It’s fall. The weather is getting cooler, trees are losing their leaves, and acorns are starting to fall from oaks. Many animals regularly feast on acorns, and one of them is a curious little critter called an acorn weevil. Weevils are a type of beetle known for their elongated snouts. There are tens of thousands of species of weevils around the world. The acorn weevil has a specially adapted snout that is perfectly suited for cracking into hard acorn shells. In this week’s newsletter and video, you’ll uncover how acorn weevils bore deep inside acorns for a nutritious meal. But that’s not the only reason they’re drilling into acorns. Find out what other vital task they use acorns for.
This Weevil Has Puppet Vibes But Drills Like a Power Tool
Image: Josh Cassidy/KQED
This fuzzy acorn weevil can’t crack open acorns like a woodpecker or chomp through them like a squirrel. Instead, they use their incredibly long snout, called a rostrum, to power-drill through an acorn’s tough and resilient shell. And female acorn weevils don't only have lunch on their minds – they're also making a nursery for their babies.
Photo: Josh Cassidy/KQED
Acorn weevils use their sensitive antennae to sniff and taste their way to a good spot for drilling into acorns. Their antennae are conveniently located halfway down their snouts, nice and close to the acorns.
Maker Faire Bay Area returns to the shipyard at Mare Island, Vallejo, CA, along the scenic Napa River, for an unforgettable experience filled with creativity. From inventions to innovations to fashion and art, learn from the top minds in their fields and experiment with hands-on projects. Attendees may use code KQED.
👃An acorn weevil's rostrum, which it uses to bore into acorns, has two layers. The hard, thin cover is called the exocuticle, and the thick, flexible inside is the endocuticle.
📡When their antennae get in the way of their drilling, weevils tuck them into side channels on their rostrums called scrobes.
👶Female acorn weevils have longer rostrums because they use their snouts not only for eating, but also for building a nursery.
🪒At the tip of the snout is a razor-sharp mouth that makes tiny cuts in the acorn’s surface to break through the hardest part of the nut.
🥚🥚Females lay their eggs in dozens of acorns all over oak trees to increase the chances their offspring will survive.
🌰After acorns mature and fall to the ground, larvae chew their way out and burrow into the soil for protection. The adults emerge the following season to feast on new acorns.
✈️ Acorn weevils develop wings and can fly when they reach adulthood.
PLAY
Name That Critter
What black and red bird lives in California’s oak forests and stores acorns individually in holes in trees, stockpiling thousands of acorns to carry them through the winter? Find the answer at the bottom of this newsletter.
Image: Josh Cassidy/KQED
EVENT
Spooky Science on Screen — Deep Look at KQED Fest
Don’t miss Deep Look’s host Laura Klivans and lead producer and cinematographer Josh Cassidy in conversation for a special spooky screening at KQED headquarters in San Francisco, Saturday, Oct. 19, at 1:45 p.m. , as part of this year’s KQED Fest. We’ll play some of Deep Look’s favorite Halloween-themed videos – about bats, crows, flesh-eating beetles, owls and spiders – and hear from experts. Plus, we’ll have special critter tables, including one with live bats! There will also be a Deep Look photobooth. Even more is happening at KQED Fest. Check out the full schedule of FREE events from 11 a.m. to 6 p.m., at KQED in San Francisco. Join us!
Become a DEEP LOOK Patreon Member today and go behind the scenes with the Deep Look team! Plus, you’ll get Deep Look swag like this Deep Look mug. We also have a special Deep Look weevil pint glass, T-shirts, stickers and more. So help us with our mission to give everyone a deeper understanding of science and nature, especially the living organisms too small to easily see with the naked eye. Just like out in the wild, everyone has a role to play.
We hope you enjoyed this week’s newsletter. Thank you for your support! Until next week!
- The Deep Look Team and Science Teams
Deep Look is KQED’s award-winning wildlife video series that reveals the tiny dramas playing out in the natural world. We’re a member-supported YouTube series from KQED and PBS Digital Studios. Learn more.
KQED’s award-winning science coverage brings you the latest climate, environment and health news from the Bay Area and beyond. KQED Science is supported in part by the members of KQED. Learn more.
Acorn woodpecker! Over generations, acorn woodpeckers can drill thousands of small holes into one or several trees close to each other, giving these so-called granaries the appearance of Swiss cheese. This sets them apart from other birds that drop acorns into already existing cavities in trees, and animals like squirrels and jays that bury acorns in the ground. The photo in the Name That Critter section is of a male acorn woodpecker in Marin County, California.
