The Lizard Log

The Langkilde Lab in Action


Leave a comment

The Natural State

Happy Memorial Day!

I am happy to report that the “uninvaded” team has returned to PA, lizards in hand–or bag as it were. Our team, consisting of Braulio,  Caty, and myself, traveled to Tennessee and Arkansas. Arkansas prides itself on being “The Natural State” for its “natural scenic beauty, clear lakes and streams, and abundant wildlife.” I can’t speak to most of that, but it does have lizards!

Fence lizard with a regenerating tail.

Fence lizard with a regenerating tail.

Rainy and overcast days slowed us down a bit. As ectotherms, lizards rely on external sources of heat, which means they like to bask in sunny spots in order to warm up. The thick clouds didn’t provide many good basking opportunities, but thankfully a few lizards made an appearance in the brief moments of sun.

Sometimes fence lizards like rocky habitat.

Sometimes fence lizards like rocky habitat.

2blendinMany other lizards like to bask on trees.

We did see a few sunny days, which gave Braulio and Caty the opportunity to catch their first lizards.

1BraulioLR

Braulio with a Tennessee lizard.

1CatyLR

One of Caty’s first catches!

1Gail

Lizard selfies are the best selfies.

We even managed some “expert” catches, on more than one occasion slowly driving by a basking lizard and noosing it through the open car window.

Because we were looking for females, we of course became experts at catching males. One male lizard really hoped I was a tree. We tried to return him to his log, but on two separate occasions he ran up my leg. Sorry little guy!

Nope, not a tree.

Nope, not a tree.

Another male, pictured below, really surprised me. Lizards vary in coloration, but not usually by much. I’ve never seen a fence lizard so dark!

3darkmorph

A very dark fence lizard. His chest badges were impressive as well!

After two weeks of catching, we headed back to the lab. Our females are now happily housed in their nesting boxes, and one has laid her first clutch of the season. We’re all excited to see the resulting hatchlings!

Check back soon for more stories and photos from the field as well as updates on the specific research projects happening this summer.

We even spotted a fence lizard on a fence. So satisfying. A fence lizard on a fence. So satisfying.

Advertisements


Leave a comment

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).

IMG_0657

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.

IMG_2605

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.

IMG_3487

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


1 Comment

So Many Lizards

by undergraduate Tommy Cerri

This semester, being my fourth semester working within the lab, I like to think I have heard about all the research that’s been going on in one way or another. I had previously finished working with Bradley Carson last Spring semester on tadpole analysis and was eager to delve into something new. Dr. Langkilde got me in touch with Gail and we quickly met to discuss more work for the next 14 or so weeks. Taking 19 credits this semester and getting ready to apply to medical school rendered me nearly unavailable during the week. Gail of course knew the feeling and set me up on something I could do on my own time, at my own pace. This something was a project I had not heard of within the lab, and this excited me. When I went to meet she immediately brought up about 7 or so videos of lizards. The set up looked something along the lines of this.

b1

When I saw this I immediately asked myself a few questions. First, why are there so many lizards in this video? And second, what’s that huge log in the middle of their bins? Gail started to explain her research to me and answered these questions. She was observing the lizards’ behavior over a short period of time within these bins to see how they would react to different hormone treatments. This experiment allows us to see if treatment with stress hormones (corticosterone), sex steroids (testosterone), or both have lasting effects on behavior–like aggression. She also let me know that huge thing in the middle of the bins is just a small shelter. I have been spending my time watching these lizards show all different types of behaviors. I see some lizards spend 10 minutes running circles around their bins and other lizards so lazy I have to zoom in on their stomachs to check if they’re actually breathing! Some of the lizards aren’t very social.

b2

While others seem to be good friends with one another.

b3

Nonetheless, these videos have occupied much of my time and have continued to keep me interested. I look forward to see what Gail does with all the behavior charts I have filled out for her and am eager to help her with the next step in this experiment.

(Ed. note: Hopefully this helps us explain how hormones affect behavior. Maybe lizards dosed with testosterone are more aggressive? Maybe stressed out lizards are more solitary? Stay tuned for the results!)


Leave a comment

Lizard in PA

So, here’s a song about being a lizard in the cold, cold, northeast US.

And for those who may not notice, it is specifically

about a male Sceloporus undulatus in Pennsylvania.

 

 

Lizard in PA  (click here if the link above is not functional)

It’s cold outside

and I can’t move my muscles

cause my physiology won’t bring the heat,

but I’ll be fine.

 

My parietal eye will tell my future

by and by

and by the sun

I will move on,

when the winter’s gone.

 

I’m a lizard in PA

and I’m coming out today

to heat my bones

and eat a bug.

 

Heat my bones

Heat my bones

 

I’m a lizard in PA

and I’m coming out today

to heat my bones

and eat a bug.

 

I hope I find my mates

and set my territory straight

before I see a flash of blue

that comes to call,

I’ll fight um all.

 

Their push ups

don’t scare me

I’m sure they’re all one hemipene

shy of a clutch,

I’d bet my lunch.

 

Heat my bones

Heat my bones

 

I’m a lizard in PA

and I’m coming out today

to heat my bones

and eat a bug.

 

Heat my bones

Heat my bones

.Heat

……….my

……………….bones

and eat bug.

 

(c) 2014

Music, lyrics, vocals, and harmonica by Travis R. Robbins

Music, vocals, and guitar by Kristan Robbins

Produced at Gwendolyn’s Sleeping Studio (TM)

 


Leave a comment

Spring Break Herpin’

While on a quick Spring Break trip, I needed to get a herp fix since I’ve been stranded in a land of ice and snow (errr, State College) for the past four months. Alabama to the rescue. While I mostly just hiked in the glorious (to me) 65-70 degree weather (and did manage to actually get a sunburn on my pasty white arms), I did see some herps along the way, whether by flipping a random rock and log or just stumbling across the odd lizard. Here are some quick pics to tide you over the next month or two until spring unleashes warm enough weather for the herps to come out in force a little farther north.

P1030706

My first fence lizard of the year! This lady was quite cold but basking at the base of a tree trying to get a jump on her activity season.

After quickly catching the fence lizard (hands only...how a real lizard ninja does it!) I contemplate just how the heck I'll set up my projects this summer.

After quickly catching the fence lizard (hands only…how a real lizard ninja does it!) I contemplate just how the heck I’ll set up my projects this summer.

Fire ants were still active as well, although they needed a little motivation (errr, an attacking stick) to get them to show themselves in the cooler weather.

Fire ants were still active as well, although they needed a little motivation (errr, an attacking stick) to get them to show themselves in the cooler weather.

A seal salamander (Desmognathus monticola) works on its tan streamside in the mountains of northern Georgia.

A seal salamander (Desmognathus monticola) works on its tan streamside in the mountains of northern Georgia.

Another desmog takes a peek out of the stream to cast a wary eye at the bumbling human who just pulled a rock away from it's burrow mouth (I put the rock safely back).

Another desmog takes a peek out of the stream to cast a wary eye at the bumbling human who just pulled a rock away from its burrow mouth (I put the rock safely back).

A marbled salamander (Ambystoma opacum) squints its eyes in the bright light after being found underneath a log in southern Alabama.

A marbled salamander (Ambystoma opacum) squints its eyes in the bright light after being found underneath a log in southern Alabama.

Welp, that’s all for now! Hopefully a panoply of critters will be out here in PA soon enough, and we’ll be rolling in fence lizards (and hopefully not fire ants!) in the near future.


Leave a comment

Why Did the Fence Lizard Cross the Road?

To get away from fire ants of course! Fence lizards, like most organisms, generally prefer to avoid being messily devoured by predators, and, to elude predators, animals employ a variety of defensive strategies. Animals may hide, flee, avoid detection (by camouflage or other means), be poisonous, pretend to be poisonous, have armor, and even preemptively attack a predator. For example, the Eastern Hognose Snake (Heterodon platyrhinos) employs a truly astounding suite of defensive strategies, including: puffing itself up to look bigger and more like a venomous snake (hence their nickname, the “spreading adder”), striking with a closed mouth, vomiting, and defecating to make itself as gross/distasteful as possible, vibrating its tail to mimic a rattlesnake, and playing dead by turning over on its back and sticking out its tongue.

A hognose snake feigns death (thanatosis) as a defensive strategy. Photo credit: Douglas Mills.

A hognose snake feigns death (thanatosis) as a defensive strategy.
Photo credit: Douglas Mills.

Fence lizards have defensive strategies too. Research in our lab has shown that one of the main ways that fence lizards adapt to fire ants is by fleeing from ants more frequently. Fence lizards from areas without fire ants will only flee from fire ant attacks about 50% of the time; the other half of the time, they freeze and remain motionless, and the lizards would likely die if we did not remove the ants and allow them to recover. However, when we study fence lizards from areas with fire ants, we notice that up to 95% of lizards flee when attacked by fire ants, a much higher percentage. This strategy is very effective, since fire ants can only prey on adult fence lizards when they can recruit to attack in large numbers.

However, in our lab meetings we began to wonder: why do fence lizards from areas without fire ants freeze so much of the time? It seems most likely that lizards from areas without fire ants freeze when attacked because this is an effective, adapted defensive strategy against native predators. In other words, just as fire ants have put pressure on fence lizard populations to adapt (in this case, by running away more often), native predators have put pressure on fence lizards to freeze (about half the time, at least). While not running away from a predator when given the chance may seem like a bad strategy, this approach makes more sense when we consider what the native predators of fence lizards are. They include many types of predatory birds, such as hawks and falcons, as well as several snake species, including black racers (Coluber constrictor) and coachwhips (Masticophis flagellum) among others. These predators are primarily visual hunters and also very speedy. A fence lizard in danger from one of these predators would have little chance of outrunning it, unless a refuge were near at hand (or claw); however, as fence lizards have excellently camouflaged patterning, freezing could be a very effective strategy, as the bird or snake might, like the erroneous T-rex in Jurassic Park, have a difficult time seeing the fence lizard if it remained motionless.

After these discussions, I, along with two undergraduate researchers, Shannen McGinley and Elexa Baron, decided to test whether fence lizards from different areas (those with fire ants and those without), would react differently to a simulated predator attack. To conduct these tests, we first needed a predator; after some quick research, I discovered that a common avian predator of fence lizards is the American Kestrel, a smaller falcon that preys on many species of lizards. The Penn State University Bird Collection happened to have a preserved kestrel salvaged from a car strike that they were kind enough to lend us. After naming our kestrel “Cadfan”, I proceeded to get him ready for his close-up: I braced his wings into a half spread position, as if he were swooping in for a strike; built him a wire harness, to allow us to hang and swing him from the ceiling in a simulated attack; and gave him a pair of really intense eyes (as we know from personal experience that fence lizards will respond to large eyes and being stared at).

Cadfan and me chilling in the lab. Note his intense and intimidating gaze.

Cadfan and me chilling in the lab. Note his intense and intimidating gaze.

Next, we needed to design an arena in which to conduct behavioral trials. We set up a small arena in the middle of an animal room that contained a tub identical to those our lab lizards live in, and we lined it with sand and put in a half log, a type of lizard shelter. To allow us to simulate a kestrel attack, we hung Cadfan from the ceiling of the animal room using fishing line. We also built a blind for Cadfan and for ourselves, to prevent the lizard from seeing either the kestrel or the humans. As part of the construction, we built a webcam into our blind to allow us to observe and record all the trials for later analysis.

Left: Cadfan hanging over the arena showing how close he can swoop to the lizard perch. Right: The backside of our blind, with datasheets, laptop, and webcam set up to allow data collection.

Left: Cadfan hanging over the arena showing how close he can swoop to the lizard perch. Right: The backside of our blind, with datasheets, laptop, and webcam set up to allow data collection.

After finally getting the room set up to our exacting specifications, we were ready to run trials with our lizards. Conducting a trial required two people. One person stayed behind the blind and held Cadfan up and out of view of the lizard. The other person fetched a random lizard from its housing and walked it quickly to the trial room, where we took it’s body temperature and set it on the log perch in the middle of the arena. That second person, the lizard-getter, then walked behind the blind, starting recording with the webcam, and gave a big thumbs-up signal to the bird-holder. The bird-holder simultaneously released Cadfan, and also turned on a small lightbulb that could be seen in the webcam but not by the lizard (this allowed accurate timing of the trial). We let Cadfan make four swoops over the head of the lizard and then returned the lizard to its housing, while recording if the lizard reacted to the simulated attack and how long it took to react. We also classified how strong any reaction was; some lizards just ducked their heads or shifted to the side, much as you or I might if a large insect flew at our heads. Other lizards reacted much more strongly and dove into the sand or underneath the log shelter. See below for a video showing our setup and a couple of trials!

We’re still analyzing the data from these trials now, but, to the naked eye, we haven’t seen a large difference in responses to the bird predator based on where the fence lizards come from as we’ve seen in response to fire ant attacks. This could mean that lizards might be able to distinguish between different types of predation threats or that something else is going on. We’ll post again when we publish a paper on our trials, so keep an eye out for those results here (and any attacking kestrels that might be nearby)!


Leave a comment

Papers papers papers!

The best way for scientists to share their research is to publish it in scientific journals. This can be a lengthy process, so it’s always very exciting when your work is finally published. We’re so excited that we wanted to share some of our recent publications with you.  Click the links below for the abstract (or to download the paper if you’re a fancy pants scientist/academic with access!)

No evidence of selection by predators on tadpole boldness.
Bradley E Carlson and Tracy Langkilde. Behaviour
Read more about this on our blog here.

Figure-1

Tadpoles!

Latitudinal and seasonal variation in reproductive effort of the eastern fence lizard (Sceloporus undulatus).
Wei-Guo Du, Travis R Robbins, Daniel A Warner, Tracy Langkilde, Richard Shine. Integrative Zoology

Rise and Fall of a Hybrid Zone: Implications for the Roles of Aggression, Mate Choice, and Secondary Succession.
Travis R Robbins, Lorelei E Walker, Kelvin D Gorospe, Stephen A Karl, Aaron W Schrey, Earl D McCoy, Henry R Mushinsky. The Journal of Heredity

On the incidences of cannibalism in the lizard genus Sceloporus: updates, hypotheses, and the first case of siblicide
Travis R. Robbins, Aaron Schrey, Shannen McGinley, Aaron JacobsHerpetology Notes
Read about this on our blog here.

The cannibalized Sceloporus undulatus lizard (right fecal pellet) and one of his siblings (left).

A cannibalized Sceloporus undulatus lizard (right fecal pellet) and one of his siblings (left).

Bearded ladies: females suffer fitness consequences when bearing male traits.
Lindsey Swierk and Tracy Langkilde. Biology Letters.
More about this one on our recent blog post here.

A male (left) and female (right) fence lizard. The female is a “bearded lady” with pale blue badges.

We’ve also had a whole bunch geographic distribution notes published in the journal, Herpetological Review. That usually means we observed a species outside of its known range. We had four notes in September’s Issue and seven in December’s issue. Authors from our lab included Chris, Brad, Gail, Sean (lab alum), and undergrads Mark Herr, Mark Goldy-Brown, and former intern Jennie Williams. Pretty cool!

If you missed our recent posts about some of these topics, be sure to read more about tadpole boldness, lizard cannibalism, and bearded ladies!