Reflections on teaching insect biodiversity

Last semester I taught my Insect Biodiversity and Evolution course in a slightly new way, and now that it’s over I have a chance to revisit the experience and read my student evaluations. Overall I have to say that I am quite happy! I do see lots of room for improvements, of course, but first a little context …

Three ongoing situations drove me to revamp the course: (1) I get a lot of requests from colleagues to share my teaching materials, and I often found myself uncomfortable with their state (not always clear, sometimes with images of questionable provenance); (2) so many TAs have worked on the materials (often improving, sometimes meddling) that they lost some cohesion; (3) the collection exercise was never quite right, requiring so many specimens/taxa that the resulting product was often not usable for research or teaching (poor preps, sloppy labels, … rushed work).

My goal was to rebuild the course, almost from the ground up, and avail the new materials in such a way that they could be iteratively improved, commented on, and used by anyone. See the results at our GitHub repo. I hoped to release the new materials under a Creative Commons Attribution license (CC BY), to maximize peoples’ ability to refine the materials. I think it’ll be a long time before that can really happen, as many of the images I used are licensed in a way that doesn’t allow commercial use or derivatives.

grad students sitting on stone steps inside a dorm

The ENT 432 crew, at Raven’s Roost at Powdermill Nature Reserve — lots of smiles! September 2016. Photo (CC BY 2.0) by Hillary Morin

What went wrong 🙁

Overall I was happy with the course, but several elements could be improved. Here are three that come to mind, but you can read more in our issues feed:

  1. I’ll probably get rid of the requirement that lab notebooks be graded. Honestly I forgot about that line in the grading rubric (oops!), and so everyone got 100/100. They probably deserved that grade, though. These students answered all of our lab questions, many of which didn’t have “right” answers and were not easy. For example, we asked students to hypothesize the function(s) of the elaborate surface sculpturing one can see in Tingidae (see photo below and question 9-13 in the handout). I don’t know the answer if there is one!
  2. Students need more guidance regarding how to take field notes – or at least what I expected from them for this aspect of the Discover Your Inner Darwin exercise – and iterative examination of their notes. Their field notebooks were quite inconsistent in their detail.
  3. I need to lecture (even) less and bring back required readings that are discussed as a group. I jettisoned this element in order to bring the work load more in line with what Penn State recommends for a 4-credit course (about 160–180 hours of work in a semester). Time to rework the load again. I missed the readings!
top of a lace bug, whose surface is elaborately sculptured like lattice work

Amazing photo of a lace bug (Hemiptera: Tingidae), by Gilles San Martin (CC BY-SA 2.0) Why is their cuticle so elaborately sculptured? I don’t know! And my students didn’t seem comfortable with that.

What went right 😀

I definitely feel like this course is morphing into one that is both effective and fun. Although imperfect, it was easily my best semester as an instructor. Highlights for me:

  1. The observation component of the natural history exercise was really fun for me to witness and read about, and most students found it incredibly rewarding. With more direction from me, and maybe multiple iterations per semester, it could emerge as a highlight for students and an avenue for future research.
  2. The collection is also heading in the right direction. Each one was relatively small but sufficiently diverse, and the specimen preps were almost immaculate. Clearly a lot of time and care was put into these collections!
  3. The blog post exercise was also good fun, and it was an opportunity for students to dig deeper into observations and subjects that inspired them.
  4. The collections resulted in real data that can be used for research! Each student submitted his/her data as Darwin Core Archives, which are basically ready to share through GBIF (I want to doublecheck them first!) With a little help from GBIF, I think we can make this element almost as compelling as the collection.

Changes and opportunities

I’ve discussed one possible change with three semesters of students now, and I feel confident now that it’s an idea worth pursuing: I’d love to partner with a likeminded professor at a university relatively close to ours, say within a 6-hour drive of Penn State, for a combined field trip. We mix our students into teams that collect, prep, cook, and learn together … It could be fun! Another possible change to my course could disrupt the potential for any partnerships – a move to the spring semester.

More on that later!

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Better than a Christmas tree: my first Conostigmus tree

As part of a molecular approach, I’ve been designing and testing CO1 primers to use for mitochondrial barcoding in Conostigmus. Unfortunately, I’ve run into problems: CO1 does not appear to be conserved in Conostigmus, and the portions that are conserved are frustratingly rich in adenine and thymine. Since A-T bonds are weaker than G-C bonds, it is harder for primers to bind securely to A-T rich areas, making these areas useless for primer design. Though I do have primers that work for some species, I’m not sure if it’s possible to make a universal primer that will work for all Conostigmus.

However, with the work that I’ve done so far, I had enough CO1 sequences that I was able to make a preliminary tree of Conostigmus and Megaspilus species. As you can see below, the three Megaspilus specimens are all grouped together, which is what I would expect to see since they all belong to the same species, Megaspilus armatus.

A preliminary tree with CO1 sequences from Conostigmus and Megaspilus. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

Something else interesting is that Megaspilus armatus is nested within Conostigmus. It’s possible that Megaspilus might just be a larger Conostigmus, due to its close resemblance to larger Conostigmus species such as C. crassicornis and C. ballescoracas. The only main difference between Conostigmus and Megaspilus is the presence of a bifurcated propodeal spine, which is present in all Megaspilus. While there are no bifurcated spines in Conostigmus, there are a few species that have a single spine, including those species that resemble Megaspilus such as C. ballescoracas.

Whether you prefer a Christmas tree or a phylogenetic tree, we here at the Frost would like to wish you happy holidays and a happy new year!

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An Ode to Winter Ode Sorting

In the summer, it’s so easy to take for granted all of the sunny days

when dragonflies and damselflies were collected in a frenzied haze

when the geek vest seemed almost too hot to don

as I ran with my net along the lawn

Photo of a woman looking contemplatively into the mountains of Utah.

One of the beautiful places that I was able to observe odes this year, Zion National Park. Photo was taken by Riley Nelson for me (CC BY 2.0).

But in the winter, my teeth chatter in the collection room

as I attempt to sort the odes in their cold unit tray tomb

the brittleness of the wings catches me off guard

as I take one out of its triangle and put it on a card

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Exploring the Semitransparent Patches using EDS and SEM

Energy-dispersive X-ray spectroscopy (EDS) can be used to examine the elemental composition of of a sample. Flor used EDS to map the presence of zinc in the mandibles of fall armyworms, Spodoptera frugiperda, showing that the metal is accumulated at the edges of the mandibles to strengthen them (take a look at her blog post here).

As part of my work on the semitransparent patches found in Ceraphronoidea, I wanted to use EDS to see if there were any differences between the semitransparent patches and the surrounding cuticle (for an overview of what the semitransparent patch is, take a look at my blog post from István’s “Know your Insect” seminar).

m An SEM image showing the ventral semitransparent patch and felt field in Megaspilus armatus. Notice how scaly the felt field looks! Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

While using EDS to explore the semitransparent patches in Megaspilus armatus, we were able to take some nice SEM (scanning electron microscope) images. I was surprised at how scaly the nearby felt field looked. When we zoomed in, we were able to clearly see the pores that I found during TEM and SBFSEM.

A close-up of the felt field in Megaspilus armatus, showing the pores among the setae. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

Though our initial EDS work didn’t seem to show a difference in the elemental composition between the semitransparent patches and the surrounding cuticle, there might be a concentration of calcium, sodium and phosphorus around the felt fields. Could these elements be components of the substances secreted from the pores? I look forward to analyzing my data so I can find out!

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Good Natural History Reads: Field Notes on Science and Nature

With the weather getting chilly, I’ve been spending the weekends at my favorite coffee shop reading all of the papers and books that have piled up over the semester. This week I wanted to share my thoughts on a book relevant to those interested in natural history called Field Notes on Science and Nature, edited by Michael Canfield. This book has been a popular read in our lab (Andy first discovered it back in June!)

The foreword to the book is written by E. O. Wilson, who asserts that “the wellspring of the new biology is scientific natural history”. Since so little is known about the natural world, a huge rate of discoveries occur when scientists venture into the field to make observations. To ensure that these discoveries make it out of field and into the greater scientific community, it is essential to take good notes that capture as much of what was observed in the field as possible.

Each chapter of the book is written by a different author and discusses a different aspect of keeping field notes, from how to record observations to what kind of pen and paper should be used. Along with sharing their own personal methods of taking notes, the authors give sage bits of advice for those pursuing the life sciences. George Schaller warns in the first chapter that when you collect data on how far an animal has traveled or how many leaves it ate, you are only compiling fragments of that animal, not capturing the animal in its entirety. I think this is something to keep in mind, especially as research in the life sciences seems to become more and more disconnected from the natural world that inspired it.

The rolling green fields of Utah. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

One of my favorite chapters in the book was written by Anna K. Behrensmeyer, a paleontologist who can speak of the importance of using fragments as windows as to what happened in the past. She says that when taking notes, it is important to keep in mind that people years from now might be studying them to find out what you did. Thus, you should write your notes for them, not just for yourself.

Overall, the book is full of useful tips for researchers working in the field. I compiled some of the best pieces of advice from the book below:

  • Take notes immediately! If you don’t record what you observed as soon as you can, you’ll likely forget it, and then it will be as if it never happened.
  • Write everything down! You never know what might or might not be needed later on. Even if you don’t think something is important at the time, you might look through your field notes later and realize just how significant it is.
  • Input data and transcribe handwritten field notes right away. Not only will this give you back-ups of your notes, but you can also fix any mistakes right away, instead of looking back months later and trying to figure out what happened.
  • Use both quantitative and qualitative data in your studies. Focusing on just one aspect means that you can lose sight of what you are studying, considering only fragments instead of the whole.
  • Don’t just rely on one kind of data collection method. Take notes, snap pictures, draw maps, write lists; try all different kinds of approaches and see what works best for you.
  • Use drawings in your field notes. While taking a picture is easier, sketching causes you to pay more attention to detail and notice aspects of it that you would have missed otherwise. Drawing can help you interpret what you are looking at and help you see things in a new way.
  • Don’t underestimate the value of lists, especially if you are working with highly visible organisms like dragonflies and butterflies. It is valuable to keep a separate list of all of the species you saw that day, or what species you saw in an area. For citizen science approaches, you can use this data to compile a checklist of species to watch for. Many discoveries with birds have been made by amateurs and not by professionals.
  • Be careful to record facts and direct observations. Distinguish these from your interpretations of what you are seeing. Clearly note them or separate them- you don’t want to cloud your facts with opinions.

An overall theme of the book is “don’t seek out things just because they are scientific; seek them out because you enjoy them, and in doing so, this will often lead you to make scientific discoveries”. Observing nature is a good way to get fresh scientific ideas, as well as reconnect and see the world for what it really is- not just a string of data points on a computer screen, but a chaotic, wonderful mess.

I still have a lot of books to tackle before I can see the surface of my desk again, but as I keep reading I’ll try to post reviews of more good natural history-related books that are worth checking out.

There are always more books to read. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

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