Researching Pelecinids – Part 6

Last year I chronicled my experience researching Pelecinus polyturator in Dr. Norman Johnson’s lab. This research journey included learning the biology and behavior of P. polyturator, photographing specimens, collecting in town using Malaise traps, extracting DNA and amplifying it using polymerase chain reaction (PCR), learning the importance of literature reviews, and trying to collect live adults at Zaleski State Forest. Take a look at my previous blog posts to know more about these topics and catch up on my research so far.

author using laptop

The author analyzes DNA sequences using the Sequencher software

Over the last six months I continued working on my research, and now I have several exciting updates to share. While I took a hiatus from the lab in autumn semester to focus on my academic coursework, the research process did not stop. The DNA we extracted was sent out to be  commercially sequenced. Once I returned in spring semester, it was a matter of assembling those sequences and performing phylogenetic analysis before we could start drawing conclusions.

The focus of our study was the sex ratio variation between northern and southern populations of P. polyturator. Using molecular techniques we amplified sequences of the cox1 gene, which can be used as a genetic barcode to differentiate species. Additionally, we amplified the ftsZ gene in Wolbachia, an intracellular symbiotic bacterium that can effect sex ratio in insects. We suspected that if different strains of Wolbachia were present in the different P. polyturator populations, this could be a contributor of the observed sex ratio variation.

The Wolbachia turned out to be nearly identical from every locality sampled. On the other hand, the cox1 gene varied greatly between the northern and southern populations, and even between different localities of the southern population. From this information we concluded that the Wolbachia strain was not a direct cause of the sex ratio variation. The differences in the cox1 gene, however, suggested that there may be speciation occurring between the northern and southern populations.

Doing the research and analyzing the results was only a part of the process. Science is a collaborative endeavor, and it is important for a scientist to be able to communicate the results and ideas to others in a clear and concise way.

On March 1, I had the opportunity to present my research at the CFAES Undergraduate Research Forum. This is an event where students within the CFAES (that stands for College of Food, Agriculture, and Environmental Sciences) can showcase their research to other students and faculty, as well as a panel of judges. This forum attracts a wide audience of people from many different scientific disciplines and backgrounds. It is a great opportunity to interact with people who may not be familiar with entomology or molecular genetics. At first I was nervous to talk about my research, but it ended up being surprisingly fun to answer people’s questions. I even had a female P. polyturator specimen to show visitors, courtesy of Dr. Luciana Musetti and the Triplehorn Insect Collection.

Designing and presenting the poster was a great experience for me. I quickly learned that designing a poster is much different from writing a traditional scientific paper. Both formats are separated into similar sections such as an introduction, methods, results, and conclusions. A poster, however, has space constraints and must be attractive to a general audience. Large blocks of text typical of papers are unattractive and intimidating on posters. Overall, readability is the most important trait of a good research poster. The font should be large and easy to read, and everything should be spatially organized in a logical manner.

author and research advisor with poster

The author and her research advisor, Dr. Norman Johnson, stand in front of the research poster at the CFAES Research Forum.

author explaining research

The author explains her research to entomologist Dr. Megan Meuti

Presenting my poster at this research forum was a great preparatory experience for the upcoming Denman Undergraduate Research Forum. Because most of the research within CFAES was focused on agriculture and food science, I gained experience speaking to people unfamiliar with the topics of my research. The Denman will feature an even more diverse array of students and faculty, from business to chemistry to art, so I will need to be prepared to explain my research to those completely unfamiliar with entomology or molecular work. I will also be revising my poster using suggestions from the judges of the CFAES forum.

If you would like to learn more about my research project, as well as the research of other hardworking undergraduates, stop by the Denman in the Archie Griffin Grand Ballroom of the Ohio Union on Tuesday, April 3. I will be displaying my poster from 3:00 pm to 5:00 pm, and I would love to see you there!


About the Author: Hannah McKenzie is an undergraduate entomology major at the Ohio State University. She currently works as a curatorial assiatnt at the Triplehorn Insect Collection and is greatly enjoying her undergraduate research project on Pelecinus wasps.

Researching Pelecinids – Part 2

One of the most useful resources the Triplehorn Insect Collection has to offer is its extensive HOL database, an online taxonomic initiative that documents collected specimens of various insect groups. This database already contains records for over 845 thousand Hymenoptera specimens, and it continues to grow every week through the hard work of countless contributors.

One way to contribute to HOL is to photograph and upload images of collected specimens, further enriching the available data on specific taxa. Prior to the start of my research on pelecinids, there were zero images of the genus Pelecinus available in the database. To remedy this, I had the opportunity to work with Jordan Reynolds, an undergraduate student in Art & Technology who is currently working on specimen photography for the collection. Over the last several weeks, Jordan taught me about the technologies and techniques required for taking high-quality images for the database.



My goal in photographing a selection of the collection’s Pelecinus polyturator specimens is three-fold. First, I will obtain a more in-depth understanding of the external anatomy of these intriguing insects. Second, I can compare the morphologies of males and females of different sizes and localities. Third, I will contribute previously unavailable data to the HOL database.

Photographing collection specimens is not as simple as taking a picture with a camera. Because the specimens are relatively small, and because we require intricate detail in the images, we instead use a method known as focus stacking. With this method, the camera gradually moves along a track and takes multiple images at different distances. The focused areas of each image are then “stacked” together by a computer program so that the entirety of the final image is clear. Because the P. polyturator specimens required a large depth of field, we sometimes had to photograph and stack up to 100 images to create a sufficiently focused final image.

In addition to taking individual specimen images, we also took several comparison images. These provide a quick side-by-side comparison between two different specimens. Some of the images we took compare males and females of similar localities. Other images showcase females of similar localities and their dramatic variance in size.

comparison image of P. polyturator females

Comparison image illustrating the size variation in P. polyturator females

Of course, no system is perfect, and we faced many challenges along the way. Most of the parasitic wasps that get photographed by the collection are very small in size (no more than a few millimeters long). Therefore, the collection’s microscopic camera that is traditionally used for parasitoid photography is designed to take highly detailed images of very small specimens. P. polyturator females are unusual in that they are very large parasitoids that can exceed 40 mm in length. Because of this, many of the specimens we wanted to photograph could not fit under the microscopic camera. We instead opted to use a DSLR camera, which is used for macrophotography of larger specimens such as beetles and butterflies. Using this nontraditional method of parasitoid photography, we were able to produce high-quality images of the larger specimens by exploiting various imaging techniques.

Another challenge we faced was the handling of the specimens. All mounted insects in a collection must be handled with great care because they are dry and brittle. Pelecinids must be handled with extra caution because their long, string-like antennae and fragile abdomens will break with even the slightest bump.

We ended up with many beautiful images of these wasp specimens. The complete collection of images has been uploaded to HOL and is available on the page dedicated to P. polyturator. I would like to thank Jordan for all of his help with this photography endeavor. Without the countless hours he spent performing behind-the-scenes image processing, the final images could never have turned out so well.


About the Author: Hannah McKenzie is an undergraduate entomology major at the Ohio State University. She currently works at the Triplehorn Insect Collection and is participating in undergraduate research on Pelecinus wasps.

Researching Pelecinids – Part 1

image of a pelecinus wasp

Wasp in the genus Pelecinus, image by Cynthia L. McLaughlin and licensed under CC BY 2.0

Many years ago, arthropods were one of my greatest childhood fears. I was so petrified of bugs that I hardly ever went outside during the summer. Anyone who knew me as a child would never have guessed that I would someday develop a passion for entomology and a love for the insect world. I began to collect insects in little plastic jars, but my rudimentary “collection” might as well have been a dermestid buffet; this was long before I understood how to properly store, curate, and preserve specimens.

It wasn’t until my final year of high school that I realized that I could become an “entomologist” as a profession, a life-changing revelation. During the summer of 2016, I finally learned how to make a proper insect collection at the Ohio State University’s Stone Lab, where I enrolled in a week-long course on insect field biology. That autumn I started my first semester at Ohio State as an entomology major, commuting every day from my home in Westerville, Ohio.

I recently completed my first year in the entomology undergraduate program, and I couldn’t be more excited about my academic future. I have met so many great peers and faculty members within the entomology department, and I have had the chance to explore entomology in ways that my younger self could never have imagined. I joined my general entomology class on an all-day collecting trip in Hocking Hills. I visited the on-campus insectary and learned about rearing insects with Chrysalis Entomology Club. But perhaps the most enlightening experience I have had so far was my interaction with the Triplehorn Insect Collection. I participated in an internship at the collection during autumn semester, then continued to work there part-time during spring semester. This summer I plan to continue working at the collection, but now the collection has presented me with yet another exciting opportunity: working on my first undergraduate research project.

image of a June bug

Unidentified June bug (Phyllophaga) from central Ohio, image by author

I will work with Dr. Norman Johnson and Dr. Luciana Musetti over the summer to research wasps belonging to the genus Pelecinus. These beautiful insects may appear intimidating with their long, slender abdomens, but they are not aggressive toward humans and stings inflicted by their small ovipositors are rare. Their flexible abdomens are instead used to parasitize the larvae of Phyllophaga beetles, more commonly known as “June bugs”. The female wasp does this by thrusting its abdomen into the ground and ovipositing into the subterranean grubs.

My research will focus on Pelecinus polyturator, a species that can be found in areas of South America and in North America east of the Rocky Mountains, including here in central Ohio. One of the most interesting aspects of P. polyturator is that males are extremely uncommon north of Mexico but become much more common further south.

The goal of my research is to examine P. polyturator specimens from both northern localities and southern localities and determine if they are one species or if they are actually multiple distinct species. This can be determined using nondestructive DNA extraction and barcoding, which consists of using a species-specific genetic marker in a specimen’s DNA for species identification. I do not have any prior experience with DNA barcoding, or even molecular genetics in general, so I see this as an incredible opportunity to learn new skills that will benefit me throughout my entire scientific career. I will also get to learn first-hand how specimens such as Pelecinus wasps end up in an insect collection by going through the complete collecting process, from malaise trapping all the way to entering specimen data in the collection’s online Hymenoptera database.

At the conclusion of this research project, I plan to present my findings at both the Denman and the CFAES Undergraduate Research Forums. One of my main hopes for this project is that it can be used to illustrate the research experience for other students interested in undergraduate research, both entomological and otherwise.

As I continue to learn more about topics such as DNA barcoding, specimen collection, and Pelecinus wasps themselves, I will update this blog so that everyone reading can learn alongside me and watch the progress of my research in real-time. Keep watch for another post from me next week about taking photographs of P. polyturator specimens currently owned by the collection. I can hardly wait to share these images and the photography process behind them.


About the Author: Hannah McKenzie is an undergraduate entomology major at the Ohio State University. She currently works at the Triplehorn Insect Collection and is participating in undergraduate research on Pelecinus wasps.

Chalcidoidea: Minute “Gems of the Woodlands”

Lelaps sp., parasitoid wasp (Hymenoptera: Chalcidoidea: Pteromalidae) from the Amazon Basin, specimen ID = OSUC 45851; image by the author.

Lelaps sp., parasitoid wasp (Hymenoptera: Chalcidoidea: Pteromalidae) from the Amazon Basin, specimen ID = OSUC 45851; image by the author. (original title: Unidentified chalcidoid wasp (Pteromalidae) from the Amazon Basin)

I have always been fascinated by insects, but it was not until, at age 15, I took a week-long field insect taxonomy course at the Ohio State University’s Stone Laboratory. There, I learned the conventions of arthropod collection and preservation and something of proper curatorial practices. Ever since, I have steadily accumulated a collection with pretensions made modest by the limited resources of a teenager; and collection and identification remain an exceedingly enjoyable activity for me.

Therefore, it was only natural that I gravitated to the Triplehorn Insect Collection upon commencing my undergraduate career. Sorting unidentified specimens was easily my favorite task there. Although the collection contains the full range of insect diversity, those specimens that I was tasked with identifying almost always belonged to the order Hymenoptera—often casually referred to as “ants, bees, and wasps”, but technically including far more taxa than simply those that happen to have colloquial names.

Being one of the four most diverse insect orders, the variety of Hymenoptera is considerable: and I encountered much of their phylogenetic span through this process, while becoming intimately familiar with Goulet and Huber’s tome Hymenoptera of the World: an Identification Guide to Families (1993) (PDF), the monochromatic line drawings within which—printed on thick, coarse paper—have caused hymenopterists to nickname it “the coloring book”.

As an exemplar of the many taxa with which I thereby became familiar, I have chosen to briefly discuss the superfamily Chalcidoidea herein. These parasitoid wasps (using what is a phylogenetically useless term) are one of those aforementioned many prominent insect taxa that have no name in the vernacular—understandable, given that the vast majority of these particular parasitoids are a few millimeters in length or less. (Indeed, the smallest insect known to science—the 0.13-mm.-long male of Dicopomorpha echmepterygis [Mockford, 1997]—is a chalcidoid.)

This diminution has also resulted in a lack of taxonomic attention from entomologists, and chalcidoid systematics is by consequence a frustratingly opaque matter—something one is immediately impressed with while attempting to identify the miniscule things: keys are peppered with qualifiers like “usually” and “most”, not to mention annotated with lengthy footnotes elucidating the exceptions to each couplet. The fundamental problem at hand, as Goulet and Huber point out, is that chalcidoid families are often defined by combinations of characters, as opposed to singular traits that are unique to that taxa and none other (synapomorphies, in cladistic terms). This has resulted in a superfamily littered with taxa whose boundaries are under constant debate (e.g., the Agaonidae) or that do not hold up to scrutiny whatsoever (the grossest wastebasket taxon of flagrant wastebasket taxa, the Pteromalidae).

Chalcidoids are hardly deserving of this neglect, considering their ecological and numerical diversity (they possibly constitute 10% of all insect species; Noyes, 2003). I would have impartially respected this significance regardless of my work at the Collection, but parsing through unit tray after unit tray of nigh-microscopic specimens representing untold numbers of species—each one a chalcidoid—gave me a concrete grasp of that abstraction.

I still have strong visual impressions of many of them: the subtly turquoise, spatula-shaped abdomen I swiftly came to associate with the Tetracampidae; the minute serrations on the inner rims of a stocky chalcidid’s femora, making its thighs appear like chitinous razors; the oar-like forewings of many an insubstantial mymarid, fringed with haloes of setae; the metallic, spindle-shaped abdomen that accounted for two-thirds the length of a sycoryctine. I am not the only one to have thought them often quite showy under sufficient magnification: Alexandre A. Girault, a notoriously verbose chalcidologist, spoke of the tiny wasps as “gem-like inhabitants of the woodlands, by most never seen or dreamt of” (Thomer & Twidale, 2014).

Suffice it to say, without my work at the Collection, I would not have seen nor dreamt of so many chalcidoids.


Mockford, E. L. (1997). A new species of Dicopomorpha (Hymenoptera: Mymaridae) with diminutive, apterous males. Annals of the Entomological Society of America, 90, 115-120.

Noyes, J. S. (2003). Universal Chalcidoidea Database. Retrieved 5/18/16 from http://www.nhm.ac.uk/our-science/data/chalcidoids/introduction.html

Thomer, A. K. and Twidale, M. B. (2014). How Databases Learn. In: iConference 2014 Proceedings (pp. 827-833). Retrieved 4/8/15 from https://www.ideals.illinois.edu/bitstream/handle/2142/47268/409_ready.pdf?sequence=2

 

About the Author: Zach Griebenow is an undergraduate majoring in entomology at the Ohio State University. You can read his personal blog on entomological matters here.

Funding hiatus weakens collections.

The suspension of the Collections in Support of Biological Research (CSBR) Program was announced by the National Science Foundation (NSF) in mid-March.  That program is the only source of significant extra-mural funding for biological collections infrastructure and as such vital for the long-term survival of university collections like ours in the USA.  The so-called ‘CSBR hiatus‘ generated great concern within the museum and collections community. The funding hiatus reached the big scientific and media outlets like Science, Nature, The Atlantic, and the NY Times, just to name a few.

How long is the hiatus for? Is this the first step towards cancelling the CSBR program? Will the program be revamped/re-purposed, and if so, what will its new purpose be? Those are some of the important questions in our minds right now. Even a one-year break in this program will likely have a very negative effect on long-term maintenance of irreplaceable biological collections around the country.

Why should anyone outside of the collections community care about this? I’ll describe the impact of NSF funds for collection infrastructure on the Triplehorn Insect Collection over the past 25 years in hopes that our experience will provide some insight.


 

 


Historically, space was always at a premium and the specimens in the Triplehorn Insect Collection had always been packed very tightly. It was a relief when, in 1992, the collection was relocated from the rooms and hallways of the old Botany & Zoology Building to the more modern and spacious Museum of Biological Diversity.  At that time, Johnson and Triplehorn were able to secure funds (Award #9123439) from NSF’s Improvement to Biological Research Collections Program (the previous name of the CSBR) to purchase new cabinets, drawers and trays.  That allowed for the replacement of the very old wooden cabinets for new steel cabinets and the proper storage of at least part of the large amount of material packed in Schmitt boxes.  This was before computers became a thing in biological collections so we were not concerned about that.

Fast forward to 2004.  Driven by our current research interests, the Hymenoptera portion of the collection had been re-curated (moved from the old drawers and trays to new ones) and the specimen data for that group was gradually being digitized.  After re-curation and specimen level databasing the hym collection increased by 50%.  We were also mounting parasitoid wasps that were newly collected or being sent to us for identification from all over the world, and the storage space was disappearing fast.

Meanwhile, we were still trying to transfer the specimens that remained in the miscellaneous Schmitt to proper trays and drawers.  That operation ended up taking ten of our 25-drawer cabinets — almost all the available empty cabinet space — simply to accommodate existing material. By the end of 2005 we were almost out of storage space and we had very little space to accommodate the people and equipment necessary for specimen level databasing. Our hands were tied.


 

Chuck Triplehorn holding a drawer of scarabs that is still exactly like Joe Knull left it.

Chuck Triplehorn, Curator Emeritus, holding a drawer of scarabs that is still exactly like Joe Knull left it.

As I mentioned in another post, beetles are one of the most extensive, well-studied and heavily used groups of insects held by the Triplehorn collection.  As such the beetles are at the top of our curatorial and databasing priorities.  But in order to re-curate and database the beetle collection, we had to tackle the issue of space.

We turned to the NSF again, and in 2008 we received another infrastructure grant (Award #0749705) that allowed for the installation of a compactor system (movable shelving) and the purchase of new cabinets, drawers and supplies. With the new system we had a 66% increase in storage capacity with the added bonus of a 30% reduction in the collection footprint (space the cabinets occupy). As part of the same project we also curated and databased all our more than 3,000 primary type specimens.  All the data are freely available online.

With more physical space, more storage space, and some resources available, we could at last start tackling the much needed upgrade of our beetle collection in preparation for the specimen-level databasing we wished to accomplish. We started with Carabidae (ground beetles) and Tenebrionidae (darkling beetles).

 

At the Triplehorn collection we keep the specimens in holding trays or ‘unit trays’ for short, inside USNM style glass-covered wooden ‘drawers’ which are in turn kept stored in tightly sealed 25-drawer steel cabinets. A large number of our drawers and trays are still the same ones from Joe Knull’s time (curator between 1934-1962), and therefore at least 50 years old. The real thorny issue to address is the unit trays.

A unit tray is the basic storage unit in the collection – it holds and protects the pinned specimens.  Our old ones are lined with cork and many specimen pins, deeply lodged into the cork, have corroded and are now practically cemented to the trays. To makes matters worse, due to the chronic lack of space, most of the old unit trays are, and I cannot overstate this, very tightly packed with specimens. Handling these over-packed trays is a very damage-prone, not to mention nerve-wracking, operation. It takes us months to train (and trust) a curatorial assistant to do that kind of job.

Prior to databasing, more than 100K carabid and tenebrionid specimens were carefully moved from old to new trays.  Some specimens were damaged during the process and had to be repaired, some specimens had to have the corroded pins removed and replaced by new, stainless steel ones. Only then we were ready to add a unique ID label to the specimen and to transcribe the specimen data.


The real burning question is: do we need to do this? Do we need to move the specimens, replace trays and drawers, add unique IDs, and capture the specimen data? One quick answer is obviously ‘no’. We don’t need to do any of this if we don’t want to make our specimen data available to science and the general public. But we do want that! In fact, I firmly believe we must do it! And doing it requires work far beyond the so-called ‘normal operating procedures’ that collections are rightfully expected to self-fund. In fact, with the crippling erosion of local funding and personnel that afflict biological collections, the definition of ‘normal operating procedures’ could soon become so limited that before long many collections might not make their specimens available for study at all anymore. That, my friends, would be an unmitigated disaster for science, and consequently for human society.

Many people, and here I include some scientists, don’t know or understand the role of collections in the systematic study of the world around us that we call ‘science’ and, consequently, the critical importance of collections to all of us.

A common misconception is that biological collections want money to add more space to continue growing ad infinitum.  This could not be further from the truth! Curators are very conscientious and mindful of their facility, space, and budgetary restrictions. We all endeavor to live within our very limited means and facilities. But like the hospitals (or any other business) that are now replacing their old paper records with new computerized systems, standards best practices continually evolve. In order to provide high quality service to our users and to best preserve the specimens that are entrusted to us, collections must keep up with these new curatorial standards, adopt new best practices, and replace substandard materials.

Unlike for-profit businesses, collections provide services to the scientific community and to society for free, or nearly so.  As a result, there is practically no cash-flow, part of which might be allocated to long-term investments. That’s where federal grant funds are needed to come in and support those upgrades.

Newly curated specimens of the genus Eleodes (Tenebrionidae)

Newly curated specimens of the genus Eleodes (Tenebrionidae)

In the case of the Triplehorn collection, the two infrastructure grants we received from NSF enabled the more efficient use of our available physical space, allowed for upgrades in the quality of materials, and the application of modern curatorial standards. Without those grants, numerous research projects (see examples listed below) that we have been involved with, that resulted in numerous scientific publications, would never have been possible.

Biological collections and natural history museums in general need funding in order to continue to fulfill their mission as critical sources of scientific data that support research in numerous areas of science, from medicine to agriculture to forestry, from ecology to conservation to climate change. These are not just buzzwords that we throw around for effect. This is real!  Collections are used daily by scientists to help solve problems that affect all of us. It is our responsibility, as citizens, to do our best to support and maintain collections in the long run.

Let’s please keep writing to the National Science Foundation requesting that they end the CSBR hiatus & renew their support for the long-term funding of biological collections infrastructure. Make your voice heard by sending your comments to NSF via email: DBICSBR@nsf.gov.


Infrastructure grants received by the Triplehorn Insect Collection:

Award #9123439 (1992) Modernization in the Care and Use of the Systematic Entomology Collections at The Ohio State University.

Award #0749705 (2008) Increasing Efficiency of Space Utilization for the Triplehorn Insect Collection (OSUC).

Research and databasing grants resulting in part from infrastructure grants received by the Triplehorn Insect Collection:

Award #0344034 (2004) REVSYS: Classification, Phylogeny, and Biology of the Parasitic Wasp Family Scelionidae

Award #0614764 (2007) PBI: Diversity and The Parasitoid Life History Strategy – The Superfamily Platygastroidea (Hymenoptera).

Award #1503659 (2015) Digitization PEN: Integration of data from the Triplehorn Insect Collection with the Southwestern Collections of Arthropods Network.


 

About the Author: Dr. Luciana Musetti is and Entomologist and currently the Curator of the Triplehorn Insect Collection.