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Carnivorous Pitcher Plant Food Web Analysis with Alicia McGrew

Alicia McGrew, a PhD student at the University of Florida, visited Fluid Imaging Technologies headquarters in Scarborough, Maine to get trained on the FlowCam for her upcoming research. I snagged an interview with her to discuss her research and her journey into science. Read on!

Hi Alicia! Can you tell us who you are and where you come from?

I'm a PhD student in the Baiser Lab of Community Ecology at the University of Florida. Our lab has a website!

What are you researching?Alicia McGrew PhD Student at University of Florida

I work with the carnivorous pitcher plant Sarracenia purpurea, which is unique among the carnivorous plants. While most carnivorous plants use digestive enzymes to release nutrients for the plant to take up, the pitcher plant has a complex food web which consists of bacteria, protozoans, rotifers, mites and insect larvae.  Some of these species are co-evolved with S. purpurea, and are only found in its food web. This food web works together to digest the prey that falls into the plant. 

This summer I'll be manipulating bottom-up and top-down processes in the pitcher plant's food web by varying nutrient levels as well as levels of the top predator (which in this case is the mosquito larva). I’ll manipulate those two aspects and observe the interraction and impact on the size spectrum of organisms of the community. A larger aquatic system such as a lake would prove a much more challenging task.  Lakes vary greatly (there are so many different variables) whereas pitcher plants are much more consistent and contained.

healthy red pitcher plant

Why do you use the pitcher plant for your research?

It provides a nice a model system for testing things in ecology and evolution. The pitcher plant shares a lot of traits with larger aquatic systems-- nutrient cycling dynamics, complex species interactions, and some separation of organisms and trophic interactions within the water column, among others. The pitcher system is also much more tractable and easier to manipulate than a large mesocosm of lake water, or an entire pond or lake.

I'm taking an idea developed in larger aquatic and marine systems and applying it to the pitcher plant. In the pitcher plant, I am able to measure the food web across all trophic levels, which is much harder to do in a lake or an ocean. Usually, researchers focus on a subset of the food web, such as zooplankton or fish, but with the pitcher plant I'm able to measure how my experimental treatments impact organisms from the base of the food web up to the top predator.

Ultimately, I want to see if I can apply my conclusions from a smaller system and scale them up to make comparisons with larger aquatic systems.

Why are you using the FlowCam?

I've looked at a number of instruments and none of them allow me to measure the full size range that I need for my experiments. The FlowCam accommodates the size range of organisms that I am studying. Also, I can actually see what's going on in the sample. With the other instruments, I can't tell if that data point is an air bubble, a piece of dust, a piece of detritus, or an organism. The FlowCam gives me a picture and 40 something properties per particle. I'll be using Dana Stephens' FlowCam at Northwest Florida State College for my experiments this summer.

Where does your interest in science come from? How did you end up where you are?

Haha I'm a long way from where I started! I was a dance and French literature major. Honestly, I never planned on going to graduate school. In my last semester in my undergraduate course, I needed to fulfill course requirements and ended up taking all aquatic science classes. I looked at Daphnia under a microscope, and I was like, "This is the coolest thing in the whole world. This is what I want to do."

Pitcher plant from Saco Heath Preserve

Wow, in your last year?

In my last semester! I was very late in the game. Following graduation, I worked for a semester as a lab tech and ended up doing my Master’s in that lab.

What was it about seeing Daphnia under the microscope that was so inspiring?

I realized "There are so many things I don't know in this world (and they are tiny!) " I think when people think about animals, they think vertebrates and mammals. And then here are these tiny things with amazing life histories that rule the world. We wouldn't have anything if not for the tiny things.

So that was the day you became a scientist?

That day in my Limnology Methods class, when we looked at plankton samples under the microscope. Yes, that was the day that set me on my current path.

Do you have any advice for those pursing or interested in pursuing a career in science?

Three things: First, there will be drudgery and dreary times, but you have to push through. There are awesome moments that make the dreary times worthwhile, and there will be something awesome at the end of it all.

Second, you must love to learn and to be open to trying new things.  Learn how to accept criticism, and be open to changing as you progress along your path.

Finally, as an aside for young women exploring STEM fields, I want to say that the door is open. There are opportunities, and there is absolutely a place for you and people who will root for you. You have to be willing to work for those opportunities, to push past the obstacles, and to remind yourself, "I can do this. I want to do this."

McGrew sampling pitcher plants at the Saco Heath Preserve during FlowCam training
McGrew sampling pitcher plants at the Saco Heath Preserve in Saco, Maine during her training at Fluid Imaging Technologies. 


Alicia McGrew received her B.S. in Biology (Natural Resources) and M.S. in Conservation Biology from Central Michigan University in Mount Pleasant, Michigan. She is in the second year of her five year PhD program at the University of Florida. You can read more about Alicia's research on the Baiser Lab's website.

Topics: Freshwater Research, User Spotlight, Aquatic Research