Translucent Cuticle in Orussidae

I’m starting to wrap up my research on the patches of translucent cuticle that are found in all Ceraphronoidea (for more information on the patches, check out my blog post from Istvan’s “Know Your insect” seminar).

One of the questions we had was whether similar patches are found on the abdomens of other Hymenoptera. Surprisingly, we found them in Orussidae!

Dorsal view of the abdomen in an Orussus sp. specimen. The translucent patches of cuticle appear dark and smooth in this specimen. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

Just like ceraphronoids, orussids have two patches of translucent cuticle on the dorsal and ventral surfaces of the abdomen. The patches were dark in the specimen above, but translucent in the specimen Istvan dissected below.

Dorsal patch of translucent cuticle in the abdomen of an Orussus sp. specimen dissected in glycerin. Photo by Carolyn Trietsch (CC BY 2.0) Click for source.

There are also two patches on the ventral surface of the abdomen, but these are normally hidden by the hind coxa, so you have to dissect them out to see them, like we did below.

Ventral patch of translucent cuticle in the abdomen of an Orussus sp. specimen. Photo by Carolyn Trietsch (CC BY 2.0). Click for source.

It is exciting to find these patches in Orussidae because they are the most derived of the sawflies, and represent an important step in the evolution of aprocritan wasps and the parasitoid lifestyle in Hymenoptera. It is unknown how Ceraphronoidea are related to other Hymenoptera, but it is possible that they may actually be the most basal apocritan wasp, which would put them close to Orussidae. The fact that both Orussidae and Ceraphronoidea have translucent patches of cuticle seems to suggest that they could be more closely related that previously thought.

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Lindsay Erndwein: New Curatorial Assistant

Lindsay Erndwein with spotted lanternfly instars

A fruitful lycorma delicatula hunt, indeed.

Greetings, my entomologist compatriots!

My name is Lindsay Erndwein and I am working at the Frost to assist graduate student, Emily Sandall, with the curation and digitization of odonate larvae.

I am a senior in materials science and engineering with a minor in entomology. My life’s ultimate passion is studying the polymeric materials that insects produce and recreating these materials for applications in science and technology. From the rigid yet flexible chitin of the cuticle, to the powerful, energy-storing resilin in saltatorial legs, I believe that insects exhibit a myriad of unique materials that can improve the world.

This year, I am conducting a senior thesis involving the 3D printing of double network hydrogels inspired by the underwater strength and adhesive properties of Trichopteran silk. My future plans involve pursuing a Ph.D. in biomedical engineering to study the development of artificial cartilage inspired by the resilience and flexibility of resilin. I also wish to become a professor and invigorate the next generation of scientists.

Unfortunately, this is my final semester at Penn State and I will miss many memorable experiences with the entomology department. Summer 2015, I aided Dr. Mike Saunders and graduate student, Erica Smyers with the initial field studies on the spotted lanternfly. It was surreal being a pioneer assistant researcher in such a recent infestation (and catching swarms of colorful, hopping, hemipterans for a summer job was also incredibly fun). Last year I participated in the wonderful class, ENT 432 with Dr. Andy Deans and loved broadening my knowledge of insect taxonomy in addition to enhancing the Frost’s diversity with my collection. I am honored to be able to work with this amazing department one last time before my departure upon graduation.

I look forward to an amazing semester and bid a warm hello to all!

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Our new Collections Management Policy

Our museum finally has an updated and more comprehensive Collections Management Policy, drafted and approved by our Frost Entomological Museum Curators & Interest Group and reviewed by Penn State’s Risk Management team. It was a fun(!) exercise, especially the drafting of a mission statement, and I’m glad we finally have a clearer set of policies.

I started this process last summer, as a product of my participation in the Entomological Collections Network Collections Management Workshop. The workshop was great, and I’ve slowly been turning those lessons into a manual that will guide our curation at the Frost. The finished drafts of our new policies and standard operating procedures (SOPs) are available for review: https://sites.psu.edu/frost/policies/ (also see “Policies” in menu above)

jar of alcohol filled with vials that have insects inside them

How do we store specimens preserved in ethanol? Here’s an example from the Smithsonian. Photo (CC BY 2.0) by Andy Deans https://flic.kr/p/JmZm3Q

My hope is that by making these policies available we get feedback about their shortcomings (or how great they are!), and others will have models they can adapt for their own collections. I suspect that some collections still lack this kind of documentation, like we did, or at least they could use some updates.

I did have a crazy idea back in 2010 for a wiki (hosted by ECN?) of community-vetted entomological collections best practices, something that could be curated and updated by knowledgable colleagues. What should a loan policy look like? What is the best way to freeze-treat dermestid infestations? What’s the best vendor for drawers? Let’s check the collections wiki! A lot of this information is out there already in an ad hoc fashion. One could query or search the ECN listerv or NHColl archives, for example, or visit websites of various collections. It would’ve been incredibly useful, though, to have a single, comprehensive, and mostly vetted resource. I still think it’s an awesome idea, although I am a bit more of a realist now, with respect to the amount of effort required to initiate a wiki! What do you think?

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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 https://flic.kr/p/LPuPrV

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) https://flic.kr/p/9hv9Nj. 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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