Teaching mark-recapture with dor beetles

The key step in the planning of any good field course is to spend some time at the field site observing and asking questions. What is the habitat like, what lives there, what are the facilities, what are potential challenges or dangers to working there, etc? When I first went to do this at Svanninge Bjerge, the location of my zoology field course, I immediately started seeing big blue dung beetles all over the place. Bikuben Foundation, who operate the place, run cattle there. There is no lack of dung. These big plodding dor beetles (Geotrupidae) were all over the place, and it didn't take me long to decide I wanted to work them into the course. I wanted to introduce mark-recapture methods, and these seemed like perfect subjects. Mark-recapture methods involve catching animals, marking them in some way that would allow them to be recognized if re-sighted, letting them go, and then trying to recapture them. Such methods have a huge range of applications from tracking individual movements and estimating population sizes to monitoring growth and survival and studying behavior and sociality. To teach this in a field course, I wanted an invertebrate animal that wasn't too likely to leave the study area, that is easy to capture, mark and handle without damage, and that has enough charisma to capture students' attention. Dor beetles have all this. They are big and slow, and so easy to find and catch by hand. They don't bite or sting. They will collect in large numbers in pitfall traps baited with cow dung. They have big hard upper wings (elytra) that can be marked in any number or ways without harming them (we used this system with nail polish, but I've now got a battery-powered cautery). They are extremely numerous. They are shiny and blue. They can fly, but don't often do so.

Students mark a live beetle for release. Photo by Kim Lundgreen.

They make such an ideal intro to mark-recapture that I almost worry that I've given the student a false sense that this is easy, where in fact such studies are often very hard work. Still, if you want an efficient system for teaching mark-recapture methods and have beetles like this at your location, I strongly recommend them to you.

Why lightning talks work

Last week was the second annual meeting of the Evolutionary Demography Society. It was fabulous. Close to 100 people, over three days, at Stanford. Man there is a lot of good food around there. A friend and I were sitting outside, eating burritos when this dude from a farmers' market booth came over and started giving us samples of gluten-free baked goods. Delicious. Great weather, friendly people. Oh, yes, something else. What was it now? Ah! We talked about a lot of great science. Roughly 70 presentations. Post-reproductive lifespan, evolution of aging, all the topics I like best and every talk on a topic of at least some interest. Fabulous.

Many conferences (but not this one) have what are called concurrent sessions. In one room there might be a series of perhaps 15 minute long talks about matrix models, while in another they are talking about theoretical modelling, and in a third it could be all about field data on hunter gatherers. The benefits of this are allowing more people to give talks in a short period of time, and letting audience members pick and choose which topics they spend their time hearing about. At EvoDemoS, we address these same problems in a very different way. Most presenters give a lightning talk plus poster. The lightning talk is five minutes (plus five for questions), and then after each session there is a break for coffee and posters. But the posters are mostly from the same people who gave the lightning talks, on the same subject. So you get up, give a rapid intro to the work, answer a few questions, and then because there are no concurrent sessions, everyone at the conference knows who you are and what you are working on. If they are interested in it, they come talk to you at your poster. If you didn't bother to print your poster, they already know what you are working on and come talk to you anyway. If they aren't  interested, they don't have to sit through 15 minutes of you talking about it. The frequent and lengthy breaks (made possible by the shortness of the presentations) make it easier to stay alert through the talks, and let us achieve a much higher conversation-to-passive-listening ratio, and it is really the conversations that are the point of the conference for me.

Now the obvious downside is that many speakers are used to having more than five minutes. Some won't come because they can't have more time, use their connections and seniority to push for more time, or simply prepare the same talk they would for a much longer slot and largely ignore the warnings that their time is almost up. One speaker, to remain nameless, was on slide 4 of 26 when the one minute warning came and sped up only slightly. So the moderators need to be a bit firm in some cases. The more senior the speaker, the more likely an overage, in my experience. This is partly a matter of habit, but also that the more senior people often have more work to present. There were a few talks where the theoretical framing got almost completely cut to make time for more methods and results, and that was sometimes problematic. A is consistently greater than B, but what does that tell us? That said, the great majority of the five minute speakers were able to state the question clearly, say a word or two about methods, give a main result (or maybe two) and draw a conclusion or three before inviting us to see the poster. And almost everyone I talked to at the conference, both as speakers and audience, thought it worked well in this context.

For a conference with thousands of people, I'm not sure lightning talks would work. I'd be interested to hear from anyone who has tried it. But for anyone organizing a small conference like ours, I absolutely recommend it.