I just came across this great photographer in Timemachine magazine. This is beautiful, evocative work – have a look! It is all about the changes taking place in Hungary and central Europe, with such a sense of loss and mystery. Tamas Dezso
This is copied from the Australian Museum, because I was wondering if anyone else had missed these wonderful insects and googled the question. It seems the answer is yes, but because no one has had the funding to do a proper study, the evidence is “only anecdotal”. How many other less obvious insects have gone the same way? I feel strangely alone in my concerns; the world is becoming diminished and little notice is taken.
It’s that time of year when retailers bemoan the fickle habits of consumers, people clean out their barbeques and Christmas beetles crash into windows and pile up around streetlights . . . or do they? Entomologist Chris Reid investigates.
Each year I am asked, ‘Where have all the Christmas beetles gone?’ Have they really declined, and what is a Christmas beetle anyway?
Christmas beetles are a type of scarab (a group that includes dung beetles and chafers). Compared to other scarabs, Christmas beetles (genus Anoplognathus) are large and chunky, somewhat flattened in shape and with metallic brown, yellow or pink colours. They most obviously make themselves known in midsummer by swarming around lights in towns throughout eastern Australia.
The adults generally feed on eucalyptus leaves. They prefer open woodland to forest and thrive in pastures wherever trees have been left in place. In farmland they can form dense masses on the remaining eucalypts, chomping through leaves, sometimes killing their hosts. In contrast to the adults, the larvae (grubs) feed on roots, usually of grasses. Some species are economically important pests of eucalytpus plantations while others are implicated in dieback – the decline of mature trees in landscapes like those in NSW’s New England Tableland.
There are 36 species in the genus with all but one unique (endemic) to Australia and 21 species found in New South Wales. At least 10 species occur in the Sydney region – more if the Blue Mountains are included. Because they are such a feature of the eastern Australian experience some common species have been given English names, such as the Washerwoman, Anoplognathus porosus, and (rarer) King Beetle, Anoplognathus viridiaeneus (see photos, right). Distinguishing some species can be tricky, but it helps to examine the hairs on their ‘bums’ (posterior). (This is something of an in-joke among entomologists but it actually works for this group!)
The evidence suggesting a decline is anecdotal yet compelling. In the 1920s, they were reported to drown in huge numbers in Sydney Harbour, with tree branches bending into the water under the sheer weight of the massed beetles. You won’t see that these days, and I’ve never seen a Christmas beetle come to light where I work, next to Hyde Park. While public concerns suggest that numbers are also much smaller in the suburbs, I’ve found at least five species near my home, clustered around street lights at the southern edge of Royal National Park, 55 kilometres south of Sydney.
If we accept that Christmas beetles have declined in central Sydney, the next question is ‘why?’. The dual life history provides a clue. The adults need eucalypt leaves, and the larvae need the roots of grasses, presumably native grasses. An important habitat for them, the Cumberland Plain woodland, was once widespread in Western Sydney, but less than 10% remains.
Sydney is now bulging at the seams with 4.5 million people, and Western Sydney has absorbed much of the growth. The beetles’ former habitat is now a brick, concrete and tarmac jungle. Christmas just isn’t what it used to be, is it?
Chris Reid, Principal Research Scientist
For a fully illustrated key to the Christmas beetles of New South Wales, go to keys.australianmuseum.net.au.
First published in Explore 33(4), summer 2011.
Brendan Atkins , Publications Coordinator
Last Updated: 16 January 2012
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– See more at: http://australianmuseum.net.au/Christmas-beetles#sthash.Y7dgEzZJ.dpuf
I was listening to a BBC podcast the other day; Sophie Lake from VINE (Values In Nature and the Environment http://www.vineproject.org.uk/) was talking about her theory of ‘generational amnesia’, whereby each generation “re-calibrates” environmental diversity according to their own childhood experiences. It really resonated with me, the way it does when your own private musings are put forward publicly by someone else. I have been thinking exactly this; that each generation learns the natural world as it is when they are children, and this becomes the benchmark by which they measure change. I remember when we first came here in 1978. Giant green tree frogs were constant visitors; every evening we could hear the ‘plop’ as they landed wetly on the deck, they were so placid, you could pick them up and they would nestle comfortably in the palm of your hand, quite filling it up. And their smaller relatives, about 2 -3 cms long, which loved to sit on the windows in the most elegant frog shapes, catching the insects drawn to the light. There would be at least half a dozen of those at any one time. Now the only green tree frogs left around here are the tiny ones that hide in the trees; the only time you are aware of them is when they call just before it rains. The giant tree frogs disappeared when our children were quite small; there is a photo below of one being introduced to our 18mnth old first child, but to the now adult children their absence is ‘normal’. Similarly – where have all the butterflies gone? – the brilliant black and white and red swallowtail butterflies, and the blue triangle butterflies, and a myriad complex patterned moths; a long-necked swamp tortoise is rare now when it used to be not uncommon. Generation by generation our countryside is depleted, and as a society we are scarcely aware of it. People shift their feet uncomfortably if you mention it even casually. They don’t want to be reminded.