As you walk along some of the tracks criss-crossing Munibung Hill you might notice holes in the tracks under your feet. These are most likely caused by cicadas emerging from the ground where they spend several years as an immature stage called the nymph, feeding on the sap of plant roots.
People will almost certainly notice the cast off exoskeletons from which the adult cicadas emerge (they usually climb onto plants or tree trunks before this happens). The mature insects live only a few weeks during which time they feed off plant sap, mate, and then the females deposit their eggs in crevices of plants or tree branches.
When the nymphs hatch they fall to the ground and burrow beneath the surface. Most of the cicadas on the hill seem to be black with red eyes. Only the males ‘sing’. They do this by flexing their tymbals, which are drum-like organs found in their abdomens.
There are a lot of different coloured cicadas but most of the ones on Munibung Hill seem to be the Red Eye variety.
Here is a summary of Cicada facts courtesy of the Australian Museum. You could use one or more of these as part of a trivia quizz, if ever you were stuck for topics:
- Only male cicadas sing. They do this in an attempt to find a mate.
- Different species have different songs to attract only their own kind.
- Adult cicadas have short lives, usually only a few weeks.
- Most of their lives are spent as nymphs underground. For some species this can be up to several years.
- Cicadas feed only on plant sap using their piercing, sucking mouthparts.
- Cicadas feed on a huge range of plants, including eucalypts and grasses.
- Birds, bats, spiders, wasps, ants, mantids and tree crickets all prey on cicadas. https://australianmuseum.net.au/learn/animals/insects/cicadas-superfamily-cicadoidea/
For a soundtrack of the Cicada mating song, click on this link to Australian Geographic magazine: https://www.australiangeographic.com.au/topics/wildlife/2018/01/the-deafening-soundtracks-of-australias-cicadas/