The focus of this research project is to determine the temperature-sensitive sex determination (TSD) factor in Chelydraserpentina, the snapping turtle. In most species of vertebrates the initial trigger for sex determination is genetic and, in a much smaller number of species, the sex determination relies on environmental factors. In the snapping turtle sex determination is temperature dependant; eggs incubated at 26 degrees (celsius) produce all male hatchlings, while eggs incubated at 31 degrees (celsius) produce only females. The exact mechanism that regulates sex determination is unknown, but it is believed to depend on the expression of a series of sex determining genes. I am focusing my work on the protein-protein interactions of DAX1 and SF1. Evidence suggests that these genes may work together to regulate the downstream expression of SOX9 and AMH, eventually leading to testes differentiation. DAX1, is a promising candidate for the "master switch," because it appears to regulate the expression of both the male and female sex determining genes. That's why I'm trying to figure out if DAX1 has different binding capabilities to SF1 at 26 and 31 degrees. My hypothesis is that DAX1 binds to SF1 at 31 degrees and inhibits the downstream expression of male sex determining genes. Conversely, at 26 degrees, DAX1 may be incapable of binding to SF1, resulting in the expression of the female sex determining genes. I will be performing experiments this summer in an effort to test this hypothesis.
I completed the experimental design for the greenhouse portion of my research project. I have also been using the scientific papers from my literature searches to locate companies that sell activated carbon and have been contacting them. Activated carbon will be used in two treatments of the experiment and it is often used to reduce the interference of allelopathic chemicals in the soil. It does this because it has a high affinity to organic compounds and a weak affinity to inorganic nutrients (Prati and Bossdorf 2004). The seeds for my experiment also came in and they will stratify for a month in cold, moist conditions at about 5 degrees. I’ve been watering them every other day with deionized water.
Cold Stratifying Seeds
Seeds of Eurbia divaricata That Are Stratifying
For the past two weeks I have been participating in a research project with Dr. Aronson that observes the response of Hempstead Plains’ prairie plants in urban environments. We have been conducting this project on a field plot on campus. Hofstra’s Public Relations crew has interviewed all of the participants and created a video on this exciting research. Last week, I continued to measure the initial growth of these plants as well as label and maintain each specific plot.
Dr. Aronson and I have also started another research project with Dr. Sanford looking at the dispersal rates of the bulbils that are produced by the invasive species that I am working with, Ranunculus ficaria. I am excited about this project because it takes my research a step further and I will be able to make a direct correlation to its dispersal rates and its invasiveness. This plant is a major ecological problem in the Northeast as well as the Pacific Northwest, therefore, I am eager to gain some understanding to how it is dispersed and how far the bulbils can travel so that native plant conservation can be managed as well as provide some insight on other invasive species.
I have done literature searches on seed dispersal in water because this plant usually grows along streams. These papers have helped me a great deal in organizing an experimental design for this project. In order to start this project, we need to find the buoyancy of each bulbil. Therefore, I have weighed over 200 bulbils and will begin to find the volume of each. Each bulbil weighs approximately 0.1 grams. Dr. Aronson and I were not exactly sure how to find the volume of an object this small so we reached out to the chair of the Physics Department, Professor Hastings. He is also excited about the project and is prepared to assist us in any questions we might have. This process makes my research experience richer with all of the possibilities and ideas that we have collectively discussed for the rest of the summer and upcoming year with these projects. I am honored to be a part of such a profound cause and it gives me a sense of fulfillment to know that my research will significantly contribute to the control and management of this species.
Last day of the week and it was the most successful mammal trapping we’ve had yet! Dry Bay was our first site and we found 3 mice had run into the Sherman traps last night. There were two girls and 1 boy and all were deer mice (Peromyscus maniculatus). Like all the other mice we have caught so far, they had no ticks that we could tell. These mice were so cute until they started to squirm the first two were biters and we discovered that they really like to bite the rubber part of a mechanical pencil. It was a great distraction for them and they stayed relatively still. The third mouse was more of a squirmer then a biter, plus her fur was wet so she was quite slippery. But I did learn how to give them an ear tag. It’s simple enough you just need a steady hand, a pair of pliers and the ear tag. I gave the last two mice their ear tags. With high hopes for more mammals we headed over to Long Tin. All of the Sherman traps were empty and we were about to check the last pitfall and last medium mammal trap of the array when our luck hit again. In the pitfall trap we found a house mouse (Mus musculus). This girl took us a while time to key out because this species is usually found in buildings but sure enough her home is in the woods. Like the other mice she had no ticks. Then we realized we caught a big one. In the Tomahawk trap was a male opossum (Didelphis virginiana). He was just laying in the back of the cage very calm, he barely even showed his teeth when approached him. The protocol for handling medium size mammals requires us to use a sedative by injection. He barely even flinched when the needle pierced his skin. Within ten minutes he had dozed off. Since I’ve never handled anything larger than a mouse Russ and Kaety processed him but I paid careful attention because after the next trip I will be handling everything with Kaety because Russ will no longer be coming down. The opossum had 6 engorged Lone-star ticks on the back of his ears. He was having a rough week, besides being caught in a cage he had recently been in a fight. He had cuts on his head and back and the padding on his front paw had a hole that looked like it was infected. The poor boy was then released and by released I mean he was carried into the woods and laid on a comfy bed of leaves to wake up on. All in all a great way to end the week, until next time folks. The first picture is of the opossum in the cage playing dead. The second picture is of the opossum's front foot were he has a big cut.
Today was the first day that we did not have to run around everywhere trying to get things done. Unfortunately we did not find any mice and we only found an anolis (Anolis carolinensis), which was not in any of our traps. But we did find a cotton rat (Neotoma floridana) this morning. It managed to get into a Sherman trap, which it barely fits into. Russ and Kaety we able to maneuver her out of the trap by collapsing the cage while everything was in a bag. The hold to pin down a mouse or rat is typically to grab the tail, which is what we did. Then the outer layer of skin of the tail slid off the bone. Surprisingly she did not bleed nearly as much as you would expect. Once we had her in a good hold she calmed down and did not seem too distraught. Like all the other mammals we caught there were no ticks as far as we could tell. The anolis we caught also had no ticks but this species is not known for carrying ticks. It rained last night so the amphibians came out. We caught 15 frogs and toads, most were the southern leopard frog (Rana utricularia) and we also had pickerel frogs (Rana palustris), which are morphologically extremely similar. Our two biggest toads were the Southern toad (Bufo terrestris) and the Woodhouse’s toad (Bufo woodhousei woodhousei). Both of these toads were as big as my palm. I never thought I would counting warts on a toads to id what species it is but they were the cutest toads. The first picture is of an Anolis. The second picture is of the rat being checked for ticks.
Day 2 of week 2 and unfortunately we did not find as many lizards as yesterday, but we did find a lot of frogs. My favorite frog we found today was a green tree frog that was the size of my thumbnail. When they are that small they are the color of my skin and almost see through. Turns out I really like frogs, new career possibility? We also trapped a mouse last night and I was able to hold on to him the entire time… first time. I think this is my favorite job I’ve ever had. Who else gets to chase after a lizard in the woods? I also learned how to flag for ticks that are not on any animals. All it takes is a white felt cloth on a stick and brushing it on the ground or low plants then checking it for ticks. The larval stage of ticks is so tiny they are almost see through. They are about the size of a poppy seed. So basically it’s a pain to try and find them but when you do it makes it worthwhile. Plus, we are the first people to collect larval ticks in the south by flagging! That’s all folks. The first picture is of a green tree frog. The second picture is of me with my first mouse.
Today was our first day back in the field for this trapping session. The day started out with us looking under the metal cover boards at Long Tin. We caught 11 lizards in the hour and a half that we were there. This has so far been our most productive outing yet. Not only did we catch a lot of lizards but we found a lot of ticks, our last one had 5 ticks and mites on it. We also found a male broad head skink that was 114 mm long and 54 g, the biggest one yet. Once we finish there we ran some errands for a few hours, picking up more supplies and getting a badge for another undergrad who is helping out this week. Then it was off to Dry Bay and Four Mile to set up the mammal traps and open the pitfall traps. We’re using a new bait mix for the small mammal traps so hopefully we will catch more mice tonight then we have been. Tomorrow is going to an early day, fingers crossed we get a lot of animals! The picture is of the huge male broad head we caught.
Last day of my first week and it’s a very short yet early day. We didn’t have to go to Dry Bay because we already completed the three nights of trapping. We went straight to Four Mile and checked all the traps, there wasn’t anything in the Sherman traps and only some frogs (the southern leopard and southern toad) were in the pitfalls. Next trip we will be using new bait for the small mammal traps (it’s lard, peanuts, and sunflower seeds all mixed in a blender) so hopefully we will catch more mammals, plus the longer the traps are out the less they will smell of people and the more they will become part of the environment. Fingers crossed we can figure out why there have not been any ticks on the mice (as far as we can tell). Either way I have a feeling that what we find out is going to be very important to understand the ecology and behavior of Iscap. Now it is time to get in the car and drive back up north!
This is the last morning to check the traps at Dry Bay and we found another deer mouse (Peromyscus maniculatus) in one of the Sherman traps. Like the mouse we found yesterday I didn’t hold him until we were done processing him because I’m not 100% confident in my hold yet, but I did hold him after we were done. It’s really odd that the mice we have caught so far this week have not had any ticks. There are a few explanations but none that can be completely supported right now. First let me explain that resent research has shown that the deer ticks (Iscap) of the south (from Tennessee and south) are of a slightly different genetic strain than those else where in the country. They still considered the same species but there is little work on Iscap in the south. The time of year the nymphs, larvae and adults are not known or if they prefer to feed on the same Iscap in the north. It is possible that the adults aren’t searching for food yet and one or both of the other life stages are (but we have found all three life stages). Another possibility is that the southern Iscap does not like to take a blood meal from mammals or that the adult Iscap are not out when the mice are foraging. Another possibility is that the larvae stage is on the mice and we are not seeing them because they are basically see- through and the size of a poppy seed. In the pitfalls we found more spiders that were the size of my palm than lizards. Along with the spiders we found a ground skink (Scincella lateralis), several southern leopard frogs (Rana sphenocephala) and southern toads (Anaxyrus terrestris) in the pitfalls. We finished at Dry Bay fairly fast (since we didn’t find much all we had to do was close the traps) and off to Four Mile we went. All the Sherman traps were empty but the three pitfalls that we finished yesterday had a lot of frogs and toads in them. They are all the same as yesterday except we also found a Woodhouse’s toad (Bufo woodhousei). These look very similar to the southern toad but the major defining feature between the two species are the parietal ridges. The Woodhouse’s toad ridge is very prominent especially when compared to the southern toad’s ridges.
Day two of our trapping cycle started with a finding a mouse in one of the pitfalls at Dry Bay. It was a deer mouse (Peromyscus maniculatus) and had no ticks. I watched as Kaety and Dr. Burke processed her so that I could learn how to check for ticks and weigh her. Once they were finished I held her, my first experience holding a wild mouse. It was so much fun, all you have to do is grab hold of the tail and pin her down on her stomach. Once in this position you just grab as much scruff on the back of the neck and hold on. When you have this kind of grab they can’t turn their head far enough around to bite you and it also doesn’t hurt them. We also found a few more broad-headed skinks (Plestiodon laticeps) and 5-lined skinks (Plestiodon fasciatus) in the pitfalls. Several amphibians were found including the northern slimy salamander (Plethodon glutinosus). I’ve never seen one before, at first it was covered in sand from being in the pitfall, so we covered it with water and instantly it began to secrete a mucus so sticky that my fingers got stuck together and anything else they happened to touch. It even stayed on after I pour water on it, to get it off I had to scrub it with a leaf and more water. Once we finished at Dry Bay we headed over to Four Mile to check the small mammal traps, unfortunately we didn’t catch anything. So we got to work digging the pitfalls. If this was in a field oh how easy it would be, granted compared to other places where the flora is much denser but some buckets were quite easy, others not so much. Several buckets had thick tree roots across the entire width of the bucket hole. Let’s just say it was a long day and we only got 3 pitfalls done. Luckily we only have 1 more to do at this site and it will be completely ready to go.
In order to start my research project I needed to call numerous plant nurseries to order seeds and plants. This assignment helped me to develop great leadership skills and encouraged me to use critical thinking skills to make the correct decisions. I showed initiative and was able to contact some great nurseries, mainly Pinelands in New Jersey and Greenbelt in Staten Island for the materials that I needed. Unfortunately, Pinelands was a little expensive, leading us to believe that the plants were too big. Since it is late in the spring, availability of plants was very limited. Due to these factors, we held off on ordering plants and decided to just use seeds. I contacted Greenbelt and ordered five different species. These species included:
White wood aster (Eurbia divaricata)
Blue wood aster (Symphyotrichum cordifolia)
Wild sarsaparilla (Aralia nudicaulis)
Late meadow rue (Thalictum pubescens)
Wood reed ( Cinna arundinacea)
The next step in the preliminary stages of the project was to secure a site. Dr. Aronson and I visited Muttontown Preserve in Long Island to look at possible locations within the preserve to conduct our research. There were many sites where the Lesser celandine was but they were all pretty much dead. It was obvious where these plants grew because the remnants were yellow, slimy and there were many bulbils present. Some tubers were noticeable but not many because they were all most likely underneath the soil. The amount of bulbils that were left behind by the ranunculus was amazing. There was so many and if there was ever a doubt as to where the plant grew, the presence of the bulbils confirmed it. We found a great spot in the preserve to conduct my research project. We flagged plots of invaded (where the lesser celandine grew) and non-invaded soil. These plots were drastically different because the invaded soil was very slimy and practically had no growth except for Violet and Impatiens. However, it was obvious where the non–invaded plots were because there was a lot of other plant species and no bulbils were present. No soil was collected at this point because we had to wait for the necessary permits to collect. It was a great experience to actually observe the plant that I have been researching for the entire spring semester and its effects on native forest herbs. Bulbils were also collected for another possible research project on plant dispersal. Even though the plant was decaying, many bulbils were still attached to plant parts and some were lying separately on the ground.
Last week, Dr. Aronson and I also attended a meeting at South Side High School in Long Island for a possible location to conduct the greenhouse portion of my research project. They have students who are interested in research during the summer and are eager to work alongside myself and Dr. Aronson in our research projects. This group of about four or five students are participating in various scientific competitions themselves and can use the experience from our research. This high school has a great greenhouse that they recently renovated and we decided that we would use it for our greenhouse study. These students can help with the smaller aspects of my research such as watering and monitoring my plants during germination periods. They will assist me when I go out to the field and I am excited about this great opportunity to mentor these students. It will give me a chance to nurture my leadership and communication skills.
We also went out to another possible research site in Freeport where we were told lesser celandine had invaded. However, the plant was no longer visible. I am currently working on designing the greenhouse study for my research project with “Allelopathic Inhibition of Germination by Alliara Petiolata (Brassicaceae) (Pati and Boddsorf 2004) as a guideline. I found a lot of great papers during my literature searches to help me with my experimental design. These papers will help me to gain insight on using field soil in the greenhouse. They will also help me to understand the use of activated carbon and its relationship to allelopathy for one of the treatments.
Lesser celandine in April
Lesser celandine in May
Bulbils that were left behind by the lesser celandine
My name is Johanna Andrews and I am a Biology major at Hofstra University with a concentration in Pre-Medicine and a minor in Chemistry. I will be a senior in the fall and I was awarded an undergraduate research fellowship in the Biology Department. After attaining my degree, I plan to go on to Medical School and pursue a career in Obstetrics and Gynecology. I have always had an interest in children and the miracle of life. Although, I have always loved medicine, the Biology program has exposed me to many disciplines in this major. As a result, my eyes have been opened to a world of new interests.
After taking introductory biology courses, I realized that I was very interested in the field of Ecology as well. I was amazed at the complexity and diversity of plants and I was very interested in doing a project that would broaden my knowledge in this field. Therefore, I began working with one of my biology professors, Dr. Myla Aronson, for my research experience. With her guidance, I was introduced to the invasive species Ranunculus ficaria. A biological invasion occurs any time an organism is introduced to a new area outside of its current range. These invasions are often linked with anthropogenic disturbance of the environment, but pristine natural habitats may also be susceptible to invasion (Meekins and McCarthy 1999). The phenomenon of biological invasions is a growing concern of scientists, nature preserve managers, and conservationists (Meekins and McCarthy 1999). One reason for studying invasions is that many invasive species have become serious pests. Due to the economic importance of invaders, it is important to realize how little we understand and how predictions of the outcome of new invasions can only be weak and reliable (Williamson 1996). Invasive species may negatively affect a community by leading to decreases in population numbers, increases in species extinctions, or alterations in ecosystem function. These effects may be achieved by many factors. These factors include competition, predation, diseases or amensalism (Meekins and McCarthy 1999).
One non-native invasive plant of recent concern in riparian and forested areas of the Northeast is Ranunculus ficaria, also known by its common name lesser celandine. While the invasion of R. ficaria has been well documented by land managers, this plant is not well-studied ecologically. It is not known exactly when this plant was introduced to the United States. This plant is currently found in nineteen states in the Northeast and Pacific Northwest. It is reported to be invasive in nine states including Connecticut, Delaware, Maryland, New Jersey, Oregon, Pennsylvania, Virginia, Wisconsin, West Virginia and in the District of Columbia (USDA Forest Service). The variety that is invasive in the US is Ranunculus ficaria var. bulbifera (Metcalfe 1938). This plant is an herbaceous, perennial plant in the buttercup family, Ranunculaceae. They have a basal rosette of dark green, shiny, stalked leaves that are kidney-shaped to heart-shaped. The flowers open in March and April, have 8-12 glossy, butter-yellow petals that are 1 inch wide, and are borne singly on delicate stalks that rise above the leaves. Along the stems of the above-ground portions of the plant, pale-colored bulblets are produced. However, these bulblets are not visible until late in the flowering period. The root system is composed of a cluster of tuberous roots and when in bloom, large infestations of R. ficaria appear as a green carpet with yellow dots, spreading across the forest flower. As a result of the plant’s production of many bulbils and tubers, it spreads rapidly across habitats as well as colonizes them when it grows and dies (USDA Forest Service).
The objective of my study is to examine the effects of R. ficaria on native forest herbaceous plants. It has been observed that after R. ficaria dies in the beginning of June, no other plants grow in the invaded areas. Due to the life history of late-blooming forest herbaceous plants, R. ficaria should not compete directly for space, water and nutrients. Therefore, I believe that R. ficaria may have allelopathic effects on native plants. I will be planting seeds of five native species in invaded areas and non-invaded areas as well as examining the growth and reproductive response of these native plants to R. ficaria invasion. These seeds will be planted in July after the R. ficaria plants die, thus indirectly examining possible allelopathic effects left in the soil.
Ranunculus ficaria is primarily a threat to native plants and native plant diversity in lowland woods and on flood plains. It outcompetes native plants through its extremely early seasonal growth and the development of a dense network of roots and tubers in the soil. Over time it forms extensive carpets in natural areas, crowding out native plants, especially native ephemeral wildflowers. There is little understanding of this plants ecological effect. After a thorough literature search, no published peer-reviewed studies were found on the effects of R. ficaria on native plants. Therefore, research on this species will help manage native plant conservation as well as understand other invasive species.
Day started really early so we could check the traps at Dry Bay, unfortunately we did not find any mammals but we found a lot of lizards including Anolis, 5-line and broad-heads in the pitfalls. All of which we processed and began toe clipping which is our way of identifying individuals we recapture. We found many deer ticks (Iscap) on these lizards, which we removed and placed in a vial with ethanol for later analysis in the lab. Once we finished at Dry Bay we found out our second site (four-mile) was approved so we headed out to start mapping out the grid. First we picked the origin corner then using a meter tape made one row with seven points 15 meters apart, each marked by a flag. From each point we made a perpendicular line with 6 point 15 meters apart. At each point we setup and opened a Sherman trap, eight medium size mammal traps (Tomahawk Trap) were set up around the perimeter, and at each corner a pitfall trap was flagged. It doesn’t sound like much but this took several hours. We then headed back to Dry Bay to open the Sherman traps for the second night of trapping and checked to pitfalls again to make sure nothing alive fell in during the day. We found 2 leopard frogs (Rana sphenocephala) and a southern toad (Anaxyrus terrestris) in the pitfalls. Frogs and toads are not our target species so we note that we found them and check them for ticks (which they don’t have, but we still have to check). The picture is of me with an Anolis.
Today was my first day in the field, which I was pretty nervous about but once we got going that all disappeared and all that was left was excitement. I always knew that whatever I spent my life doing would not be spent sitting behind a desk everyday; I have a lot of energy and hate sitting for long periods of time. So when it hit me that my office is the woods I was really excited. First we got me my temporary badge to get onto the field site, because this is a DOE nuclear facility. Then we went to this place called Long Tin. It’s as it sounds, a bunch of long tin sheets scattered on the ground in the woods. These are often referred to as cover boards and when they are out for a while the bugs show up first, followed by lizards, mice and snakes. To check the boards you simply lift the board up and if you see a lizard you slap your hand down on the body (Do Not grab the tail… It will fall off). We caught a lot of broad-head skinks (Plestiodon laticeps), Southeastern 5-lined skink (Plestiodon inexpectatus) and 5-lined skinks (Plestiodon fasciatus). I can tell I have to learn a lot of new scientific names. As juveniles these three species look exactly the same they have a black head, a bright blue tail and 5 bright yellow lines that are the full length of their body. The only way to tell them apart is to first look at the width of the scales under the tail, if they are the same width then it is the southeastern 5-line, if the scales are larger then you have to look at the labial scales. These are the scales that line the upper lip of the mouth and are between the sub-occular scale (which is right under the eye) and the tip of the mouth. If there are 5 scales it is a broad-head, but if there are 4 then it is a 5-line. But you have to count the scales on both side of the mouth because some lizards will have 4 on one side and 5 on the other. If this happens then you must look at the post labial scales behind the eye. If its enlarged its broad-head, if not it’s a 5-line. After Long Tin we went to Dry Bay (the only array that is finished enough to start trapping so far) and opened all the traps. I learned how to set up a Sherman trap, which is meant to catch mice and other small mammals. Then we opened the pit fall traps, which are associated with drift fences that are set up like an X. The pit falls are 5-gallon buckets dug into the ground and the fences are 4 pieces of tin partially dug into to the ground to form the X. At the end of each piece is another bucket in the ground. This works because a lizard (sometimes mice or shrews) will walk into the tin and will follow the tin until it falls into a bucket. Once all the traps were opened we ran errands and worked on getting our second site approved.
Hey everyone my name is Kristin Anicito and I am working on a study in South Carolina with Hofstra University along with 4 other universities. We are all working together to compare the prevalence of Lyme disease in the south, northeast and north Midwest of America. Each region is looking at tick density on the lizards, small mammals (i.e. mice) and medium sized mammals (i.e. raccoons and opossums). South Carolina, unlike the northeast and north Midwest, has very few cases of Lyme disease even though there are plenty of ticks in the area. This discrepancy is believed to be in part due to the biodiversity or the difference in genetic codes in the southern deer ticks (Ixodes scapularis). Lyme disease is caused by the bacteria Borrelia burgdorferi and is carried most commonly by I. scapularis (which we affectionately call Iscap). All research on these ticks has shown that they will feed on mammals, birds and lizards. The white-footed mouse (Peromyscus leucopus) is the most common host of Ixodes sp. and easily obtains and transmits Lyme disease. Some animals are able to clean the ticks of the bacteria, and are unable to carry the infection themselves. The animals that are unable to carry the infection are called reservoir incompetent. By cleaning the ticks of infection, the rate of infection will decrease in the wild population; this is referred to as dilution. Lizards and some birds species commonly act as diluters. The western fence lizard (Sceloporus occidentalis), found in west North America are completely reservoir incompetent and are credited to be a major role in decreasing the density of Lyme disease. In South Carolina we will be catching many lizards including the eastern fence lizard (Sceloporus undulates) and Anolis (Anolis carolinensis). We will also be trapping a variety of mice species including deer mice (Peromyscus maniculatus), opossums (Didelphis virginiana), and raccoons, along with many others.
The Biology department, with financial support from OSI Pharmaceuticals sponsors a competitive summer fellowship program for Hofstra undergraduate students. Recipients of these fellowships work for a minimum of 10 weeks with individual researchers on a specific topic related to the student’s long-term career goals. Research mentors have come from the faculty at Hofstra, cardiology physicians in the North Shore–LIJ Health System and research scientists from the North Shore–LIJ Health System’s Feinstein Institute for Medical Research.
Through this richly rewarding experience, students develop analytical and critical thinking skills and gain practical experience that help them prepare for careers in medicine and/or research. This blog is created to provide a “window” into this experience, to allow the research fellows to share their experiences with others who may be interested.
Lesser celandine in April
