It's becoming one of the traditions of the festive season: Canberrans wishing and hoping for a return of the beloved Christmas beetle. Once abundant during the summer months, the beetles have been a rare sighting in recent years - particularly through long periods of drought. But while the wet of La Nina had promised a return of the beetles, the past few years have disappointed those longing for the good old days of beetle abundance. Outreach officer at Invertebrates Australia and scientist at CSIRO Dr Hauke Koch said weather was not the only factor behind their fall in numbers. "From a scientific perspective we can't point to one reason for their decline but a loss of habitat especially the eucalyptus grasslands is another reason for their decline," Dr Koch said. There is suspicion that the beetles' larvae do better in the wetter seasons and according to Dr Koch the La Nina years might have helped the population rise. The larvae then turn into pupae, before digging their way underground as adults in much the same way cicadas do. It's believed Australia's long years of drought before La Nina had possibly affected the development of Christmas beetles during their larva stage, which lasts about 2 years. And Dr Koch said it was too early to know if anecdotal reports of Christmas beetle sightings were proof of even a modest comeback. "I've seen a few in my backyard in Chapman and if Canberrans want to catch a glimpse of the beetles the best areas to see them are where there is a lot of eucalyptus and grasslands," Dr Koch said. He said a couple of different Christmas beetle species had been spotted on Mount Ainslie and Black Mountain. Spurred by a lack of long-term data, Dr Koch and his colleagues called on Canberrans to contribute to their monitoring of Christmas beetle populations. In collaboration with Invertebrates Australia, the researchers are encouraging members of the public to snap pictures of the beetles and upload the images to the iNaturalist app or website. "There hasn't been any real research on Christmas beetles over the last decade and we're hoping the citizen- led social project will help us understand the species," Dr Koch said. He said some of the entries into the register were being mistaken for other beetles that look similar, such as the Argentinian Scarab. "A lot of people are confusing the Argentinian Scarab with the Christmas beetle because they usually come out at night and they fly around the lights just like the Christmas beetles," he said.