Return of the Screwworms

Key takeaways

The screwworm was a major pest that caused significant suffering to livestock, wildlife, and humans, but collective scientific efforts successfully eradicated it from North America.
Modern biotechnologies, like gene drives, offer potential ways to permanently eliminate species like the screwworm, but raise important ethical and ecological questions.
The re-emergence of screwworms highlights the challenges of biological control and the importance of sustained monitoring and international cooperation.
Deciding to eradicate a species involves complex moral considerations, balancing ecological impacts with human interests and the animal welfare involved.

Summary

Introduction and Background on the Screwworm

The episode introduces the screwworm, a flesh-eating parasite that was eradicated from North America but is now re-emerging. It highlights its gruesome nature, its history of devastating livestock and wildlife, and the major scientific efforts led by Edward Nippling to control and eradicate it, including innovative methods like releasing sterile flies.

Historical Efforts to Control and Eradicate the Screwworm

Discusses the history of the screwworm eradication project, including Nippling's pioneering work with radiation to sterilize male screwworms and the successful use of aerial releases across North America. The episode details how these efforts effectively wiped out the screwworm in the US and parts of Central America, showcasing a major success in biological control.

The Reemergence of the Screwworm and Current Threats

Details the resurgence of screwworm cases in Central America and their creeping northward, threatening the US. The episode explores possible reasons for its return, including increased animal movement and disruptions from COVID-19, and discusses the risks to humans and the economy, particularly the cattle industry.

Controversial Approaches and Ethical Considerations

Examines the possibility of using advanced genetic technology, like gene drives, to eradicate screwworms permanently. The episode features debates among scientists and ethicists about the morality of extinction, the ecological importance of species, and the potential risks and benefits of deploying gene drives to wipe out the screwworm.

Broader Implications and Reflections

Concludes with reflections on humanity’s role in ecological stewardship, the lessons from screwworm eradication efforts, and the moral dilemmas of species extinction. It emphasizes the importance of scientific innovation while questioning whether we have the right to decide which species should live or die.

Show notes

If a species is horrible enough, do we have the right to kill it forever?

Seventy years ago, a nightmare parasite feasted on the live flesh of warm-blooded creatures in North America: the screwworm. That is, until a young scientist named Edward F. Knipling discovered a crucial screwworm weakness and hatched a sweeping project to wipe them out. Knipling’s seemingly zany plan to spray screwworms out of planes all over the continent— with US taxpayer money— succeeded, becoming one of humanity’s biggest environmental interventions ever.

Today, screwworms have been gone so long that none of us in North America even remember them. But now, they’re coming back. And they’re forcing us to ask: in an era of climate change and rapid mass extinction— should we kill off a species on purpose?

Special thanks to James P. Collins, Max Scott, Amy Murillo, Daniel Griffin, Phil Kaufman, Katie Barnhill, Arthur Caplan, Ron Sandler, Yasha Rohwer, Aaron Keefe, Gwendolyn Bogard, Maria Sabate, Meredith Asbury, and Joanne Padrón Carney

EPISODE CREDITS:
Reported by - Sarah Qari
with help from - Latif Nasser
Produced by - Sarah Qari
Sound design contributed by - Sarah Qari
Fact-checking by - Emily Krieger

EPISODE CITATIONS:

**The latest information on screwworm outbreaks and precautions:
screwworm.gov

Videos:

Oral history interviews of Edward F. Knipling: here (https://zpr.io/njhMedFN5jsZ) and here (https://zpr.io/VQReQbfznCrq)

Podcasts:

Here’s a Spotify playlist (https://zpr.io/PNMEM274G7vh) of all of our Golden Goose-inspired episodes!
Sam Kean’s podcast The Disappearing Spoon – his episode about screwworms is called The Screwiest and Perhaps Most Original Idea of the 20th Century (https://zpr.io/UYf6dR2yG3eN)
Our episode on CRISPR & gene drives (https://zpr.io/UYf6dR2yG3eN)
New to Radiolab? Check out our Radiolab Starter Kit (https://zpr.io/QpPnrHAZVQLR) playlist of all-time favorite episodes!

Articles:

Sarah Zhang’s latest piece in The Atlantic: American Milk Has Changed (https://zpr.io/xebbdq2MWV4L)
Her most recent piece on screwworms: The ‘Man-Eater’ Screwworm Is Coming (https://zpr.io/ECmjCs7ScbS4)
Her initial reporting on screwworms: America’s Never-Ending Battle Against Flesh-Eating Worms (https://zpr.io/PNMEM274G7vh)
Gregory Kaebnick’s paper (https://zpr.io/yqNC3q5FbCcq) about screwworm eradication in Science

Archival materials:

The USDA’s Screwworm Eradication Records (https://zpr.io/dY7zuVdGYKjf) contain lots of cool images and letters

Signup for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)!

Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today.

Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing radiolab@wnyc.org.

Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Hosted by Simplecast, an AdsWizz company. See pcm.adswizz.com for information about our collection and use of personal data for advertising.