ABOVE: Dead Christmas beetles found by Dr Kym Watling who collected them in this box.
November has come and gone in Unumgar without the sighting of a Christmas beetle – once a reliable reminder that the Christmas season was about to commence.
It wasn’t that long ago that Christmas beetles were plentiful in the Northern Rivers.
Many locals will remember the swarms of 2014-2015, where you could fill buckets with Christmas beetles under a single eucalypt in Kyogle. Tree farms were defoliated and residents were concerned by the mysterious eucalyptus dieback.
Christmas beetles are large scarab beetles in the genus Anoplognathus, with about 35 species native to Australia. They are as uniquely Australian as a koala, kangaroo or platypus, and equally as embedded in Australian culture.
The foreword of Fred Powis’s 1946 children’s book Billie the Beetle states that “during the summer season, the Australian Christmas beetle is a well-known little fellow to children in both town and country”.
Now, over 75 years later, particularly in Australian cities, children under the age of 10 may grow up without ever having seen one.
According to the Northern Star in 2016, Associate Professor Doland Nichols of Southern Cross University considered the area northwest of Kyogle to be a hotspot for Christmas beetles.
At our home in Unumgar, surrounded by a tree farm and pasture, hundreds of Christmas beetles were attracted to our house lights each night. We kept them in a glass bowl to avoid trampling them, fed them gum leaves and embedded deceased beetles in resin as artworks and keepsakes. We had no idea how important this would be.
The drought took hold and the tree farm was returned to pasture. We saw less Christmas beetles, and they appeared later each year. We found only one beetle in late December 2019 after the fires, and none in 2020-21. One brave latecomer was seen to arrive in March this year, closer to Easter than Christmas.
Christmas beetles have a secret double life, spending their first year or two underground as a curl grub larvae, eating debris and the roots of native grasses, before forming a pupa to transform to the adult stage. The adults emerge from rain-softened ground to go about the work of eating and mating.
Adults are nocturnal and feed on specific eucalyptus trees, including spotted gum (Corymbia maculata), Dunn’s white gum (Eucalyptus dunnii), rose gum (E. grandis), and western white gum (E. argophloia), before returning to pasture to lay their eggs in the soil.
Larvae are susceptible to a range of factors while in the soil, with temperature and moisture being crucial. High temperature stress begins when it is above 32.5C and 40C is considered lethal.
There are high rates of death in very dry and very wet soils.
Are the Anoplognathus species in decline? The answer from Associate Professor Tanya Latty of the University of Sydney, is an emphatic “We don’t know”.
Anecdotal evidence indicates they are in decline but without a formal monitoring program there is no baseline to measure changes in population.
This is how people like us can help. The University of Sydney has partnered with Invertebrates Australia to host the Christmas Beetle Count. This allows locals to report sightings of Christmas beetles in their own backyard, using the online iNaturalist platform.
The researchers plan to continue the count each year to see whether the loss is real and if so, to find the reasons why.
If the populations are in decline, the most likely reasons may be habitat loss, insecticides and extreme weather, but at the moment, we just don’t know.
If you’d like to assist with this project and report your Christmas beetle sightings visit.