The Lizard Log

The Langkilde Lab in Action


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The Lone Master’s Student

The first year of my MSc will be coming to a close in May! After a semester of my first graduate school classes and my first experiences as a teaching assistant I was just starting to get the hang of it and the semester ended. This semester has been filled with research planning and manuscript writing. Just coming from my undergraduate degree, the thought of not taking any classes for an entire semester sounded insane, but so far, I have been very productive. I have one field season down, one coming up this spring, and one manuscript started.

Writing my first manuscript has been interesting to say the least. I have learned so much about statistical analysis of data, and the dreaded R. I am having a difficult time with the introduction section but the results and methods were a breeze. I look forward to getting back out into the field, that is why I got into this field after all.

My upcoming field season will begin sometime in March as the vernal pools begin to thaw and the wood frogs return to them to lay their eggs. I will be doing a transplant study that will follow up on research that I did in the lab for the first chapter of my thesis. I used a 3×3 full factorial design to look at how pH and UV-B affected developmental rates, mass, body condition, survival, and baseline and stressed CORT levels in wood frog tadpoles. The second chapter will take place within local vernal pools. Stay tuned for the results from the upcoming season!

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One JMIH in the books

Destination: New Orleans, Louisiana

Purpose: 100th Joint Meeting of Ichthyologists and Herpetologists

Dates: July 6th- July 10th

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Early morning flight out of State College and I couldn’t resist a cloud picture.

Flying has never been my favorite thing but I was really excited for this trip. To say I was also nervous would be the understatement of the century. I had been told about all of the important and, in my mind, “big name” people I would meet. These same people would potentially be at my talk. No pressure though, right? Wrong! I booked a practice room the morning of my talk (the 7th) and had a half an hour to work out all of the bug in my talk. I was certain I would never be ready but I had no choice. After weeks of preparation for my first talk, it was finally time to get up in front of a room full of strangers, important strangers. The whole thing was a blur but everyone clapped and a few of the observers even came up to talk to me after. It was a huge relief for me to be done with my talk because that meant I could go to other talks and meetings and enjoy myself. I met some of those “big name people” and believe it or not, they were people just like you and I. Who would have thought?!

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Seeing your name in print for everyone else to see is a pretty great feeling.

Throughout the conference I got to see quite a bit of the city of New Orleans. I saw live music, street performers, and the place where the Mardi Gras floats are made. I had some amazing food, some a little too spicy for my tastes but, when in Rome.. I made friends from all over the country and learned a lot about what I wanted to do with the rest of my life. I had no idea there were so many options in this field. There was a live concert put on by those members of the conference who brought instruments, an unlimited Rock ‘N’ Bowl, and so much free food. I cannot put into words how rewarding and fun this trip was for me.

To wrap up the conference, there was a live auction with a lot of interesting things to bid on. The first thing I could work up the courage to bid on was a “The Book of Frogs”. Lucky for me it was a student only item so only other poor graduate students could bid against me. The auctioneers were so entertaining that I didn’t mind that I wasn’t bidding. The night ended a little later then anticipated but I think it was worth it.

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I was irrationally excited about this win!

The whole trip made me grateful to be studying wood frogs and to be a part of this scientific community. I would recommend that every new graduate student attend a meeting/conference of some sort as early as they can. The networking possibilities are endless, communicating your work to others is priceless, plus it is a blast! If giving a talk seems like too much, poster presentations are another great option. You truly never know who you are going to meet! Stay tuned for more updates from the Lizard Lab!


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Rattlesnake Research Round-up

One in a continuing series of posts highlighting the work of undergraduate researchers in the Langkilde Lab.

Michaleia Mead

My name is Michaleia Mead, and I am a senior in Wildlife and Fisheries Science, Wildlife Option. This is my first year working in the Langkilde Lab.  I spent the summer 2015 working for the lab on maternal stress of Eastern Fence Lizards.  But currently, in my research under Dr. Chris Howey, I am looking at ecological trade-offs between thermal quality and risk of predation at timber rattlesnake (Crotalus horridus) gestation sites.  A gestation site is the area that a female snake spends the duration of her pregnancy in from early spring, and throughout the summer to parturition (birth of the litter).  These sites typically receive a good deal of sunlight and allow the female to maintain an elevated, preferred, body temperature.

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An adult female found basking at a gestation site later in the year.

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A neonate rattlesnake found at a gestation site.  Note the size of the neonate as it is hiding under a small birch leaf.  Neonates will typically remain at the gestation site for about 1 week, basking in the sunlight, prior to following their mother to a nearby den site.

The “openness” of gestation sites range from very open to densely forested sites, enclosed by many tall trees.  For this study, we identified three sites that were very open and three sites that were more enclosed.  We compared the canopy openness, thermal quality, and risk of encountering a predator between these two types of gestation sites.  In particular, we are comparing the relationship between site openness and thermal quality as well as site openness and the probability of timber rattlesnakes encountering a predator.  Thermal quality is the amount of time that the range of temperatures a rattlesnake prefers overlaps with the temperatures that are available (thermal quality would be better at a site if it provided more time when available temperatures overlapped with preferred body temperatures).  I am testing the hypotheses: 1. Thermal quality of the open sites would be better due to a greater percentage of time that the available temperatures would exceed preferred temperatures, and 2. Risk of encountering a predator would increase as site openness increases.  

Cameras were placed at each of the six gestation sites to monitor rattlesnake behaviors and occurrence of potential predators traveling across gestation sites, despite the fact that bears sometimes take our cameras out…jerks.  We also placed biophysical models at each gestation site to measure the available body temperatures at those sites. Via these cameras, I’ve observed potential predators and also documented potential food sources for the rattlesnakes, such as chipmunks.  We’ve determined that open gestation sites are in fact warmer than more enclosed gestation sites, and the thermal quality of these sites is better.  The improved thermal quality of these open gestation sites may lead to shorter gestation times by gravid females, more successful reproductive bouts, and increased population health.  Contrary to our second hypothesis, we do not see more predators at more open gestation sites; however, we do see more predators as the overall area of the site increases.  This suggests that we may increase the openness of gestation sites in order to improve thermal quality for rattlesnakes, and, as long as we do not increase the overall open area on the ground, risk of encountering a predator should remain constant.  All of the data have not been analyzed, but they are showing signs of supporting the first hypothesis.  I am currently working on writing a manuscript for these data and should be completed sometime in late January.

A red-tailed hawk swoops in on top of a foam timber rattlesnake model (not seen). A yellow-morph timber rattlesnake model is pictured behind the hawk.

A red-tailed hawk swoops in on top of a foam timber rattlesnake model (not seen). A yellow-morph timber rattlesnake model is pictured behind the hawk.

Tommy Cerri

My name is Tommy Cerri, and I am currently a senior biology major. This is my 3rd year working in the Langkilde Lab. My current research working with Chris Howey focuses around the behavior of rattlesnakes and relationship these snakes have with predators in the community while entering into their den (referred to as ingress). The main objective of my study is to observe rattlesnakes of varying ages entering and exiting rattlesnake dens and the relationship these behaviors have with the occurrence of predator visits at those den sites. For this study, we are predicting that:

  1. Adult and juvenile rattlesnakes will arrive to the den before neonates
  2. Predator visits will increase as more snakes begin to enter the den
  3. Snake activity in front of the den will increase positively with environmental temperature and decrease when temperatures drop, and
  4. Snakes will retreat to the den as predators approach.

This research is proving to be important to the scientific community because we are beginning to see some behaviors that have never been documented before.  For example, we are finding that rattlesnakes are very active around the den for at least a couple weeks prior to hibernation.  Additionally, prior to exiting the den, rattlesnakes appear to stay under the overhang of the den and observe their environment.  We are unsure if this observation behavior is to test the thermal characteristics of the environment or to look out for predators.  In addition to this, the study may provide insight into what snake age is the preferred prey of predators within the community.  Snakes varying in age from neonate to juvenile and adult have all been seen coming in and out of multiple den sites that have been studied via different cameras that have been set up facing four different rattlesnake den sites located throughout Pennsylvania and New York.  From these cameras, we are able to see predators that visit the den as well as the behavior of rattlesnakes as they enter and exit the den during the day. While collecting data, this is what the view of the den from the camera looks like.

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Can you spot the rattlesnake in this picture from one of our trail cams?

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In this case, the rattlesnake is only a few feet from the mouth of its den.

In the pictures above we are actually able to see two adult rattlesnakes basking right outside two of the den sites under question. While right now the study is still in its preliminary phase of data collection, we have already observed some interesting trends between snake activity and temperature.  For example, snakes tend to be active outside of the den during both the day and night until ambient temperatures reach a specific threshold (roughly 42 degrees F).  Some of these activities appear to be basking behaviors, however, night time activities are unknown.  As of right now, we are not seeing any trends between predators and specific age-related prey choices, and we have not recorded any predation events. We hope to be finished data collection by the end of December and have a paper reporting the results completed by May.

Stay tuned, as we’ll publish a follow-up here with our official results!