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!

In this episode, Femke Batsleer talks with us about her new paper Batsleer et al. 2022: ‘Behavioral Strategies And The Spatial Pattern Formation Of Nesting.’ We chat about digger wasp behavior, building natural history-grounded models using the inverse modeling approach, studying complex and context dependent behaviors in wild populations, and more. You can read Femke’s full paper here: https://www.journals.uchicago.edu/doi/10.1086/717226.

Buzzing with more questions? Email Femke at Femke.Batsleer@ugent.be!

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Credits

Featured Guest: Femke Batsleer, University of Ghent

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

Original Music: Daniel Nondorf, University of Virginia

Transcript:

Welcome to Naturalist Selections, an interview series featuring graduate student and postdoc-authored work in The American Naturalist, produced by the American Society of Naturalists Graduate Council. Today we hear from graduate student first-author Femke Batsleer about her paper ‘Behavioral Strategies And The Spatial Pattern Formation Of Nesting’, hot of the press of the January 2022 edition of the journal. Femke is a fourth year PhD candidate with Dr. Dries Bonte in the Terrestrial Ecology Unit at Ghent University in Belgium. Femke’s research focuses on the digger wasp Bembix rostrata. During their short summer breeding season, female wasps lay a single egg in a self-dug sand burrow. While most females build only one burrow with one larva, a few may construct up to four active burrows during a breeding season. Females then capture prey meals and carry them back to their burrows to feed their larvae. Sometimes, parasitic flies lay their eggs on the larva’s prey meal. When this happens, the fly larvae steal resources from the developing wasp larva, jeopardizing the wasp larva’s survival. Femke maps clusters of hundreds of wasp burrows stretching across many meters of the Belgian coastal dunes. In her paper, Femke and her coauthors want to understand the ecological drivers of the wasps’ complex clustered nesting patterns. They build an impressive series of natural history-based models to compare to field data from Femke’s digger wasp population. Are wasps clustering their burrows based solely on the availability of suitable habitat? Or are wasps using personal or social information to cluster their nests in groups with other individuals? Well, there’s strong evidence from Femke’s models that all three of these things are going on, but maybe not at the same time. I spoke to Femke to dig a little deeper.

Sarah:  I was, of course really excited about the digger wasps, because I love that system. And I love all the classic behavioral ecology work that’s been done with the digger wasps in Europe. And I’m really curious what it’s like to visit your field sites in Belgium. You know, what do you see and hear and smell when you’re visiting the wasps?

Femke: Yeah, indeed, it’s very special to be in the field when a lot of activity is going on with these digger wasps. But for me, the thing that pops out when I remember my field visits, is the mixed smell of sunscreen and sweat. It doesn’t really have to do anything with digger wasps themselves. But that really gives me flashbacks to the field visits. But yeah, the wasps themselves. It’s really amazing when there’s a lot of activity, especially in the beginning of the season. Then the males are really active and also from literature it’s often called a “sun dance.” And that makes it sound very poetically of course, but it’s these males that are a little bit above the crowd flying around in circles and eights trying to defend their little territory they have, where they really look out for any intruder, other males or even butterflies flying past. They just jump really quickly to them. And then sometimes when the females emerge, you can see that because there are so many males that try to find females, they all come to this one female and then you can see flying balls of digger wasps in the trees, and it’s really amazing to see. I’ve seen it twice or three times.

Sarah: Wow, that sounds incredibly chaotic, but also really beautiful.

Femke: Yeah, it is. It’s also just being there in the field, wow. And then in every corner you can see these digger wasps. They’re quite big, so two or three centimeters. And they just are guarding their nest or flying around coming with prey. And it’s really just standing there and watching them. It really gives this feeling of this little natural wonder you can see.

Sarah: And they create these beautiful patterns of nests all over the landscape, which is what you were interested in in this paper.

Femke: Indeed. Indeed.

Sarah: So I was really interested in the inverse modeling approach that you used in this paper. And I was hoping you could tell me a little bit about what that means, specifically, and how you think the inverse modeling approach helps us understand these complex patterns, like the spatial clustering of your wasp nests.

Femke: Yeah. Okay. So the inverse modeling, very shortly, it’s kind of putting the data on the model and not the model on the data, very shortly. But it also has to do with patterns and mechanisms and how you derive mechanisms and patterns. So in a more ecological, like classical ecological framework, you see a pattern, and then you fit a model, and then try to see what kind of mechanisms or hypotheses of mechanisms you can get out of this. And then if you really want to look into mechanisms themselves, you do experiments, where you hold certain variables under control, and then try to do experiments and see what comes out. But the problem is that now we, more and more, we are looking into these very complex systems where a lot of things are going on at the same time, and we want to look at the effects of mechanisms that work at different spatial scales. And then it’s very hard to tease them apart with modern classical experiments. So I used an individual-based model where you model or simulate