General News
30 January, 2023
New finds put township on butterfly map
Take a tightly growing patch of sweet bursaria, add in a colony or two of a relatively little-known bush ant, and top it off with a liberal scattering of the handsome but critically endangered Eltham copper butterfly. What do you have? The result is...
Take a tightly growing patch of sweet bursaria, add in a colony or two of a relatively little-known bush ant, and top it off with a liberal scattering of the handsome but critically endangered Eltham copper butterfly.
What do you have? The result is the delicately balanced triumvirate that scientists have just discovered, to their delight, at not one but two previously unknown sites in the Wimmera.
The Eltham copper butterfly (Paralucia pyrodiscus lucida) might be small, at about the size of a 10-cent coin, but it’s a native species that conservationists are working hard to preserve.
The butterfly hasn’t fared well since land clearing began in earnest in south-east Australia and now only a few populations remain, isolated from each other by expanses of agricultural land.
Further complicating its chances of surviving, the butterfly must have both sweet bursaria (Bursaria spinosa) and the ant in order to breed.
Adults lay their eggs on the shrub and once the larvae emerge they feed on its leaves.
Enter the Notoncus ectatommoides ant, described in decidedly non-scientific terms as “a bouncer” for the vulnerable larvae, “scaring off predators that would otherwise feast on their juicy bodies”.
What’s in it for these ants?
They in turn devour the sticky-sweet waste that the butterfly babies excrete.
“The Eltham copper butterfly was first found in the Wimmera in 1988 at Salisbury Bushland Reserve and in a small area of Kiata Flora Reserve,” Wetland Revival Trust ecologist Elaine Bayes said.
“In 2011, another tiny population – six hectares – was found on a Wail roadside.”
In the interim, however, the Salisbury population had slipped into extinction, most likely as a result of sheep grazing out its only food source.
This makes the new discoveries a major win for Ms Bayes, who has been working since 2009 to protect this tiny butterfly.
“This year our team searched 1600ha of public land, 1400ha of which was in the Wimmera,” she said.
“We were certainly rewarded for the effort, with around 500 ECB seen between two Gerang Gerung reserves.”
Search areas included Gerang Gerung Mallee Dam, Gerang Gerung South Reserve. Glenlee Nature Conservation Reserve, Barrett Nature Conservation Reserve, Lierschs Nature Conservation Reserve, Coker Dam Wildlife Reserve and Lil Lil Dam.
In fact, the health of the two new Wimmera communities puts to shame those on the Melbourne fringe where the butterfly was first observed and after which it’s named, as well as the few that have been identified in the centre of the state.
“To give perspective, in north central Victoria last year we searched 1000ha and found a total of 43 ECB peppered across a large area,” Ms Bayes said.
“To see 500 ECBs in one season is exceptional, and so far this is the largest number of ECB and the largest area of ECB habitat ever found.”
Ms Bayes encourages Wimmera landholders to carry out their own Eltham copper butterfly surveys.
“ECB only occur where sweet bursaria plants are dense – more than 30 plants in a quarter-hectare,” she said.
“Look for the copper sparkle of flying adults on still days that are between 20 and 30 degrees."
Sightings can be reported on www.butterflies.net.au; the inaturalist app, www.inaturalist.org; or the Butterfly Australia app, butterflies.net.au