14,000 Tagged Moths Go Missing—And Scientists Are Thrilled

Scientists just lost 14,000 tagged moths and they couldn't be happier about it.

Researchers tagged over 14,000 bogong moths this past February in the caves of Mount Kosciuszko, hoping to finally solve a decades-old mystery about where these tiny travelers go each year. The plan was simple: volunteers would check 50 light traps across Australia's Snowy Mountains and record any tagged moths they spotted.

But not a single tagged moth has turned up. And that's actually incredible news.

"It's actually a good thing because the probability of sighting a tagged animal is dependent on how many there are in the population," says Eleanor Drinkwater, an entomologist at Invertebrates Australia. "In our case, it shows there might be more moths than we thought."

Every year, billions of bogong moths make an epic journey across Australia to escape the summer heat in the Snowy Mountains' cool caves. When autumn arrives, they travel thousands of kilometers back to their breeding grounds inland, but scientists still don't know which route they take.

The stakes for understanding these migrations are high. Bogong moth populations crashed by 99.5 percent in 2017 due to drought and climate change, earning them endangered status in 2021. These peanut-sized insects were once so abundant they were a traditional food source for Indigenous Australians and attracted visitors from across the region.

Kristi Bryant, a volunteer from Cooma, checks her backyard light trap every morning with her young family. "It's like Willy Wonka and the Chocolate Factory, you want to find the golden ticket," she says. While she's seen plenty of bogong moths, none wore the tiny paper tags researchers attached with eyelash glue.

The Bright Side

The missing tags tell a hopeful story. If the tagged moths are getting lost in a much larger crowd, the population might be recovering faster than scientists dared to hope. There's also a chance the moths are taking different routes than expected, which would reveal new information about their behavior and habitat needs.

Meanwhile, citizen scientists have recorded over 2,700 bogong moth sightings on iNaturalist in the past year, more than double the previous year's count. Researchers will use these observations to create heat maps showing moth movements and train artificial intelligence to detect the insects in camera footage.

The team plans to expand from 50 to 150 light traps by next year. As temperatures rise again, moths are already heading back to the Alps for another summer season.

"I don't have any theories as to where the tagged moths are, but I'm hoping they're living safe and happy lives and building more communities of bogong moths," Bryant says.