The Interaction Between Exploitative and Interference Competition: Limits to R* Theory

Smith, D. J. B.; Masel, J.

doi:10.1101/2023.09.27.559600

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bioRxiv · 10.1101/2023.09.27.559600

The Interaction Between Exploitative and Interference Competition: Limits to R* Theory

Smith, D. J. B.·Masel, J.

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Abstract

Many ecological models treat exploitative competition in isolation from interference competition. Corresponding theory centers around the R* rule, according to which consumers who share a single limiting resource cannot coexist. Here we model motile consumers that directly interfere while handling resources, mechanistically capturing both exploitative and interference competition. Our analytical coexistence conditions show that interference competition readily promotes coexistence. In contrast to previous theory, coexistence does not require intra-specific interference propensities to exceed inter-specific interference propensities, nor for interference behaviors to carry a direct (rather than merely an opportunity) cost. The underlying mechanism of coexistence can resemble the hawk-dove game, the dominance-discovery trade-off (akin to the competition-colonization trade-off), or a novel trade-off we call the "dove-discovery trade-off", depending on parameter values. Competitive exclusion via the R* rule occurs only when differences in exploitative abilities swamp other differences between species, and more easily when differences in R* reflect different search speeds than when they reflect different handling times. Our model provides a mathematically tractable framework that integrates exploitative and interference competition, and synthesizes previous disparate models.

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Smith, D. J. B., Masel, J.. 2023-09-29. The Interaction Between Exploitative and Interference Competition: Limits to R* Theory. https://doi.org/10.1101/2023.09.27.559600

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