Honors Program


Document Type


Date of this Version

Spring 3-10-2023


Miller, J. and DeLong, J. P. (2023). “Cell volume as a determinant of virus-mediated population growth in ciliates”. Undergraduate Honors Thesis. School of Biological Sciences, University of Nebraska-Lincoln


Copyright Jace Miller and John Paul DeLong 2023.


Many protists and other small aquatic organisms consume virus particles, a behavior known as virovory. Some species of protists, such as the ciliate Halteria grandinella, can grow and divide using viruses as their sole food source. Other ciliate species have previously been shown to consume large quantities of viral particles, but it is unclear if they are able to support population growth with viruses alone. Because large ciliates have a higher energy demand, we hypothesize that they will be unable to support population growth on a virus-only diet. We fed nine ciliate species a diet of chloroviruses and found that most species’ populations grew better with viruses added relative to controls. We found that the increase in growth rate relative to controls was independent of cell volume. Our results indicate that virovory-driven population growth is widespread among ciliates, but that the factors which determine the impact of viruses on population growth remain unknown.