I’m Rebecca Lerdau, a Junior at Carleton College. I’ve had a great time these past three weeks as a Carleton College extern at the Echinacea Project. I, and my classmate, Vo Dominguez were working with Jared Beck on the RemAg project looking at Andropogon gerardii’s (big bluestem) reproductive response to fire.
Having a good time counting the X-Ray images
A big part of our work has been with creating new protocols for determining Andropogon seed set. Previously, the main method for finding Andropogon seed set has been dissecting every floret, but this isn’t realistic on a large scale. Around half of Andropogon’s florets aren’t able to produce seeds, but it can be difficult to distinguish between the two types of florets. We wanted to figure out a way to use inflorescence mass to find total amounts of florets that can produce seeds. We were able to count awns and look at the relationship between awn count and mass. We found a beautifully linear relationship between awn count and seed mass (our R^2 = 0.96!) which allowed us to make an equation to use mass to determine the amount of fruiting florets. We set out to try X-raying Andropogon to determine seed counts. This was also successful, and we created a classification system for counting seeds with X-ray images.
We also got to try out our new seed set quantification system on some samples from the pilot RemAg experiment. We looked at the effects of burning on Andropogon seed set in 2022 from the pilot plots. While we were unable to find significant results with the data we were looking at, it was good to see that our protocols were working. The protocols are promising, and I look forward to seeing what happens with the larger RemAg project!
All in all, it’s been an awn-some experience working as an extern these past few weeks. I’ve learned so much. I’ve enjoyed getting to meet scientists and exploring CBG. We went on some lovely walks and got to see all sorts of cool plants. I had fun working with Andropogon and we even found a few seed predators! Thank you to Stuart, Jared, Wyatt, and Abby for this experience, and thank you to my fellow externs as well.
Biology Major with a focus in Ecology and Evolution, Carleton College, 2025
Pronouns: They/Them
Research Interests
Evolutionary ecology, prairie restoration with a focus on fauna community interactions to restored prairies, bees, anteaters, a number of other things.
Statement
I just had a great time working with the Echinacea project (or should I say Andropogon project) for a three week long externship with Carleton college.
My classmate, Rebecca Lerdau, and I were brought on to work with Jared Beck on the RemAg project, looking at big bluestem’s (Andropogon gerardii) response to fire.
We wrote a new protocol for assessing seed sets (the number of pollinated seeds divided by the number of viable fruits produced by an individual plant) for big bluestem. Previously, the only methods for assessing seedset in big bluestem involved dissecting individual seed cases. This method is extremely time consuming, and Echi-nation sustains too many seeds and not enough time or spare under-graduates for it to be a viable protocol for the scope of the RemAg project. Because of a lack of lab protocols for assessing big bluestem seed sets, this project has been sitting on hold in Jared’s office for a while, and we were really excited to help get it moving.
We found a strong relationship between the mass of subsamples of grass florets and the number of awns, a structure found only on perfect, viable Andropogon florets which allowed us to use mass to calculate awn count and awn count as a proxy for fruit count.
We also developed protocols for classifying florets and pollinated (containing a seed) or unpollinated (not containing a seed) from X-ray images. Using the number of pollinated seeds counted from the X-ray to calculate seed count and the awn count approximated by mass for the fruit count, we are able to efficiently classify big bluestem seed sets.
We used our methods to analyze some samples from a pilot RemAg study. Despite some issues with the study design, we were able to prove the feasibility of using our lab protocols to analyze RemAg data.
It’s been a great three weeks working with the Echinacea Project. I have greatly enjoyed making awn-some puns with my collaborators, meeting people at the botanic garden, inhaling Andropogon smut fungus, and proving to my family that I am a real biologist who knows how to use an x-ray machine. Thank you to Stuart, Jared, Wyatt, and Abby for making this experience possible.
I am an aspiring botanist. I am specifically interested in ethnobotany/economic botany.
Statement
I am from Newton Grove, NC. In my spare time I like to read, listen to sad music, cook, and try/make new hot sauces
Projects
During my Fall ’23 externship, I processed wmSP and wmS0 heads to be used for Wyatt Mosiman‘s thesis. I used the resulting reproductive data from said heads with the corresponding plant measure data to assess the relationship between cumulative vegetative effort over 5 years (2018-2022) and reproductive effort and success in 2023. The path to my materials is: ~/Dropbox/ccExterns2023/ioHarris
I want to study biology and learn more about plant science.
Statement
I am from Houston, Texas.
In my spare time I like to play the trumpet and play games.
Echinacea Research Project
Introduction
The goal of my externship was a research project about Echinacea where I asked two questions and then conducted a study. The first question is does having taller head height increase pollination rates by insects in Echinacea. My second question is does having more heads increase or decrease pollination by insects in Echinacea.
Background
Echinacea is insect-pollinated mainly by bees and other studies I found have shown that in plants like C. behrii and V. thapsus taller heads are more likely to be pollinated because they are more visible to pollinators. Since we don’t know if head height plays a similar role in Echinacea I am conducting this study to see if there is any correlation between head height and pollination rates in Echinacea.
Another study I found saw more heads leading to greater pollination rates. However, Echinacea is self-incompatible, meaning it can not pollinate itself, unlike the plants in that study so its possible that if an insect stays at a single Echinacea plant with more heads instead of moving on to other plants it could actually hurt its pollination rate. This led me to my second research question to determine if there is a correlation between number of heads and pollination rates in echinacea.
Methods
I used data from a sample of about 229 heads that were put through a data collection process aimed at separated and analyzing the achenes in Echinacea heads. Achenes are the fruit that contain seeds in Echinacea heads so by analyzing if they contain seeds or not we can gather pollination data for this experiment. In the first step of the process we cleaned the heads for achenes. Then we rechecked our first count for accuracy and scanned the achenes into the computer for counting. Lastly, we randomized our achenes, separated them to be x-rayed, and classified them to see which achenes contained seeds giving us our pollination rates.
Question 1
After the data collection process the data was compiled into spreadsheets that were uploaded into R. I put the data on a scatterplot with head height vs pollination rate to create a regression line that had a positive correlation but was also very scattered. To see if that correlation was significant I conducted a linear regression analysis and found that it was significant so taller head height does seem to be related to higher pollination rates.
Question 2
I used boxplots to visualize this data with number of heads for an individual Echinacea plant vs average pollination rate and the pollination rate seems to go up as number of heads increase, the opposite of what I was expecting with self-incompatibility. I then conducted an ANOVA test and found that the difference in average pollination rate by number of heads was not significant so number of heads does not seem to have an effect on pollination rates.
Conclusion
My results gave a positive correlation between head height and pollination rate and no correlation between number of heads and average pollination rate. However, a big limitation to my study was the sample size, especially for question two. Only having one data point for the 5 and 7 heads categories could have a large effect on the data. Lastly, since this was an observational study we can only infer correlation not causation so someone conducting an actual experiment would be a good direction to go in the future.
Acknowledgements and Bibliography
Bibliography-
Dickson, C.R., Petit, S. Effect of individual height and labellum colour on the pollination of Caladenia (syn. Arachnorchis) behrii (Orchidaceae) in the northern Adelaide region, South Australia. Plant Syst. Evol. 262, 65–74 (2006). https://doi.org/10.1007/s00606-006-0472-3
LORTIE, Christopher J., and Lonnie W. AARSSEN. “The Advantage of Being Tall: Higher Flowers Receive More Pollen in Verbascum Thapsus L. (Scrophulariaceae).” Écoscience 6, no. 1 (1999): 68–71. http://www.jstor.org/stable/42901102.
Ohashi K, Yahara T. Effects of variation in flower number on pollinator visits in Cirsium purpuratum (Asteraceae). Am J Bot. 1998 Feb;85(2):219. PMID: 21684905.
Wagenius S, Lyon SP. Reproduction of Echinacea angustjfolia in fragmented prairie is pollen-limited but not pollinator-limited. Ecology. 2010 Mar;91(3):733-42. doi: 10.1890/08-1375.1. PMID: 20426332.
Thanks to Wyatt and Abby for helping me with data collection, Stuart for helping me develop ABTs and to the National Science Foundation for providing funding.
Materials that were used for my project can be found in the filepath: ~/Dropbox/ccExterns2023/conlanRamirez
I am interested in plant conservation and learning how a long-term research project is conducted. I am also interested in seeing what impacts of climate change can be observed in a study like the Echinacea Project.
Statement
I am from New Hampshire and enjoy photography, especially nature and wildlife photography.
I want to study bees while I am on team echinacea, specifically how burning the prairie impacts them. I also want to learn to identify native plants!
Statement
I am from Plainfield, IL originally but I spend most of the year in Wooster, OH on my college campus.
In my spare time I like to get on some wheels (skateboarding, biking, rollerblading, roller skating etc.) to take my dogs out, camp, read, binge shows, craft, play games or nap with my cat.
I want to study all varieties of wild flowers and native grasses. I also wish to learn about how the environment affects them and the impact they have on the ecosystem around them. i am also very exited to be part of a team and learn how a research project like this one works!
Statement
I am from Hoffman, MN
In my spare time I like to hang out with friends, run, listen to music, and go hiking to explore the outdoors.
High School Teacher- Peachtree Ridge HS, Suwanee GA
Pronouns: she/her
Research Interests
I want to learn all I can about prairie grass! I currently teach 9th grade biology. This summer I am focused on project based learning and incorporating Team Echinacea’s work into the classroom. I live far from any prairie but want my students to have the opportunity to learn from engaging and inquiry based lessons about prairie ecology.
Statement
I am from Suwanee GA
In my spare time I like to embroider and go on long walks.
As someone coming from a pre-health background, I am still exploring my interests in the different areas of plant research. I am interested in learning more about native plants, conservation, and plant ecology. I am also interested in learning more about human and animal interactions with plants.
Statement
I am from Chicago! I have always been interested in science and biology, so going into pre-med/pre-health seemed like the most rational decision to make. However, after taking more biology classes involving plants and ecology, I became more interested in plant ecology and human-plant/animal-plant interactions.
In my spare time, I like to knit/crochet (would love to get back into embroidery and sewing), spend time by the lakefill, watch dramas, and be a virtual farmer in Stardew. This summer, I would love to explore the garden more and to learn more plant names.
I’d like to pursue more research in pollinator-plant interactions and how the environment can affect pollinator behavior. I’m interested in conservation ecology and I’m excited to study how fire might affect bee nesting this summer.
Statement
I grew up in Texas, but luckily escaped and lived in Illinois for college. I became really interested in entomology and conservation while working closely alongside my professors, and I hope to dive into this intersecting field more in the future!
In my spare time I like to read, draw/paint, watch movies, listen to a ton of music, and go camping.