two of the animals.

This is the first new Australian Ixodes tick species described for more than 50 years. 

The woylie, also known as the brush-tailed bettong, is endemic to Australia. While the marsupial once inhabited 60 per cent of the mainland, its numbers have crashed in the past decade.

Juvenile woylie

A juvenile woylie, or brush-tailed bettong. (Image: Sabrina Trocini/Murdoch University)

The researchers believe parasite infections may have played a role in the population decline, which is why they have been collecting data on woylie parasites such as ticks.

“When considering the critically endangered status of woylies, having undergone a 90 per cent decline in seven years, and the apparent host specificity of Ixodes woyliei, there is a very real risk of a future co-extinction event,” said Dr Amanda Ash from the parasitology research team at Murdoch University’s School of Veterinary and Life Sciences.

While commonly considered a pest, Amanda said parasites such as ticks can in fact play an important role in conservation for host species, acting as “ecosystem engineers”.

“As such, it is important to understand more about this host-parasite relationship,” she said.

“Parasites can influence the behaviour of hosts, regulate population sizes and act as ecosystem engineers. So parasite extinction may have important impacts on how an ecosystem functions and can affect biodiversity,” she said.

Amanda said the transmission of the new tick species may be confined to the location of woylie nests, usually under grass trees, which would explain why the species is largely found on the endangered marsupial. This means the tick species could face extinction as a result of translocation events aimed at saving surviving woylie populations.

“Woylies are currently the focus of intense conservation management strategies involving the frequent and wide scale translocation of the species across Australia. Some translocation protocols involve treatment for parasites, with ticks eliminated,” she explained.

However, the species has been found on woylies at Karakamia Wildlife Sanctuary, suggesting they can survive translocation under the right conditions. “But more research is required to understand this relationship fully,” she said.

The research was published in the journal Parasites and Vectors.