Congratulations to Asa Gray Distinguished University Professor of Ecology and Evolutionary Biology and
Arthur F. Thurnau Professor, John Vandermeer, for the publication of the paper titled "Adding species to an intransitive triplet: competition, hierarchy, and recoupling", in Theoretical Ecology.
Abstract:
There is some debate as to whether intransitive or transitive competition dominates natural communities (Soliveres et al., 2015; Shipley and Keddy, 1994). Certainly, in relatively large communities, it would be unlikely that either form could be completely avoided, leading to the issue of communities containing both transitive and intransitive elements. Based on a study of ants in coffee agroecosystems (Vandermeer and Perfecto, 2023; 2024), it has been noted that a strong intransitive loop seems connected to several transitive elements, in a formulation wherein a transitive “tail” is “recoupled” to a basic intransitive loop. Elaborating some theoretical consequences of this qualitative structure, when species numbers are odd, either the ultimate or penultimate species goes extinct, leaving a community of an intransitive structure with a transitive tail, with no recoupling to the intransitive part. When species numbers are even, on the other hand, increased recoupling results in a Hopf bifurcation, then expanding limit cycles, then chaos, and finally a heteroclinic cycle.
