Long before Daniel “Danny” Villanueva, ’15 BS Biological Sciences, was studying one of the world’s rarest fish species, he was a kid watching nature documentaries with his dad and becoming fascinated by the wildlife featured on screen. That curiosity eventually led him to UNLV, where he studied ecology and evolution and found the experiences that would shape his future as a conservation biologist.

As an undergraduate, Villanueva gained hands-on experience through opportunities like volunteering for the Nevada Department of Wildlife (NDOW) and joining Professor-in-Residence Jef Jaeger to work in his Relict Leopard Frog Lab. 

“One of the defining moments for me was participating in my first wildlife survey with the Nevada Department of Wildlife, which completely hooked me,” Villanueva says.

Villanueva discovered he wanted a career where he could contribute to species conservation through research, highlighting the importance of students having access to undergraduate lab and fieldwork opportunities.

“Often students struggle with finding research opportunities that ‘fit’ with their future plans,” Jaeger says. “I argue that what one does at the undergraduate level [in research] is less important than the experience itself.”

This proved true for Villanueva, who works as a biologist at the Ash Meadows Fish Conservation Facility. His role helping manage the captive refuge population of Devils Hole pupfish shaped his research and led him back to graduate school, where Jaeger serves as the principal advisor for his master’s research.

“Danny didn’t just take a gap year; he built a career, took seasonal positions until he could find more permanent positions and waited until the opportunity for his dream job became available,” Jaeger says.

With his dream job secured, the opportunity arose to combine his professional work and research interests by pursuing a graduate degree focused on Devils Hole pupfish conservation.

“Returning to UNLV felt like a natural choice because of the strong mentorship, research opportunities and connections I had developed during my undergraduate years,” Villanueva says.

Although balancing school, research, a career, and time with his wife and pets has been challenging, returning to school 10 years after completing his undergraduate degree is one of his proudest moments.

Tell us about your research.

My research focuses on predator-prey interactions between predaceous diving beetles (Neoclypeodytes cinctellus) and hybrid Devils Hole pupfish (Cyprinodon diabolis × Cyprinodon nevadensis mionectes). I am examining how predaceous diving beetles interact with pupfish eggs and larvae, with a particular focus on determining which developmental stages are most vulnerable to predation.

Through a combination of laboratory experiments and field observations, I am evaluating how both adult and larval beetles affect pupfish survival and whether environmental factors, such as temperature, influence these interactions.

In addition to studying predation, I have also been investigating aspects of the diving beetle’s life history, including egg development, larval growth and pupation, to better understand the factors that contribute to beetle population outbreaks.

By improving our understanding of these predator-prey dynamics, my research aims to provide information that can help inform management strategies for captive Devils Hole pupfish populations and contribute to the long-term conservation of this critically endangered species.

What is the benefit of combining your career and research?

I have a unique opportunity to observe the challenges involved in conserving one of the world’s rarest fish species. These firsthand experiences often raise questions that can be addressed through scientific research.

In recent years, predaceous diving beetles have become increasingly abundant in the refuge tank, prompting concerns about their potential impacts on pupfish eggs and larvae. Because I work directly with the refuge population, I was able to observe these interactions and develop research questions that are immediately relevant to conservation and management efforts.

This connection between day-to-day management and scientific investigation allows me to conduct applied research that can directly inform decisions made at the facility.

The partnership between my work and graduate research has been especially rewarding because it allows me to contribute both to our understanding of predator-prey dynamics and to the conservation of the Devils Hole pupfish. My goal is to produce research that not only advances scientific knowledge but also provides practical information managers can use to support recovery efforts for this critically endangered species.

What excites you about your research?

The opportunity to answer questions that have direct implications for conservation is exciting. Because the Devils Hole pupfish is one of the rarest fish species in the world, even small improvements in our understanding of factors affecting its survival can be meaningful.

It is rewarding to know that the research I am conducting has the potential to inform management decisions and contribute to the long-term conservation of the species.

I am also excited by the discovery aspect of the work. Predaceous diving beetles and their interactions with pupfish have received relatively little study. So, many of the questions I am investigating have never been examined in detail.

Through my research, I have been able to observe behaviors and life history traits that were previously undocumented, which makes each experiment an opportunity to learn something new.

What’s the bigger picture people should see in your research?

The Devils Hole pupfish is a unique part of our nation’s natural heritage and exists nowhere else in the world. Conserving endangered species like the pupfish helps preserve biodiversity and ensures that future generations can benefit from the ecological, scientific and cultural value these species provide.

Once a species goes extinct, it is gone forever.

My research also highlights the importance of understanding how species interact within ecosystems. Predator-prey relationships are fundamental ecological processes that influence population dynamics and ecosystem health.

By studying these interactions in a conservation setting, we gain knowledge that can be applied not only to the Devils Hole pupfish but also to the management and recovery of other endangered species facing similar challenges.

How is your earlier research on the pupfish guiding your next study?

I am proud of the progress I have made in my research. Early in my graduate studies, I conducted experiments that provided evidence that predaceous diving beetles prey on developing pupfish eggs and hatchlings, helping address an important conservation and management question.

Those initial findings formed the foundation for the larger series of experiments I am conducting today and helped shape the direction of my thesis research. It has been rewarding to see observations from the field develop into a research program with the potential to contribute directly to species conservation and management efforts.

My next project examines how temperature affects predation by predaceous diving beetles on larval hybrid Devils Hole pupfish. I am conducting laboratory experiments at temperatures that mimic three real-world environments: captive hybrid systems (27°C), the refuge tank population (31.5°C), and Devils Hole itself (33°C).

By comparing predation rates across these temperatures, I hope to better understand how environmental conditions influence predator-prey interactions and whether temperature may play a role in pupfish survival.

This work will build on my previous studies of beetle predation and help provide a more complete picture of the factors affecting this endangered species.