Healthy herds in the phytoplankton: the benefit of selective parasitism

Davis Laundon, Thomas Mock, Glen Wheeler, Michael Cunliffe

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


The impact of selective predation of weaker individuals on the general health of prey populations is well-established in animal ecology. Analogous processes have not been considered at microbial scales despite the ubiquity of microbe-microbe interactions, such as parasitism. Here we present insights into the biotic interactions between a widespread marine thraustochytrid and a diatom from the ecologically important genus Chaetoceros. Physiological experiments show the thraustochytrid targets senescent diatom cells in a similar way to selective animal predation on weaker prey individuals. This physiology-selective targeting of ‘unhealthy’ cells appears to improve the overall health (i.e., increased photosynthetic quantum yield) of the diatom population without impacting density, providing support for ‘healthy herd’ dynamics in a protist–protist interaction, a phenomenon typically associated with animal predators and their prey. Thus, our study suggests caution against the assumption that protist–protist parasitism is always detrimental to the host population and highlights the complexity of microbial interactions.
Original languageEnglish
Pages (from-to)2163–2166
Number of pages4
JournalThe ISME Journal
Issue number7
Early online date4 Mar 2021
Publication statusPublished - Jul 2021

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