The Lizard Log

The Langkilde Lab in Action

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New Kid on the Block

Hello, my name is Dustin Owen and I’m one of three new PhD students in Tracy Langkilde’s Lab. I’m originally from east-central Indiana where I got my B.S degree in Biology from Ball State University. While there I was able to work on a lot of different questions on a lot of different organisms. My first research project was on the allometry of shell morphology in a freshwater snail, Elimia livescens, in Dr. Mark Pyron‘s Lab. After that I worked on several other projects including looking at hydrology and freshwater drum (Aplodinotus grunniens) with Dr. Pyron, artificial scent and small mammal trapping and various bat projects with Dr. Timothy Carter, and even my own independent research project on how roads impact the stress physiology of copperheads (Agkistrodon contortrix).


Copperhead (Agkistrodon contortrix) on a gravel road.

After my undergrad, I went to Austin Peay State University and continued my interest in stress physiology and reptiles. While there, I studied stress physiology in several species of snakes.


Racer (Coluber constrictor) Selfie

Now that I’m here at Penn State I plan on continuing my interest in stress physiology, using the invasive Fire Ant (Solenopsis invicta) and Eastern Fence Lizard (Sceloporus undulatus). While I have never directly studied Fence Lizards in the past, I have assisted expert Fence Lizard catcher Kris Wild on his Master’s Thesis work on fire and Fence Lizards. Now, armed with my new Kris Wild custom lizard noose, “The Pub Maker”, I’m ready to lay siege to some fence lizards in the name of science!

In my spare time I enjoy being outside, football, basketball, and hanging out with my girlfriend Heather. I also enjoy exploring with my niece Lilly. Teaching her about biology (she’s especially interested in bats and snakes) has been one of the greatest joys in my life. One day, she’ll be a far greater biologist than I’ll ever be, but until then I’m happy just taking her outside and watching her learn about nature.


Me with a juvenile Common Water Snake (Nerodia sipedon) and Lilly with a Ring-necked Snake (Diadophis punctatus).

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Wrapping Up A Great Field Season

As the days are getting colder, snakes are slowly making their way back to their dens.  My technicians are still tracking their progress, but little-by-little each of our 15 radio-tagged snakes are getting closer to the location where they will spend their winter sleep.  This summer was a huge success as we collected ecological data for our rattlesnakes in our pre-burned habitat.  Much of this success was made possible due to a great team of technicians: Alyssa Hoekstra, Andrew Brown, Zack Maisch, Alex Dyson, and Mark Herr (lab undergrad extraordinaire)!

Our snakes led us to some great data this past summer.  Males did not disappoint us, and they typically had us hiking over large tracts of land. Sometimes, males were able to travel over 1-km in 24 hrs, up and over large mountains.  Much of this traveling was to find receptive females, and we observed many mating encounters as well as male-male combats!

Male and Female Timber

Large male (black phase) wrapped around a female (yellow phase). Typically males will follow females and attempt to entice her to mate by rubbing his head along her body. This female obviously didn’t want to play those games and just remained coiled. (Photo by A. Dyson)

Females stayed a little closer to the den sites and study area. The females main concern was foraging for food, but sadly none of our females at the main study site were gravid this year. Given the high abundance of chipmunks and mice throughout central PA this summer, I would not be surprised if many female rattlesnakes were gravid next summer.  It is believed that good reproductive years for timber rattlesnakes typically follow good food years.  Although we were not measuring small mammal abundance last year, I suspect it was lower than this year. Following the conclusion of our project, we may be able to shed some light on this relationship between rattlesnakes and their prey.  Additionally, prescribed fire can enhance small mammal abundances, which may lead to increased reproductive rattlesnake fitness!

Rattlesnake Eating Chipmunk

Rattlesnake consuming a chipmunk… Alvin!!!! (Photo by Z. Maisch)

In addition to following the snakes around, we also took some time to characterize the pre-burn study sites and the available resources for timber rattlesnakes.  We measured small mammal abundances, operative temperatures, available vegetation, and acorn mast production.  We will compare these available habitat characteristics to next year’s to see how these variables change based on year-effects and the prescribed burn.

chipmunks in tomahawk

Two chipmunks captured in a Tomahawk trap. Each small mammal receives an ear tag so we can identify it at a later data when it is captured again. This mark-recapture technique allows us to measure small mammal abundance throughout the study area. (Photo by A. Dyson)

In addition to the prescribed fire project, we also embarked on two new projects with the help of Tom Radzio!  Tom is a colleague from Drexel University, and he is using cameras to observe tortoise behavior outside of burrows in the southeastern United States for his dissertation.  Tom was gracious enough to loan us a few cameras so that we could embark on these great, new side-projects.

For the first side project, we are currently looking at the ecological trade-offs between thermal resource acquisition and predation at gestation sites of various sizes.  We collected some great data regarding potential predators, including black bears, bobcats, raccoons, and hawks.  Whereas we have already pulled all of our cameras from the field, we are still collecting data from these videos.  Currently, I have a great team of undergraduates assisting me with this process, including: Mark Herr, Michaleia Mead, and Tommy Cerri.  We hope to have all of these data collected and analyzed by the end of November!  We are predicting that we will see a higher amount of predator activity at more open, larger gestation sites, but we will also find higher quality thermal habitat at these same sites as compared to smaller, more enclosed gestation sites.  We are looking forward to the results!

Bobcat at Study Site

Bobcat walking through a large, open gestation site. Whereas the bobcat did not show any interest in the foam, rattlesnake models that we placed at the site, the mere presence of the predator suggests that an encounter is possible.


A black bear attacking a foam model at an enclosed, smaller gestation site. The bear first approached two foam, rattlesnake models and swatted off their heads. It then bit two more models (one shown here) before taking off out of the gestation site.

For the next side project, Tom Radzio and I are looking at when rattlesnakes decide to go back into their dens, how this correlates with environmental temperatures, and if predators are attracted to these den sites during this time of rattlesnake ingress.  We are currently collecting data at these den sites and we have a great undergraduate, Tommy Cerri, who is assisting us with analyzing these videos.

Rattlesnake basking in front of a den site. If you look closely you can see some small grey iButtons recording environmental temperatures.

Rattlesnake basking in front of a den site. If you look closely you can see some small grey iButtons recording environmental temperatures.

This fall will be filled with a lot of data analyses, writing, and hopefully a few published results. Stay tuned as we finish up a few of these projects.  I will make sure to update everyone on the results to each of the finished products.

Field work in action! Me capturing a small timber rattlesnake. (Photo by T. Langkilde)

Field work in action! Me capturing a small timber rattlesnake. (Photo by T. Langkilde)

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From Brazil to Happy Valley

Hi everyone, my name is Braulio, and I’m one of the three new members of the Langkilde lab in 2015. I come from Brazil, where I got my bachelor’s degree in Biological Sciences from Universidade Vila Velha. My first research experiences as an undergrad were related to the effects of toxic compounds, natural or synthetic, on the activity of enzymes related to oxidative stress in plants and vertebrates.


Me as an undergrad in Brazil


After graduating, I joined the M.S. in Biology program at Adelphi University in Long Island, NY. Since then, my research interests have shifted towards the study of evolution, particularly sexual selection. Some of the questions I would like to answer in the future are why do some animals exhibit such unusual mating behaviors and under what circumstances can certain sexual traits become advantageous.

During my years at Adelphi I worked with a fascinating species of orb-weaving spider that has some unusual mating behaviors, including, but not limited to, sexual cannibalism and spontaneous male death.

Now that I am part of the Langkilde lab, I want to follow up on the research being done here and further investigate the adaptive significance of male ornaments on female fence lizards (a.k.a. “bearded ladies”). Since previous lab members have demonstrated that they are unattractive to males (as you would expect), we still don’t understand how they are so frequent in certain populations. We suspect that male ornaments might come as a side-effect of high testosterone, which could be advantageous to females in certain situations. For instance, they could be faster runners or exhibit more aggressive behaviors (stay tuned…).

In my free time, I like doing sports (especially swimming), playing Nintendo video games and playing the electric bass.

My first impressions of the lab, the people and the town of State College are that people are indeed happy here in Happy Valley. I like the friendly atmosphere and the variety of outdoors activities that can be done around here. I’ve been slowly getting into the some of American sports, mostly baseball and hockey. I still don’t get what’s the big deal with American football, but maybe being at Penn State will change that in the future.

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Return to Research Land!

Hi, I’m Caty Tylan, one of the new Ph.D. students in the Langkilde Lab. Since this is my first post, it will mostly be an introduction. Short version: I’m a huge science nerd who reads, cooks, and plays a LOT of board games in my spare time. I have 1 adorable husband, and 3 adorable pets – a cat, a rabbit, and a very large dog.

Me with our giant puppy.

He luuuuuurrrvves me.

He’s a little needy.

Our tiny Holland Lop.

My nieces and nephews LOVE our bunny.

The cat is not amused.

But she is adorable.

I just graduated with my D.V.M. from Purdue University, but as the title of this post implies, I spent a lot of time in various labs before going to veterinary school, and I am excited to be doing research again! I obtained my B.S. in Biology from Drexel University, where I worked in a couple of different ecology laboratories, and also had the opportunity to work at Merck & Co., Inc. for my cooperative education experiences. After undergraduate I moved to Indiana and worked as a laboratory technician in the Bacteriology department of the Purdue University Animal Disease Diagnostic Laboratory. During this time, I was lucky enough to work with a wide variety of species, which I loved. However, I wanted to know more about how they worked on a basic biological level before doing more research with them, so I decided to attend veterinary school. I was initially co-enrolled in a Ph.D. program, where I rotated through a couple more laboratories, but I eventually left the Ph.D. program due to conflicts with my D.V.M. program.

While completing my D.V.M. I started a project to test out a novel euthanasia method for use in domestic ducks. There is currently no good method for euthanizing large numbers of ducks, which is sometimes needed in cases such as disease outbreaks. The method that we’ve been testing out involves injecting alcohol into the duck’s brain, which has proven to be arguably the least traumatic method for the ducks.. The brain does not have the correct type of receptors to feel pain from the needle’s insertion, so the ducks experience no more pain than if they were having their blood taken, quickly followed by unconsciousness and death.  We are currently working on publishing our results.

I have minimal background in herpetology, having done some field work with turtles during undergraduate, but I’m excited to apply my medical knowledge to enhancing the study of fence lizards and other animal species in the Langkilde lab. I’m starting out focusing on the study of stress and separating out the effects of glucocorticoid hormones from the other mediators of stress in fence lizards.

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Closing the Never-ending Loop

One in an occasional series of guest posts by Langkilde Lab alumni:

Hi Everyone!

My name is Jill Newman, and I’m a Langkilde Lab alumni. I came to the lab as a Research Experience for Undergraduate (REU) student during the spring and summer of 2012. During my six-months with Tracy’s lab, I did some cool things including working on several different graduate student projects, co-authoring seven manuscripts, and exploring a state that I never really saw myself going to: Alabama. It was a really unique opportunity that I was able to experience as an undergraduate student!

I graduated from Northeastern University in Boston, MA in August 2013. Northeastern likes to boast that 90% of its graduates become employed or enrolled in graduate school 9 months after graduation. Feeling the “pressure of being a statistic” on my shoulders, I applied to tons of jobs and explored the option of graduate school. After 8 months of painful unemployment, I became one of Northeastern’s “90%-ers” when I accepted my first field technician job out of college.

Down on the Florida panhandle, Virginia Tech works with an interesting species of amphibian called the reticulated flatwoods salamander. Listed as Endangered by the USFWS, reticulated flatwoods salamanders are a species of interest because they are very dependent on their habitat (longleaf pine, ephemeral wetlands, and likely fire suppressed areas). Virginia Tech’s study is looking at metamorph and adult movement to and from breeding ponds. As an amphibian tech, I surveyed for these salamanders using drift fences/funnel traps. I captured, measured, VIE-tagged (basically giving salamanders a tattoo!), and PIT-tagged salamanders for a multi-year mark-recapture study.

Reticulated flatwoods salamander (5)_cropped 3

Reticulated flatwoods salamander (Ambystoma bishopi)

In my opinion, many of the “cool” herp jobs are down South because the southern states have a much wider diversity of herpetofauna. However, when an opportunity to work in the White Mountains of New Hampshire arose, that was very difficult to turn down! For this project, we were interested in looking at species dispersal and species interactions in an aquatic system. We conducted stream salamander surveys in which half of the streams were known to have brook trout and half of them did not. We captured, measured, and VIE-tagged salamanders for a mark-recapture study. For more information about this project, check out the Lowe Lab!

Wood frog, Lithobates sylvaticus

Wood frog, Lithobates sylvaticus

Spring salamander, Gyrinophilus porphyriticus

Spring salamander, Gyrinophilus porphyriticus

Immediately following my New Hampshire job, I was rehired by Virginia Tech to go back to Florida to work on their gopher tortoise project. The gopher tortoise is a keystone species in the Southeastern U.S. because it digs burrows that provide shelter for over 300 other species! However, USFWS has this species listed as Threatened for reasons including habitat loss, pet trade, human consumption, relocation, and disease. For this tech position, we used occupancy models to survey gopher tortoise populations where their population is known to be in heavy decline. We also used camera traps to check gopher tortoise burrows for activity levels and for commensal species.

[Funny thing about this job: after three months of actively looking for tortoise burrows, I NEVER ONCE saw an actual tortoise while in the field! The only one I’ve seen in the wild was working for Tracy!]

Juvenile gopher tortoise, Gopherus polyphemus, caught on camera trap eating a leaf outside of its burrow

Juvenile gopher tortoise, Gopherus polyphemus, caught on camera trap eating a leaf outside of its burrow

Eastern diamondback rattlesnake, Crotalus adamanteus, redemption picture...make sure Sean Graham sees this!

Eastern diamondback rattlesnake, Crotalus adamanteus, redemption picture…make sure Sean Graham sees this!

Another really unique opportunity that I had was working for the Smithsonian Conservation Biology Institute Wood Turtle Ecology Department. Wood turtles are endemic to North America and are listed as an endangered species. These turtles obtained their conservation status as a result of habitat destruction, agricultural accidents, and road traffic. I had the opportunity to stream survey and radio-track these turtles as part of a 20-year-long mark-recapture study. We tracked male and female turtles as they made large movements across landscapes. This is important for management purposes because over the course of these “large movements,” turtles will occasionally change watersheds (making it imperative to protect multiple watersheds).

Wood turtle, Glyptemys insculpta, shell

Wood turtle, Glyptemys insculpta, shell

An older wood turtle known as “Gramps”

An older wood turtle known as “Gramps”

Sometimes as a field tech you feel like you’re in this “never-ending loop” of traveling around every few months and constantly meeting new people that you may never see again. It can be very difficult at times but there is a lot to gain from these types of jobs. First, you gain important wildlife skills that prepare you for graduate school (if you choose that route), and second, you have the chance to network with great people from all across the country. It’s a challenging but often necessary step before entering the field of wildlife biology.

In my case, the diversity of experiences from my undergraduate and technician positions have paid off. This fall semester, I’m joining Dr. Kyle Barrett of Clemson University to pursue my Masters of Science in Wildlife and Fisheries Biology. My thesis is still in the works, but I will be surveying target herpetofauna in the Blue Ridge Mountains of South Carolina for the South Carolina Department of Natural Resources. This is a great opportunity for me to apply skills that I’ve learned in my past field experiences. Additionally, it’s also a fantastic way for me to learn new skills in the field and classroom. Furthermore, I am also very excited for my first college football game (no offense, Northeastern)!

My opportunity with the Langkilde Lab opened many doors for me when I graduated from college. I’m very appreciative of the chance and great honor to have been an REU student in this lab, and I really enjoyed working with Tracy and all of her graduate students! I would highly recommend that all undergraduate students do an internship/co-op/REU if possible. The more experience you can get earlier on in your career the better off you will be!