This is the third short news article written by students, during the professional development class of Spring 2025, about each other's research.
Mia Esoldo
Student Spotlight: Mia Esoldo
By Nina Devine
As a white-footed mouse, life isn't easy. You're constantly dodging snakes, owls, and other predators, not to mention those brutal winter hibernations. And if that wasn't enough, you just felt something latch onto your back right where you can't reach it. It's one of Pennsylvania's most feared arthropods: the tick. As a mouse, you've dealt with your fair share of these eight-legged bloodsuckers, but this one feels… different. How will you deal with this new bloodthirsty parasite? Graduate student and mouse wrangler extraordinaire Mia Esoldo is about to find out.
Mia is a Master's student in Dr. Erika Machtinger's lab, where she has been studying what makes ticks tick since she started as a research assistant in 2021. Her research focuses on competitive dynamics between the native blacklegged tick (Ixodes scapularis) and regionally invasive ticks such as the Gulf coast tick (Amblyomma maculatum), and the lone star tick (Amblyomma americanum).
Says Esoldo, "I'm fascinated by those competitive interactions and gaps in the knowledge, where we don't really know how immunity towards ticks works in important reservoir hosts like mice. It's interesting to think that getting bit by a blacklegged tick could cause immunity to a lone star tick."
As climate change warms the planet, it creates opportunities for southern tick species to expand their range northward. But with these newcomers comes conflict. Researchers need to understand if they will potentially outcompete native ticks and what that means for the transmission of tick-borne illnesses like Lyme disease. Inspired by the CDC's One Health initiative, Esoldo seeks to bridge the gap between wildlife and human health.
Esoldo explains: "Here's a mouse, here's a human. I want to educate the public on how vector-borne disease moves through ecological systems and answer pressing questions, like how will mice cope with infestations from regionally invasive and native tick species at the same time? And how might competitive interactions between ticks of different species influence tick feeding success?"
To answer these questions, Mia uses a combination of laboratory experiments with mouse colonies as well as computer vision software that tracks mouse behavior. Her lab experiments use "tick capsules": small foam capsules that are glued onto the back of a mouse to localize tick feeding and make it easier for her to locate and identify the ticks. In one project, she successively infests a mouse with each tick species separately, then measures the ticks' growth and weight gain. She hypothesizes that prior exposure to one tick species will reduce the feeding success of subsequent species, indicating cross-species immune protection. In another capsule experiment, she co-infests the mouse with both a native and invasive species, and records where in the capsule the ticks are feeding, as well as whether ticks of the same species prefer to group together at a feeding site. For her third project, she uses Ethovision software to track mouse grooming behavior after tick infestation. She thinks that infestation with Gulf coast ticks will cause increased grooming behavior, because their bites are said to be more painful – ouch!
Understanding these competitive dynamics is critical for managing the transmission of Lyme disease, which can only be transmitted by the blacklegged tick in Pennsylvania. A tick's first meal is often a white-footed mouse, so information on how ticks affect mouse immunity is essential for a vector control program. Esoldo’s research will pave the way for new avenues of tick research, and further our understanding of the impact of invasive species on disease transmission.
Mia Esoldo is a MSc Student in the Machtinger Veterinary Entomology research group in the Department of Entomology at Penn State.
