Student Interns

Story by Student Intern Rick Orozco

I had the opportunity to sit and talk to Dr. Ira F. Greenbaum about his research on Peromyscus maniculatus (deer mice) in the Pacific Northwest region. First, a little bit of background on Dr. Greenbaum: he attended Hofstra University where he acquired his Bachelor’s degree in Biology in 1973. After that, he worked on his Master’s and PhD in Zoology at Texas Tech University in 1975 and 1978, respectively. He then joined the Department of Biology at Texas A&M University and is currently Professor and Director of Lower Division Instruction where he is enhancing the education of undergraduate students.

When asked why he thought the Peromyscus study was important, Dr. Greenbaum mentioned how the original research was designed to do something very different. When he started his research, during the time of his PhD, all the deer mice in the Pacific Northwest were one species, Peromyscus maniculatus. Dr. Greenbaum’s research focus was on the chromosomal structure of the mice, such as short and long arms and how they influence chromosome pairing and how they segregate during meiosis. One point that Dr. Greenbaum mentioned dated back to Barbara McClintock’s work in the 1930’s, which revealed when you have heterozygosity for inversions you tend to have duplicated and deleted products during meiosis. This is problematic because individuals affected with this are generally less fit with low reproductive success due to half of their gametes being unbalanced. Dr. Greenbaum started finding frequent pericentric invesions within populations of Peromyscus maniculatus and wondered how this could be occurring? How could you get what’s called a meiotic under- dominant rearrangement, a chromosomal arrangement that should not be maintained at high frequencies within these Peromyscus populations? A problem Dr. Greenbaum encountered in preparing to answer this question was determining how to establish an experimental design that depends upon populations when you have a mouse that is distributed from the Atlantic to the Pacific and from the Northern Tundra to Central Mexico. Basically, it is difficult to study population genetics when you can’t recognize a population. Dr. Greenbaum solved this by creating the assumption that mice from one island are a different population than those on another island. His hypothesis was that “it’s not that the mice can’t swim, but the fish swim a lot better.”

Dr. Greenbaum sought to test the hypothesis that the type of chromosomal evolution observed in P. maniculatus was driven by genetic drift, which occurs much faster and intensely in smaller populations (i.e., islands) than large populations. What actually happened when the research started was that Dr. Greenbaum arrived at the Pacific Northwest region and discovered not just one species but two: Peromyscus maniculatus and Peromyscus keeni (he had no idea of this prior to the hypothesis). Keeping it short, he mentioned that no hybrids were found so it was clear that these two species were not interbreeding.

So how exactly did Dr. Greenbaum discover that there were two species? He wasn’t sure exactly where he did the first capture of both species but he thinks it was on Salt Spring Island, Canada. Dr. Greenbaum and his crew set Sherman traps in the afternoon, sat around the campsite, ate dinner, had a bourbon or two, and went to bed (to me this sounds like a perfect night). In the morning, the traps were collected and the live mice were placed in cages. What happened next baffled everyone; the mice started fighting one another. Since healthy mice were preferred, they sorted them into groups that didn’t try to kill each other. After some trial and error, they noticed some differences between the two groups: one group was smaller and lighter in color than the other. This conclusion was made with just physical characteristics; fast-forwarding through the entire lab process, bone marrow, hearts, livers, and kidneys provided the last sets of data to support the existence of two different species. Going back to his hypothesis, Dr. Greenbaum and his colleagues found several small islands where both species co-occurred and were both polymorphic for pericentric inversion at high frequencies (50%) for chromosomes 6 and 7. This revealed that genetic drift was not a primary factor in the chromosome evolution or chromosomal polymorphism.

Aside from the actual research, I was also interested in the behind-the-scenes events that weren’t reported in the published manuscripts. Dr. Greenbaum specifically mentioned Harry Sowchhuck a logger who showed them great hospitality by fixing their two flat tires, charging no fees, and then took them home so they can eat, bathe, and sleep. It’s not every day that one stumbles upon a special person like that. Another interesting event was when Dr. Greenbaum and his crew were staying at a motel in Washington. He said that they were thrown out of this motel due to taking live mice into the facility. Imagine what people thought when they saw some random guys getting off a truck carrying cages full of mice, centrifuges, test tubes, microscopes, liquid nitrogen tanks, and much more. Because of that, they started telling people what they were doing before they booked a room. When they told the owner of a motel in the city of Nanaimo, Canada, he said that they could continue but on the condition that they trapped the mice around the motel. Dr. Greenbaum said “we caught more mice around that motel than at many of our trapping localities.”

The way Dr. Greenbaum spoke about his time in the field was stunning. His tone showed me that he absolutely loved every moment out in the field. A good estimate of the time Dr. Greenbaum spent in the field was about 30 years, which included his time in Latin America. He said that there will always be difficulties during those trips such as getting a cold, food poisoning, and severe weather. Simply put, “stuff happens.” When I asked for Dr. Greenbaum’s top 5 favorite trips, he could not come up with a list because every trip was his favorite, except for that one trip with the extremely hot summer in Baja California. I was a little anxious before doing this interview since this was my first interview and I had not met Dr. Greenbaum previously. However, it turned to be a fun and great learning experience. Dr. Greenbaum is an easy-going, family oriented, big-time fisherman who does his best every day to make a societal contribution by helping young people educate themselves and get to where they want to go in life. He had always wanted to be a college professor and run a graduate research program. In fact, he loved his college years so much that he decided he was going to stay on a college campus for the rest of his life. When asked to describe his overall experience with his career, Dr. Greenbaum said “I can’t. I love it. It’s what I do.”

Read Rick’s reviews of two of Dr. Greenbaum’s research articles: Hogan et al 1993 summary Allard and Greenbaum 1988 Summary

Case Checks

The Biodiversity Research and Teaching Collections, or the BRTC, at Texas A&M University is one of the largest university based natural history collections in the United States. Home to over a million preserved specimens, the BRTC serves as a worthwhile educational tool for the students of Texas A&M. As a student, I have had the pleasure of working at the BRTC in the mammal division under Dr. Jessica Light. The mammal division of the BRTC is comprised of mammal skin, skeleton, and alcohol specimens that have been collected from various parts of the world (mostly Central and South America, the Gulf of Mexico, and the United States) over many years. The skin and skeleton specimens are housed in museum-grade cases for protection; one of the first tasks I was assigned was to check these storage cases for insect infestations.

Some of the first specimens housed in the collections were from the 1930s. Therefore, Dr. Light and her colleagues in the mammal division have gone to great lengths to make sure each specimen is properly protected so that it remains in good condition for future research. Each museum-grade case physically protects the specimens from the elements (exposure to air, light damage, etc.) and insects such as cigarette beetles that feed on the specimen skins. To further deter insects, moth balls are placed within each case. But, since these cases are opened often, they need to be routinely checked for possible infestations. My job required inspecting each individual skin for live cigarette beetles as well as adding more moth balls to cases when needed. I originally thought I would be able to complete this task fairly quickly. However, I could not have been more wrong.

On average, each case is able to hold about 16 drawers, with some drawers holding over 50 specimens depending on size. Naturally, the cases to which I was assigned were either bats or rodents, so there were a good number of specimens per drawer and it took me quite a few weeks to finish this task. Although monotonous, it was a simple job: if I saw a cigarette beetle, I would squish it between my fingers. If the beetle was dry, then it had been dead for a while and the debris needed to be cleaned out from the drawer. If the beetle left moisture, there could be a possible infestation that would require the entire case to be quarantined. If there were no cigarettes beetles visible on a tray, the next step required examining each specimen for any holes or other signs of infestation. During my case checks, I never came across any live cigarette beetles, but there was one specimen that caught my eye. I was almost finished with my case checks when I found a rodent that had several small holes on the ventral side of the specimen. I did not notice any cigarette beetles on the specimen itself, but I thought it would be best to bring it up to Dr. Light. Luckily, Dr. Emma Gomez, the mammal division collections manager, and I were able to determine the small holes in the specimen were a product of an old infestation and would not require any special attention.

I am very grateful to have had the opportunity to work with Dr. Jessica Light and researchers and staff at the BRTC. During my time at the collections, I have gained valuable experiences working with fragile specimens as well as expanding my organizational skills. As a senior, I am confident my experiences will benefit me in my future endeavors.

Hands down, the best job I have had while interning at the BRTC was preparing mammal skins for the collection.  Although I haven’t had much time to prep any skins on my own, I am hoping that will change in the last few weeks of my internship.   Of all the tasks given to me this semester, it is not only the most fun but has also been the most rewarding experience of my time here.   Prepping a mammal and providing a skin and corresponding skeletal material to the collections allows me a rare opportunity as an undergraduate to actually contribute to the scientific community –even if it is on relatively small scale.  Hands-on projects that require a certain degree of dexterity and finesse have always been my strong points so this was something I was eager to learn about from the beginning.   However, after a few sessions of sitting with Dr. Light learning on how to carefully remove the skins from a couple of different types of mice, I realized just how hard this can be.   Working delicately to remove the skin while preserving the fragile tail, nose pad, ears, and limbs of a specimen that weighs only a few grams proved more challenging than I anticipated.   I learned it is definitely a skill that takes a lot of practice before anyone becomes good at it.  Specimen preparation is somewhat of an art and working on this task gave me an appreciation for all the specimens currently in the museum that are so neatly stuffed and sewn together that they almost appear life-like.   From the start of my career as a Wildlife and Fisheries Sciences student, I was always told to give a lot of respect to the animals that gave their lives to science.  After viewing the work that goes into each specimen preparation, I gained a greater insight as to why that is.

Specimens are generally either collected from field research or are donated by private sources. The BRTC has several of these specimens that still need to be prepared and entered into the collections.  To start the process, a mammal is taken out of the storage freezer and left in the fridge or table to thaw out.  A solid frozen mouse would obviously be very hard to work with, so it needs to thaw and soften up before the skin can be removed.  Once the specimen is ready, we record the genus and species into a log book along with lengths of body, hind foot, tail, and ear, and approximate weight.  The next step is to determine the gender of the species by observing the genital region followed by collecting any potential ectoparasites in a vial by brushing the fur.   After these steps, the skinning process can begin and a small incision is made in the abdomen.   It is ideal not to cut too deep so you avoid cutting into the gut.   I made this mistake my first time when I accidently nicked the large intestine and had to deal with goop leaking out for the remainder of my prep.  Most of the work after this is done with your fingers and a probe to separate the skin from the body cavity wall.  Working outwards from the incision towards the hindlimbs, the skin is peeled back over the legs towards the foot until another small incision is placed at the foot to slip the limb out of the skin like a sock on the left side of the body. This results in the bones from the left limbs staying with the skeleton so future researchers can examine the bones from the specimen.  On the right side of the body, the bones of the hind and forelimbs are cut and kept with the skin allowing for research of the skin (toe pads, etc.).  Once the hindlimbs are removed, the tail sheath is pulled off the tail to release the tail vertebrate, and the skin is pulled back up over the forelimbs leaving the head for last.  The skin is pulled up over the neck and the tissue connecting the ear canal, eye socket, and nose pads are snipped to release the skin in what should hopefully result in an intact empty “skin suit”.   The skin is then carefully stuffed with cotton to create a full body effect, sewn up, and pinned to a rack to dry.  The skeleton is given a tag and saved in the freezer until there is room in the dermestid colony to process the skin.  The entire process can take several hours, and for a novice can be incredibly frustrating at times.   Once a mistake is made, it is very difficult or impossible to undo.  Regardless of the challenges behind it, I still immensely enjoyed learning the skinning process and was glad to contribute even just a handful of specimens.

Noel Lyon – BRTC intern

One of the more hands on tasks at the Biodiversity Research and Teaching Collections (BRTC) is to prepare scientific specimens to be cataloged into the mammal database. Scientifically prepared skins held in natural history collections provide morphological and physical characteristics of individuals and the species as a whole. These data can illustrate how individuals and a species can vary through time and geography, creating a snapshot of a species in a given time and location. Furthermore, additional data such as the life stage, tissues, and parasites gathered during the collection of a particular specimen can also provide researchers with useful data.

During my internship, I prepared several specimens in the order Rodentia. I did not have trouble skinning after receiving excellent instructions provided by Dr. Light. But stuffing specimens proved to be a challenge. Skinning of all mammals follows a general procedure that can be altered depending on the desired outcome (pelt, museum specimen, meat).  A cut is made up the ventral side of the body from just above the urogenital area to about the forelimbs. This allows room for the skin to be worked off the limbs and body using a counter pull system. This system involves pulling the body one way while simultaneously pulling the skin in the opposite direction. Extra care is taken around the limbs and tail to prevent the skin from tearing. Similarly, the face needs to be worked off of the skull very carefully to ensure that the nose, ears, and eyes remain intact. The bones that comprise the digits and feet on the right side of the animal, as well as the baculum for males, are kept in the skin to maximize the amount of information that the specimen provides.

Wire is traditionally placed in the tail and limbs to ensure that these portions of the specimen are laid out straight. Small specimens such as mice require very thin wire, which unfortunately is easily bent. I found inserting the wire into the right forelimb and hindlimb to be the most difficult and sometimes frustrating part of preparing a specimen. Wire is inserted in the feet so that it sits between the bones and the skin. There is very little room in this area, and inserting the wire requires gentle poking and manipulation to slide into place. Cotton is often wrapped around the section of wire that sits in the area of the legs vacated by the femur and tibia in the hindlimb, or the humerus, radius and ulna in the forelimb. This is done to give the prepared skin as much of a lifelike appearance as possible.

Cotton is also wrapped around the wire used in the tail. The process of inserting the wire into the tail is much easier than in the limbs. However, the cotton must be wrapped very tightly around the wire or it will slip and bunch up which makes insertion impossible. Additionally, the thickness of the cotton must taper towards the tip of the tail, with it being widest at the base of the tail.

Cotton is also used to stuff the body cavity and head of the animal. Cotton has to be placed just right in the nasal region of the animal, otherwise it looks very odd; for rodents, you want the specimen to have a pointy nose just like in life. I found the aid of forceps crucial in this step. After estimating the amount of cotton needed and cutting it into the shape of a triangle, I would fold up one corner very tightly and grasp it with the forceps. After carefully placing this end into the tip of the animals nose, I would release the forceps and the cotton would expand and fill in the nose. After that, I would fold the rest of the cotton into the body and sew up the incisions made during skinning. This step often took the longest, as removing and manipulating the cotton was necessary to ensure that body proportions were more or less realistic, and dorsal and ventral surfaces were smooth. The final step is to pin the specimen to a piece of foam to dry. This step requires an artistic touch to make the animal appear as lifelike as possible. The nose, head, and tail are lined up while the legs are stretched out pointing directly to the front and rear of the animal. Lastly, brushing the fur and minor tweaking can make a huge difference in appearance.

With biodiversity declining around the world, properly prepared and cared for specimens are becoming increasingly valuable. As species become scarce, studying them becomes more difficult. Natural-history collections provide samples of species that may otherwise be unobtainable. Data gathered from prepared skins may provide insight into why a species is in decline in the wild, as well as how individuals vary over time and space.

Noel Lyon – Spring intern 2015

The mammal collection at the Biodiversity Research and Teaching Collections (BRTC) contains thousands of scientific specimens. These include alcohol specimens, skeletons, skulls, and scientifically prepared specimens. One of the greatest dangers to skeletons, skulls, and alcohol specimens is being dropped, whereas scientifically prepared specimens are threatened by insect pests. One of the many insect pests detrimental to preserved animal skins is the cigarette beetle. Larvae feed by burrowing into the skin, which can damage or ruin a museum specimen. Feeding by adults on the proteins within the skins can also ruin specimens. Adults are small, about 2-3 mm in size, and are reddish brown in color. The eggs of cigarette beetles are coated with a layer of B vitamins when they pass through the oviduct upon laying, which larvae can utilize as a food source (Cabrera 2001). Females lay 10-100 eggs in the food source and larvae typically emerge in 6-10 days (Cabrera 2001). The life cycle of the cigarette beetle ranges from 40 to 90 days depending on temperature and availability of food (Cabrera 2001). With the large number of eggs produced by each female in addition to their relatively long life cycle, an unchecked infestation of cigarette beetles has the potential to destroy many valuable museum specimens and the data they provide.

An important, although seemingly dreaded task, is to thoroughly search every case in the collection for signs of a cigarette beetle infestation. I spent a good deal of time inspecting hundreds, if not thousands of specimens for signs of beetles. Opening drawers and looking for beetles simply isn’t sufficient. Every specimen must be removed and checked. The average case holds about 10-15 drawers, and depending on the size of the animals, one drawer can hold up to 30-40 specimens. If I found a live beetle, then the case was fumigated using ethyl acetate to kill the beetles and remove the infestation. Whenever I came across the body of a dead beetle, I pinched it between two fingers to estimate its age. If the beetle was juicy, than it was relatively fresh, and every specimen was examined extremely carefully to determine if there was an active infestation. If an infestation was found, the case was fumigated. If the beetle crumbled to dust when I pinched it, than it was old, and the bug and specimen debris was vacuumed out. In addition to looking for signs of insect damage, I also replaced or added mothballs to the jar lids that are in every case to deter cigarette beetles and other insect pests. Lastly, I also recorded my findings on a log kept inside each case to monitor infestations over time. Thankfully, I did not find any infestations.

A great deal of information is contained with each specimen housed within the BRTC. For mammal specimens, this information includes collector and collector number, the location they were collected, any measurements taken at the time of collection, and sometimes other tidbits such as the cause of death and whether the animal was reproductive. This information is included in the database and on tags associated with each specimen. However, these specimens and their information lose their value if the specimens are eaten or destroyed by cigarette beetles. As I went through the drawers and cases, I read the information contained on many of these tags, and I was amazed at the age of some specimens. Some are from the 1920’s and 30’s and are in excellent condition. This would not be possible if not for vigilance by many people looking for cigarette beetle infestation signs over time. I was not the first, nor will I be the last person to check the cases. I can’t say it was the most exciting thing I’ve ever done, but I did learn a lot more than I thought I would.

Literature Cited

Cabrera, B.J. 2001. Cigarette beetle. Entomology and Nematology. University of Florida. http://entnemdept.ufl.edu/creatures/urban/stored/cigarette_beetle.htm

 

 

Another bit from our WFSC undergraduate intern Lauren Wimbish, this time she’s in our collection of bats organizing their skins and skulls-

This past June I spent many hours reorganizing the bat collection at the BRTC. Bats are mammals that belong to the Order Chiroptera, which is the second largest mammal group (only rodents belong to a more diverse Order). They are also the only mammals that are capable of sustaining true flight. The collection consists of many different species of bats from all over the world, but mostly the specimens are from the Americas. Reorganizing each case consisted of going through each drawer and making sure the specimens were in alphabetical order by family, genus, species, and geographic locality. Each drawer would contain at least one family of bats. The bats within that family were alphabetically placed by species name and geographic region within that same species. Usually, each case had about 12-15 drawers and would take roughly an hour to go through. Most of the specimens I organized were fairly small and did not vary much in size. While shuffling through the bats I would always put my headphones in and enjoy some music to help give a relaxing work setting.  On days when the air conditioning was struggling to cool the building this was especially necessary. Texas summers can be pretty brutal, even inside. On a few occasions my work lead me outside and I would have to tough it out in the Texas heat.

Hi! My name is Lauren Wimbish and I am a Wildlife and Fisheries Science major at Texas A&M University. Part of my experience here at Texas A&M is having an internship. This past summer I worked as an intern at the Biodiversity Research and Teaching Collections (BRTC). Although I have had multiple classes at the BRTC, such as Natural History of Vertebrates, Mammalogy and currently Ornithology, this past May was my first time working within the collections. For a good chunk of May and June, I spent a fair amount of time working in the mammal alcohol collection. These are fully intact specimens that are put into jars filled with alcohol to preserve them. The mammal collection has about 12,000 specimens preserved in alcohol and when I began my journey of organizing them I started on rodents. I primarily worked with different species of rats and mice and occasionally a gopher. There also are many other mammals in the collections besides rodents, such as bats, felines, and my favorite: a Pronghorn Antelope. My main task working in the mammal alcohol collection was to assess what was in each jar. I would get a jar and take out each specimen; some jars would have one or two specimens while others would have 20 or 30. I would take every specimen out of the jar and then essentially check to make sure it is where our records say it should be. If anything was off/missing, I would make a note for the curator so corrections could be made later.  The work was generally quiet and slow. So most days when I would come in I would put in my headphones and listen to some music while I would go into my own little place for a few hours. The cool part of doing this was getting to see all the little differences in the species.  Some of them have had large amounts of tissue samples taken from them, so not every specimen was perfect per se. Some of the internal organs were exposed in these not-so-perfect specimens. One of the coolest things I recall was being able to see the fetal offspring in some of the female rats. Not every day was as exciting as when I saw the fetal rats.  On days that were moving a little slow I would mix things up by working with the collection of bats we store in cases.