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A Real Alien Invasion Is Coming to a Palm Tree Near You | Deep Look

October 1, 2019


Aah, Southern California. Y’know, the whole “surf’s up, Tinseltown,
sun-soaked glamour” thing? Too bad this idyllic landscape is mostly make-believe. Take the palm trees. They’re not even real trees. They’re more closely related to grass. And they’re imported. Like this Canary Island date palm. It came halfway around the world to be one
of the more dazzling stars in the landscape. But this Hollywood success story is turning
into a horror movie. This little monster is the South American
palm weevil. Scientists first found it in San Diego in
2011. Weevils are just beetles… with snouts. This female uses hers as a drill, to get at
the palm’s apical meristem. It’s a bowl of juicy goodness at the top,
where the leaves sprout. She lays her eggs down in those tunnels. And her spawn eat the palm from the inside
out… starting with its heart. That’s right; it’s the same stuff you
can get at the supermarket. They’ll turn this palm’s healthy flesh
into a rotting mess that smells like a dumpster in the sun. Once they’re big enough, the larvae will
spin cigar-shaped cocoons from the leftover fibers they can’t eat. As the trees’ fronds starve and die, the
larvae hang out and gestate, morphing into pupae, and… Ew, that’s just, oh man… That’s gross. As adults, they burst out, take flight and
seek out a new host… leaving behind the dying, hollow shell of a once majestic palm. Mark Hoddle, at UC Riverside, is tracking
the weevil infestation. He puts them on a kind of aerial treadmill
in his lab to test their stamina. He’s trying to figure out how they got here,
whether they hitched a ride on imported palms, or made the trip themselves. Turns out they can fly up to 15 miles a day,
enough to hopscotch from palm to palm on their own. The only way to stop them: treat every palm
tree in their path with pesticides before the weevils get there. That’ll be tough to do. So these particular botanical icons could
be on the fast track to being just another Hollywood has-been. These weevils are pretty gnarly. So we asked Anna Rothschild from Gross Science
to do those animations for us. Thanks, Anna! ANNA: You’re welcome! It’s my pleasure. I love gross stuff. LAUREN: So there is one other way to manage
these larvae, sort of a biological control, which people do in some places, like Thailand,
Peru and Ghana. ANNA: Entomophagy! LAUREN: Eating bugs. Mmm. Tasty. ANNA: So hop over to my channel for a whole
episode about it. LAUREN: And thanks for watching this Deep
Look.

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