Horoscope haters beware: a turtle’s birthday may decide more than we think

Illinois State University contributor

Featured Scientist: Haley M. Nichols, B.S. 2017, School of Biological Sciences, Illinois State University

A selfie of Haley Nichols in her home.

Birthplace: Okinawa, Japan 

My Research: I studied the role of nesting season and maternal investment on the behavior of juvenile freshwater turtles. 

Research Goals: In the future, I would like to study how maternal nutrition or nesting conditions affect animal development and behavior. 

Career Goals: I would like to work in managing invasive reptile species, particularly in sensitive areas such as the Florida wetlands. 

Hobbies: I enjoy road trips with my fiancé and taking care of our cold-blooded pets and house plants! 

Favorite Thing About Science: My favorite thing about science is learning new things to better understand the world we live in. I think it allows us to appreciate each moment a little more. 

Organism of Study: I work with the red-eared slider turtle (Trachemys scripta). 

A picture of a T. scripta hatchling half emerged from its shell. The head, left leg, and part of the carapace are visible. The eggshell appears torn and there is a number written on the top of the egg in pencil.
Image of T. scripta hatchling emerging from its shell. 

Field of Study: Animal Behavior & Physiology

What is Animal Behavior & Physiology? Animal behavior studies the way animals interact with themselves, others, and their environment. Their behavior can be affected by both internal and external conditions. Animal physiology studies the internal conditions like hormone regulation, temperature, or metabolic function. External conditions may be access to food and water or the presence of predators. Basically, we look at WHAT animals do and WHY they may be doing it. 

Check Out My Original Paper: “Red-eared slider hatchlings (Trachemys scripta) show a seasonal shift in behavioral types” 

A QR code that links to the original publication.
QR Code to the original publication

Citation: H. Nichols, A.W. Carter, R.T. Paitz, R.M Bowden, Red-eared slider hatchlings (Trachemys scripta) show a seasonal shift in behavioral types. J Exp. Zool. Part. A. 331.9: 485-493 (2019). 

Research at a Glance: Behavioral types can be thought of as an animal’s personality. They are patterns of behavior that repeat. The behavioral type that best supports survival may differ across environments, like seasons. We hypothesized that mothers could use their own behavior and physiology to help their hatchlings survive in the conditions that they are born in. That is, they can help them by making sure that the hatchling behavioral type matches the environment. To test this hypothesis, we measured righting response of juvenile red-eared slider turtles across the nesting season. The righting response is the ability of the turtle to turn itself over onto its abdomen (plastron) after it has been placed on its back (carapace). It is a signal for behavioral type, or “personality”. We studied turtles hatching from early and late season clutches to understand if their personalities change based on nesting season. We found that the nesting season has a significant effect on righting response, with early season hatchlings righting more quickly than late season hatchlings. 

To figure out why this happens, we explored two potential causes: maternal estrogen and maternal investment. From prior research, we know that eggs from late season clutches have more estrogen than eggs from early season clutches. To see if maternal estrogen was causing the difference in righting response, we coated early season eggs with an estrogen hormone to mimic the amount of estrogen found in late season eggs. We found that this did not affect hatchling behavior. To see if maternal investment was causing the difference in righting response, we looked to see if mothers were giving extra energy resources to her eggs when she lays them. We measured the mass of the egg, the hatchling mass, and the mass of the residual yolk on the hatchling’s body. We found that early season eggs have more yolk than late season eggs. We also found that early season hatchlings were larger; they used a higher percentage of their yolk to grow new tissue, rather than just keeping existing tissues healthy. Interestingly, in both seasons, hatchlings that had less yolk also used a higher percentage of the yolk to make tissue, but we found no direct relationship to righting response. Overall, our research shows that behavioral types vary across the nesting season, but it appears that neither maternal estrogen nor maternal investment directly leads to this change. 

Highlights: We we were able to show seasonal differences in the red-eared slider turtle (T. scripta) righting response between seasons, but were not able to determine its cause. We showed that early season turtles are given more yolk and use more of this yolk to grow tissues than late season turtles. We were able to determine the amount of yolk given to each hatchling by measuring the yolk from one egg of each clutch shortly after they were laid. After hatching, we measured the mass of each turtle and the mass of their remaining yolk. We then used statistical tests to look at the differences between these groups. 

Figure 1 shows the results of our righting response behavioral test. It shows that turtles that came from eggs laid late in the nesting season righted themselves more slowly than those laid early in the nesting season

A data figure that shows the time that it takes a hatchling to right itself, relative to the season in which it was born. It shows that turtles born in the early season took about 450 seconds to right themselves. It shows that turtles born in the late season took about 550 seconds to right themselves.
Figure 1. Hatchling righting response trial. The x-axis shows whether the turtle was laid in the early or late season. The y-axis shows the amount of time, in seconds, that it took for the hatchling to turn itself over. Adapted from Nichols et al. 2019. 

What My Science Looks Like: The photo below shows the arena that we used during the righting response trial. The turtles in the top left corner cell and center cell have completed the desired behavior: they were able to turn from the carapace (back) to the plastron (abdomen). Each turtle is given a unique number based on their egg and clutch. We took photos of the plastron of each individual to verify the identity of the hatchling. 

A picture of the righting response trial arena. It is an aerial view of a 3 by 3 grid of small cardboard boxes, each with an open top. Each box has a hatchling inside it. The top left and center box have turtles that are on their feet. All other boxes have turtles that are on their backs.
T. scripta in the trial arena. 

The Big Picture: My research is important because it helps us understand how animal behaviors and physical responses form. We used a species that is sensitive to the environment. Knowing how the environment shapes the body and behavior can help us predict how animals will respond to these changes. 

Decoding the Language: 

Behavioral types: A pattern of behavior in an animal. 

Carapace: The top part of a turtle’s shell. 

Clutch: A group of eggs that are laid together at the same time by a single female. 

Estrogen: One of the primary female hormones; previous studies show it increases in eggs over the nesting season, causing more females in later clutches (Carter et. al 2017, see below).

Maternal investment: The services a mother provides her young, such as, provision of food, care, and protection.

Nesting season: The time of the year eggs are laid. For my species there is an early nesting season (late May to mid-June) and a late nesting season (mid- June to late June). 

Residual yolk: The unused yolk remaining after turtle hatching. 

Righting response: The behavior of turning oneself over from carapace to plastron (the “right” position for walking etc.).

Plastron: The bottom part of a turtle’s shell.

Physiology: A branch of biology that studies how different parts of the body carry out chemical and physical functions.

Trachemys scripta (T. scripta): The scientific name for the red-eared slider turtle.

Yolk: The yellow-orange, nutrient-rich portion of the egg that supplies food to the developing embryo. 

Learn More: 

Physiology, Neuroscience, and Behavior sequence at ISU

Animal physiology:

Animal behavior

Information about the red-eared slider turtle

A.W. Carter, R.M. Bowden, R. T. Paitz, Seasonal shifts in sex ratios are mediated by maternal effects and fluctuating incubation temperatures. Funct. Ecol. 31: 876–884 (2017). 

Synopsis edited by: Rosario Marroquin-Flores (she/her/hers), PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University

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Infection outcomes not significantly affected by thermal variability in a bumble bee host-parasite system

Featured Scientist: Kerrigan B. Tobin, M.S. 2019, School of Biological Sciences, Illinois State University

A picture of Kerrigan Tobin on the slope of a rocky hill, with pine trees on either side. She has one foot planted on a small boulder, with her hands on her hips. She has a butterfly net in one hand.

Birthplace: Normal, IL

My Research: I study how climate change influences bumble bee immune function and survival. 

Research Goals: I want to continue to use a combination of laboratory and field techniques to address native pollinator conservation. I think it’s important to understand how human impacts on Earth may have an effect on the organisms around us. 

Career Goals: I’m currently a lab technician for the USDA, but eventually I’d like to be an Ecology professor, where I can teach and mentor students from various backgrounds about fascinating relationships in nature and how we can support biodiversity. 

Hobbies: Crafts, especially throwing pottery and crocheting. 

Favorite Thing About Science: It’s so satisfying to find evidence and support for a theory! 

Organism of Study: Bombus impatiens, the common Eastern Bumble Bee 

A up-close picture of the Eastern bumble bee. It is holding onto a grain of pollen.
The Eastern bumblebee, B. impatiens 

Field of Study: Ecology

What is Ecology? The study of how living organisms interact with each other and their surroundings. It’s an interesting field because we can study ecology at different scales. We can look at how a single organism interacts with its environment or study how complex networks of species interact in a community. 

Check Out My Original Paper: “Infection Outcomes are Robust to Thermal Variability in a Bumble Bee Host–Parasite System” 

A QR code that links to the original publication.
QR Code to original publication

Citation: K.B. Tobin, A.C. Calhoun, M.F. Hallahan, A. Martinez, B.M. Sadd, Infection Outcomes are Robust to Thermal Variability in a Bumble Bee Host–Parasite System. Integr. Comp. Biol. 59.4: 1103-1113 (2019). 

Research at a Glance: In this paper, we wanted to test whether changes in temperature make it more difficult for a bumble bee to fight off infections. Climate change is predicted to make temperatures more variable. These changes are likely to have an impact on many animals and how they interact with their environments. Living creatures have an optimum range of temperatures where their bodies perform the best. Outside of this range, their bodies cannot carry out important tasks. These ideas suggest that climate change might hurt animals because they will have to survive outside of the range of temperatures they are used to. Some scientists explain this using the “beneficial acclimation hypothesis” or BAH. This idea suggests that animals adjust to their environment, which gives them advantages for survival. For example, animals that live in the desert are particularly good at surviving in desert conditions. But, animals from the arctic are bad at surviving in the desert. On the same line of thought, we wanted to know if bumble bees were better at fighting off infections when they were living at the temperature that they were used to, their acclimation temperature. We wanted to see if bees living in a temperature outside their normal range were more likely to get parasites than bees kept at their normal temperature. To test this, we used the Common Eastern Bumble Bee as a host and a gut parasite that often infects bumble bees, Crithidia bombi

In our experiment, we used bees from four different colonies. Each bee was given one week to acclimate, or get used to, a specific temperature. They were acclimated to 21°C, to room temperature (between 25-26°C), or to 29°C. Next, we gave each bee one of two strains of the parasite, C. bombi. This parasite is commonly found in the gut of the bumble bee. We gave the bees the parasite by mixing C. bombi into sugar water that was fed to them. After parasite exposure, bees were then put in a performance temperature of 21°C, room temperature (between 25-26°C), or 29°C. This means that some bees went back to the temperature that they were acclimated to, but others were placed into a different, mismatched, temperature. At four and six days after parasite exposure, we checked to see if the bees were infected by collecting their feces and looking for parasite cells inside. Eight days after parasite exposure, we froze the bees and measured how intense the infection was. 

We found that the strain of C. bombi matters, because the two strains of parasites did not infect bees at the same rate. We also found that bees from different colonies had a different susceptibility to infection. This means that some bees are more likely to get an infection based on their colony of origin. Finally, we found that constant and mismatched temperatures did not impact whether the bees became infected or how intense an infection became. These results mean that we did not find support for the BAH. Overall, our results suggest that small changes in temperature are not changing the relationship between bumble bee hosts and their parasites. We also showed that some parasites are better at infecting hosts than others, and some colonies are more likely to get infected than others. More work must be done to really understand how climate change might impact bee health, but our study is a good first step. 

Highlights: The goal of this research was to test the BAH in the bumble bee host-parasite system. The BAH says that bees used to one condition, but given an infection with a parasite in different conditions, would have worse outcomes than bees that stayed in constant conditions. We tested this by keeping bees in constant temperatures or letting them get used to one temperature and then moving them to a new temperature. Then, bees that were kept at constant temperature and bees that experienced mismatched temperature were each given a dose of parasites. We screened the feces of each bee at 4 and 6 days after parasite exposure. We measured the intensity of the infection eight days after exposure to the parasite by performing qPCR on the gut of each bee. qPCR is a laboratory method that allows us to estimate the number of parasite cells contained in each bee. 

We compared temperature treatments and infection over time to analyze our results. Figure 1 shows the number of bees that had parasite cells in their feces 4 days after they were infected. On day 4, there was no difference between bees that were kept at constant or mismatched temperatures. 

Figure 1. Infected bees 4 days after C. bombi exposure. The x-axis shows the temperature treatment and the y-axis shows the proportion of bees that became infected. Adapted from Tobin et al. 2019. 

Figure 2 shows the number of bees that had parasite cells in their feces 6 days after they were infected. On day 6, more bees were infected, but there was still no difference between bees that were kept at constant temperature and those that experienced a mismatched temperature.

Figure 2. Infected bees 6 days after C. bombi exposure. The x-axis shows the temperature treatment and the y-axis shows the proportion of bees that became infected. Adapted from Tobin et al. 2019. 

Figure 3 shows the intensity of the infection 8 days after the bees were infected. There was no difference between bees that were kept at a constant temperature and those that experienced a mismatched temperature. 

Figure 3. Intensity of C. bombi infection 8 days after bees were exposed to the parasite. The x-axis shows the temperature treatment and the y-axis shows a measurement of infection intensity. The data was log-transformed to make it easier to interpret. Adapted from Tobin et al. 2019 

Taken together, Figure 1-3 show that temperature did not change whether or not a bee was infected with the parasite or how intense the infection was. This means that we did not find support for the BAH in the bumble bee host-parasite system within the range of temperatures that we tested. More research needs to be done to understand the impact of climate change on this and other systems. 

What My Science Looks Like: The methods that I used in my experiment are presented in Figure 4. The boxes on the left show the temperature that a bee experienced during the 7-day acclimation period. After this, the bees were exposed to one of two strains of the C. bombi parasite. After exposure, bees were either returned to their original temperature (long dashed black arrows, constant), or they were assigned to a different temperature (short dashed gray arrows, mismatched). The boxes on the right side of Figure 4 show the performance temperature. We quantified transmission 4 and 6 days after parasite exposure and we quantified the intensity of the C. bombi infection 8 days after parasite exposure. 

Figure 4. Breakdown of the methods used for the described experiments. Bees started in one temperature (left), were exposed to parasites (center), and were moved to a new temperature before being sampled (right). Adapted from Tobin et al. 2019.

The Big Picture: Human-driven climate change has many effects on earth, but its full range of impacts are not well understood. This research looked at how one part of climate change, thermal variability, will influence a specific host- parasite system. Although we didn’t find support for the hypothesis that we tested, other effects of climate change, like prolonged exposure to high temperature or heavy rainfall, may impact bumble bees and other pollinators. Humans need pollinators to help create the food that we consume, but we are not the only living things that rely on them. Many ecosystems need pollinator services to help plants thrive and produce the fruits that feed many other animals. Pollinator species are in decline and we cannot help them until we understand why it’s happening. Research like mine is important because it helps us to see why pollinators are disappearing. Our work will help to focus conservation efforts. 

Decoding the Language: 

Acclimation temperature: The temperature that an organism adjusts to over time. In the context of this experiment, this was the temperature that bees had 7 days to get used to before we introduced parasites and tested them. 

Beneficial acclimation hypothesis (BAH): The BAH is a hypothesis that suggests that animals that have lived in a particular environment for a long period of time have adapted to that environment. These animals are particularly suited to this environment and will survive better than animals that are from somewhere else. 

Bombus impatiens (B. impatiens): The scientific name for the common Eastern Bumble Bee. 

Climate change: A change in global or regional climate patterns, often seen as major changes in temperature or precipitation. 

Crithidia bombi (C. bombi): The scientific name for the gut parasite that was used to infect bees in this study. 

Constant: The bees that started in one temperature and were shifted to the same temperature later in the experiment experienced a constant temperature. 

Log-transformed: When data are in a format that is hard to analyze or show graphically, scientists can scale their data set by performing a mathematical operation, like a logarithm, to scale the data.  

Mismatched: The bees that started in one temperature, but were shifted to another temperature later in the experiment experienced a mismatched temperature. 

Native pollinator: “Pollinator” refers to any animal or insect that helps to carry pollen from flower to flower. A native pollinator is an animal that provides pollination services to flowers and is local to the area. For example, bumble bees are native pollinators because they naturally occur in the United States. The honey bee is not a native pollinator because these bees were imported into the country. 

Performance temperature: In the context of this experiment, the performance temperature was the temperature that the bee was experiencing when we tested for the effects of the parasite infection. 

Quantitative polymerase chain reaction(qPCR): qPCR is a lab technique where known quantities (or standards) of DNA are amplified at the same time as unknown DNA samples. It is used to estimate the DNA concentration in each unknown sample based on how much the unknown samples were amplified relative to the standards. 

Transmission: Transmission refers to whether or not the bee became infected with the parasite. 

Learn More: 

Pollinator Partnership

U.S. Department of Agriculture pollinator page, Logan, UT (This is where I work!)

Pollinator Conservation Resource Center

The Intergonvernmental Panl on Climate Change (IPCC)

Synopsis edited by: Elyse McCormick, M.S. (Anticipated Spring 2022) and Rosario Marroquin-Flores, PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University

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Turning up the heat: how turtle hatchlings respond to environmental temperature

Featured Scientist: Dr. Amanda Wilson Carter 

A picture of Amanda Wilson Carter at her field site. She is in a marsh wearing waders. She is next to a canoe, holding a turtle that was just removed from a trap.

Birthplace: New York City, NY 

My Research: I study how animals are affected by changes in their environment. 

Research Goals: I want to understand how changes in temperature affect animal physiology. I would like to be able to better predict how climate change will affect all types of animals. 

Career Goals: I am currently working towards increasing the participation of underrepresented groups in science. My goal is to become a biology professor and researcher. 

Hobbies: Traveling, playing with my dogs, and renovating my 1940’s bungalow. 

Favorite Thing About Science: I love having the freedom to explore questions that I think are necessary and important. Throughout my schooling and career, I have also discovered a passion for mentoring students through independent projects in the lab. There is something very special about watching an undergraduate conduct their first study and transform into a confident and capable young investigator. 

Organism of Study: I study many animals, but my PhD research focused on turtles, mainly the red-eared slider (Trachemys scripta). In my current position, I conduct research on dung beetles. 

A picture of a red-eared slider turtle on the ground. The turtle has a red band on the side of its head.
Red-eared slider turtle (T. scripta). Image source 

Field of Study: Eco-physiology | Climate Change | Plasticity | Development | Parental Effects.

What is Eco-physiology? I broadly consider myself an eco- physiologist. I study how the physiology and behavior of animals are affected by their environment (mainly temperature). 

Check Out My Original Paper: “Short heatwaves during fluctuating incubation regimes produce females under temperature-dependent sex determination with implications for sex ratios in nature” 

A QR code that links to the original publication.
QR Code to the original publication

Citation: A.W. Carter, B.M. Sadd, T.D. Tuberville, R.T. Paitz, R.M. Bowden, Short heatwaves during fluctuating incubation regimes produce females under temperature-dependent sex determination with implications for sex ratios in nature. Sci. Rep. 8.3: 1-13 (2018). 

Synopsis written by: Elyse McCormick, M.S. (Anticipated Spring 2022), School of Biological Sciences, Illinois State University.

Research at a Glance: Temperature is very important for many parts of biology. For baby turtles, it is essential. Many turtles become male or female based on incubation temperature. This process is called temperature-dependent sex determination, or TSD. Warmer incubation temperatures make females, while cooler incubation temperatures make males. Until now, TSD has been studied in lab settings where the incubation temperature is held constant. However, since temperature doesn’t stay constant in nature, this is pretty unrealistic. Amanda wanted to see what happens to sex ratios when turtles experience real, changing temperatures. She hypothesized that changes in temperature are very important to determining sex in turtles that have TSD. She predicted that turtles are very sensitive to short exposures to temperatures above the “pivotal temperature”, or the temperature that will produce a population-wide 50:50 sex ratio. She also predicted that ovaries will start to grow within a few days of exposure to these warmer temperatures. 

Amanda raised eggs using temperatures that went up and down with daily daytime and nighttime temperatures to mimic what a turtle would feel in nature. She then introduced eggs to short exposures of temperatures above the pivotal temperature to mimic heat waves. She was able to show that sex ratios can be changed by exposure to very short increases in temperature. Amanda used an Illinois population of the red-eared slider turtle, T. scripta, for her research. Under the conditions in this study, T. scripta only needed approximately 8 days of exposure to warmer temperatures to produce a 50:50 sex ratio. At 5 days under the same conditions, 16% of the turtle embryos became female. This shows that even short exposures to warm temperatures can make an embryo become female. Amanda’s research shows that using natural temperatures can lead to a more accurate prediction of turtle sex ratios in nature. Her research also sheds light on another mystery. In Illinois, average temperatures are often so low that female turtles would be unlikely to be born. But somehow, females are still found in the population. Her research shows how female turtles end up in the Illinois population: turtle embryos only need a few days incubating under warmer temperatures to become female. 

Amanda also wanted to see if embryos had the same response to temperature changes across the nesting season. She looked at differences between early and late season embryos to see how long it took under warmer temperatures to make female turtles. Late season embryos required less time at warmer temperatures to produce a 50:50 sex ratio than early season embryos. Mother turtles increase a hormone called estrogen in the yolks of their eggs across the nesting season, which leads to more females later in the season. Thus, late season clutches probably have a ‘head start’ on other embryos because they have more female hormones in their yolk. As a result, eggs don’t need as much time in warmer temperatures to make females. Amanda used the results from her experiments to then develop a mathematical model to better predict sex ratios using natural temperatures measured from the field. This model helps predict the number of male and female turtles based on real field temperatures. 

Highlights: We just learned that females can be made after just a few days at warmer, female-producing temperatures. This finding helps us understand how sex is determined under more natural, changing temperatures. This finding is important because we can now more accurately determine sex ratios in turtle populations using available temperature datasets, like those available through the National Oceanic and Atmospheric Association (NOAA). We are currently experiencing changing global temperatures, where turtle embryos are more likely to experience warm incubation conditions. Being able to predict sex ratios in turtles is important for their conservation. We might be able to accurately identify turtle species or populations that are most at risk of 100% female populations, which would be unable to make more offspring. We can use that information to direct conservation efforts and resources. 

What My Science Looks Like: Figure 1 from this paper is a great example of how different field temperatures can be. Figure 1 reports temperature (y-axis) over the course of the summer nesting season (x-axis) for Illinois turtles. The solid horizontal line shows the pivotal temperature (Tpiv). It shows that, on average, temperatures have not been warm enough to produce females in this population for 23 years. But when you break it down by year, there are bursts temperature warm enough to make females (see 1993 and 2012). In nature, temperature is not constant. Instead, it fluctuates. Amanda had to find a way to test what happens to turtle embryos in their natural environment. She needed temperature data from her study area to show that natural temperatures fluctuate around the Tpiv

Figure 1. Average soil temperatures from Peoria, IL. 
Figure adapted from Carter et al. 2018. 

The Big Picture: Amanda’s research took a more realistic look at TSD. It allowed her to create a mathematical model to predict realistic sex ratios for hatchling turtles. These types of studies allow scientists to better understand what’s happening in nature. Knowledge about how turtles live in the wild is important for more than just improving our understanding of turtle biology. They allow us to understand the wide-reaching effects of environmental impacts, such as climate change, on animals that are extremely sensitive to changes in temperature. Climate change could impact the sex ratios of hatchling turtles in ways we don’t fully understand yet. But this study allows us to start to understand it. Amanda’s model can be used to predict how climate change might affect future generations of turtles. It’s possible that her model can help us understand how climate change will affect turtles, as well as the animals and plants that they interact with. If we can understand how climate change might impact a broad array of plants and animals, we may be able to help lessen its effect on our environment. 

Decoding the Language: 

Climate change: A change in global or regional climate patterns, often seen as major changes in temperature or precipitation. 

Clutch: A group of eggs that are laid together at the same time by a single female.

Embryo: An unborn or unhatched offspring that is actively growing. In the context of Amanda’s research, the embryo is the developing turtle inside the egg. 

Estrogen: A steroid hormone that promotes the development and maintenance of female characteristics in the body. 

Female/Male-producing temperatures: Female-producing temperatures are higher/warmer temperatures that cause red-eared slider turtles to become female. Male-producing temperatures are lower/colder and cause these turtles to become male. 

Incubation: The process of keeping an egg warm enough to develop until hatching. In the context of Amanda’s research, a male-producing incubation temperature is approximately 26°C and a female-producing temperature is approximately 31°C. 

National Oceanic and Atmospheric Association (NOAA): A scientific agency within the United States Department of Commence that focuses on oceans, major waterways, and the atmosphere. 

Nesting season: The duration of time that animals are actively laying eggs. In the context of Amanda’s research, the nesting season lasts from late May to early July.

Temperature-Dependent Sex Determination (TSD): A form of sex determination where the incubation temperature determines whether the developing embryo will become male or female. 

Pivotal temperature (Tpiv): The temperature that produces a population-wide 50:50 sex ratio.

Physiology: A branch of biology that studies how different parts of the body carry out chemical and physical functions. 

Sex ratios: The amount of males compared to the amount of females, or vice versa. 

Trachemys scripta (T. scripta): The scientific name for the red-eared slider turtle.

Yolk: The yellow-orange, nutrient-rich portion of the egg that supplies food to the developing embryo. 

Learn More: 

Illinois Turtles Fact Sheets (Illinois DNR)

NASA’s climate model site

Synopsis edited by: Rosario Marroquin-Flores, PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University

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Making tiny gold particles to speed up chemical reactions

Featured Scientist: Pascal Nnaemeka Eyimegwu, M.S. 2019, Department of Chemistry , Illinois State University

A picture of Pascal Nnaemeka Eyimegwu in a research laboratory. He is wearing a blue lab coat and safely goggles.

Birthplace: Nkalagu, Nigeria

My Research: I study how to make reactions go faster using nanoparticles.

Research Goals: I would like to continue to study nanoparticles (tiny materials) and how they might be used to speed up chemical reactions. This research would help scientists make medicine more efficiently. 

Career Goals: I want to be a Professor of Chemistry. 

Hobbies: I like to travel and play soccer. 

Favorite Thing About Science: Science is interesting because we can use it to interpret everything around us. It provides solutions to our problems. It’s no wonder that we say “all in nature is chemistry”. 

Organism of Study: Gold nanoparticles 

A series of small dots. To the right is a chemical reaction where phenylboronic acid is converted to biphenyl.
Microscopic image of gold nanoparticles (left) and the chemical reaction that I used them for (right) 

Field of Study: Analytical Chemistry

What is Analytical Chemistry? Analytical Chemistry focuses on identifying and quantifying chemicals. For example, analytical chemists are responsible for making sure that your food and water are safe to eat and drink. Analytical Chemistry has been used to develop tools that can check if drivers are under the influence of alcohol, or to tell the difference between illegal drugs and medicines. In addition, this form of chemistry is used to check the quality of food and drugs to make sure that they are safe. 

Check Out My Original Paper: “Atypical catalytic function of embedded gold nanoparticles by controlling structural features of polymer particle in alcohol-rich solvents” 

QR code to the original publication
QR Code to original publication

Citation: P. N. Eyimegwu, J.H. Kim, Atypical catalytic function of embedded gold nanoparticles by controlling structural features of polymer particle in alcohol-rich solvents. J. Nanotechnol. 30.28 (2019). 

Research at a Glance: The goal of this study was to make stable catalysts that can speed up the chemical reactions used to make starting materials in pharmaceutical industries. A catalyst is a substance that makes a reaction go faster. The type of catalyst that I work with can be recycled multiple times without losing its efficiency, unlike the most common type, which can only be used once. In this research, gold nanoparticles are used as the catalysts. However, these nanoparticles attract each other and need to be stabilized to be used effectively. In my study, I stabilize gold nanoparticles using a specialized polymer, an organic compound used in making plastics. The catalyst that I made was highly stable, reactive, and produced no undesired by-products. The catalysts that I designed in my study can be used to produce important starting materials to organic compounds that are often used in pharmaceutical industries. 

Highlights: The catalyst (gold nanoparticles in a polymer) that I made can be used to produce biphenyl, which is a useful starting material for making many organic compounds. I tried to use many different solvents to make biphenyl. The turning point of my research was in the decision to change the solvent for my catalytic reaction. The first solvent that I tried to use was water, but it resulted in poor yields of my target product, biphenyl. Ethanol was able to solve this problem. 

A. Many gold orbs are contained in a circle. The temperature is below 32 degrees Celsius. An arrow points to a catalyst in ethanol above 32 degrees Celsius (B). In this instance, the circle looks similar to the circle of origin. Another arrow points from A to a catalyst in water above 32 degrees Celsius (C). In this instance, the circle is smaller, and the gold orbs are more compact.

The gold nanoparticles are used as the catalyst. The image on the left (a) shows the structure of the catalyst in water below 32°C. The images on the right show the catalyst in ethanol (b) and in water (c) above 32°C. As you can see, the catalyst in water looks smaller but remains swollen and slightly bigger in ethanol. 

Why was ethanol the trick? Unlike water, ethanol tends to remove the organic compounds that prevent the catalyst from performing well. Additionally, I used a polymer in my reaction. The polymer swells more when it is in ethanol than when it is in water, which guarantees more movement of reactants and products in and out of the polymer. The reaction with water creates a by-product, but when I used the ethanol, the by-product was no longer produced. Finally, I found out that the yield is highest when I used ethanol (Figure 1). This is because ethanol can remove things from the catalyst that hinder the reaction. 

A data figure that shows the amount of biphenyl produced when various solvents are used. Pascal used water, methanol, ethanol, propanol, butanol, and t-Butanol as solvents. The percent yield was highest when he used ethanol (~100%) and lowest when he used t-Butanol (~25%). The yield of biphenyl was ~30% when he used water.

Figure 1. Production of biphenyl using phenylboronic acid as the starting material. The x-axis shows the solvents that I used in the catalytic reaction.The y-axis shows how much biphenyl was made. The orange bars represent the amount of biphenyl that was produced after a reaction in each individual solvent. Adapted from Eyimegwu et al. 2019. 

Next, I wanted to make sure that my catalyst was stable. To do this, I needed to run a test to make sure that my catalyst was recyclable. Being recyclable means that the same catalyst can be used to speed up different batches of reactions without losing its strength. The first, second, and third cycle gave the same yield, but the yield went down on the fourth cycle and went down further on the fifth cycle. I was able to bring it up again after purifying it in water and putting it back into ethanol for the 6th cycle (Figure 2). 

A data figure that shows the percent yield of biphenyl after being used in multiple reactions. The yield stayed near 95% after 3 reactions but dropped down to about 65% on the 5th reaction. Pascal was able to bring the yield back up to 95% after the 6th reaction.
Figure 2. Testing catalyst stability. The x-axis shows how many times the same catalyst was used in different reactions. The catalyst was used for six different reactions. The y-axis shows how much product was made in each cycle. Adapted from Eyimegwu et al. 2019. 

As you can see in Figure 2, the catalyst produced just as much biphenyl after the 6th reaction as it did in the 1st reaction. This means that my catalyst should not be thrown away after one reaction because it will still be useful in another one. 

What My Science Looks Like: The image below has two solutions. The one on the left (A) shows gold nanoparticles stabilized by a polymer, so that they don’t clump together. The one on the right (B) shows the gold nanoparticles by themselves. These are the types of solutions that I work with in my research. 

An image that shows two beakers. The one on the left contains a purple solution that is cloudy and opaque. The solution on the left is the gold nanoparticle in polymer. The one on the right shows a purple solution that is more transparent, almost clear. This one only contains gold nanoparticles by themselves.
On the left (A), gold nanoparticles are inside of the polymer. On the right (B), the gold nanoparticles are by themselves. Nanoparticles are clear. This is because they are more unstable and there was no polymer to prevent other reactions. 

The next image shows the steps that I used to carry out the chemical reaction for my experiment. The goal was to make my target product, biphenyl

The steps necessary to make the catalyst. It starts with a polymer without gold (opaque white solution), then a chemical compound that contains gold is added to the solution (HAuCl4) to create a polymer with gold (a yellow opaque solution). Then, sodium citrate is added to the solution to create the purple opaque solution from the previous figure. This is the solution that goes into the reaction to create biphenyl.
These are the steps that are necessary to use gold nanoparticles to speed up chemical reactions. The first step is the mixing of the polymer and gold solution. The second step is the reduction of gold solution to gold particles. The third step is to use the gold particle to make biphenyl

The Big Picture: Gold nanoparticles are safe and inexpensive. People are working hard to use them to make chemical reactions happen more quickly. My research introduces interesting properties of these nanoparticles: they change their catalytic activity when they are put in a polymer and are introduced to ethanol. The products of these reactions can be used to make medicines. 

Decoding the Language: 

Biphenyl: A useful starting material for making many organic compounds used by pharmaceutical companies. 

Catalyst: Materials that make reactions go faster 

Gold solution: The first state of gold, before it is reduced to form particles. 

Nanoparticles: Particles between the range of 1-100 nm in size. 

Organic compounds: A chemical compound is made up of two or more elements. For example, table salt (NaCl) is a chemical compound because it is made up of both sodium (Na) and chlorine (Cl). An organic compound is any chemical compound that contains carbon. For example, sugar (C6H12O6) is an organic compound. It is made up of carbon (C), hydrogen (H), and oxygen (O). 

Phenylboronic acid: A chemical and the starting material that I used to make biphenyl. 

Polymer: An organic compound used in making plastics and nylon. In my research, I used it to stabilize gold nanoparticles so that the gold nanoparticles would not clump together.

Reactants: The materials that come together to produce another material.

Recyclable catalyst: A catalyst that can be used more than once. 

Reduction: A way of making gold solution to become particle. 

Solvent: A liquid that is used to carry out a reaction or to dissolve a solid material. Water is an example of a solvent. 

Products: The result of a reaction, what we are trying to make. 

Learn More: 

Catalysis

Another research paper on catalysis: P.N. Eyimegwu, J.A. Lartey, J.H. Kim, GoldNanoparticle-Embedded Poly (N-isopropylacrylamide) Microparticles for Selective Quasi-Homogeneous Catalytic Homocoupling Reactions. ACS Appl. Nano Mater. 2.9: 6057-6066 (2019) . 

Synopsis written by: Rosario Marroquin-Flores, PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University

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Hormones and embryos: Understanding steroid metabolism in European starling eggs

Featured Scientist: Nicole A. Campbell, M.S. 2019, School of Biological Sciences, Illinois State University 

A picture of Nicole Campbell at the aquarium Touch Pool. She has her hand in the water and there is a stingray beneath her hand. She is looking up and smiling at the camera.

Birthplace: Joliet, IL 

My Research: I am fascinated by the process of embryonic development. As an embryo develops, it is critical that the correct hormones are expressed at the right times to ensure that the embryo is healthy. My work focuses on embryos of the European starling, but my research can also help us to understand human systems. People used to think that hormones directly affect an embryo as it grows and develops, but this idea is at odds with what we know about how these hormones are broken down in the body. As an embryo grows, hormones are quickly processed through metabolism. With the help of my adviser Dr. Paitz, I examined a different idea: that the effects of hormones are driven by their metabolites

Research Goals: I hope to continue research in the future by working with animal breeding programs to help endangered species. 

Career Goals: I want to have a career where I can apply science to help breed and restore endangered animal species. I am hopeful that this work will help me transition to a career where I get to work directly with endangered species, like the red panda. 

Hobbies: I love crafting cute projects that I find on Pinterest and managing my dog’s Instagram page. 

Favorite Thing About Science: My favorite thing about science is being able to visually see things, like embryos, while they are developing. I get to see natural processes in person. It’s pretty amazing how something so small can contain all of the information about how an animal develops.

Organism of Study: European starling 

A picture of a bird on a tree branch.
Adult European starling 
A picture of an egg being “candled”. The scientist shines a light under the egg to see where the embryo is. The embryo is a small red dot on the top left corner of the yolk.
European starling egg/ embryo 

Field of Study: Comparative Endocrinology

What is Comparative Endocrinology? Comparative Endocrinology is the study of hormones and their effects on various aspects of development in animals. My research uses animal models to test the effects of different hormones, which can inform us about their roles in the human body. 

Check Out My Original Paper: “Characterizing the timing of yolk testosterone metabolism and the effects of etiocholanolone on development in avian eggs” 

QR code to the original publication
QR code to the original publication

Citation: N.A. Campbell, R.A. Angles, R.M. Bowden, J.M Casto, R.T. Paitz, Characterizing the timing of yolk testosterone metabolism and the effects of etiocholanolone on development in avian eggs. J. Exp. Biol. 223.4: (2020)

Research at a Glance: When birds lay eggs, the yolk contains both hormones and nutrients for the developing embryo. In this paper, I investigated how starlings break down hormones in the egg. I also studied important metabolites of this breakdown and conducted tests to see if the metabolites affected embryonic growth. 

It’s important to know how long specific hormones remain in an embryo. If we know how long a hormone is present, then we can determine whether or not it will influence the embryo. In this study, we looked at the hormone testosterone, to see how quickly it breaks down during early development in starling embryos. Surprisingly, we found that most of the testosterone is broken down within just a few hours. This result raised another question: how does testosterone affect the embryo if it is broken down so rapidly? 

We guessed that testosterone may affect the embryo’s secondary metabolites. Secondary metabolites are the products that are made when hormones are broken down. Our work showed that these metabolites stick around inside the egg yolk much longer than testosterone. We set out to see if these metabolites affect the growth of the embryo. We injected extra amounts of a secondary metabolite, etiocholanolone, into the eggs. Our results did not show that extra etiocholanolone affected embryonic development. One explanation for our results is that there was already etiocholanolone present in the eggs. 

Highlights: I think the most important step for my research is the study that we did on in ovo testosterone metabolism. We performed this experiment over the course of two laying seasons. In the first season, we gathered 38 freshly laid starling eggs from our study site and took eggs from 36 different clutches. We purchased a radiolabeled form of testosterone that would allow us to keep track of testosterone levels as the embryos grew. We injected each egg with testosterone mixed with sesame oil. The oil was used to keep the injection of the radiolabeled testosterone in one spot near the embryo. We did this so that the testosterone could diffuse from that central area into the embryo. Then, each egg was allowed to grow for different lengths of time in an incubator. The period of time that the eggs were allowed to grow was assigned randomly. 

Next, we wanted to see what happened to the testosterone. We removed the eggs from the incubator, froze them, and separated the egg into two parts: the yolk and albumen. We weighed each part, then separated out the hormones. We were able to isolate the hormones using two techniques: solid phase extraction and column chromatography. Finally, we put the samples through a scintillation counter. The scintillation counter helped us test which metabolites had our radiolabel on them. By figuring out which metabolites had our radiolabel, we could tell how much of the testosterone we injected had broken down. 

When we repeated this experiment in the second season, we used more testosterone for our injections and shortened the length of time that eggs were allowed to grow. 

We sampled embryos within a 12-hour window. We also mixed the yolk with the albumen when we sampled and used a yolk/albumen mix to extract hormones. Our results show that after incubation starts, the testosterone in the egg breaks down quickly. This means that testosterone probably does not directly affect how the embryos develop. Instead, we think that the testosterone metabolites are responsible. 

What My Science Looks Like: Figures 1-3 show the results of my experiment from the second season, where we added testosterone to the eggs and tracked how testosterone was broken down over the course of 12 hours. Each figure shows the average radioactivity on the y-axis. This tells us how much of the testosterone or metabolite is found in the yolk/ albumen mixture. 

We looked at testosterone and two of its metabolites, androstenedione and etiocholanolone. In Figure 1, we see that the amount of testosterone in the eggs is rapidly dropping over time. 

A data figure that shows the amount of radiolabeled testosterone over time. The x-axis shows Incubation Time (hours). The y-axis shows Radioactivity (CPM/g). The figure shows that testosterone is significantly higher at zero hours (it falls between 100,000 and 120,000 CPM/g) than at 12 hours (it falls between 40,000 and 60,000 CPM/g).
Figure 1. The amount of testosterone in the embryo 
after 12 hours of incubation. Figure adapted from Campbell et al. 2020. 

In Figure 2 and Figure 3, both androstenedione and etiocholanolone start to increase after only 4 hours of incubation. The fact that they both show up so early indicates that testosterone is being broken down quickly once the egg is incubated. 

A data figure that shows the amount of radiolabeled androstenedione over time. Axes are the same as in Figure 1. The figure shows that radiolabeled androstenedione is low at zero hours (just over zero CPM/g) and significantly increases after four hours of incubation (20,000 CPM/g). The amount of androstenedione stays relatively constant after 4 hours of incubation.

Figure 2. The amount of androstenedione, a testosterone metabolite, in the embryo after 12 hours of incubation. Figure adapted from Campbell et al. 2020. 
A data figure that shows the amount of radiolabeled etiocholanolone over time. Axes are the same as in Figure 1. The figure shows that radiolabeled etiocholanolone is low at zero hours (25,000 CPM/g) and significantly increases after four hours of incubation (45,000 CPM/g). Similar to the other metabolite, the amount of etiocholanolone stays relatively constant after 4 hours of incubation.

Figure 3. The amount of etiocholanolone, a testosterone metabolite, in the embryo after 12 hours of incubation. Figure adapted from Campbell et al. 2020. 

The Big Picture: We show that testosterone metabolites are present near the embryo before many key processes begin. We put forth the idea that testosterone itself may not be a major driver of developmental effects. Instead, testosterone metabolites may cause these effects. This type of research is important because it can tell us what may happen if normal hormone levels in early development are disturbed. 

Decoding the Language: 

Albumen: The white part of the egg that is water-soluble and that contains proteins.

Androstenedione: A hormone and metabolite of testosterone.

Clutch: A group of eggs that are laid at one time.

Column chromatography: A method used to isolate a single chemical compound from a mixture of compounds. Each compound moves through the column at different rates and this allows them to be separated. 

Diffuse: To permit or cause to spread freely. In the context of this study, we wanted testosterone that was placed inside the egg to diffuse into a growing embryo.

Embryo: An unborn or unhatched offspring that is actively growing. In the context of this research, the embryo is the developing starling inside the egg. 

Embryonic development: The process that takes place as an embryo grows and develops into an organism.

Etiocholanolone: A metabolite of testosterone.

Hormones: The signaling molecules that regulate the body and keep it in balance. These are produced by different glands within the body and are transported by the blood to target organs. 

Incubation: The process of keeping an egg warm enough to develop until hatching.

Metabolites: The products of metabolism, or breakdown.

Radiolabel: A way to tag a substance or compound with a radioactive tag. 

Scintillation counter: A machine that detects and measures the amount of radioactivity in a sample. It uses light pulses created by excited electrons or ions. 

Solid phase extraction: A technique where compounds are suspended in a liquid mixture and are separated from other compounds in the mixture based on their physical and chemical properties. 

Testosterone: A hormone that is important in the development of male secondary sex characteristics, but is also important in other body processes of both males and females. 

Yolk: The yellow-orange, nutrient-rich portion of the egg that supplies food to the developing embryo. 

Learn More: Below are some research papers for further reading. 

C. Carere, J. Balthazart, Sexual versus individual differentiation: the controversial role of avian maternal hormones. Trends Endo. Metab., 18.2: 73–80 (2007). 

N. Kumar, A. van Dam, H. Permentier, M. van Faassen, I. Kema, M. Gahr, T. G.G. Groothuis, Avian yolk androgens are metabolized instead of taken up by the embryo during the first days of incubation. J. Exper. Biol. 222.7 (2019). 

R.T. Paitz, R.M.Bowden, J.M. Casto, Embryonic modulation of maternal Steroids in European starlings (Sturnus vulgaris). Proc. R. Soc. B Biol. Sci. 278.1702: 99–106 (2011). 

Synopsis edited by: Kate Evans, PhD (Anticipated Spring 2025) and Rosario Marroquin- Flores, PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University. 

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Who were the people of Spracklen? Studying Native American community through their tools

Illinois State University contributor

Featured Scientist: Tyler R. E. Heneghan, M.S. 2018, Department of Sociology and Anthropology, Illinois State University

A picture of Tyler Heneghan is in front of a table, setting stone piece onto trays.
Tyler fills the Midwest Archaeological Lab with the Spracklen collection, sorting and separating the lithics by material type. 

Birthplace: Shelbyville, IN 

My Research: I study tools made of stone to understand prehistoric Native American communities. The tools I study come from a place called Spracklen, an archaeological site located in Ohio. 

Research Goals: I use a technique called use-wear analysis to better understand what the Ohio Hopewell peoples did in the uplands, and show archaeologists that more information can be gleaned from current collections, without the need to excavate more. 

Career Goals: I am currently a student at Boston University School of Law studying international cultural heritage law. Cultural heritage law involves protecting, regulating, and repatriating cultural items, including the return of historic real property, ancient and historic materials, artwork, and intangible cultural heritage. The Native American Graves Protection and Repatriation Act is one federal legislation regulating museums’ and federal agencies’ collections. 

I hope to aid in the return of cultural heritage around the world and bring it back to the people and communities to whom it belongs. This summer, I will intern with the environmental nonprofit law firm, Earthjustice: Tribal Partnerships. This law firm provides legal aid to Tribes, such as the Standing Rock Sioux, in their fight against the Dakota Access Pipeline. Upon graduation, I hope to use my legal degree, coupled with my M.S. in Anthropology from ISU, to continue in this field and better protect the past for the stakeholders of today and tomorrow. 

Hobbies: Flintknapping (creating stone tools), vexillology (study of flags), scuba diving, and board games. 

Favorite Thing About Science: I love the fluidity of science and how we will never run out of things to learn and improve upon. 

Organism of Study: Stone tools 

A series of 6 small stones, carved into different shapes.
Sample of bladelets recovered from Spracklen. 

Field of Study: Prehistoric Archaeology 

What is Prehistoric Archaeology? Prehistoric archaeology is the study of human culture through the analysis of the things that people leave behind. These may be structural items, plant, animal, lithic, or ceramic remains. 

A magnified image of different stones, focusing on the grooves and points of the tools.
These are examples of use-wear traces from the stone remnants found at Spracklen. We look at the grooves of the stone to figure out what it was used for. Evidence of scraping can be found at the edge of the stone. Repeated scraping leads to striations that are perpendicular to the blade edge, but cutting leaves more generic striations. Evidence of use for softer materials (i.e. hide and meat) can be found further back on the stone. Evidence of harder contact materials can be found on the edge of the stone. 
A) Meat cutting (magnified 50x) ; B) Bone cutting/incising (magnified 200x) ; C) Dry hide scraping (magnified 200x) ; D) Dry hide cutting (magnified 200x) ; E) Fresh hide scraping (magnified 200x) ; F) General/Unknown (magnified 50x) 

Check out my original paper: “Spracklen (33GR1585): New Insights into Short-Term Middle Woodland Sites in the Uplands”

QR Code for original publication
QR Code for original publication

Citation: G.L. Miller, T.R. Heneghan, Spracklen (33GR1585): New Insights into Short-Term Middle Woodland Sites in the Uplands, J. Ohio Archaeology. 5: 1-15 (2018). 

Research at a Glance: This paper is a summary of my recent fieldwork and analysis at Spracklen (33GR1585), a small upland site in Greene County, Southwest Ohio. Most of my analysis of prehistoric Ohio focuses on large Hopewell earthworks. Earthworks are man-made or otherwise artificial soil deposits that result from the humans that inhabit the area. Examples of these such earthworks are the Fort Ancient Earthworks, Mound City, and Seip Earthworks. The regions that surround these earthworks are called uplands and they remain understudied. Because of this, the whole picture of Hopewell peoples is incomplete. 

At my field site, Spraklen, we found artifacts and structural features that showed us that the site was occupied for short periods of time, mainly during the Middle Woodland Hopewell period (100 BCE to 500 CE). During this time, the Hopewell peoples used stones to create tools. Bladeletes are the sharpened tools they used for cutting. Bladelet cores are the stones that were used to create these tools. As the bladelets are carved from their cores, small pieces remain. These are referred to as chert debitage. Spracklen contains dozens of bladelets, bladelet cores, and non-local chert debitage, consistent with other Middle Woodland Hopewell sites. 

Highlights: The major portion of my master’s thesis focuses on the use-wear of the completed stone tools at Spracklen. However, my publication focuses on the stone remnants, or by-products, that were found at my archaeology site. This is called lithic debitage. My job was to find the source for all of the lithic debitage I gathered at the site by comparing it to remnants from other known locations. Upwards of seventy percent of the 3,679 lithic debitage pieces I found were from Indiana Hornstone (a.k.a. Harrison County). Indiana Hornstone and Spracklen are not neighboring sites, so these tools must have been carried from one site to the other. I am continuously fascinated by how tools can reconnect prehistoric trade networks and voyages.

Another contribution I made to the article involved identifying lithic debitage, or “flake,” size and shape. Previous research had identified signs of initial tool making. However, my advisor Dr. Miller and I found what we believe are by-products of tool resharpening. At the Spracklen site, we found thin flakes that were short and/or narrow in size. We compared the median thickness to the median relative thickness of these flakes to classify them into one of four categories: unitensive core reduction, intensive core reduction, tool resharpening, and tool manufacture (Figure 1). Unintensive and intensive bladelet core reduction is the process of shaping chert into small pieces. Once those pieces are small enough for transportation, they are turned into finished tools by the tool manufacturing process. 

A data figure that shows the relative size of stone flakes and their location of origin. A group of flakes are of similar size and are classified as being used for Tool Resharpening. Flakes of this size come from Flint Ridge, Upper Mercer, Harrison County, and Unknown locations. Essentially, this figure shows that flakes found in Spraklen were largely used for Tool Resharpening and are from multiple different areas.
Figure 1. Debitage shape analysis from Spracklen. For each individual flake, I recorded median thickness and a relative median thickness. I plotted these two values against each other. The size of each individual flake is denoted by an X on the chart. Flakes of different sizes were grouped together based on their predicted use (colored ovals) and the color of the X signifies the original location of the flake. As you can see, the majority of the X’s fall in the tool resharpening region, supporting the idea that Spracklen was a short-term settlement. This chart shows that tool resharpening was the primary process of stone reduction at Spracklen. 

The flakes found at Spracklen indicate that the tools were mostly resharpened at this site. Spracklen was a short-term campsite and tools had to be durable for a successful trip to the uplands. Thus, tool resharpening allowed the Spracklen people to spend more time at the site before locating materials to make more tools. Since we found non-local stone remnants, or cherts, we can say that the general tool strategy for the Hopewell peoples was tool resharpening. This also supports that Spracklen was a short term site. 

What my Science looks like: To the right are magnified images of use-wear analysis traces. 

A picture of a single stone tool. Four edges around the stone are magnified to look at the patterns on its edges.
Use-wear traces indicating lithic use. The top two images show fresh hide scraping use-wear (100x). We can tell because of the perpendicular striations from the snapped bottom edge. The bottom two images show meat butchering use-wear traces (100x) we can tell by the polish developing further back from the blade edge. This polish pattern would develop as bladelets penetrate the meat. 

The Big Picture: Many archaeological sites consist of lithic and/or ceramic remnants. Without structural remains, these tools and ceramics are the best way to understand past life. I predominantly study the polish and striations on stone tools. I study this using a microscopic analysis called use-wear analysis. Use-wear analysis provides key insights into past life and allows for a better understanding of what people were doing at a point in time. Additionally, it is neither intrusive nor destructive to the tool. 

Decoding the Language: 

Bladelets: A stone tool used for many purposes and synonymous with the Ohio Hopewell peoples (think a prehistoric Swiss Army knife).

Bladelet cores: A stone used to create bladelets. 

Debitage/flakes: The by-products of stone tool production. 

Earthworks: Large man-made deposits of soil that indicate the presence of prehistoric human inhabitants.

Lithics: Stone remnants found at an archaeology site.

Non-Local Chert: Chert is a fine-grained sedimentary rock. This was a universally preferred material for making stone tools. In the context of this paper, non-local chert is chert that was transported to the site via trade or travel (i.e. chert originating from Indiana found in Southern Ohio). 

Striations: Lines that indicate the direction that the tool was used. These are created by repeated motions from using the tool, such as cutting or scraping. This use creates diagnostic lines. For example, lines going perpendicular to the edge of the tool towards the center indicates scraping.

Use-wear analysis: The process of looking at stone tools under a microscope to analyze the polish and striations to understand how the tools were used. 

Learn More: 

Use-wear analysis: https://texasbeyondhistory.net/varga/images/use.html Hopewell culture: http://www.ohiohistorycentral.org/w/Hopewell_Culture Tyler’s thesis: https://ir.library.illinoisstate.edu/etd/928/ 

Synopsis edited by: Aleksandra Majewski, M.S. (Anticipated Summer 2020) and Rosario Marroquin-Flores, PhD (Anticipated Spring 2022) School of Biological Sciences, Illinois State University

Muscular activity makes Duchenne muscular dystrophy worse in a worm model

Featured Scientist: Kiley Hughes, PhD candidate (Anticipated Spring 2022), School of Biological Sciences, Illinois State University

A picture of Kiley Hughes in a research laboratory. She is looking into microscope.

Birthplace: Seattle, WA 

My Research: I study how Duchenne muscular dystrophy progresses. My research is focused on figuring out how the absence of the dystrophin protein causes the disease. 

Research Goals: I want to continue using behavioral and molecular techniques to research neuromuscular disorders

Career Goals: I want to be a scientist! I would love to work on a larger research team for a research institute that shares their work with the public. 

Hobbies: I like to cook and paint, go outside when the weather allows it, and play with my two cats. 

Favorite Thing About Science: My favorite thing about science is the unknown, there is always more to know and understand. I allow my curiosity to drive me. 

Organism of Study: I study a species of microscopic worm, Caenorhabditis elegansC. elegans is a model organism, which means that scientists have been using it for research for many years and we know a lot about it. This species of worm is often used to study human diseases. 

An image of Kiley’s model organism, C. elegans. It shows the image of a worm, where the internal organs are visible.
The picture above is the nematode worm, C. elegans. They are about 1mm long, transparent, and feed on microbes

Field of Study: Molecular Neuroethology 

What is Molecular Neuroethology? In this field, we use molecular techniques to understand the way organisms interact with the environment and specifically look at the cause of different types of behavior. 

Check Out My Original Paper: “Physical exertion exacerbates decline in the musculature of an animal model of Duchenne muscular dystrophy” 

QR Code to the original publication
QR Code to the original publication

Citation: K.J. Hughes, A. Rodriguez, K.M. Flatt, S. Ray, A. Schuler, B. Rodemoyer, V. Veerappan, K. Cuciarone, A. Kullman, C. Lim, N. Gutta, Physical exertion exacerbates decline in the musculature of an animal model of Duchenne muscular dystrophy. PNAS. 116.9: 3508-3517 (2019). 

Research at a Glance: Duchenne muscular dystrophy is a degenerative disease that affects 1 in 3500 males and there is still a lot that we do not know about this disease. My research looks at how the loss of the muscle protein, dystrophin, leads to muscle death. I study the extent to which exercise might be able to protect dystrophic muscles. In this study, we used the nematode worm, C. elegans, and our worms have Duchenne muscular dystrophy. We used them to show that calcium was not being properly regulated in their bodies, even before the worms show symptoms of the disease. We also observed that some types of muscle activity increased muscle repair. However, no treatment positively affected the life expectancy of dystrophic animals. 

Highlights: For a muscle to contract, the body needs both energy and calcium. We used a special worm that has a green protein that will glow when it is in the presence of calcium. Worms move in a wave-like fashion. Because of this, each contracting muscle should have an opposite relaxed muscle. We used our special worm to do in vivo calcium measurements (Figure 1). 

A figure that shows the image of a worm, with its body in a wave-like shape. Actively contracting muscles are bright green, opposite to the contracting muscle is a relaxing muscle, which is a darker color. The brightness ratio is the difference between these two colors.
Figure 1. Image of the C. elegans dystrophic worm. The contracting muscle is bright and the relaxed muscle is dark. We used imaging software to measure the ratio of bright to dark muscles. 

We found that in dystrophic worms, not only was muscle calcium higher, but this persisted in both contracting and relaxing muscles. 

What My Science Looks Like: We can use electron micrographs to see what happens to the muscles in worms that have Duchenne muscular dystrophy. We make them by taking a worm and freezing it under very high pressure. The frozen worms are treated with heavy metals, then cut into really small slices (like pastrami). The slices shown in Figure 2 are from the midbody of a worm and they show the worm’s muscle structure.

A figure that shows two images. The image on the left shows the musculature of a wild type worm. The tissues are organized such that the mitochondria, basal lamina, sacromeres, A band, M line and muscle belly can be seen (each are denoted with a small black line). The image on the right shows the musculature of a worm with muscular dystrophy. There is not clear organization of the tissue and no parts are labeled.
Figure 2. Magnified image of C. elegans muscle tissue in a wild type worm (left) and a dystrophic worm (right). Adapted from Hughes et al. 2019. 

The image on the left is from a wild type worm, which means that this worm does not have the disease. The left image shows what a normal, healthy, muscle should look like. The image on the right shows the muscle structure of a dystrophic worm. The muscle in the dystrophic worm is degenerating. 

The Big Picture: Thousands of people are living with Duchenne muscular dystrophy in the United States. These patients are wheelchair bound by the age of 12 and die prematurely from heart failure in their 30’s. Research has been slow in this field because most of the animals that have the human version of Duchenne muscular dystrophy do not show the same type of degeneration. However, when our dystrophic worms burrow, they show muscle decline similar to humans. Using this model, we hope to understand how people with this disease are getting so sick. 

Decoding the Language: 

Caenorhabditis elegans (C. elegans): The worms that we use to study Duchenne muscular dystrophy. This might seem strange, but they’re a great model organism to understand the disease. What we find can be translated to humans! 

Degenerative disease: Diseases that are caused by the abnormal break down of cells over time. 

Duchenne Muscular Dystrophy: A fatal neuromuscular disorder that causes weakness in and loss of skeletal and heart muscle. This disease is caused by abnormal dystrophin proteins. 

Dystrophic: A term used to refer to animals that have absent or abnormal dystrophin proteins. 

Dystrophin: The muscle gene/protein that is absent in patients with Duchenne muscular dystrophy. 

Electron micrograph: A form of imaging that can be done using a specialized microscope.

In vivo: Measurements or experimental procedures that take place inside of a living organism. 

Microbes: A microscopic organism, like bacteria.

Model organism: A species that has been very widely studied. These species are often easy to breed and to take care of in the lab. Because they have been studied for so long, scientists have developed a lot of genetic resources that can be used to model human diseases using these animals. 

Neuromuscular disorders: These are diseases that affect muscles and how the nervous system controls those muscles. Molecular techniques: A method used to manipulate and understand DNA, RNA, or protein. 

Wild type: An animal that has not been manipulated. It should have the same genetic and physical characteristics as if it were found in the wild. 

Learn More: 

Why use the worm?

Synopsis edited by: Eric Walsh, M.S. 2020, and Rosario Marroquin- Flores, PhD (Anticipated Spring 2022), School of Biological Sciences, Illinois State University.

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One way to better predict sex ratios in species with temperature-dependent sex determination

Featured Scientist: Amanda Wilson Carter, PhD 2017, National Science Foundation Postdoctoral Research Fellow at the University of Tennessee (former PhD Candidate at Illinois State University, School of Biological Sciences) 

A picture of Amanda Wilson Carter at her field site. She is in a marsh wearing waders. She is next to a canoe, holding a turtle that was just removed from a trap.

Birthplace: New York City, NY 

My Research: I study how animals are affected by changes in their environment. 

Research Goals: I want to understand how changes in temperature affect animal physiology. I would like to be able to better predict how climate change will affect all types of animals. 

Career Goals: I am currently working towards increasing the participation of underrepresented groups in science. My goal is to become a biology professor and researcher. 

Hobbies: Traveling, playing with my dogs, and renovating my 1940’s bungalow. 

Favorite Thing About Science: I love having the freedom to explore questions that I think are necessary and important. Throughout my schooling and career, I have also discovered a passion for mentoring students through independent projects in the lab. There is something very special about watching an undergraduate conduct their first study and transform into a confident and capable young investigator. 

Organism of Study: I study many animals, but my PhD research focused on turtles, mainly the red-eared slider (Trachemys scripta). In my current position, I conduct research on dung beetles. 

A picture of a red-eared slider turtle on the ground. The turtle has a red band on the side of its head.
Red-eared slider turtle (T. scripta). Image source 

Field of Study: Eco-physiology | Climate Change | Plasticity | Development | Parental Effects 

What is Eco-physiology? I broadly consider myself an eco-physiologist. I study how the physiology and behavior of animals are affected by their environment (mainly temperature).

Check Out My Original Paper: “The Devil is in the Details: Identifying Aspects of Temperature Variation that Underlie Sex Determination in Species with TSD” 

QR Code to original publication
QR Code to original publication

Citation: A. W. Carter, R.T. Paitz,R. M Bowden, The Devil is in the Details: Identifying Aspects of Temperature Variation that Underlie Sex Determination in Species with TSD. Int Comp Biol. 59.4: 1081-1088 (2019). 

Synopsis written by: Josselyn Gonzalez, M.S. (Anticipated Spring 2021), School of Biological Sciences, Illinois State University

Research at a Glance: The goal of this research was to help understand how animals respond to changes in temperature. To do this, Amanda used the red-eared slider turtle to study temperature-dependent sex determination (TSD). TSD is when the sex of an animal is affected by incubation temperatures. For example: red-eared slider turtles are typically male unless they experience warmer temperatures during development. If eggs are in warmer temperatures, even if it’s just a few days, then it will cause the turtles to develop as female instead of male.

It is important to be able to predict sex ratios, or the amount of male and female turtles, in nature. We want to know how future changes in temperature may affect animals, especially for those that are sensitive to temperature. Constant Temperature Equivalents (CTEs) are used to guess the number of female turtles produced when eggs are exposed to temperatures that go up and down, similar to how temperatures go up during the day and down during the night. They are very common in this type of research and have been used to predict sex ratios for many years. Recent research suggests that CTEs may not be the most accurate way to predict sex ratios in the wild. 

Amanda’s goal was to determine if using the number of days at higher temperatures (female-producing temperatures) is a better way to predict the sex ratios than using CTEs. To test her question, Amanda used two groups of red-eared slider turtles (one from Illinois and one from Louisiana). She also looked to see if the turtles from Illinois and Louisiana responded similarly to temperature changes.

Amanda found that the best way to predict turtle sex ratios is to count the number of days that eggs are at higher temperatures. Using the CTE that eggs experience throughout incubation was not as accurate. She also found that turtles from Louisiana were more sensitive to temperature changes than turtles from Illinois. 

Highlights: Amanda collected 183 turtle eggs and put them into different temperatures as they developed. Amanda chose temperatures that go up and down, similar to how temperatures go up during the day and down during the night. All of the eggs started at male-producing temperatures (25 ± 3°C) for 25 days. She used 22°C (71.6°F) for her nighttime temperature and 28°C (82.4°F) for her daytime temperature. Then, she switched all of her eggs to female-producing temperatures (29.5 ± 3°C). She used 26.5°C (79.7°F) for her nighttime temperature and 32.5°C (90.5°F) for her daytime temperature. The eggs stayed at female-producing temperatures for 8, 11, 14, 17, 20, 23, 26, 29, 32, or 35 days. Finally, all eggs were returned to male-producing temperatures (25 ± 3°C) until they hatched. Once turtles were 6 weeks old, Amanda determined the sex of each hatchling. The sex of each hatchling from this experiment was combined with the previous year’s data to help determine the best way to predict sex ratios

What My Science Looks Like: In Figure 1, Amanda graphed the number of days that turtle eggs were at female-producing temperatures (x-axis) and the percent of turtle eggs that became female (y-axis). 

A data figure that has four panels and show the temperature of the soil across the Illinois turtle nesting season. The x-axis of each panel is time in months. The y-axis shows temperature in degrees Celsius. In each panel there is a black line at 29 degrees to indicate the pivotal temperature. Panel A shows a 23-year average; the average never reaches the pivotal temperature. Panel B shows average temperatures in 1993; there are periods of time when the temperature reaches or passes the pivotal temperature. Panel C shows average temperatures in 2004; the average never reaches the pivotal temperature. Panel 4 shows average temperatures in 2012; between July 1st and August 1st, temperatures are consistently above the pivotal temperature. This figure shows that temperatures naturally fluctuate, but temperatures are the highest in 2012 and heatwaves are longer in duration and higher in amplitude.
Figure 1. The proportion of female turtles produced when eggs are exposed to 0-35 days of female-producing temperatures. Figure adapted from Carter et al. 2019. 

For the experiment described in this paper, the male-producing temperatures used was 25 ± 3°C (dashed line). A similar experiment was done the year before but the male-producing temperature was 27 ± 3°C (solid lines). Both male-producing temperatures (dashed and solid lines) follow the same shape on this graph. Because of this, Amanda concluded that the number of days at female-producing temperatures is an accurate way to predict the number of female turtles produced. 

In Figure 2, Amanda also graphed the CTE (x-axis) and the percent of turtle eggs that became females (y-axis). 

Figure 2. The predicted number of females produced using CTEs. Figure adapted from Carter et al. 2019. 

In her first figure, Amanda was able to show that both male-producing temperatures (dashed and solid lines) resulted in the same sex ratios. But in this figure, she shows that they have different CTEs. Even though they had different CTEs, they resulted in the same amount of females. This means that CTEs are not a good way to predict sex ratios

The Big Picture: Climate change is a growing threat, and it is important to understand how animals will respond to these changes. Amanda studies the effect of temperature on animals with TSD to help us predict how species will respond to future climates. This research also helps with our conservation efforts. The more we know about how the environment will affect species, the better we can help to curb these effects. 

Decoding the Language: 

Climate change: A change in global or regional climate patterns, often seen as major changes in temperature or precipitation. 

Constant Temperature Equivalents (CTEs): A tool used to guess the number of females produced when eggs are exposed to temperatures that go up and down, similar to how temperatures go up during the day and down during the night. CTEs are calculated using formulas based on what you use as the nighttime and daytime temperature. For example, Amanda used male-producing temperatures of 25 ± 3°C. Using the CTE calculation, she would expect to get the same number of females as if she incubated the eggs using a constant temperature of 25.98°C. 

Female/Male-producing temperatures: Female-producing temperatures are higher/ warmer temperatures that cause red-eared slider turtles to become female. Male-producing temperatures are lower/colder and cause these turtles to become male.

Incubation: The process of keeping an egg warm enough to develop until hatching. In the context of Amanda’s research, a male-producing incubation temperature is approximately 26°C and a female-producing temperature is approximately 31°C. 

Physiology: A branch of biology that studies how different parts of the body carry out chemical and physical functions.

Sex ratio: A ratio that compares the number of males to the number of females in a given population. For example, a 1:1 ratio means the number of males and females is the same and that 50% were male and 50% were female. The sex ratio is important because without enough males and females, the population may decline because there will be fewer opportunities to mate and produce offspring. 

Learn More: 

Temperature-dependent sex determination

Synopsis edited by: Madison Rittinger, M.S. (Anticipated Fall 2021), and Anthony Breitenbach, PhD (Anticipated Spring 2021), School of Biological Sciences, Illinois State University.

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