Each year Macquarie holds an Open Day, where the university opens its doors to prospective students, families and anyone interested in looking around the uni. It is a day to explore what courses you can study, but also to see what facilities the university has, a bit about their research and have some fun. The Biology Department usually puts on a good show. This year there was free fairy floss made by students in lab coats and safety glasses, face painting and a live animal show where you could touch a tawny frogmouth, an olive python and a sleepy lizard.
I put up a display about Scribbly Gums: icons of the Australian Bush. It is easy to recognise the extraordinary scribbles on some smooth-barked Eucalyptus or gum trees, but it is hard to resist tracing them with your finger or trying to decipher the scribbles! They frequently feature in Australian literature (such as May Gibbs’ Snugglepot and Cuddlepie, Patrick White’s The Tree of Man and Judith Wright’s Scribbly Gum) and place names (there’s a Scribbly street, place, circuit, crescent, close, square, road and drive in Australia). But what makes the scribbles?
Scribbles are burrows made by the larvae (grubs) of the scribbly gum moths as they eat the wood just under the bark. By the time the bark has been shed and the scribbles are exposed, the larvae is gone – it has pupated at the base of the tree and metamorphosed into a moth. A scribbly gum moth was described in 1939 and named Ogmograptis scribula. The wingspan of the moth is only 8 mm across!
Although scribbles occur on over 20 species of Eucalypts, for many years there was only one species described. In 2007 I published measurements of scribbles showing that the size and shape of the scribbles differed between eucalypt species. Together with Ted Edwards, we suggested that there was more than the single species of moth described – in fact there could be a different moth for each eucalypt species. More recently scientists from CSIRO caught larvae and moths from many eucalypt hosts and have identified several new species, with their findings due to be published later this year.
– Julia Cooke
References:  Nielsen ES & Common IFB. 1991. Lepidoptera (moths and butterflies). In: The Insects of Australia (ed. J Naumann), pp. 817–915. Melbourne University Press, Melbourne, Australia.  Meyrick E. 1935. Elachistidae. In: Exotic Microlepidoptera, pp. 600–601. Taylor & Francis, London, UK. Brooker MIH, Slee AV, Connors JR & Duffy SM. 2002. EUCLID: Eucalypts of Southern Australia, (CD ROM) 2nd edn. CSIRO Publishing, Collingwood, Victoria, Australia. Cooke, J. and Edwards, T. ‘The behaviour of scribbly gum moth larvae Ogmograptis sp. Meyrick (Lepidoptera: Bucculatricidae) in the Australian Capital Territory’, Australian Journal of Entomology, vol. 46, 2007, pp 269–75. Day, M. 2012. Deciphering the Message Stick. Meanjin 71(2): 30-38