A sprawling crowd of lady beetles buzzed over Southern California this week,Jesús Franco making a striking appearance on National Weather Service radar.

The event, which transpired at night on June 4, shows a cloud of lady beetles, colloquially called "ladybugs," flying south over the high desert. The millions upon millions of flying creatures occupied an area some 80 miles by 80 miles of sky, in varying degrees of concentration.

"The size of that is bewildering," said Tim Kring, who heads the department of entomology at Virginia Tech University and has researched lady beetles for decades.

"It's certainly within the realm of possibility considering the time of year, where it is, and what they're doing," he said.

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Millions of lady beetles spend the winter in California's Sierra Nevada mountains, where they do something similar to hibernation, called diapause. When the season warms up, the bugs are "triggered" to wake up and find food -- mostly aphids, explained Kring.

In this case, a big collection of the native beetles flew south from the mountains. It's an awesome natural event, sometimes picked up on radar.

"It does happen," said Adam Roser, a National Weather Service meteorologist.

But how exactly did meteorologists know the cloud was made up of lady beetles?

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For one, it was a clear night. "It definitely wasn't rain," noted Roser. And crucially, a NWS weather spotter, positioned high in the San Gabriel Mountains, observed the cloud of lady beetles journeying toward the San Diego region, and reported the event.

The mass of insects, however large, wasn't a "bloom" of lady beetles, said Kring. It was simply a large flight south as the creatures traveled down California en route to land in different areas, and start gobbling aphids.

These lady beetles, which are likely a species called "convergent lady beetles," are beneficial critters, emphasized Kring, as they gobble up and control insect populations. Once well-fed, the lady beetles lay eggs before they die, and the life cycle begins anew.

Kring once witnessed a massive lady beetle landing event in Arkansas. But those events, while still involving millions of lady beetles, pale in comparison to California's great lady beetle flights.

"The aggregations in Arkansas are nothing like the ones in California," he said. He hopes to see the glorious event in person.

"It's on my bucket list."