Data from: Emergence of weak‐intransitive competition through adaptive diversification and eco‐evolutionary feedbacks

Indirect biotic interactions—such as intransitive competition—are
increasingly recognized as being important in shaping ecological patterns
in natural systems. Over long time‐scales, such indirect interactions may
affect the evolution of species phenotypes, which in turn can modify these
interactions, thereby begetting eco‐evolutionary feedbacks. If indirect
intransitive interactions can emerge in situ during lineage
diversification, they could profoundly affect species’ phenotypic
diversity, temporal stability, and subsequent diversification rates. We
address these questions by investigating the conditions under which
indirect intransitive competition can emerge from a lineage diversifying
in sympatry. We use an adaptive dynamics model to study the ecological and
evolutionary properties of this lineage under different scenarios where
competition for resources between phenotypes varies in strength and
(a)symmetry. Results show that weak‐intransitive competition can emerge
during the sympatric diversification of a single lineage.
“Weak‐intransitivity” here refers to situations where species interactions
are not perfectly transitive, that is, there is no strict hierarchy in
species competitive abilities. The strength of such weak‐intransitivity
increases when the competition between phenotypes increases in strength
and asymmetry. The strength of intransitivity also correlates with other
system properties. We notably found that the strength of intransitivity
increases with the number of phenotypes, and that greater intransitivity
correlates with the evolution of greater functional trait divergences
between phenotypes, greater resistance to invasion by new phenotypes but
lower resistance to disturbances as well as slower evolutionary rates.
Synthesis. This theoretical exploration of the evolution of intransitive
competition provides the first formal bridge between the ecological and
evolutionary aspects of intransitive competition. We show that, when
competitive interactions are strong enough, weak‐intransitive competition
is more likely to emerge through adaptive diversification than from a
random community assembly. Intransitive competition is, therefore, not
only restricted to between‐species interactions but can also function as a
regulator of diversification within species, thereby affecting lineage
functional diversity, and ecological and evolutionary stability.