*Featured image photo credit: Redouan Bshary

In this episode, Zegni Triki (new PI fall 2022, University of Bern, Switzerland) takes us on a wild journey under the sea to learn about cleaner fish mutualisms on the great barrier reef in her paper: Triki, Richter et al. 2022: ‘Marine Cleaning Mutualism Defies Standard Logic of Supply and Demand.’ Zegni tells tales of the complex natural history of cleaner fish and explains how models can help dissect messy, sometimes confusing empirical data. We also discuss the value of incorporating individual decision making into biological market theories of mutualistic species interactions. Plus, we learn once and for all who has the best mucus on the reef. Listen to our conversation and then read Zegni’s full paper here!

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Dive even deeper by emailing your questions to Zegni at zegni.triki@gmail.com.

And learn more about the Lizard Island Research Station here: https://lirrf.org/

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<figure class="wp-block-image size-large"><figcaption class="wp-element-caption">Labroides dimidiatus services a client. Credit Zegni Triki</figcaption></figure>



<figure class="wp-block-image size-large"><figcaption class="wp-element-caption">Cleaner fish plays dentist. Credit Zegni Tricki</figcaption></figure>



<figure class="wp-block-image size-large"><figcaption class="wp-element-caption">Zegni underwater. Credit Justin Marshall</figcaption></figure>



<figure class="wp-block-image size-large"><figcaption class="wp-element-caption">Zegni following fish. Credit Reduoan Bshary</figcaption></figure>



<figure class="wp-block-image size-large"><figcaption class="wp-element-caption">Zegni makes a fish friend. Credit Reduoan Bshary</figcaption></figure>
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NATURALIST SELECTIONS IS AN INTERVIEW SERIES PRODUCED BY THE AMERICAN SOCIETY OF NATURALISTS GRADUATE COUNCIL. WE SHOWCASE GRADUATE STUDENT AND POSTDOC AUTHORED WORK IN THE AMERICAN NATURALIST, A PREMIER PEER-REVIEWED JOURNAL FOR ECOLOGY, EVOLUTION, AND ANIMAL BEHAVIOR RESEARCH. CATCH UP ON EXCITING NEW PAPERS YOU MAY HAVE MISSED FROM THE JOURNAL, AND MEET SOME TRULY BRILLIANT EARLY CAREER NATURALISTS!

Listen on Spotify and Apple Podcasts!

Credits

Featured Guest: Zegni Triki, Universität Bern, Bern, Switzerland

Host, Editor, Producer: Sarah McPeek, University of Virginia, US

Original Music: Daniel Nondorf, University of Virginia, US

Transcript:

You’re listening to Naturalist Selections, the American Society of Naturalists graduate council’s science podcast featuring graduate student and postdoc-authored research in The American Naturalist.  I’m grad council rep Sarah McPeek and today I’m talking with postdoc first-author Zegni Triki. Zegni is currently starting her own lab at the University of Bern in Switzerland. She formerly completed a postdoc with Dr. Redouan Bshary at the University of Neuchâtel Switzerland, where she conducted fieldwork at the Lizard Island Research Station in the Great Barrier Reef of Australia. Her paper: “Marine Cleaning Mutualism Defies Standard Logic of Supply and Demand” explores the cleaner fish-client fish mutualism on coral reefs as a complex biological market. The cleaner wrasse species Labroides dimidiatus consumes skin parasites of other fish species, reducing their client’s parasite load in the process of feeding. However, cleaner fish don’t always give a 5 star performance. Sometimes, cleaners cheat their clients by eating some of their client’s nutritious skin mucus. Rough biting can cause the client to ‘jolt’ away from the cleaner fish and sometimes, lead them to abandon the interaction altogether. Talk about a ‘yelp’ review! Zegni and her labmates wondered if the density of active cleaners on the reef might contribute to the frequency of cheating behaviors. Perhaps cleaners can charge a ‘higher price’ in the interaction if there are fewer local suppliers of cleaning services. To test this idea, they temporarily removed half the cleaner fish from one part of the reef. One month after the fishes’ removal, they found no change in the quality of remaining cleaner fish’s services. To understand this puzzling result, her lab partnered with two theoretical modelers, Xiang-Yi Li Richter from the University of Stockholm, Sweden and Shun Kurokawa from the University of Tokyo. The resulting model examines how cleaner fish and client fish behaviors play off one another in subtle ways that shift the costs and benefits of cheating, potentially explaining why cleaners on the reef didn’t change their behavior despite the drastic change in market conditions. I talked to Zegni to learn more about this messy, context-dependent mutualism.

Sarah

So the first thing I would love to hear is a little bit more about what it’s like to watch these cleaner wrasses do their work. What do these interactions look like on the reef?

Zegni                                            

You are underwater. We often have like slate and pencil so you can write in the water. Once you are in the water and close to the reef, it’s so easy to find cleaner fish. Often when you see a group of fish together, lots of colors going next to each other, you assume that there is a cleaner fish and often you are right. We try to make videos of half an hour at least so we can get a decent amount of data. So all that you need is really to station yourself somewhere that you are comfortable. You have your camera, you start recording. And just follow these fish. We keep a distance about probably 2 meters from them. Honestly they don’t care whatsoever like coral reef fish, when you are there, especially in this place is research station. They are so used to have researchers around. Our presence, I don’t think it affects their behavior in any way.

Sarah                                                                    

That sounds like such fun field work.

Zegni

It’s really fun. After a while it’s like, really like you are in meditation, all this fish swimming and water and you are just floating with the waves.

Sarah

That’s beautiful. How many interactions do you observe in the course of watching one fish for half an hour?

Zegni

They clean almost nonstop and when they stop it’s often they are checking probably that they might find the better spot. I would say probably more than 80% of their time is really spent in cleaning and interacting with clients fish. So in the span of half an hour I mean we can easily have few hundred interactions that we record. And often we have the male female interactions because they live in a harem and you have a group of probably six to eight female cleaner fish and there’s only one male. And this male cleans a little bit but often checks on his females that they are doing good job, not cheating, they are behaving well. And the females, they adjust to that. So if they’re alone they behave in a way and if the male is around they change their behavior.

Sarah

Wow. I had no idea that it was mostly females doing the cleaning and the males were monitoring their behavior? That’s fascinating.

Zegni

Yeah. The males also they do clean because of course they eat but on top of that they have like extra responsibilities to make sure. And also they need to spawn with the females so they need to gain energy and then turn and spawn with the different females.

Sarah

Is the hypothesis that the males regulating the females cleaning benefits the male because the better she cleans the more resources she gets for reproduction? I’m trying to think about why they do that.

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