Jess – principle investigator

Hi! I’m Jess Stephenson, Assistant Professor at the University of Pittsburgh (since July 2018). Before this, I was a post-doc in Zürich, Switzerland, and before that I was doing my PhD in Cardiff, UK. You can download my C.V. here for more info, or just email:

Izabelle Weiler

Izabelle manages the people and things in the lab and keeps everything running smoothly! So. Many. Lists. She is interested in developing research at the intersection of disease ecology and conservation. Email her at

Mary Janecka – post doc

Mary is working on the guppy-gyro system from the parasite’s perspective, by addressing cool questions such as ‘What factors affect their transmission and mating strategies?’ To do this, she is applying her molecular biology skills, and developing some next-gen know how! For more info, email, or see Mary’s website:

Jason Walsman – post doc

Jason develops and tests theory of the interactions between individual-level, disease processes and population-level ecology. Particularly, he is studying interactions between parasite virulence evolution, host social behavior, and within- and between-host interactions.

For more info, see

or email

David Clark – grad student

David is interested in host-parasite eco-evolutionary dynamics. More specifically, he wants to explore the cost of parasite infection, how hosts offset this cost, and what factors could influence this interaction. 

To learn more about David and his awesome research, visit his website:

Or email him:

Rachael Kramp – grad student

Rachael is particularly interested in looking at the frequency of hybridization/sexual reproduction of Gyrodactylus turnbulli in response to environmental changes. Specifically, how host skin microbiome disturbance influence infection burden, transmission, and adaptation of our model parasite. Find out more at!

Faith Rovenolt – grad student

Faith is interested in modeling host-parasite interactions, especially the role of host resistance and tolerance in disease dynamics as well as the impact of host sex differences and sexual selection. You can contact her at

Undergraduate researchers

Currently in the lab we have:
Madalyn Lambe
Emmy Calcaterra

Past lab members

We have worked with a lot of excellent undergrads, many of whom are not on the website because I (Jess) am very slow at updating it.

John Hansen

John worked on a few different things because he’s awesome and interested in everything. He analysed behaviour videos, extracted data from published studies, and taught himself R.

Maura Sackett

Maura analysed lots of behavioural videos, read a lot about guppies, gyros, and behaviour, and wrote a manuscript! She majored in communications as well as biology so we shouldn’t be surprised (but still impressed!).

Stevie also analysed a lot of videos (theme emerging!), reads a lot, and has brilliant ideas that improved our experiments.

Stevie Kisty

Regina Patrick – lab manager

Regina helped set up the lab and kept it running smoothly – pandemic and all! She has now moved on to bigger and better water quality things!

Maya Jog – Pitt undergrad researcher

Maya analysed a lot of behaviour videos, reviewed the literature on social context and sickness behaviour, and then graduated early to go to med school. Sorry to lose you, Maya, but congrats again!

Elizabeth Rudzki – grad student

Elizabeth is advised by the awesome Kevin Kohl, and during her time in the lab contributed a lot to our project on the role of the guppy microbiome in mediating its relationship with gyros.

Here are some of our collaborators – lovely people!