Explaining Science – vermiform mites

You have heard of mites – minute arachnids that have four pairs of legs when adult, are related to the ticks and live in the soil, though some are parasitic on plants or animals. But what are vermiform mites? Maybe you have heard of vermi-compost, a composting technique that uses worms (like your earthworm in the garden) to decompose organic matter. So vermiform mites are mites with a body shape like a worm:

worm-shaped nematalycid Osperalycus

Why are they shaped like a worm, you may ask – To find out more I interviewed Samuel Bolton, former PhD student in the acarology collection at our museum, now Curator of Mites at the Florida State Collection of Arthropods. Sam’s main research interest is in mites that live on plants and in the soil, especially Endeostigmata, a very ancient group of mites that dates back around 400 million years, before there were any trees or forests. Sam’s PhD research with Dr. Hans Klompen here at OSU, was focused on a small family (only five described species) of worm-like mites, called Nematalycidae.

side note: You may have heard of Sam’s research in 2014 when he discovered a new species of mite, not in a far-away country, but across the road from his work place in the museum.

When Sam started his research it was not clear where these worm-like mites in the family Nematalycidae belong in the tree of life. To find out Sam studied several morphological characters of Nematalycidae and other mites. He focused in particular on the mouth-parts of this group. As he learned more about the mouth-parts of this family, he found evidence that they are closely related to another lineage of worm-like mites, the gall mites (Eriophyoidea). Eriophyoidea have a sheath that wraps up a large bundle of stylets. They use these stylets to pierce plant cells, inject saliva into them and suck cell sap.
Although Nematalycidae don’t have stylets, one genus has a very rudimentary type of sheath that extends around part of the pincer-like structures that have been modified into stylets in Eriophyoidea.

So what did Sam and his co-authors discover?

“.. Not only are gall mites the closest related group to Nematalycidae, but the results of our phylogenetic analysis places them within Nematalycidae. This suggests that gall mites are an unusual group of nematalycids that have adapted to feeding and living on plants. Gall mites use their worm-like body in a completely different way from Nematalycidae, which live in deep soil. But both lineages appear to use their worm-like bodies to move around in confined spaces: gall mites can live in the confined spaces in galls, under the epidermis (skin), and in between densely packed trichomes on the surface of leaves;  Nematalycidae live in the tight spaces between the densely packed mineral particles deep in the soil.”

This research potentially increases the size of Sam’s family of expertise, Nematalycidae, from 5 species to 5,000 species. We have yet to confirm this discovery, but it is highly likely that gall mites are closely related to Nematalycidae, even if they are not descended from Nematalycidae. This is interesting because it shows that the worm-like body form evolved less frequently than we thought. This discovery also provides an interesting clue about how gall mites may have originated to become parasites. They may have started out in deep soil as highly elongated mites. When they began feeding on plants, they may have used their worm-shaped bodies to live underneath the epidermis of plants. As they diversified, many of them became shorter and more compact in body shape.

I wish I could tell you now to go out and look for these oddly shaped mites yourself, but you really need a microscope. Eriophyoid mites are minute, averaging 100 to 500 μm in length. For your reference, an average human hair has a diameter of 100 microns.

eriophyoid Aceria anthocoptes

Reference:

Bolton, S. J., Chetverikov, P. E., & Klompen, H. (2017). Morphological support for a clade comprising two vermiform mite lineages: Eriophyoidea (Acariformes) and Nematalycidae (Acariformes). Systematic and Applied Acarology, 22(8), 1096-1131.

 

About the Authors: Angelika Nelson, curator of the Borror Laboratory of Bioacoustics, interviewed Samuel Bolton, former PhD graduate student in the OSU Acarology lab, now Curator of Mites at the Florida State Collection of Arthropods, in the Florida Department of Agriculture and Consumer Services’ Division of Plant Industry.

 

Explaining Science – taxonomy of parasitoid wasps

Professor Norm Johnson, Director of our C.A. Triplehorn Insect Collection, studies systematics of parasitoid wasps and so do his students. Graduate student Elijah Talamas collected many insect specimens during his PhD work at Ohio State and revised several taxa. Recently he published a photographic catalog of some primary types of parasitoid wasps in the large insect order Hymenoptera.

I contacted Elijah in his current position at the The Florida Department of Agriculture and Consumer Service and asked him to give us some insights into his life as a researcher. He recently published results from work he did as a a postdoctoral fellow for the U.S. Department of Agriculture at the National Museum of Natural History in Washington DC:

Elijah TalamasElijah: “I am the curator of Hymenoptera (bees, ants and wasps) at the Florida State Collection of Arthropods, which is part of the Florida Department of Agriculture and Consumer Services. I have broad interests in the taxonomy, morphology, and evolution of platygastroid wasps, especially groups with potential for biological control. I was trained by Dr. Norman Johnson at The Ohio State University, and maintain active collaboration with him and members of his lab.”

Angelika: “What species did you study?”

Elijah: “As a taxonomist, I study many species and genera in the superfamily Platygastroidea. These are parasitoid wasps that require development in a host to complete their life cycle, i.e. their larvae live as parasites that eventually kill their hosts. The past few years have focused on the genus Trissolcus which are parasitoids of stink bug eggs.”

(Angelika’s note: You may recall that the brown marmorated stink bug is an invasive species from Asia, now found in the eastern half of the U.S., as well as California, Oregon, Washington, Arizona, New Mexico and Texas. You may have seen one in your home, especially in late fall when they are looking for a sheltered place to overwinter)

Angelika: “What was your research questions in this particular study?”

Elijah: “A typical taxonomic project will “revise” a genus and involves many questions: What are the characters that define the genus? How many species does it contain and how do we identify them? The separation of organisms into species is the foundation of organismal biology and this is one of the jobs of a taxonomist.”

brown marmorated stink bugAngelika: “What do we know already, and why is it important to know this?”

Elijah: “We know that many parasitoid wasps attack the eggs of agricultural pests. This is important because they are often the best, and sometimes only solution to control numbers. The invasive brown marmorated stink bug is an invasive pest that can be found in Ohio, and it is not controlled by natural enemies in the United States. However, there are parasitoid wasps in its native distribution in Asia that kill the stink bugs’ eggs very efficiently. Biological control research about these wasps requires thorough study of their morphology to ensure that
species are properly identified.”

Angelika: “How did you study this question?”

Elijah: “I study parasitoid wasps by examining them under a microscope, documenting their anatomical structures, and the variability that can occur within a species. This often requires examination of specimens from all over the  world, and sometimes international travel is required to access specimens in foreign institutions and to collect fresh material. I rely heavily on photography to document and share information about these wasps, but I also use other techniques, including scanning electron microscopy and analysis of DNA.”

When looking at detailed features one may notice that some of them are different from how they were originally described and the specimen may be more closely related to to another group of specimens. This means that sometimes the classification of the species needs to be revised and renamed to reflect these new relationships. For example, in the figures below you can see the holotype, the specimen that was used to describe the species Psilanteris nigriclavata. This species was originally described with the name Opisthacantha nigiclavatus in 1905. The specimen was embedded in glue, which obscured some of its diagnostic characters and hampered a clear assessment of its identity. As part of this project, Elijah dissolved some of the glue and determined that it shared characteristics with other species in the genus Psilanteris. Thus this species was moved to this genus and now operates under the name Psilanteris nigriclavata.

62 head, mesosoma, metasoma, lateral view; 63 head and mesosoma, anterodorsal view (sk=skaphion); 64 head and mesosoma, lateral view. Scale bars in millimeters.

Angelika:  “Why is this research important?”

Elijah: “Taxonomy informs us about many aspects of the biological world. It is the science that reveals the planet’s biological diversity and discovers the evolutionary relationships between organisms. It enables other disciplines to identify organisms for the studies of behavior and ecology, and applications with large scale societal impact, such as biological control of invasive pests.”

Angelika: “What do you hope to have achieved with this study?”

Elijah: “For parasitoid wasps in the superfamily Platygastroidea, this study provides photographs of all holotype specimens in the National Musuem of Natural History and makes them freely available online. Taxonomists all over the world now have immediate access to these specimens through the internet, enabling them to make better informed decisions for classification, and more refined hypotheses about evolution.”

Let us know if you have any questions, we would like to hear form you!

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Some explanations you may find helpful:

Anterodorsal means in front and toward the back.

A holotype is a single type specimen upon which the description and name of a new species is based.

Lateral means from the side.

The body of arthropods is composed of three parts, from front to back, the prosoma, mesosoma, metasoma.

A parasitoid is an insect whose larvae live as parasites that eventually kill their hosts.

Superfamily is an intermediate classification rank directly above family and might contain one or more related families. For example, Muroidea, a superfamily of rodents, contains six families of rats, mice, hamsters and gerbils. Taxonomists use several levels to classify living things. They follow the International Code of Zoological Nomenclature which specifically mentions superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.

Reference: Talamas, E. J., Thompson, J., Cutler, A., Schoenberger, S. F., Cuminale, A., Jung, T., … & Alvarez, E. (2017). An online photographic catalog of primary types of Platygastroidea (Hymenoptera) in the National Museum of Natural History, Smithsonian Institution. Journal of Hymenoptera Research, 56, 187.

About the Author: Angelika Nelson is the curator of the Borror Laboratory of Bioacoustics and the Outreach and social media manager for the museum. Here she interviewed Elijah Talamas, currently Postdoctoral researcher with the U.S. Department of Agriculture at the National Museum of Natural History, Smithsonian Institution in Washington DC.

Summer in the field

This is the time when many students and faculty spend their days in the field doing research or attending conferences and meetings where they present their latest research results. Follow us on social media #ASCinthefield. We will not post here until the beginning of classes on August 22.

Have a great summer!

 

Squirreling in the Pacific Northwest

You may have heard that researchers discovered a new species of flying squirrel. These squirrels had lived in plain sight for decades but only recently did Brian Arbogast and colleagues investigate the DNA of some of these animals. Their findings were revealing: The Pacific squirrels cluster separately from the northern and southern flying squirrel. The researchers analyzed mitochondrial DNA as well as microsatellite data to reveal this new evolutionary relationship.

Note: Mitochondrial DNA and microsatellites are parts of a species’ genome that are regularly used to construct evolutionary trees. In addition to the DNA in every cell’s nucleus in our body, mitochondria, the energy powerhouses in our cells, have their own genome. This mitochondrial genome is relatively small, is inherited from the mother only and has relatively high mutation rates. It is like a small clonal lineage within an organism which makes it ideal for evolutionary studies.   Microsatellites are short sequence repeats in the nuclear genome that do not produce proteins. Thus they are free to mutate at a higher rate than coding sequences – mutations will not mess up protein production- and they frequently vary in length and thus reveal relationships among organisms. 

A few weeks ago, before this study was published, 2 species of flying squirrels were considered to exist in North America, the northern and the southern flying squirrel. Here in Ohio the northern flying squirrels is resident – it is nocturnal though, that’s why you probably have not seen one yet.

Map showing distribution of now 3 species of flying squirrels

Map showing distribution of now 3 species of flying squirrels

DNA analysis showed that the coastal squirrels in Washington and Oregon are distinct from their northerly relatives and that they actually only co-occur with them at 3 sites in the Pacific Northwest. Northern and the newly described Humboldt’s flying squirrel do not interbreed at these sites. By the way, the researchers named the new species Glaucomys oregonensis because the specimen that was used to describe the species was collected in Oregon.

You may recall from a previous post, that Dr. Andreas Chavez in our department of EEOB studies relationships among squirrels in a different genus, Tamiasciurus, the red squirrel T. hudsonicus and the Douglas squirrel T. douglasii. These two species share habitat in the Pacific Northwest and they do hybridize.

Dr. Chavez was not available for an interview for his thoughts on the new species description of flying squirrels, because he is currently pursuing his own fieldwork in the Pacific Northwest. He and his field assistant Stephanie Malinich are collecting data to better understand the hybrid zone dynamics between the Douglas and red squirrel.

We will give you an update on Dr. Chavez’ research once he returns.

About the Author: Angelika Nelson is the curator of the Borror Laboratory of Bioacoustics and writing this post for Stephanie Malinich, collection manager of the tetrapods collection. Stephanie is currently doing fieldwork on the red and the Douglas squirrel in the Pacific Northwest.

Songs on both sides of the Atlantic

Like every year I will leave for Hog Island, Maine tomorrow morning. I will teach at two of the Audubon summer camps that have been held on the island almost every summer since 1936. You may recall this from my previous post.

This year I am particularly excited to watch birds along the Atlantic coast as I just returned from a trip to Ireland, on the other side of the Atlantic ocean. There I spotted birds of several species that also occur along the US coast. I doubt that the birds themselves make the crossing, but members of their species reside and breed on both sides of the Atlantic.

Rathlin Island

So which birds are we talking about? In Europe we visited Rathlin island, a small island off the coast of Northern Ireland, where we watched Atlantic Puffins Fratercula arctica, Razorbills Alca torda and Common Murres Uria aalge – or Common Guillemot as they are referred to in the UK. The Royal Society for the Protection of Birds (RSPB) runs a seabird center along the cliffs of the island where volunteers and staff regularly survey the breeding colonies and answer visitors’ questions. The resident naturalist shared with us the latest numbers: they estimate 100,000 Common Murres to breed on the cliffs, with them 20,000 Razorbills and some 700 pairs of Atlantic Puffins, everyone’s favorite due to their colorful breeding plumage.

Two Atlantic Puffins on Eastern Egg Rock

Atlantic Puffin on Eastern Egg Rock

On the US side of the Atlantic, in Maine, some 550 breeding pairs of these colorful seabirds have been reported in the largest colony on Seal island, ME.

Enjoy some photos of the Irish coastal scenery – I wish my photos conveyed the noise and smell that comes with large seabird colonies like these … David Attenborough in his Life of Birds series refers to these breeding conditions as the” slums in the bird world”.

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Most of these seabirds are not known for their vocalizations (although Black Guillemots may be exceptional with their distinct whistle; you can hear some in the background of the puffin recording below). Here are some recordings that I found in our collection:

Doug Nelson recorded this Atlantic Puffin on Matinicus Rock, Knox county, Maine, USA on 3 June 1981 (BLB23883):

Lang Elliott recorded a Common Murre on water near the Gaspesie Provincial Park, Bonaventure Island, Quebec, Canada on 1 July 1989 (BLB17181):

Common Eider is another bird that breeds on both sides of the Atlantic. Hear some nestling calls recorded by Don Borror on Eastern Egg Rock, Muscongus Bay, Knox county, Maine, USA on 23 June 1958 (BLB3508):

As you can see, most of these recordings were made a long time ago; time to go back and get some more recent recordings!

About the Author: Angelika Nelson is the curator of the Borror Laboratory of Bioacoustics and team-teaches at the Audubon summer camp on Hog Island, ME.

Dynamics of Neo-Tropical Arachnids

Today’s post is a guest post by Andrew Mularo,  an undergraduate student in the Department of Evolution, Ecology and Organismal Biology. He is currently doing his Tropical Behavior Evolution and Ecology research project under Dr. Rachelle M. M. Adams and Dr. Jonathan Shik.

You may love them or you may fear them, but no one can deny the incredible ecological importance of spiders and scorpions. As an aspiring biologist, I have chosen to study the interactions between arachnids and their environment in the tropical rainforests of Panama for the 2017 Tropical Behavioral Evolution and Ecology course. The tropics are a biodiversity hotspot for the majority of the world’s organisms, so there are plenty of creatures to look at. From the smallest spiderling to the largest tarantula, I am curious to see how these cryptic and intriguing animals interact with their ecosystem.

For my project, I am doing an observational study where I am assessing the relationship between leaf litter and arachnid diversity and abundance. I am accomplishing this by creating several 50 meter transects in the Panamanian rainforest, sampling leaf litter with 1 square meter quadrants along each transect. For each quadrant, I take a measurement of leaf litter depth, and sift through the leaves to extract any organisms out of the area. Back at the lab, I sort through the organisms, first finding any arachnids in the sample, and then any other insect or invertebrate, such as ants, beetles, millipedes, snails, mites and many others. With these data, I hope to make a correlation between leaf litter abundance and arachnid diversity and abundance, as well as a correlation between the diversity of potential prey items and arachnid predators.

Naturally, the majority of the organisms that I have been assessing have been very small, from the size of a thumbnail to not even being visible to the human eye. However, there

Wandering Spider (Photo by A. Mularo)

are several occasions where I have observed some extremely imposing arachnids in the tropical forest. One of these includes the huntsman spider, an extremely large nocturnal species that does not rely on a web to capture its prey. This family of spiders is very poorly researched, and is largely unknown how dangerous the venom is for the majority of species. However, they are quite shy, and often scurry away at the sight or sound of a human.

Another fascinating group of organisms I see occasionally are scorpions. The two pictured below are from the genus Tityus, whose venom is very potent. I found the two in the picture below, which we believe to be different species, huddled in close quarters in the water well of a bromeliad. While potentially dangerous, these are a relatively uncommon sight in the rainforest. Nevertheless, it is always good to be careful where you step.

Tityus scorpions (photo by A. Mularo)

While many of them are feared, arachnids are some of the most fascinating organisms on the planet. They come in all shapes and sizes, and have a wide array of interesting characteristics that are of great interest to scientists. Being interested in biology since I was a child, I have always dreamed of coming to the tropics so I could study the vast diversity of organisms, and I could not have picked a better group of organisms to focus on!

Ain’t No Mountain High Enough .. To Stop Tree Squirrels From Hybridizing

The Chavez Lab will be going to the North Cascades of Washington this summer to do field work in the Tamiasciurus tree squirrel hybrid zone. We have been studying hybrid zone dynamics between Douglas squirrels (T. douglasii) and red squirrels (T. hudsonicus) for 10 years using mostly genetic and phenotypic data. Now is the time to start some observational field research to better document hybrid dysfunction and behavioral interactions between species and their hybrids.

This study contains a richness in questions as to the role that ecological divergence has in the maintenance of isolating barriers and ultimately speciation between these two species. These parapatric species, separated by an extreme change in habitat, meet each other in the different mountain ranges in the Pacific Northwest. Both species live primarily in coniferous forests and have diets and lifestyles that are specialized for feeding on seeds from conifer cones. In the North Cascades region, Douglas squirrels are mostly found on the west side of the Cascade Mountains in a mesic forest environment with a moderate coastal climate. Red squirrels on the other hand are mostly found in the rain-shadow of the Cascade Mountains on the eastside and live in a drier forest with a more seasonally variable climate. Due to the higher fire frequencies in the eastside forest communities, some of the conifer species that red squirrels depend on produce cones with very hard scales or are serotinous (only open during extreme heat from fires). As a result, red squirrels in this region have very strong jaw muscles and bite force in comparison with Douglas squirrels that only feed from trees that produce softer cones. There are many other environmental differences between the westside and eastside environments and thus strong potential for adaptive divergence between these species.

So, you may ask, what does all this ecology have to do with hybridization and speciation? Well, these species may be producing hybrids that have phenotypes that are not well adapted to either type of forest and thus are at a selective disadvantage. Our goal for this study is to examine more directly whether hybrids have lower fitness and dysfunctional traits that decrease their chances of surviving and reproducing. We plan to do this by live-trapping squirrels in a hybrid zone location where I know from previous genetic research that both parental species and hybrids occur. We expect all squirrel types to be living in close proximity with each other and thus we should have good opportunities to study behavioral interactions, as well as document differences in various performance behaviors, such as feeding, mating, vocalization, territorial defense, anti-predator defense, etc…

Stephanie Malinich with bird crownStephanie Malinich is going to be the lead field technician and she will supervise a crew of eager field assistants. Since this is our first field season, we expect a lot of surprises, hopefully more pleasant than difficult ones. This is an exciting time for our lab and we will update you on our findings on this blog later in the year.

 

Andreas ChavezAbout the Author: Andreas Chavez is Assistant Professor in EEOB as of Fall 2016. He is also Director of Mammals in the Tetrapod Collection at the Museum of Biological Diversity. This is his first blog post for the Chavez Lab on the MBD website.

*** Leave a comment to welcome Andreas Chavez ***

We Break for Science

A few weeks ago, I highlighted the artistic and scientific variety of illustrations of Metridium senile. These images were on my desk because Metridium is on our minds a lot these days as the focus of the dissertation research of EEOB PhD student Heather Glon. Heather aims to address one of the persistent problems with this widespread and highly variable anemone: whether the name Metridium senile is being used for a constellation of related but distinct species or whether it represents a single, cohesive circumpolar species.

Answering this question requires sampling across the broad range of this species, analyzing DNA from multiple individuals within populations, and comparing morphology and micro-anatomy. Although our partner museums, like the Smithsonian National Museum of Natural History, American Museum of Natural History, and California Academy of Sciences, hold collections that can help solve this puzzle, none of these collections have sampled at the depth we require and the vast majority of the samples in museums are preserved in ways that complicate DNA analysis. With only a few years to amass the data needed for a dissertation, we have no choice but to spend spring break on the road, searching for Metridium along the California coast.

After nearly 10 weeks in classes, this chance to be outside in the field, focusing on research is a welcome change of pace for both me and Heather. The recent rains in California and generally high low tides of the coming week means that we’ll work mostly from floating docks, searching for small pink anemones among the sea squirts, hydroids, and worm tubes coating the floats and pilings. Our travels will take us from Bodega Head to Morro Bay, with detours through Monterey, Half Moon Bay, and Marin. Follow us on Facebook and Instagram, or check back here on Friday for a wrap up of our efforts.

 

OSU Professor Meg DalyAbout the Author: Dr. Meg Daly is Professor in the department of Evolution, Ecology and Organismal Biology, director of the Museum of Biological Diversity and leads the laboratory of marine invertebrate diversity at OSU. She and her students study systematics of cnidaria, sea anemones, jellyfish and their like.

Why describing new species is exciting and important!

For many researchers describing a new species seems like a tedious task. The differences between species might not be obvious, and the language confusing and foreign. This fact became apparent to me when I first presented my work to the Ant Lab at the Museum of Biological Diversity (MBD). As I described subtle differences in morphology, a little spine here and the shape of a hair there, I could tell that I had lost my audience by the dulled looks on my lab mates faces. How could they not see the differences in these two species?

comparison of Trachymyrmex new species and T. zeteki

Fig. 1 – Trachymyrmex new species on the left and T. zeteki on the right

“Some key differentiating characters: The integument is granulose, spatulate bi-colored setae occur between the frontal carina, the scape extends past the occipital corners. This is compared to a weakly irrorate integument, simple bi-colored setae between the frontal carina, and the scape reaching the occipital corners.”

Fig. 2 – In case you are not familiar with the some terms used in describing ant species


Totally clear, right?

While the differences in characters that separate Trachymyrmex new species and T. zeteki, are exciting for me, it seems to bore people to death. After my presentation, I received very helpful constructive criticism from my lab group. They thought it was interesting but a lot of my presentation went over their heads. My advisor, Dr. Rachelle Adams (Assistant Professor in the Department of Evolution, Ecology and Organismal Biology), encouraged me to find a way to turn the jargon into something people can digest and appreciate. I am still working on that, and it is a challenge many researchers face.

Species descriptions are important and a necessary part of daily life

Hopefully your parents told you when you were younger, never eat mushrooms you find in the woods. Taxonomy helps us understand what kind of mushroom you found, if it is edible, or if it might seriously hurt you if you eat it. Mushrooms are a great example of why taxonomy is important. Scientists need to describe and name species so that others can learn which characteristics define a species. Then chemists can tell us which are toxic. This information communicated to the public can potentially save lives! Taxonomists donate representations of species in museums so that they can be compared by other scientists in the future. Aside from publishing their species description, they submit the specimen used to describe the new species, a type specimen. Anyone who works with any type of animal or plant should be submitting voucher specimens, physical specimens that serve as a basis of study, as representatives of their work.

Cody working at microscope

Fig. 2 – Photo courtesy of Plain Janell Photography

My Taxonomic Conundrum

While working on my species description, I reviewed all the literature that included T. zeteki. The 30 papers covered a number of areas such as fungus-growing ant genomes, mating systems, alarm pheromones, larvae development, and gut bacteria. Sadly, almost half of the papers do not mention depositing voucher specimens! Two articles deposited their DNA sequences as vouchers to a database for molecular data. Any research that uses DNA sequences has to submit DNA vouchers to that database; without it your work cannot get published. However, they do not have any physical vouchers linked to their sequences! This lack of physical vouchers was quite a surprise to me. The time I spent as an intern at the MBD Triplehorn Insect Collection, my advisors and other mentors strongly advocated the deposition of vouchers. Without being able to link your DNA sequence to a correctly identified organism, that DNA voucher loses its value. You cannot quickly identify an organism from DNA. Using morphology is the easiest way to do so! It seems many researchers don’t recognize the importance of vouchering and most non-taxonomic journals do not demand it. Research published without vouchers lacks reproducibility, an essential component of the scientific method.

In my research project, I am cleaning up the mess left behind from nearly twenty-years’ worth of poor vouchering and misidentification. I’m not only describing a new species and key characters that differentiate two cryptic species, I am listing all of the papers that have been published in the past twenty years using the names Trachymyrmex zeteki and Trachymyrmex cf. zeteki. By linking the new species description to these articles scientists can move forward knowing the proper identification of these hard-to-identify fungus-growing ants.

The deposition of vouchers should be required for all publications, and is crucial for, past, present, and future research in biology. In my undergraduate research, I discovered there is a disconnect between research museums like the MBD and many scientists. While I am still struggling to turn the technical jargon into information that can be swallowed by non-experts, there are discussions to be had about the importance of taxonomy as a cornerstone in biology.

If you want to learn more about fungus-growing ants and the importance of university research collections, come see us at the MBD Open House April 22, 10am – 4pm.

CodyCardenas, undergraduate student ant lab, EEOBAbout the Author: Cody R. Cardenas is a Senior Undergraduate student in Entomology  working in the Adams Ant Lab.

*** We would like to hear from you – Please leave a comment ***

The Science Behind an Ant Sting: Delivery, Function and Chemical Composition

To date, around 71% of all described ant species have been found to sting or spray secretions from their venom glands. Some spray acid such as Formica mound building ants (clip from Life in the Undergrowth – Supersocieties by David Attenborough):

while others inject venom like the red imported fire ant Solenopsis invicta (video by Brave Wilderness channel):

Still other species wipe or paint their victim with poison and can dispense it like a smelly gas into the air. The toxic cocktail of organic compounds that make up ant venom is diverse. The venom of some species contains peptides and proteins, but these molecules typically only constitute 0.1-5% of the total venom extract. Instead, many species of ants depend upon alkaloids, a group of organic compounds defined by a heterocyclic ring containing a nitrogen atom. First discovered in ants in 1970, a diversity of venom alkaloids has been found throughout the subfamily Myrmicinae, with six structural classes represented and various differences in the substituents or side chains attached to the main molecule.

Why study ant venom?

Venoms have been found throughout all major animal phyla and play important roles in a number of ecological interactions, especially in predator-prey relationships where they are used as offensive or defensive chemical weaponry. While the venom alkaloids of many ant species have been identified and characterized, the biological activities of these compounds have only been investigated in a minority of groups. Alkaloids are presently known to have adverse toxic effects on a range of organisms; for example, the major component of S. invicta venom has not only been shown to act as a toxin on predatory and prey animal taxa but also possesses herbicidal and antimicrobial properties. Additionally, some alkaloids have been demonstrated to be utilized in a non-toxic capacity and serve communicative functions as well.

One of the goals of the Adams Lab here at OSU is to understand the biological functions and properties of the various venomous alkaloids of ants, and an area of active research has been within the genus Megalomyrmex. Although the majority of species are free-living predators, some are social parasites that infiltrate the colonies of fungus-farming ants. They consume host brood and fungus garden by dominating the farmers with their alkaloidal weaponry. A well-documented example of this interspecific interaction has been between the parasitic Megalomyrmex symmetochus and its host Sericomyrmex amabilis, in which the venom of M. symmetochus is a crucial component in the aggressive interactions that take place throughout the establishment and maintenance of the host-parasite relationship.

During these aggressive interactions, M. symmetochus ants often use three main types of alkaloid dispensing behaviors: gaster flagging, side-swipe sting, and gaster-tuck sting.

ant behavior "Gaster flagging"

Gaster flagging

A) Gaster flagging is when M. symmetochus ants vibrate their gaster at approximately a 45-degree angle with a drop of alkaloid venom at the tip. This allows for the venom to be dispersed into the air at a low concentration, and is thought to be a warning to their host ants to deter them from attacking, acting as both a visual and chemical signal.

ant behavior "Side-swipe sting"

Side-swipe sting

B) Side-swipe sting is when M. symmetochus’ gaster is waved from the side towards the host, dispensing the venom directly onto the host ant.

ant behavior "Gaster-tuck sting"

Gaster-tuck sting

C) Gaster-tuck sting is when the gaster is tucked under the body in between the legs towards the host ant, dispensing venom directly onto the host (see illustrations below for a visual representation of these behaviors).

However, the interactions between these species are not always aggressive, and in some cases the M. symmetochus parasites act like mercenaries and protect their host from a more lethal ant species – watch them in action (video by Rachelle Adams, Assistant Professor in the OSU department of  EEOBiology):

Our future research will continue exploring ant venoms in a broader context. The Adams Lab will be traveling to Panama to collect and observe Megalomyrmex species in their natural habitats as well as conduct experiments to gain greater insight into their biology. Look for our future blogs from Gamboa, Panama at the Smithsonian Tropical Research Institute in May!

For a more in-depth look at the relationship between M. symmetochus and S. amabilis, check out Dr. Adams’ article in the USA Proceedings of the National Academy of Sciences entitled “Chemically armed mercenary ants protect fungus-farming societies.” And to learn more about the venom of the red imported fire ant Solenopsis invicta, watch this video by Eric Keller.

Visit us at the Museum of Biological Diversity’s Open House on April 22nd to learn more about our research! We will have live fungus-growing ants!

 

Acknowledgements: We would like to thank Rozlyn E. Haley for the ant illustrations.

Reference: Adams, R. M., Liberti, J., Illum, A. A., Jones, T. H., Nash, D. R., & Boomsma, J. J. (2013). Chemically armed mercenary ants protect fungus-farming societies. Proceedings of the National Academy of Sciences, 110(39), 15752-15757.

About the Authors: Conor Hogan is a graduate student in Rachelle Adams’ lab and Mazie Davis is an undergraduate student who did a research project on parasitic ant stinging behaviors in Rachelle Adams’ lab in 2016.

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