title: Multi-mode fluctuating selection in host-parasite coevolution.
abstract: Understanding fluctuating selection is important for our understanding of patterns of spatial and temporal diversity in nature. Host-parasite theory has classically assumed fluctuations either occur between highly specific genotypes (matching allele: MA) or from specialism to generalism (gene-for-gene: GFG). However, while MA can only generate one mode of fluctuating selection, we show that GFG can in fact produce both rapid 'within-range' fluctuations (among genotypes with identical levels of investment but which specialise on different subsets of the population) and slower cycling 'between ranges' (different levels of investment), emphasising that MA is a subset of GFG. Our findings closely match empirical observations, although sampling rates need to be high to detect these novel dynamics empirically. Within-range cycling is an overlooked process by which fluctuating selection can occur in nature, suggesting that fluctuating selection may be a more common and important process than previously thought in generating and maintaining diversity.
authors.affiliation: Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, UK.|Integrative Biology, University of California Berkeley, Berkeley, CA, USA.
authors.forename: Ben
authors.initials: B
authors.lastname: Ashby
authors.affiliation: Integrative Biology, University of California Berkeley, Berkeley, CA, USA.|Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9EZ, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Boots
mesh_terms: D005075:Biological Evolution; D005838:Genotype; D006790:Host-Parasite Interactions; D008954:Models, Biological; D012641:Selection, Genetic
keywords: Coevolution; Red Queen; cycling; fluctuating selection; gene-for-gene; host-parasite; matching allele