Thursday, November 17, 2016

How to tell if your aphid is done reproducing.

If you want to know if a parthenogenetic pea aphid is all done reproducing, look at her abdomen. If there are eyespots, she still has embryos in her. If not, she's done. If she is post-reproductive, she's likely to move to the edge of the colony, where risk of predator attack is highest. Details are here, in a paper written with some very talented undergraduates at Bates College.

How not to respond to unhelpful peer reviewers

For as long as I've been a scientist, and longer, there has been extensive discussion on the many ways that peer review is broken. Peer review is how, in theory, science gets evaluated and hopefully improved, before publication, and therefore hard to dispense with, despite being widely seen as inefficient, biased, and corrupt. It goes like this: Author submits manuscript to journal, journal sends it out to independent experts for feedback, these experts (the scientific peers of the author) decide whether they are expert and independent enough to give appropriate feedback carefully read it, think about it, identify its flaws, make constructive detailed suggestions, and finally recommend to the journal whether it should be published as is, fixed and then reevaluated, or just rejected. That is, at least ideally, how is supposed to work.

There are a great many ways in which that ideal can fail. I draw a great deal of schadenfreude from reading Retraction Watch, which is effectively a blog about cases where peer review failed in one of many ways, something was published, and mistakes or misdeed were later found out. I, like most scientists, know a few people whose work may show up all over Retraction Watch some day.

Which brings me to the fact that I am currently figuring out how to respond to a review that has failed with regards to independence, expertise, detail, fact, specificity and constructiveness. I would have suggested to the journal that this person could not be an independent reviewer, except that it never occurred to me that anyone would consider him to know anything about the topic of the paper. Explaining the long history of this interaction to the journal, we have now been assured that our re-submission would be sent out to different reviewers. Even so, in resubmitting, I have to respond to all the reviewer's comments, even those that are wildly counterfactual, have nothing to do with the current manuscript, or are just complaints about the reviewer's own work not being cited more extensively. And it has to be done politely and factually. So one must never include responses like these:
  • This highlights a fundamental difference in approach to science. Reviewer's comment, and publications, suggest that scientific papers should be fishing expeditions in which everything that can be gotten out of a data set is analyzed and those results that test significant published breathlessly. We started with one, a priori original question, gathered all of the available data to address it, and got a clear result, which we state concisely. While some authors would stretch the results section out to numerous exploratory paragraphs, expounding upon questions that were tailored to fit the results of the numerous analyses, that would surely be a disservice to science.
  • It is not clear what this means. Perhaps the reviewer did not find our Methods section. It is in there between the Introduction and the Results.
  • It does not seem that the Reviewer has any idea what kind of data we are using, despite the six paragraphs on the topic.
  • Furthermore, a reading of the manuscript would have revealed that no matrix models are employed. Reviewer's comments would seem to be hastily copied and pasted from review of an unrelated paper.
  • The Reviewer's publications are not relevant or useful here. Perhaps they were relevant to the paper for which most of this review was written?
  • This is counterfactual and the Reviewer has excellent reason to know that.
  • These quotes of the journal's rules are from an entirely different journal that the Reviewer often reviews for.
  • Not only can we find no mention of this statistical rule anywhere, we note that Reviewer's own papers don't follow it. We asked an expert in these methods about this 'rule.' She called it, "hilariously made up." 
I need some empenadas.



Wednesday, November 16, 2016

Ghosts of papers that may some day be


The world is full of science that only half exists: Experiments done but not written up, manuscripts waiting for revision, results too unimpressive to prioritize for publication. Where fetuses are gestated for months but born in hours, data sets often take longer to put out into the world than they took to create. Until it is published, academic research is only a nascent fluffy squishy wispy gelatinous downy larval effervescent ephemeral eufloccinaucinihilipilificatable translucent apparition, neither seen nor heard nor here nor there. Once published, research gains visibility, permanence, and perhaps even value.

While most scientists have things they would like to get around to publishing,  I feel like I've accumulated a particularly long list of research projects I need to push out. This summer and fall I've actually had some time to dedicated to that. I've made a goodly dent, but the list is still long, and new tasks and projects emerge like mosquitoes from an abandoned hot tub.

I've published four good papers this year, another is ready to go as soon as my coauthor has time to look at it, and a sixth just needs a few final touches, and should be submitted in a week or two. Both of those 'full term' papers will, hopefully, come out next year. I think that's pretty good considering I spent most of the last year on intensive teaching, had a months-long battle with epidemic keratoconjunctivitis, have moved my family four times in the last year and a half, and have three children five and under. There are days I wonder why I am so tired, and then there are days I remember why I am so tired. And on those days, I don't feel the least bit bad about keeping all those manuscripts, and coauthors, waiting.

Monday, October 24, 2016

Why we cosleep with our infant and you (perhaps) should too

The feeling of a soft little one gradually melting into my arms is lovely, and I wouldn't soon give up rocking my baby to sleep. That said, shifting from foot to foot in the dark several hundred times night after night can get repetitive. So tonight, as I was rocking little Peregrine, I set myself an intellectual challenge. I was going to simultaneously count how many times I shifted from foot to foot and plan out this blog post. It turned out that after only 564 rocks he woke up and demanded to be nursed, but I will write what I planned anyway.

Peregrine is now almost two months old, and we've slept with him in our bed with us from the very beginning, as we did with both his older sisters. I can hear the million voices crying out in horror, but hold on and let me explain why. The benefits, I hope are obvious (snuggles, not needing to wake up to nurse the baby, baby sleeping better, family bonding, etc.) but most people (in the US anyway) don't sleep in the same bed as their baby, don't feel allowed to, because the public health advice is that it can cause the infant to strangle or suffocate.
Zero day old Peregrine cosleeping (don't tell the nurses)
Our three children were born in Germany, Denmark and Wisconsin, respectively, and we have learned to be quite skeptical of official advice and cultural mandates that vary wildly from place to place. Advice regarding infant suffocation risk certainly depends on where one lives. When we told our Japanese friends how strongly Americans are cautioned against cosleeping, they were surprised and amused. In Japan, apparently, the official advice and common practice is for the baby to sleep between the mother and father, like Lancelot's sword (misplaced cultural reference, I know.) Our German friend warned us strongly against letting our cat near our baby, as a smothering would surely ensue.
Tigerlily and Flopper, dressed for Halloween
As an American scientist with a professional interest in early mortality, and with kids, I of course looked up the science upon which the American advice is based. The most common reference regarding the risks of cosleeping is:
Blair et al. (1999). Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome. British Medical Journal. 319, 1457-1462.
There are more recent papers on this conducted in several countries, and as far as I can see none of them have basically contradicted Blair et al.'s clearly stated "Key messsages" (sic):

Key messsages

  • Cosleeping with an infant on a sofa was associated with a particularly high risk of sudden infant death syndrome
  • Sharing a room with the parents was associated with a lower risk
  • There was no increased risk associated with bed sharing when the infant was placed back in his or her cot
  • Among parents who do not smoke or infants older than 14 weeks there was no association between infants being found in the parental bed and an increased risk of sudden infant death syndrome
  • The risk linked with bed sharing among younger infants seems to be associated with recent parental consumption of alcohol, overcrowded housing conditions, extreme parental tiredness, and the infant being under a duvet
Now, my wife and I do not smoke, do not drink, are not sleeping on a sofa, do not put the baby under a duvet, do not have overcrowded housing conditions and are merely very, rather than extremely, tired. As this 2016 study makes clear, cosleeping is often associated with overcrowding because people in poverty don't have the money for an extra room or an extra bed. Poverty increases the risk of almost all causes of death, especially infant deaths, and much of the risk from cosleeping may actually be risk from poverty. Our baby is under 14 weeks, but according to Blair et al.'s findings, without these other risk factors (particularly smoking), there is no increased risk associated with cosleeping, even for neonates.

Not child endangerment (with Tigerlily)
Other studies have added parental obesity and extreme youth as risk factors. I am certainly overweight by the standard definition, but not obese. We are not particularly young parents. But still, if there is any risk at all of rolling over onto the baby, wouldn't it be safer to have him in a crib in another room? Emphatically, disastrously, not. Blair et al. write, "There was an increased risk for ... infants who slept in a separate room from their parents." Their estimate, that having the baby sleep in another room increases risk by about ten times, has been revised by more recent research to increasing risk by about half. Long story short, having the baby in a separate room is dangerous, while having him in our bed with us presents no documented risk compared to a good modern crib.

This presents two obvious questions: How should parents who aren't trained in interpreting regression tables make this decision? And, why is the official US advice (which resembles that in several other countries) what it is?
My interpretation, based on Blair et al., and the studies that have followed from their work: Always sleep in the same room as the baby. (Shockingly, this has only now become the advice from the American Academy of Pediatrics)  Never sleep on the couch with the baby (they tend to roll into the cracks, and this is truly dangerous). Don't cosleep with a baby under 14 weeks old if you are a smoker, are under the influence, are obese, are overcrowded (which is associated with poverty and all its ills), or are otherwise difficult to wake. If those risk factors don't apply to you, there are hundreds of hours of baby snuggling available to you, and you can decide to take them or leave the baby in a proper crib in your room. Quitting smoking is astoundingly good for your children's survival, even if you don't smoke inside the home.

Now why is the official advice a simple, "Never cosleep," or starker versions thereof? Because official advice has to be short and simple to be effective. My paragraph of advice, above, is 150 words. "Never cosleep" is two. "Don't live in poverty," would be great, if people were given the opportunity of escaping. People are, on the whole, really bad at following complex advice, and really good at finding reasons why things don't apply to them. Have my wife and I really never used a duvet with a baby? Questionable. Am I really overweight rather than obese? I haven't weighed myself in over a year. How tired is "extremely?" Have I ever fallen asleep on the couch with a baby? Certainly. You see, it gets messy, and it is easier for officialdom to just say, "No."
Baby Kestrel sleeping on the couch with Big Sister. Closely supervised.
So my message to you, should you be in the position of choosing where to sleep your baby is to make an informed decision. Good slogans are rarely good advice, and extensive snuggles are one of the things babies need most.
This baby (Kestrel) is not asleep. A desk drawer is not a proper crib.



Sunday, October 02, 2016

Leucistic Chickadee

We've intentionally left some dead wood and tangled sticks in the cedars at the back of our yard. This morning during breakfast a very light colored bird caught my eye. It didn't strike me as any bird I know. I ran to find my binoculars and camera.


It helpfully had come to the railing of our deck. It moved like a chickadee, but the coloration was weird.

White bill, pink legs, white patches all over the feathers, especially on the head.

A leucistic chickadee, repeatedly visiting our backyard feeder in Madison, WI.
Leucistic birds (those lacking some or all of their pigment) are not particularly rare, but still fun to spot.

Wednesday, September 21, 2016

Not for the sake of the species

I frequently come across statements implying that a particular trait evolved because it increases the fitness of the species or that a behavior observed in some animal exists because it helps the species. I hear this from not only members of the general public, but also from biology students and even biologists whose work does not directly address evolutionary questions. Please be aware that this is almost entirely wrong.

In most circumstances, natural selection favors traits that increase the fitness of those individuals that have those traits. If a heritable traits is good for the species but bad for the fitness of those organisms that have it, then those that have it will tend to survive or reproduce less well than those that don't, such that in subsequent generations, the trait will be repeatedly rarer in the population. Even if it is good for the species but has no effect on the fitness of the individual, there is no strong reason to expect that it will increase in frequency.

In some special situations, selection can favor a trait that increases the frequency of a gene in the population, even if that gene causes the individuals that carry it to live less long or reproduce less well than individuals that don't have it. And there are indeed some cases where some biologists reasonably argue that selection occurs at the group level, with traits of the population or group determining which groups survive and which die out. But in almost any popular science context, if you imply that something is for the good of the species, you have gotten it wrong.

Note: this is something I started writing about a year ago, and never finished, until now. I had some particular example in mind, but don't know what it was.

Decleration of intent to start blogging again, I hope.

In some weird way things have settled down enough that I can consider blogging (briefly) again. I do miss it. So much to say, so little time. Much of my blogging will likely be done late in the evening while holding my tiny baby and listening to my sleeping girls. But I'll try.

Let's start with this: I don't have to move my family anywhere in the near future. We are in Madison, Wisconsin, and I have a great job here: Associate Scientist in the Department of Botany at UW-Madison. Being a scientist who doesn't have to currently think about moving to another country or continent is kind of lovely.

Okay, more soon, I hope, about science, I hope.

Friday, June 12, 2015

Back to posting: Seastar Video

It has been a long time. Here, to get things rolling again, is an awesome little video (with English subtitles) that SDU made about the discovery my students made (unexpectedly) and my friends and I helped them publish. The part at the end where the starfish squeezes out the tag through its skin in slow motion is pretty damn cool.

Olsen, T. B., Christensen, F. E. G., Lundgreen, K., Dunn, P. H., & Levitis, D. A. (2015). Coelomic Transport and Clearance of Durable Foreign Bodies by Starfish (Asterias rubens). The Biological Bulletin, 228(2), 156-162.

If you want to hear more about this process and how awesome my students are, see this post and this post and this post.  Oh, and especially this post here.

Friday, March 27, 2015

Old pea aphids


You are a post-reproductive pea aphid. You have spent a long and happy life sucking the juices out of a pea plant. As the plant has grown, so has your large and clonal family, who you love as you love yourself, because genetically they are self. You were born with all your daughters already developing in your ovaries, and now the last one is out, and already reproducing, and what are you going to do with yourself? You may be only halfway thorough your lifespan. What to do with the remaining weeks? Pompano Beach is out, too many insecticides.

The obvious answer if you are a natural selection minded aphid is you'd like to help all the clones of yourself you've created to grow fast, live long and reproduce a lot. But how? Reproductive adults contribute more to the growth of the colony than do the young'uns, so throughout your reproductive lifespan, you've tried hard to stay at the center of the colony, where there is a touch of protection from predators. So maybe now you should move to the edge? If a hungry predator comes along, you can martyr yourself for the good of the clone. You don't have any chemical defenses or strong sharp pokey bits, and your kick is frankly rather unimpressive, but maybe if the predator eats you, it will allow time for your great-great-grandkids to escape, or at least make the predator full enough that it eats fewer of them. And maybe, just maybe, when that predator comes, you will be brave enough to just stay put and get eaten for the team.

Or perhaps rather than just sitting around waiting to get eaten, you can help to feed the family? Aphids suck sap, so if you could either put some chemical into the plant, or create enough suction, you could stimulates flow to that part of the plant where your family resides. Your young might grow faster or start reproducing sooner.

I mean, I don't really know. No post-reproductive aphid has ever sought my advice before. I'll do some experiments and get back to you.

Tuesday, March 17, 2015

Who has an adaptive post-reproductive life-stage?


To establish a case for an adaptive post-reproductive life-stage, one needs to show (at least) the following things:

(1) Prevalence: Across environments, but especially in a wild or non-protected environment, the population experiences more post-reproductive lifespan than is expected due solely to demographic stochasticity.

(2) Utility: Post-reproductive individuals do something selectively advantageous, such as helping younger kin to survive or reproduce.

In many cases, one would like to also address

(3) Advantage: Those individuals who become post-reproductive have a selective advantage over same-age individuals who simply continuing reproducing indefinitely.

However, this third is more complicated, because in many cases there are no individuals who fail to stop reproducing to compare to. For example, 55 year old women giving birth are rare and not easily compared to those who stopped at a more usual time. So testing (3) requires extrapolation and counter-factuals. This assumes that if continuing to reproduce past the current age of cessation were selectively advantageous, that the species' reproductive physiology would allow for it. In many cases, theoretically advantageous traits simply don't exist in the population, and therefore cannot be selected for. If the choice is not between ceasing reproducing or continuing, but rather between ceasing and being useful or ceasing and not being useful, useful wins.

So we are left with basically two fairly simple tests to make decent case an adaptive post-reproductive life-stage. And after some decades of interest in the evolution of post-reproductive lifespan, for how many species has this case been convincingly made? By my count, three. Humans, orcas and a gall-forming social aphid, Quadrartus yoshinomiyai. There are several other likely candidates. Short-finned pilot whales, and possibly other social cetaceans. African and Asian elephants. But I've become very interested in a much more accessible and experimentally tractable species. It lives in multi-generational groups of (very) closely related individuals.  Individuals play subtly different roles in the group throughout their lives. Older individuals stop reproducing and can (assuming no one comes along and kills them) live for extended periods post-reproductively (on the time scale these things live). You may have it in your garden.

Any guesses? Later this week I'll give you the answer.

Monday, March 16, 2015

Progress


For years, I've been worrying about about my chronic backlog of papers I should have written a long time ago and just haven't had time for. I'm very happy to report that my to-write list is getting a lot shorter. Three of the papers on that list will come out in the first half of this year. Number four is currently out for review, 5&6 need to be revised and resubmitted, a seventh is written and currently with colleagues awaiting their comments. The eighth has figures made and large chunks of text in their second or third drafts. If all goes well, all eight should be at least submitted by the end of the year, and I'm guessing that six will have come out. Of course there are several more that I need to get to, and new projects being planned, but it feels good to be clearing the backlog a bit. Especially nice is that after spending too long on methods papers, incidental discoveries and other tangents, the manuscripts I am working on now actually address the central points that motivated the research in the first place.

1. Levitis DA. (2015) Evolutionary Demography: a synthesis of two population sciences. In: International Encyclopedia of Social and Behavioral Sciences, 2nd Edition. ed.: J.D. Wright. (Coming out in May)
I am an evolutionary demographer, and while encyclopedia articles are not my bread and butter, this is very much on topic.

2. Olsen TB, Christensen FEG, Lundgreen K, Dunn PH, Levitis DA. (2015) Coelomic transport and clearance of foreign bodies by sea stars (Asterias rubens). Biological Bulletin. (Coming out in April)
This started as a student project to develop methods for studying the evolutionary demography of starfish, but when it became clear the animals wouldn't stay tagged, my students decided to investigate why. Their result was cool enough that we're publishing it.

3. Oravecz Z, Levitis DA, Faust K, Batchelder WH. (2015) Studying the existence and attributes of consensus on psychological concepts by a cognitive psychological model. American Journal of Psychology 128: 61-75.
My most cited paper (on the biological meaning of the word behavior) is one I started as a graduate student, even before it became clear I would be an evolutionary demographer. It got a nice write-up in the New York Times. Many of those citing it are in philosophy or psychology. A couple of years ago I was contacted by some psychologists who wanted to work with me to reanalyze those data. I never expected to publish in a psychology journal.

4. Zimmerman K, Levitis D, Addicott E, Pringle A. (2014) Maximizing the mean nearest neighbor distance of a trait to choose among potential crosses and design a fully crossed mating experiment.
This methods paper, currently out for review but with an earlier version already archived online and therefore available (journals are increasingly okay with this) grew out of a collaboration that is part of my ontogenescence project. In trying to answer my evolutionary question, my collaborator invented a new method for designing mating experiments, and we wrote it up. 

5. On raven populations in the Eastern US. One reviewer loved it just as it was, the other made numerous (and useful) comments on how to improve the analysis. Being worked on by my colleagues who are primarily responsible for the analysis.

6. Part of the same ontogenescence collaboration as #4, this was just rejected by a high impact journal on the basis that they rejected it (no reason or feedback given, as is common with such journals) and will be submitted to another in April.

7. Another ontogenescence paper, this time in a marine ecology context. Our plan is to submit in May. Between now and then the main order of business is to get feedback from colleagues and use it to improve the text.

8. Same project as #s 4 and 6.

9. On post-reproductive lifespan, building on the papers and methods that came out of my dissertation. We have cool results proving an interesting point, but it still needs a fair bit of work.

They probably won't be submitted in exactly this order, as a lot of it depends on factors beyond my control, but this is more or less the order I'm prioritizing them in. Beyond that it is hard to predict. Some older things I still do really need to write up, some fruitful student projects on post-reproductive lifespan that are looking good, some vague ideas. 

One thing I've decide is that at least for the moment, no papers that are outside the main foci of my research program (evolution of pre-reproductive mortality and post-reproductive survival) are going to make the list. Numbers 1-3 & 5 above don't directly address either of these topics, and 4 is tangential. That is a bad habit, and one I'm going to break.

Thursday, January 29, 2015

Insignificant figures

Before writing a paper I make lots of figures. Some will be improved upon and included in the paper. Others just help me understand what the data are telling me. Graphical data analysis.
Still others, like this one, end up being rather pointless exercises. This categorizes those barnacle larvae that died during our study, based on the stage during which they died, and whether they spent abnormally long in that stage and/or the previous stage before dying. The reason this is pointless, despite the nice colors and nested boxitude, is that all the same information can more compactly and clearly be displayed in a table. However, I now know how to use, and when not to use, the R package treemap.

Saturday, January 24, 2015

Choosing peer reviewers

Several years back, I was unbearably excited to be, for the first time, submitting my own manuscript to a real scientific journal. I'd spent months polishing it, and was totally confident it should be published. Working through the various steps of submission (input author names and contact info, input title, input abstract, keywords, ect.) I was surprised to be asked to input names and contact info for three recommended reviewers. Defendants in courts don't get to recommend specific peers to serve on their juries, how could science be served by asking me to recommend peers to evaluate my work? Confused, I emailed one of my advisers, who happens to be an outspoken crank when it comes to all of officialdom, and came away with the impression that this was not to be taken too seriously. I hastily plugged my keywords into Google and chose three prominent names I had never heard of before, who went on to tell the journal my paper was technically sound but not of the greatest interest. I was extremely lucky in that the editors of the journal found it very interesting, and published it anyway. Failing to have learned my lesson, a few papers I submitted since then were sent to unfavorable reviewers that I had recommended.

Now, journal editors can decide to ignore these recommendations, and those invited to review can say no, but in a large portion of cases (I have no data, this is simply a strong impression), some or all of those recommended end up writing reviews. The reason journals ask for such recommendations is to help the journal editors quickly find people who are highly qualified to review. I already know who is very knowledgeable about my specific topic, while the journal editors may not. Many journals have editors who are not paid anything for their service, and all have editors whose time is limited. Asking for and using these recommendations saves time, and probably helps avoid unqualified reviewers.

Doing so, however, has some pretty clear corrupting influence. Those who are good at this game pay great attention to whom they recommend, not only carefully considering the knowledge, viewpoints and interests of those they will recommend, but crafting the paper to raise as few objections as possible from these individuals. Papers that defy much of what is well established in one field regularly are published based on the recommendations of reviewers whose knowledge comes from another branch, and this fact is not ignored in making these recommendations. If the paper is very likely to be sent to a particular reviewer, that person's terminology and definitions will be used and his or her papers referenced. At scientific meetings, people will say, "I like this idea, list me as a reviewer." At its worst, peer review is reduced to a popularity contest, with well established authors having their work (not only journal articles, but also grant applications) evaluated mostly by their friends and allies.

Mixing moral distaste, political naivity, and hurry, I have generally spent no more than a few minutes on the question of who my recommended reviewers will be. The latest iteration of this came with a paper on which two of my undergraduate students are lead authors. We submitted it to one journal with a recommended list of reviewers that was hastily thrown together, experts on the organism we were working on but not necessarily interested in our particular topic. They trashed it solely on the basis that no one cared. We submitted the same manuscript, with very few edits, to another journal, listing reviewers with some knowledge of the organism, but a strong interest in questions related to our own. We got back three extremely positive reviews, praising our highly original and relevant work, recommending several very minor changes and urging the editors to publish this paper. Yesterday morning we submitted these revisions, and yesterday evening this journal officially accepted our paper.

So I've not only learned my lesson, but decided to heed it. Whom I ask to review a paper is (depressingly) almost as important as the quality of the work. I see truly terrible papers come out in excellent journals, presumably approved by carefully chosen reviewers, and some very good papers get rejected by less selective journals, in part because of poorly considered recommendations. From now on, I will put my qualms aside and think carefully, early in the process, about whom I will recommend as reviewers. After all, everybody else is doing it.

Friday, January 23, 2015

Very pleasing

There is something peculiarly satisfying about publishing an experiment which has, for its central instrumentation, a small magnet suspended by a human hair.

Wednesday, January 21, 2015

Good practice

Always order paper reprints for your undergraduate coauthors to give to their parents.

Friday, November 21, 2014

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.