Heterotrophic eukaryotes show a slow-fast continuum, not a gleaner-exploiter trade-off

Thomas Kiørboe*, Mridul K. Thomas

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


Gleaners and exploiters (opportunists) are organisms adapted to feeding in nutritionally poor and rich environments, respectively. A trade-off between these two strategies-a negative relationship between the rate at which organisms can acquire food and ingest it-is a critical assumption in many ecological models. Here, we evaluate evidence for this trade-off across a wide range of heterotrophic eukaryotes from unicellular nanoflagellates to large mammals belonging to both aquatic and terrestrial realms. Using data on the resource acquisition and ingestion rates in >500 species, we find no evidence of a trade-off across species. Instead, there is a positive relationship between maximum clearance rate and maximum ingestion rate. The positive relationship is not a result of lumping together diverse taxa; it holds within all subgroups of organisms we examined as well. Correcting for differences in body mass weakens but does not reverse the positive relationship, so this is not an artifact of size scaling either. Instead, this positive relationship represents a slow-fast gradient in the "pace of life" that overrides the expected gleaner-exploiter trade-off. Other trade-offs must therefore shape ecological processes, and investigating them may provide deeper insights into coexistence, competitive dynamics, and biodiversity patterns in nature. A plausible target for study is the well-documented trade-off between growth rate and predation avoidance, which can also drive the slow-fast gradient we observe here.
Original languageEnglish
Article number202008370
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number40
Number of pages7
Publication statusPublished - 2020


  • Resource aquisition
  • Maximum ingestion rate
  • Maximum clearance rate
  • Pace of life
  • r-K selection

Fingerprint Dive into the research topics of 'Heterotrophic eukaryotes show a slow-fast continuum, not a gleaner-exploiter trade-off'. Together they form a unique fingerprint.

Cite this