Issue 22
Monday, 05 December 2016
Charles Darwin University
Nerida Liddle examines the contents of bilby faecal pellets gathered in the Tanami
Nerida Liddle examines the contents of bilby faecal pellets gathered in the Tanami

Tanami bilbies dine out on root larvae

By Patrick Nelson

A Charles Darwin University student has found that bilbies in the Tanami Desert include root larvae in their diet.

Bachelor of Science (Hons) student Nerida Liddle ventured deep into the Tanami on three occasions this year to gather data about the foraging behaviour and diet of the greater bilby (Macrotis lagotis).

“We know that bilbies eat seeds, bulbs and termites, but this new evidence confirms that root-dwelling larvae also are an important part of their diet,” Nerida said.

“Remains of root larvae were detected in at least 33 per cent of bilby faecal pellets sampled.”

She said she was exploring the influence fire might have on the availability of this food source for bilbies.

“We were interested in understanding how the abundance of root-dwelling larvae in three species of Acacia and one species of Senna varied in relation to time since fire last passed through.

“Larvae were most commonly found in short-lived Senna plants aged between six months and two years, and in longer-lived Acacias aged between three and nine years.

“Six months after fire there were no fresh bilby diggings under Senna shrubs, presumably because the shrubs were still too small to host many larvae, but in areas unburnt for three to five years bilbies selectively dug under Acacia species known to host larvae.”

Nerida said she also set up motion-detecting infra-red cameras near the entrance to 12 bilby burrows at her field site at the ABM Resources NL Twin Bonanza mine near the West Australian border.

“This showed how often bilbies visited the burrows, how long they remained at the burrow entrance and what other animals came by.

“I was able to clearly identify at least three different bilbies – one had damaged ears, which made it easy to identify – but the cameras also captured images of cats, dingoes, goannas, rodents, birds and a mulga snake.”

Nerida said the greater bilby was classified as vulnerable under national legislation. 

“This research confirms that root-dwelling larvae are an important food source for the bilby. Additionally, time since fire influences the availability of larvae for bilbies. Promoting bilby food resources through strategic fire management may help conserve them,” she said.