Predators catalyze an increase in chloroviruses by foraging on the symbiotic hosts of zoochlorellae

John P. DeLong, Zeina Al-Ameeli, Garry Duncan, James L. Van Etten, David D. Dunigan

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Virus population growth depends on contacts between viruses and their hosts. It is often unclear how sufficient contacts are made between viruses and their specific hosts to generate spikes in viral abundance. Here, we show that copepods, acting as predators, can bring aquatic viruses and their algal hosts into contact. Specifically, predation of the protist Paramecium bursaria by copepods resulted in a >100-fold increase in the number of chloroviruses in 1 d. Copepod predation can be seen as an ecological "catalyst" by increasing contacts between chloroviruses and their hosts, zoochlorellae (endosymbiotic algae that live within paramecia), thereby facilitating viral population growth. When feeding, copepods passed P. bursaria through their digestive tract only partially digested, releasing endosymbiotic algae that still supported viral reproduction and resulting in a virus population spike. A simple predator-prey model parameterized for copepods consuming protists generates cycle periods for viruses consistent with those observed in natural ponds. Food webs are replete with similar symbiotic organisms, and we suspect the predator catalyst mechanism is capable of generating blooms for other endosymbiont-targeting viruses.

Original languageEnglish (US)
Pages (from-to)13780-13784
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number48
StatePublished - Nov 29 2016


  • Chloroviruses
  • Copepod foraging
  • Paramecium bursaria endosymbionts
  • Predator-prey interactions
  • Virus dynamics

ASJC Scopus subject areas

  • General


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