My guest in this episode is Adam Kranz. Adam has a BA in Environmental Studies from Lawrence University in Wisconsin, and a Masters of Science in Natural Resources and Environmental Science from University of Illinois Urbana-Champaign. His thesis was on insect pest ecology in diverse agroforestry plantings, but of late has taken a special interest in plant galls. He’s since founded Gallformers.org, which is a website designed to be the authoritative resource for all plant galls of the United States and Canada.
We start out discussing a bit of background about how Adam got into galls and how gallformers came to be. If you’re listening now and wondering “what’s a gall anyway?” Well, these are beautiful and sometimes bizarre growths on plant tissues induced by another organism, such as a wasp, midge, aphid, mite, or many others. They often develop vivid colors and evocative shapes, and all have fascinating natural histories. These growths occur specifically to support the life cycle of the inducer, and are often induced in amazingly precise ways that you’ll have to hear to believe. For example, Adam explains how the larvae inside the gall may steer the plant response throughout their lifespan! By the way, I have photos of several of these amazing species below in the show notes and on my instagram @naturesarchive. You’ve really gotta check them out.
[UPDATE 14 Sept 2021: I was just made aware of this wonderful paper in the Molecular Ecology journal published 12 September, which shows the extend to which a galling insect manipulates its host plant genome. And here is the corresponding Twitter thread from @wasp_venom.]
[UPDATE #2 16 Sept 2021: Past guest Dr. Merav Vonshak has created “Gall Week 2021”, running from 2021-10-02 to 2021-10-10. This is a global event, and to participate join the iNaturalist project and submit observations!]
[UPDATE #3 18 August 2022: Gall Week 2022 is ON! Sept 3 – Sept 11, 2022. Here’s the new iNaturalist project.]
We also discuss strategies and techniques for looking for galls in the field. They are quite common throughout much of the world, and many can be easily identified. We discuss some of the attributes of a gall that might be helpful to identify them, when and where to look, what makes for an identifiable iNaturalist observation, and other plant growths that might be confused with galls. And as it turns out, there is still much to learn about galls, so they are a great area of focus for naturalists looking to discover and describe new species.
Adam also gives a nice overview of three extremely interesting galls that are among his favorites. Each of these have fascinating natural histories, including peculiarities like hollow centers with free-rolling cells, and what might be considered a gall threesome, where a second cynipid wasp comes along and entirely changes the gall’s developmental trajectory. Of course, Adam describes this in a much more scientifically accurate way.
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Links To Topics Discussed
People and Organizations
Charley Eiseman’s blog BugTracks
iNaturalist Gall Projects:
Books and Other Things
Plant Galls of the Western United States, by Ronald Russo – HIGHLY recommended
Tracks and Signs of Insects and Other Invertebrates by Charley Eiseman – also HIGHLY recommended, introduces galls, and many other great naturalist topics including leaf mining insects, eggs, signs of feeding, and more.
Weld Cynipid Books: Free via the Biodiversity Heritage Library and Hathitrust
- Cynipid Galls of the Eastern United States
- Cynipid Galls of the Pacific Slope
- Cynipid Galls of the Southwest
Note: links to books are affiliate links
Previous Podcasts Mentioned
Opening – Fearless First by Kevin MacLoed
Closing – Beauty Flow by Kevin MacLoed
Both can be obtained from https://incompetech.filmmusic.io/