Interview with the author: Human activity can influence the gut microbiota of Darwin’s finches in the Galapagos Islands

We interviewed Sarah Knutie (an Assistant Professor at the University of Connecticut) about the research she led examining how humans can shape the microbiota of Darwin’s finches in unexpected ways. Read the full text below:

Knutie, SA, Chaves, JA, Gotanda, KM. Human activity can influence the gut microbiota of Darwin’s finches in the Galapagos Islands. Mol Ecol. 2019; 28: 2441– 2450.

Image credits: Kiyoko Gotanda
  • What led to your interest in this topic / what was the motivation for this study? 

The inspiration for this project came from our observations of Darwin’s finches trying to steal food from our plates and my co-authors’ recent paper (De Leon et al. 2018) showing that the diet of finches differed in urban and non-urban areas. Since diet can influence the gut microbiota of the host, Kiyoko and I decided to return to the same field site and look at how the gut microbiota of Darwin’s finches differ among sites with varying exposure to human activity. However, at the time, Kiyoko and I were both post-docs without funding for our idea, so we decided to crowdfund the project (Kiyoko was more successful than me!). With help from our crowdfunding campaign and our own out-of-pocket money, we were able to head to the Galapagos for a few weeks to collect the fecal samples for our study.

De León, L. F., Sharpe, D. M., Gotanda, K. M., Raeymaekers, J. A., Chaves, J. A., Hendry, A. P., & Podos, J. (2018). Urbanization erodes niche segregation in Darwin’s finches. Evolutionary Applications.

What difficulties did you run into along the way? 

We decided to do all of the bacterial DNA extractions in the Galapagos since we were unsure whether we would be able to export our samples immediately after the field season. However, equipment and lab space can be hard to come by in the Galapagos. Therefore, we created a clean extraction space in our apartment with whatever equipment I could buy on the cheap and transport from the US to our Galapagos “lab”. Specifically, I brought a sous vide for the heat step and rigged a vintage vortex for the agitation step of the extraction. Was that just an #OverlyHonestMethods moment?

  • What is the biggest or most surprising finding from this study? 

Even though De Leon et al. (2018) found that the diet of Darwin’s finches differed in response to urbanization, I was not confident that we would find parallel differences in the gut microbiota. Although the field sites vary in their exposure to human activity, they are geographically quite close to each other. Therefore, a part of me thought that our samples sizes would not be large enough to detect an effect of site on the gut microbiota. Fortunately, my gut instinct was wrong and our study demonstrated that human activity can impact the gut microbiota and body mass of finches, even among adjacent sites.

  • Moving forward, what are the next steps for this research? 

My lab is currently looking at whether the gut microbiota of urban and non-urban Darwin’s finches influences their immune response to the invasive parasitic nest fly Philornis downsi. Since the gut microbiota can affect the development and maintenance of the immune system and the gut microbiota of finches is affected by human activity, it is possible that urban finches defend themselves differently against the invasive parasite than non-urban birds.

  • What would your message be for students about to start their first research projects in this topic? 

Start by being present. My favorite project ideas are inspired by observations in the field.  Once you are inspired, be a sponge. Read everything that you can about your topic and if you have the opportunity, talk with experts in the field. Then, create a solid study design using the scientific method; think through all possible outcomes and draw graphs of your predicted results. Although establishing patterns (like in the published paper) is very important to understand the underlying function of the microbiota, try to determine causation with an experiment, if possible. If applicable, when you start your DNA extractions, especially if you are working with birds, talk to experts in the field. Many colleagues and myself have resolved issues with the extraction protocols and sequencing and might be able to help.  

  • What have you learned about science over the course of this project? 

I have learned to find collaborators who I enjoy working with on projects. Science is so much more fun when you can interact with brilliant and kind people.

  • Describe the significance of this research for the general scientific community in one sentence.

Human presence in the Galapagos Islands is affecting the gut microbiota and body mass of Darwin’s finches.

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