In Australia, It Isn’t Christmas Without the Beetles.

Swarms of iridescent insects used to mark the Southern Hemisphere season, but now they are becoming almost as scarce as snowflakes.

Americans dream of a white Christmas. In Australia, many people are hoping for brown, green and yellow beetles.

In Yuletides past, swarms of so-called Christmas beetles, a group that includes about 35 different species, would emerge around the holidays, which hit in the middle of Australia’s summer. Although the beetles are clumsy fliers that slam into walls, windows, people and pets, fans say the insects’ iridescent and colorful carapaces complemented the festive season.

But now, scientists and everyday Australians say they are seeing fewer beetles, and they’re trying to figure out why.