title: Emergence of evolutionary cycles in size-structured food webs.
abstract: The interplay of population dynamics and evolution within ecological communities has been of long-standing interest for ecologists and can give rise to evolutionary cycles, e.g. taxon cycles. Evolutionary cycling was intensely studied in small communities with asymmetric competition; the latter drives the evolutionary processes. Here we demonstrate that evolutionary cycling arises naturally in larger communities if trophic interactions are present, since these are intrinsically asymmetric. To investigate the evolutionary dynamics of a trophic community, we use an allometric food web model. We find that evolutionary cycles emerge naturally for a large parameter ranges. The origin of the evolutionary dynamics is an intrinsic asymmetry in the feeding kernel which creates an evolutionary ratchet, driving species towards larger bodysize. We reveal different kinds of cycles: single morph cycles, and coevolutionary and mixed cycling of complete food webs. The latter refers to the case where each trophic level can have different evolutionary dynamics. We discuss the generality of our findings and conclude that ongoing evolution in food webs may be more frequent than commonly believed.
authors.affiliation: University of Bristol, Faculty of Engineering, Merchant Venturers Building, BS8 1UB, United Kingdom; CvO University Oldenburg, ICBM, Carl-von-Ossietzky-Strasse 9-11, 26111 Oldenburg, Germany. Electronic address: daniel.ritterskamp@bristol.ac.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ritterskamp
authors.affiliation: CvO University Oldenburg, ICBM, Carl-von-Ossietzky-Strasse 9-11, 26111 Oldenburg, Germany. Electronic address: daniel.bearup@uni-oldenburg.de.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bearup
authors.affiliation: CvO University Oldenburg, ICBM, Carl-von-Ossietzky-Strasse 9-11, 26111 Oldenburg, Germany. Electronic address: blasius@icbm.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Blasius
mesh_terms: D000818:Animals; D005075:Biological Evolution; D020387:Food Chain; D008954:Models, Biological; D011157:Population Dynamics
keywords: Coevolution; Community cycling; Evolutionary limit cycles; Red-Queen dynamics; Taxon cycles