Ep. 548 - Gall Wasps & Their Host Plants

In Defense of Plants Podcast

In Defense of Plants

Science & Medicine, Natural Sciences

4.8 • 1.2K Ratings

🗓️ 19 October 2025

⏱️ 62 minutes

🔗️ Recording | iTunes | RSS

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Summary

Galls are among the most remarkable biological structures on our planet. The organisms that produce them are also extreme diverse and contribute a bewildering amount of biomass to their habitats. Some of the most fascinating gall makers are the gall wasps. This group of organisms is still woefully understudied but people like Dr. Louis Nastasi are trying to change that. Join us as we take a deep dive on gall wasps that specialize on herbaceous plants like the rosinweeds (Silphium spp.) and learn what these amazing little insects can teach us about biodiversity and evolution. This episode was produced in part by April, Dana, Lilith, Sanza, Eva, Yellowroot, Wisewren, Nadia, Heidi, Blake, Josh, Laure, R.J., Carly, Lucia, Dana, Sarah, Lauren, Strych Mind, Linda, Sylvan, Austin, Sarah, Ethan, Elle, Steve, Cassie, Chuck, Aaron, Gillian, Abi, Rich, Shad, Maddie, Owen, Linda, Alana, Sigma, Max, Richard, Maia, Rens, David, Robert, Thomas, Valerie, Joan, Mohsin Kazmi Photography, Cathy, Simon, Nick, Paul, Charis, EJ, Laura, Sung, NOK, Stephen, Heidi, Kristin, Luke, Sea, Shannon, Thomas, Will, Jamie, Waverly, Brent, Tanner, Rick, Kazys, Dorothy, Katherine, Emily, Theo, Nichole, Paul, Karen, Randi, Caelan, Tom, Don, Susan, Corbin, Keena, Robin, Peter, Whitney, Kenned, Margaret, Daniel, Karen, David, Earl, Jocelyn, Gary, Krysta, Elizabeth, Southern California Carnivorous Plant Enthusiasts, Pattypollinators, Peter, Judson, Ella, Alex, Dan, Pamela, Peter, Andrea, Nathan, Karyn, Michelle, Jillian, Chellie, Linda, Laura, Miz Holly, Christie, Carlos, Paleo Fern, Levi, Sylvia, Lanny, Ben, Lily, Craig, Sarah, Lor, Monika, Brandon, Jeremy, Suzanne, Kristina, Christine, Silas, Michael, Aristia, Felicidad, Lauren, Danielle, Allie, Jeffrey, Amanda, Tommy, Marcel, C Leigh, Karma, Shelby, Christopher, Alvin, Arek, Chellie, Dani, Paul, Dani, Tara, Elly, Colleen, Natalie, Nathan, Ario, Laura, Cari, Margaret, Mary, Connor, Nathan, Jan, Jerome, Brian, Azomonas, Ellie, University Greens, Joseph, Melody, Patricia, Matthew, Garrett, John, Ashley, Cathrine, Melvin, OrangeJulian, Porter, Jules, Griff, Joan, Megan, Marabeth, Les, Ali, Southside Plants, Keiko, Robert, Bryce, Wilma, Amanda, Helen, Mikey, Michelle, German, Joerg, Cathy, Tate, Steve, Kae, Carole, Mr. Keith Santner, Lynn, Aaron, Sara, Kenned, Brett, Jocelyn, Ethan, Sheryl, Runaway Goldfish, Ryan, Chris, Alana, Rachel, Joanna, Lori, Paul, Griff, Matthew, Bobby, Vaibhav, Steven, Joseph, Brandon, Liam, Hall, Jared, Brandon, Christina, Carly, Kazys, Stephen, Katherine, Manny, doeg, Daniel, Tim, Philip, Tim, Lisa, Brodie, Bendix, Irene, holly, Sara, and Margie.

Transcript

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0:00.0	Hey everyone, we have merch for sale. I've even put up new designs with cruneck sweaters and bucket hats. All of our designs are customizable and they feature some really cool botanical prints, and best of all, they help support the show. So go pick up some merch today. The links are over to indefensiveplants.com either in the show notes or click on apparel at the top. I can't thank you enough. It helps keep this show up and running.
0:21.2	But speaking of the show, let's get on with it. Hello everyone and welcome to the Indefensive Plants podcast, the official podcast of Indefensiveplants.com. What's up? This is your host, Matt. Welcome to the show. How is everyone doing this week? I am so excited for you to hear from my guest today. Joining us is Dr. Louis Nistazi, who specializes in
0:38.6	gall wasps, specifically those that appear on herbaceous plants. We've talked a little bit about
0:43.6	galls in the past, but this is a really, really fun discussion that emphasizes the bewildering
0:48.9	diversity and biomass of these organisms and the extremely specific interactions they have with plants.
0:55.9	This is one of those conversations that emphasizes the fact that plants are habitats in and of
1:00.5	themselves. Before we get into this, I just want to remind you, though, that Gauls are these
1:05.0	edible nursery chambers. It really helps keep that in mind throughout this conversation. Gauls
1:09.3	support and feed the developing organisms
1:11.9	inside, and they also help protect them. But who better to talk to you about these fascinating
1:16.5	dynamics than Dr. Nastasi himself? So let's just jump right into it. Without further ado,
1:21.0	here's my conversation with Dr. Louis Nastasi. I hope you enjoy.
1:41.3	All right, Dr. Louis Nastazi, welcome to the podcast.
1:44.2	I can't wait to talk about your research today, but first let's start off with an introduction. Tell everyone a little bit about who you are and what it is you do.
1:49.0	Absolutely. So my name is Louis Nostasi. I just recently finished my PhD in entomology at Penn State,
1:54.8	and I'm currently a postdoctoral researcher at University of Iowa under the PI Andrew Forbes,
2:00.3	whose lab is focused on evolutionary ecology,
2:02.8	right now emphasizing gall system interactions. And I'm very excited to talk a little bit about
2:08.1	what gals are and how they fit into the broader plant story. Excellent. And so what brought you to
2:14.8	looking at gals? I mean, was it just an obsession with insects and
2:17.8	Gauls are such a fascinating topic within that world? Or was there another route? Yeah. So I was drawn to
2:24.9	Gauls. They're kind of an unusual pipeline. So I had always been interested in insects, which I'm
	...

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