Bad Neighbors: How the Collateral Damage Hypothesis Modulates Predation and Parasitism Pressure in Neo-Tropical Frog Species.

Our Project:

A calling Tungara frog.

Each year, Professor Trillo brings X-SIG students to conduct research at the Smithsonian Tropical Research Institute in Gamboa, Panama. One of Dr Trillo’s research projects in Panama focuses on the role of eavesdroppers on sexual signaling in frogs. This summer, the labs’ main focus is to understand how collateral damage can influence predation and parasitism risk within a single species. Collateral damage, a concept pioneered by Dr. Trillo, refers to the dangers associated with calling near highly attractive heterospecific species. Previously, Dr. Trillo found an increase in midge parasitism for hourglass treefrogs when they called near Túngara frogs, which are highly attractive to predatory bats and parasitic midges. Dr Trillo’s hypothesis is that attractive signalers can inadvertently increase predation or parasitism on heterospecific neighbors by increasing the number of these enemies that are attracted to the aggregation as a whole.

Trachops cirrhosus, a frog eating bat.

This same idea of collateral damage across species could also be applicable within a single species, if individuals within that species use more than one type of advertisement signal, and if one of those signals is more attractive to predators and parasites than the other. This is the case for Túngara frogs. 

Corethrella, a genus of parasitic midges. These midges tend to siphon off blood through the frog’s nostrils – ouch!

When attracting a mate, Túngara frogs can modulate the complexity of their mating calls. A “simple call” (see Figure 1), which involves a whine only, is less attractive to eavesdropping predators and parasites. However, simple calls also are less attractive to potential female mates.

Conversely, Túngara frogs can produce complex calls (see Figure 1), where extra “chucks”, made of broadband sound with a greater frequency range, are produced in addition to the tonal whine. These calls are highly attractive to females, but they also increase the number of predators and parasites to the calling frog. With these ideas in mind, we hypothesize that the highly attractive complex calling Túngaras will increase the risk of predation and parasitism of their simple calling neighbors. In order to test this hypothesis, we are currently performing playbacks of simple and complex Túngara frog calls to investigate how signaling patterns of neighboring frogs change the risk of attracting eavesdropping bats and midges.

Figure 1: Comparison of frequency ranges between Tungara simple and complex calls.
Setting up a nocturnal playback trial along the Pipeline trail.

To test our hypothesis, we conduct acoustic field playback experiments to quantify bat and midge visits to complex and simple Túngara frog calls. Each night, we set up, two speakers with a combination of simple or complex calls. Our four treatments consist of simple call-simple call, complex call-complex call, simple call-complex call, or a single speaker with only one simple call. We set up camera traps to record bats visiting each speaker and we place fly traps above each speaker to collect the number of parasitic midges attracted to each type of calls. After the experiment is done, we count the number of flies present and carefully upload the bat videos taken at each site in order to score them in the future. 

Each day, after the field playbacks, we identify and count upwards of a thousand Corethrella midges.

Although we expect each experiment to run smoothly, troubleshooting is almost always necessary. Performing field work in the tropics poses unique difficulties. The humidity and heat of the tropics force us to take extra precautions with our electrical equipment. To prevent water damage due to condensation, equipment needs to be carefully stored in a heated box each night after trials. Battery charge, which could degrade quickly due to corrosion, is carefully monitored each day. Each night entails a long hike from site to site through the tropical jungle. Although collecting data in the field can be grueling, our lab is eager to see our results, and the potential effects of collateral damage on túngara frogs. 

Research off Campus

The Smithsonian Tropical Research Institute New Lab in Gamboa, Panama.

Conducting research off campus at the Smithsonian Tropical Research Institute, or STRI, in Panama offers opportunities to gain a unique perspective on academia, global research, culture and nature. STRI is one of the leading tropical research organizations where scientists come from around the world conduct field work next to the Panama canal. In Gamboa, we work alongside a closely-knit community of organismal biologists, geologists, ecologists, and other scientists dedicated to understanding and sharing information about tropical ecosystems.

Dr. Warkentin presenting at a weekly frog talk.

Each week, we go to a “frog talk” or a “Tupper talk” depending on our work schedule. These seminars are held to allow researchers in Panama to share their work and ideas, and to receive feedback from their colleagues. Frog talks, one of our lab’s favorite events, occur each Wednesday in the casual setting of a neighbor’s living room. Every week researchers of universities from a variety of different countries gather in a living room, with refreshments in hand, to listen to a speaker present their latest results. These presentations are an awesome display of cross-disciplinary and cross-cultural work: often, presentations examine biology from an interdisciplinary perspective. For instance, Dr. Warkentin, a professor in Biology and Women and Gender Studies at Boston university, gave a lecture on “queering herpetology,” which examined social biases that affected how animal behavior had been previously studied. Other talks range from examining the molecular costs of insect pheromones, to demystifying perplexing female coloration in the white-necked Jacobin hummingbirds. In all, while many assume that working in a lab as an undergraduate entails hours of repetitive tasks and uninspiring work, working at the Smithsonian Tropical Research Institute has given our lab an incredibly diversified insight into research.

Nature and Culture:

A 3-toed sloth hanging out as we made our way to the La Chunga site to set up a playback trial.
A common basilisk out and about during late-night hours.

            Aside from the questions our lab aims to answer, our surroundings have also impacted our understanding of current environmental issues. Simply put, Panama has a wealth of biodiversity. It isn’t uncommon to wake up to the raucous chorus of parrot calls each morning, to see monogamous pairs of toucans flying from tree to tree, nor to encounter a caiman during our night excursions on the pipeline hiking trail. For some of the lab members, the idea of “tropical diversity” became a tangible concept – a concept that prior to this trip had vaguely existed on the glossy pages of a National Geographic magazine.

Keel-billed toucan in Professor Trillo’ backyard.
A troop of howler monkeys passed overhead during one of our weekend hikes on the Pipeline trail.

Working in the field has also been an inherently immersive learning experience. During our first few outings, the frog chorus at experimental pond was a cacophony of croaks and whines. However, after a few weeks of nightly visits to the pond we could begin to identify the approximate number of frogs calling at the pond, their species, and the locations from which they called. We began to understand when frogs started and stopped calling or how the rain that day might affect the density of frogs that night. Likewise, as we continued our daily hiking trips through the tropical forest, we slowly began to recognize different flora and fauna, and understand how the wild plants interacted with surrounding organisms. It was as if we were slowly learning a wild language through our immersion in the tropical forest, and understanding this language helped us empathize with our surroundings.

           As we continue our project with Dr. Trillo, we are eager to analyze our data to find previously unrecognized patterns that improve our understanding of the links between predator and prey. While these last few weeks will be a whirlwind of hiking, playbacks, video viewing and fly counting, we will continue to take full advantage of our unique and incredibly beautiful surroundings.

Probing lights finite travel speed in large scale structures

In Cosmological research, data is derived from two main sources, observation based, and simulation based. Each type of data has its pros and cons. In observational data, you see real, physical situations allowing better insight into how the universe works, but getting the information is time consuming and often a large portion of the information is unable to be retrieved. In simulation data, you create pseudo-physical situations and have access to all the data and parameters for an object. The downside of this is it’s based on our interpretation of physical situations. A major issue arises when trying to compare these two forms of data, the finite nature of the speed of light.

 In simulated models, light speed is assumed to be infinite, all times are centralized and there is no delay when looking at a distant object in a simulation. That is not the case in observational data. Light takes time to travel, when you look up into the sky you are gazing into the past. This becomes an issue across the largest structures currently formed in the universe, like galaxy clusters. Objects that are further away take longer for time to reach us than objects that are closer. For a galaxy, rotating rather slowly when compared to the speed of light, this effect would probably be negligible.  For a galaxy cluster, who’s size scale is on the range of Mega-Parsecs (3-30 million light years), and the velocities of its constituent galaxies are on the order of a percent the speed of light, this effect becomes much more meaningful.

The issue that arises with observational data is that it is projected down to 2 dimensions on the sky. A 3-dimensional object in the plane of the sky loses all of its dimension of depth. Since Galaxy Clusters have a dimeter of 3–30 million light years, the light emitted from objects at the far edge of the cluster takes 3-30 million years to reach the front. So, when an observation is made of a galaxy cluster, further objects are 3-30 million years back in time when compared to objects in the front, by the time light from both objects reach the plane of the sky.

There have been many statistics I’ve had to use to try and probe this issue. The first being seeing how velocity dispersion profiles were changed when created with a time offset or not. A velocity dispersion profile maps how the distance a galaxy is radially from the center of the cluster. We ran into challenges with this method, while we saw a minor difference, we came to determine that the statistic wasn’t sensitive enough to small changes in position (relative to the size of the cluster) to provide a meaningful result.

 Our next statistic to probe was the Lee Statistic. The Lee Statistic is a bivariate analysis judging the likelihood that a collection of objects on the sky make up one group, or more. The statistic takes your data and projects it down to a one-dimensional line, it then compares each point and judges the dispersion of points to the left of the point, the right of the point, and the total dispersion. It is highly sensitive to changes in position, so we judged to it be a solid follow up. Our first method was the 2-dimensional lee statistic. I took the simulated 6-dimensional data (3-dimensional position, and 3-dimensional velocity), and project it into 2 dimensions of position (in the plane of the sky). I also copy the data and insert an artificial time offset, I then project the data sets onto a line with varying angle of phi with respect to the axis. After probing this with a single cluster, we started work with a merging cluster. There was a larger difference between the data with the artificial time offset and the one without it due to the larger distance light must travel across the merger. We then moved onto the 3-dimensional Lee Statistic which also considers a dimension of velocity along the line of sight (perpendicular to the plane of the sky) along with the 2 dimensions of position. We found this to be our most sensitive statistic to time offsets as measured so far. The goal of this research will be to determine some way to decide how necessary it is to make a correction with statistic.

Perhaps what was unequivocally the most important aspect of my summer was my daily hackey sack sessions with my research group. There’s a new person you discover inside of yourself when you are in the arena with your fellow comrades, and I’ve come to get to know, and love, that person. All struggles, big or small, seem to be insignificant when you achieve the state of hack. I have yet to forsake the hack, and I never will, as is commandment number one for hack sack master and chief – Jedi Johnson.  

Throughout this project I have experienced a myriad of problems that I needed to think critically to solve. There were times where I needed to totally adapt large portions of my code to allow different simulations to be tested and being able to just have access to various data bases and finding ways to download it is rather difficult. Other issues I faced were minor errors in my code that started early but went unnoticed that I had to spend hours debugging. Over the past two years I had to completely reinvent my thought process when it comes to coding, and it made me become a better programmer, and a better scientist.

Figure 1 – Illustris data set primarily used this summer for data collection

Figure 2 – pseudo merging cluster created from illustris data set. Shown from two separate viewpoints

Figure 2 – various 2D projections of a merging cluster at different angles from the merger axis.  This is done on data similar to the set in figure two and projected down to two dimensions at different inclination angles.

  Figure 3 – Various 3D Lee Statistic images 1000 iterations with 100 members in each group. Separation between the red and blue lines shows a statistically significant different between time corrected and non-time corrected data.

Observational Astronomy Crew: Meet the Team and Check out Our Work

This is our observational astronomy group. Pictured above left is Sheldon Johnson.  Sheldon is a rising sophomore and a physics major, with plans to be an aerospace engineer. You can normally hear him laughing at some ridiculous thing he or someone else did and normally he has his headphones on singing out loud to his heart’s content.

Pictured above right is Brian Taylor. Brian is a rising junior and physics major. He has an interest in astrophysics and would like to continue to study it in graduate school.

Pictured above middle is Autumn Tripet. She is a rising sophomore and an aspiring physicist who wishes to continue astronomy in graduate school.  On a typical workday you can find her in Master’s listening to music while simultaneously trying to sort through and reduce data from our recent trip to the Lowell Observatory in Flagstaff, Arizona.

Behind the camera is Dr. Jacquelynne Milingo. She is our faculty mentor for the work we’re doing this summer.

We started off our research by reading through the basics of telescopes and trying to get an understanding of the world around us. We spent a good amount of time becoming familiar with the material and concepts we would be working with, as well as reading through an abundance of software manuals. As our beloved professor Dr. Milingo would say… “R.T.F.M. !” (if you’re curious as to what that means, ask us in person).

After getting up to speed, we officially started working on a cap design for the baffle on our campus telescope (a baffle helps eliminate stray light).   This cap replaced the plastic bag that was covering the baffle at the Gettysburg College Observatory.  Seriously, we’ve had a plastic bag covering the baffle of our telescope for more than 15 years, so you could say it was time for a change. Pictured below is the infamous plastic bag.

After a week of measuring and tinkering around with dimensions on the OnShape CAD program, each team member was able to come up with a unique design to replace the trash bag. The programming and tinkering with the cap models looked a little something like this:

We printed our designs on a 3D printer and completed a prototype to finally switch out the bag. Here’s that glorious moment for everyone to bask in … 

Aside from working on new designs for the Gettysburg College Observatory, we also put our new small telescopes together. This allowed us to better understand the material we read on telescopes prior, letting us see first hand how the different parts work together in creating a magnified image of the sky. At the end of July we will use these telescopes during a public outreach event with girl scouts at Camp Happy Valley in Fairfield, PA. Our hope with this event is to educate kids on the possibilities in science, especially the influence of women in science. One of the telescopes we assembled is pictured below.

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Eventually, we found ourselves on an airplane flying to Arizona to do some observing at the National Undergraduate Research Observatory (NURO) which is part of Lowell Observatory in Flagstaff, AZ. NURO is a 31 inch telescope. We spent 6 days in the southwest, with 4 nights of observing. Our goal was to take images of the open cluster NGC 6866 for future studies of spotted stars in the cluster. We also took images of standard stars for calibration. A picture of the open cluster can be seen below.

NGC 6866 open star cluster

Image courtesy of the Aladin Sky Atlas: https://aladin.u-strasbg.fr/AladinLite/

 While we were observing, a typical day would start at about 6 in the evening. We made our way to the observatory around that time to setup and run startup routines for calibration frames before sunset.  Once it was dark enough (after nautical twilight) we could focus the telescope and begin making observations of our target stars. The night usually didn’t end until about 4 in the morning if Mother Nature was kind enough to give us a clear night.

During the night, we took turns on each of the computers, each working and controlling a different aspect of the telescope and camera. The dual monitor shown below left allowed us to control the camera, the filter wheel, and to analyze images as they came in.  The older style computer shown below right controlled the telescope directly giving it coordinates to move to, objects to look at, etc.  The third job was keeping a log for the night. This consisted of writing down our course of action, system failures, coordinates, air masses, filters, exposure times, and any other useful notes for that night.

Our workstation in the warm room is shown below.  Below is is the telescope control computer monitor as well as the auto guider system monitor.  The auto guider allowed us to lock on certain objects in the sky for longer exposures.

Telescope control and star auto guider

Trials and Tribulations While Observing

Observational Astronomy is not all clear weather and good data. Our team found this out while working at NURO. System failures, software crashes, and clouds were a big bump in the road while we were trying to gather data. We soon realized that this was a somewhat normal occurrence when doing observational work and dealing with complicated interconnected equipment.  Add in the mild sleep exhaustion due to our nightly runs and it’s all part of the experience of astronomical observing.

Fun things We Did While in Arizona

Even though we spent our nights at the observatory (instead of sleeping), our team managed to get up at a reasonable time every day to explore the great views of Arizona. Staying in Flagstaff, we were about a 30 minute drive to scenic Sedona, Arizona. We were lucky enough to hike the West Fork of Oak Creek Canyon, visit the Grand Canyon, explore Sedona, and be submerged into the Flagstaff community. A big part of the observing experience was being able to explore and learn about the land around us, and specifically how the certain climates and elevation affects our observational work. Some of our favorite scenic moments are highlighted in the pictures shown below.

Group Picture at Oak Creek Canyon
West Fork of Oak Creek Canyon
The Grand Canyon
Sedona, Arizona
Group Picture at The Grand Canyon
West Fork of Oak Creek Canyon, Sedona, Arizona

Good Vibrations in the Caldwell Lab

            When many people think of sound, they think of it traveling through the air to a listener’s ear for interpretation. From a broader perspective, sound is vibrational energy that can take many paths on the way to a receiver – through the air, through ground, through plants, etc. Sometimes, these vibrations are interpreted in the ear, but animal species vary in the physiological structures they use to interpret this energy. In the Caldwell lab, we are especially interested in learning how animals interpret vibrations traveling through multiple substrates to inform behavioral interactions between animals of the same or different species.

            The first thing we did was jump right into science… Just not exactly how we had expected. Fieldwork brings about a whole set of challenges that do not occur in typical controlled lab settings. Our first experiment is investigating vibrotaxis, or the movement of an organism in response to vibrations, in foraging snakes. In addition to airborne sound, calling frogs produce vibrations in the plants they sit on. If snakes are able to detect these vibrations, then they may be able to use them to hunt frogs. In order to conduct this experiment, we needed an arena that would allow us to observe how snakes use vibrations in their foraging behavior. This arena had to fit in the little hut that we had access to that doubled as a storage building, but also had to be large enough to fit a Y-shaped branch of some sort that was about two meters tall. With these guidelines, Professor Caldwell took us shopping to get a bunch of materials and then left us to figure out how to build it. 

            We started with the basics- measuring the space and making the frame. We accomplished this without any major catastrophes. Then we had to determine the best material to wrap around the sides, top, and bottom to prevent a snake from escaping the arena. We planned to use a black mesh material for most of the arena, but were unsure if a camera with an infrared light could see through it to monitor the snake. Following a trial, and after adding a large infrared light attached by wire to the ceiling, we found that the mesh worked well.

            The next step was, in theory, simple. We needed a small mesh door that could both close with Velcro and prevent a snake from escaping. What this boiled down to consisted of sewing sticky adhesive Velcro. This entailed quite a bit of frustration at the beginning due to the adhesive component of the Velcro and the repeated knotting of the thread as the material was stitched together. Eventually, however, we developed the technique and made the door.

            After several more experiences including sewing mesh together that was already stapled to the wooden frame, having screws snap in the wood as we made cross beams, and hot gluing across every seam to be doubly sure that the snake wouldn’t get out, our arena was done. Unfortunately, on our second trial a snake escaped the arena within five minutes and we were back to sewing.

            Once our arena was truly complete, it was onto the more typical science. We captured a few chunk-headed snakes and set up small terraria for them complete with a water tray, Nalgene bottle with some water and plants, and a branch that they could climb on. We named these snakes and recorded notes on their care. We ran three preliminary trials per snake in our arena with no vibrational stimulus. This consisted of attaching two Red-eyed treefrog egg clutches to different sides of the Y-shaped branch in our arena and waiting for five hours between typically 8PM and 1AM while the snakes foraged. If they ate both egg clutches before the five hours, we ended the trial. In each of these trials, the snake foraged, meaning that we could commence the experimental trials.

            To prepare for the experimental trials, we had to get raw material for the stimulus. This meant going out to the Experimental Pond nearby and recording frog calls and the vibrations produced in the plants they call from. We used a shotgun microphone to record frog calls with as few background sounds as possible, as well as an accelerometer to capture the plant-based vibrations. An accelerometer looks like a thin wire with a little cylindrical head on one side. It works by measuring the acceleration at which the plant moves, therefore detecting vibration information.

            The only issue with this was that in order to attach the accelerometer to the plant, we had to tie it on with flagging tape. If we tried to do this while a frog was on the plant, which is ideal because we want to get the vibrations produce by a calling individual, we would disturb the frog and sometimes cause it to jump away to another plant, making the accelerometer position ineffective. To remedy this, we would often attach the accelerometer to a plant and then move one or more frogs onto that plant, then quickly walk away for a few minutes, and come back cautiously to see if they stayed and started calling. If they did, we could record. If not, we had to try again. This required retrieving a lot of frogs and moving them to adequate positions. If they were not on the edge of the pond where we could reach and were instead in the center, which happened more often than not, we would have to wade into the pond and catch them, bringing them back out to the plant with our recording set up. This resulted in a lot of flooded boots and wet feet.

            After getting several recordings, we could create our stimulus for the playback experiments. We listened to the recordings and looked at the signal to noise ratio especially in the vibration data to determine which recordings would be best to use. Once that was done, Professor Caldwell created the stimuli for the experiment by first removing all extraneous sounds and vibrations. Then it was time to equalize the stimulus to the branch in our arena so that we could play back call vibrations with similar acoustic properties to those of the original call.

            Playback experiments rely heavily on the stimulus being played back sounding like the stimulus that was recorded. However, recordings never really sound exactly how they did when they were recorded, partially because the equipment acts as a filter. Audio equipment is generally good enough to avoid any serious alterations. Substrate vibrations are usually altered more drastically because they attenuate differently than sound in the air. The substrate itself filters vibrations and each substrate does so differently. For these reasons, equalization is necessary for vibration playbacks. This involves playing white noise, consisting of equal amplitudes at all frequencies, through the substrate/system being used, in our case a branch, and then rerecording the white noise. The branch will filter this noise, resulting in the new recording having altered amplitudes across some frequencies. The measure for how the system filtered the noise is a transfer function. To account for this, the inverse of the transfer function is added to the system, playing the lowered frequencies relatively louder than the unaltered frequencies. After running this process a few times to make the transfer function accurate, we apply it to our recorded stimulus to make a more natural playback.

            After making the stimulus and equalizing it, we started our experimental trials. To focus on the snake’s response to vibrations specifically, the audio portion of the stimulus was played above the center of the arena instead of on one side of the branch like the vibrations. We introduced the snake to the arena and recorded it on a camera for up to three hours. Once the snake had passed the “Y” in the branch, we recorded it for one more hour to observe its foraging behavior. Eventually, these videos will have to be analyzed thoroughly, taking note of which side or sides the snakes went to as well as the amount of time spent there.

            Our experiences in the Caldwell lab have shown us that not all aspects of science are actually collecting data. Lots of it, especially in field work, is trouble shooting, and making what we have available work for what we need to do… And troubleshooting again. Every day is engaging and although some aspects can be frustrating when things don’t work, it is highly satisfying when we come up with a good idea and solution to a problem. With more experimental trials with our snakes in the near future and ABR studies on the horizon to determine what frequencies of sound and substrate vibration snakes and frogs can sense, we are going to have a busy remainder of the summer.

Social Media, Self-Compassion, and Symptoms of Disordered Eating

The idealization of thinness is prominent in Western cultures, and much research has shown that women’s exposure to images promoting the desire to look thin in television, movies, and magazines is associated with their body dissatisfaction and symptoms of disordered eating (including excessive dieting, and binge/purge behaviors). Over the last decade, the increase in the availability of smartphones and social networking platforms has made media exposure more accessible and more constant in women’s daily lives. Now, though young adults and adolescents are less likely to be flipping through the pages of the latest Cosmopolitan magazine, over a billion active users are exposed to countless images and videos on their Instagram feed every day. It is therefore important to examine the effects of exposure to social media content on women’s well-being.

The Personality Lab has been studying a number of common so-called “positive” cultural trends that are actually detrimental to mental health because of the toll they take on self-compassion. One such trend that the lab has been investigating is  ‘fitspiration.’

Fitspiration (also known as fitspo), is an online trend focused on promoting a healthy lifestyle by motivating viewers to exercise, eat well, and take care of their bodies. Images under the fitspiration hashtag usually depict images of females who have generally skinny, toned, perfectly built bodies. Despite its good intentions, research suggests that fitspiration photos have detrimental effects on body image, body satisfaction, and self-compassion, perhaps because they transmit guilt-inducing messages and unrealistic portrayals of the ideal beauty, similar to those of pro-anorexia websites.

Self-compassion is defined as being kind to oneself, being mindfully aware of one’s flaws and accepting them as part of being human (Neff, 2003). Self-compassion is important for body image because it acts as a protective factor against body shaming, body dissatisfaction, and disordered eating behaviors. Because of this, research conducted in the personality lab has been examining how exposure to different kinds of Instagram content affects self-compassion and mood. We have been especially interested in whether the effects of exposure to different kinds of images may depend on the individual’s level of disordered eating symptoms. That is, exposure to fitspiration images may be even worse for some people than others.

Earlier this summer, we analyzed the results of an experiment conducted in a sample of Gettysburg College women and found that as predicted, looking at fitspiration images lowered participants’ self-compassion and mood more than looking at images related to body transformation (successful weight loss), healthy eating tips, and travel (control). Moreover, the effects of looking at fitspiration and body transformation images on self-compassion were even worse for individuals with higher levels of disordered eating symptoms. Interestingly, all body-related images (even those with healthy eating tips) had negative effects on participants’ mood, relative to the travel images.  

To extend this research, we have been developing a follow-up study to examine whether these effects are also true of another common online body-image trend: body positivity. Because body positivity promotes the acceptance of all body types and treating our perceived body inadequacies with care and support, it may be more compatible with self-compassion (i.e. self-kindness, mindfulness, common humanity). On the other hand, it could be that all body-related images, including those presented with good intentions, are triggering for individuals with disordered eating symptoms. We plan to research whether or not viewing images related to body positivity may be a healthier alternative to viewing images of fitspiration, and particularly in those with higher eating disorder symptoms. This research is important in today’s age, especially as we begin to rely more and more on social media as a source of what is deemed acceptable or trendy in society.

– Cindy and Thao

We look at bugs underground

Hello it’s Georgia, Owen, and Professor Urcuyo coming at you from the great caves of Pennsylvania. In our lab we are working on creating an inventory of the invertebrates inhabiting local caves in Franklin County. We collect the samples ourselves during our caving trips and then bring them back to the lab to sort, photograph, and identify.

Before our first caving trip at Carnegie Cave…

and after!

With low levels of light, coldness, and lack of cycling nutrients, caves are a difficult environment to inhabit. Besides the entrance, you soon find the only source of light is the one from your headlamp. Caves remain at a constant temperature and are typically around 52˚F in PA. There is no presence of primary productivity, so the only available nutrients come from anything entering the cave and the water that resides. Some of the passages in the cave can drop as short as a foot tall and are quite difficult to get through. There can also be pretty deep water that accumulates inside. Some passageways can become flooded sectioning off portions of the cave.

Flooded passage

Along with trapping invertebrates inside the caves, we also collect data on temperature and humidity in the back, middle, and entrance of the cave.

“If you see a raccoon in the tunnel, just get on your feet and hands and let it crawl under you”

–Ish

All of us are working together to identify our samples to the lowest taxonomic level, we’ve split up our preliminary research but otherwise we all have the same role in the lab.

Hey it’s Georgia and I’m focusing my research on Collembola. Collembola, otherwise known as springtails, are small jumping hexapods estimated to have 50,000-65,000 species worldwide. They typically range from 1-5mm long which makes them difficult to sort from sediment and to photograph under the microscope. I also control the lab music which is super important (default to Big Booty Mix 15 if we really need to focus). I really enjoyed my first experience caving and I can’t wait to go back. I’ve done some pretty intense hikes with climbing and cave like passages but I’ve never experienced something like this before. Professor Urcuyo had us lay down and turn off our headlamps at one point in the back of the caves and it was surprisingly peaceful. It was crazy to experience darkness like that, I couldn’t even see my fingers an inch from my face.

The largest collembola on the left is around 6mm long. The two to the left are in the suborder Arthropleona while the one to the right is in Symphypleona.

Owen here, I am focusing his research on the order Coleoptera (beetles), in particular the superfamily Staphylinoidea which describes over 70,000 species. The size of these rove beetles make them much easier to find and study, however the little details on morphology can be hard to discern. Based on our time slaving over dichotomy keys, we think we have found the genus Philonthina and Quedius and we’re hoping to send off a few of our samples to entomologists to analyze our findings. You’ll often see me modeling in the cave passages, when not distracted by the beautiful iridescence of rove beetles. Our first experience into the caves was quite something…cold, wet, muddy, and cramped. As a bigger individual I was often hunched over and I struggled to get through small crevices, it was quite exhausting. Regardless, all of these factors were worth it. Having to explore an area that has not been touched by many people is exhilarating. In the dark you’ll never know what to run into or what’s around the corner, and that’s the best part.

A beetle found in Carnegie Cave that we identified down to the genus Bisnius. This sample is around 1.5cm. Notice the iridescence on the abdomen and elytra.

Figuring out what we have collected is quite the project. Owen and Georgia have gotten very good at finding articles with original descriptions (some dating back to the 1800’s) and keys that allow us to identify our organism. The keys can be very particular and the genus differentiation can come down to something seemingly meaningless like whether or not the beetle has hairs between its tarsal claws. We have to go to our maximum magnification to look at certain morphological features and so for the collembola (which are much smaller than the beetles) we are considering using electron microscopy.

Along with the beetles and springtails we also have plenty of yet to be identified millipedes, gnats, flies, crickets, and other invertebrates.  So, the rest of the our research summer is going to be busy.

Ion Acoustic Waves and Double Layer studies in a Double Plasma Device

This summer we’ve been busy working on the 4th state of matter, plasma.  While plasma isn’t on the forefront of most brains, plasma is the most common state of matter in the universe, photo on the left. Crab-nebula-combined-300x300.jpg Our sun is entirely made of plasma. By studying how plasma behaves we can understand more about our very own sun. The exact mechanism for solar flares is currently being investigated and theorized by studying plasma.  One possible mechanism that is believed to accelerate solar flares is the double layer. The double layer is a phenomenon in plasma that causes ions to accelerate, but first let’s understand what plasma is before we go into the double layer.

Plasma can be understood as “hot” or high energy gas.  This gas is ionized, which is what gives the plasma its unique glow.  This mixture of electrons, and ions make up the plasma.  These charged particles arrange themselves that it becomes quasi-neutral overall, except with the double layer.  The double layer is an area of the plasma where this quasi-neutrality is violated. In this area we get two sheets of charge, one positive and one negative.  This creates an electric field between the two sheets. This electric field is the force that accelerates the ions.

Acceleration of ions has been suspected to be responsible for creating the auroras in the northern and southern hemisphere.  The acceleration ionizes gas particles in the air causing them to glow in the sky. The various colors come from the various types of gases that exist in our atmosphere.download.jpg

Our research is part of a larger research group that is investigating how the double layer and ion acceleration can be used as a method of jet propulsion in space.  These engines would behave exactly as a normal jet engine. The Engine propels material backwards and that propels the ship forward. Except instead of just normal gas it’s plasma.

.In our plasma chamber, Pickett’s Charge Plasma Device (PCPD), we haven’t yet observed the double layer.  But we continue to test various parameters and explore other options in order to see the double layer.  The DL is characterized by a change in electric potential, measurable via our Langmuir probes.  Nonetheless the search continues and remains hopeful. 

The ion acoustic wave (IAW) is a type of longitudinal wave that propagate in plasma. The ion acoustic wave, is very similar to an acoustic or sound wave.  In the same techniques that you would use to identify the speed of a sound wave, the relative temperature and density of the gas, you can calculate the “ion sound speed”. However, while sound waves travel through a pressure wave, the IAW travels through a disturbance in the electric field that propagates the wave. Similar to the sound wave, the IAW also dampens over time. Besides its velocity, we are also interested in how the surrounding plasma might affect the wave as it travels.Untitled.png

Two different sources will cause the dampening we observe in the wave. Ion-neutral collision will cause a weak damping. What we expected to see is that the wave velocity decreases within an exponential curve. Another damping source is from “particle surfing”, called Landau damping. When the ion velocity is larger than wave velocity, the energy of ions’ will add to wave. So the wave amplitude would grow. In the same manner, when the ion velocity is smaller than the wave velocity, then the waves will lose energy to ions. Ions travel faster than the wave, therefore Landau damping is our main source that slows the wave down. Normally we only need to deal with the Landau damping in the interferometer method of wave analysis.

Now with 2 weeks left in our research we have successfully measured the Ion Acoustic Wave at multiple frequencies.  While signs and possible versions of the DL have been observed, a complete study on the double layer is still elusive.  Our sights now move to the laser in order to become LIF capable in order to add a whole new depth to our data.

From Neng and Rikard from Good’s Lab!Image-3 Have a great summer