CELL VOLUME AS A DETERMINANT OF VIRUS-MEDIATED POPULATION GROWTH IN CILIATES

Many protist species consume viruses, a behavior known as virovory. Some species, such as the ciliate <em>Halteria grandinella<em>, can grow with viruses as their sole food source. Many other ciliate species have been documented consuming viral particles, but virovory’s impacts on their populations’ growth remain unclear. We hypothesize that virovory is not unique to <em>Halteria<em>, and that other species will show similar population growth when fed viruses. Because ciliates’ energy demands increase significantly with size, we also hypothesize that cell volume is one of the key factors influencing ciliate species’ ability to subsist on viruses. To test these hypotheses, we fed nine ciliate species of varying sizes and genera a diet of viruses over a two-day period. We found that most species’ populations grew better with access to viruses, supporting our first hypothesis. However, this growth was independent of ciliate cell volume, and even varied significantly between species with otherwise similar morphologies, such as the three <em>Paramecium<em> species. These results do not support our second hypothesis and are cause for further investigation. Taken together, these data suggest that virovory-driven population growth is widespread among ciliates, even if the physiological factors which determine virovory’s effects on population growth remain unknown. Because ciliates are a key node in most aquatic food webs, widespread virovorous behavior may have important implications for energy at nutrient transfers at higher trophic levels than previously realized.

Primary Presenter: Jace Miller, University of Nebraska-Lincoln Lib - Lincoln, NE (jace.k.miller2000@gmail.com)

Authors:

Jace Miller, University of Nebraska-Lincoln  (jace.k.miller2000@gmail.com)

John Delong, University of Nebraska-Lincoln  (jpdelong@unl.edu)

Jessica Corman, University of Nebraska-Lincoln  (jcorman3@unl.edu)