A recent statement by ecologist John Morgan on twitter alerted us to the possible demise of the iconic Bogong moth. He stated “Another beautiful evening in the Victorian Alps. But not a Bogong Moth to be seen……..for the 2nd year running. Once in their tens of millions (indeed it was often newsworthy), their failure to arrive in the alps to aestivate has almost gone unnoticed.”
This was closely followed by a Guardian article by Graham Readfearn that noted the direct connection between climate change exacerbated drought in their breeding grounds and the drastic drop in their numbers. “The ecologist Dr Ken Green has been monitoring bogong moths for 40 years. He said: “Last summer numbers were atrocious. It was not just really bad, it was the worst I had ever seen. Now this year it’s got even worse.”
“The moths find caves and cracks in boulders to hide away in a torpor state. A cave at Mount Gingera, near Canberra, has been known to house millions of the moths but last month Green and colleagues counted just three individuals. Searches of about 50 known sites have turned up similar catastrophic absences. They haven’t just declined. They’ve gone…” The article also emphasised the impact that this was having on the endangered Mountain Pygmy Possum – heavily dependent on the moth as a food source.
Wikipedia notes that “The bogong moth (Agrotis infusa) is a temperate species of night-flying moth, notable for its biannual long-distance seasonal migrations towards and from the Australian Alps, similar to the diurnal monarch butterfly. During the autumn and winter it is found in southern Queensland, western New South Wales, western Victoria… Adult bogong moths breed and larvae hatch during this period, consuming winter pasture plants during their growth. During the spring, the moths migrate south or east and reside in mountains such as Mount Bogong, where they gregariously aestivate over the summer until their return towards breeding grounds again in the autumn.”
Of some interest is a review I recently posted of Barbara Kingsolver’s novel Flight Behavior – an account of how the changing climate messed up the aestivation and migration of the monarch butterfly. Now it appears as though some of the bizarre fictional accounts are being realised in our own backyard, with the bogong moth a species with a similar life cycle to the monarch.
Like the recent dreadful mortalities amongst Bairnsdale’s flying-fox colony, the plight of the bogong moth is another wake-up call – another ‘canary in the coal mine’ – that tells us urgent action is required on climate change now. I hope to do a follow up post on this in the next few weeks.