So, have you noticed more Christmas beetles around your neighbourhood this year? I have seen more than usual around Tuggeranong and it's made my heart sing.

I probably wouldn't like to return to 2016-17 when the Christmas beetles reached plague proportions in some parts of Canberra.

Some people even reported Christmas beetle poo raining down on them as they picnicked under gum trees. CSIRO Research Projects Officer Alan Landford said then that a milder, wetter than usual winter and spring had made perfect conditions not just for Christmas beetles but their food source of leaves.

But we've had a drier than average winter and October was also warmer and drier, with spring stats due out soon.

Canberra insect expert Jim Bariesheff said this week that Christmas beetles operated on a four to seven-year cycle, depending on the species, which could mean some species were experiencing a boom in some areas.

"They tend to come out when you've got the warmer weather," he said.

Dr Chris Reid, principal research scientist, at the Australia Museum, wrote earlier this year there were 36 species in the genus with all but one unique to Australia.

He suggested Christmas beetles were on the decline in the concrete jungle of central Sydney.

"The evidence suggesting a decline is anecdotal yet compelling," he wrote.

"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."