title: Does frequency-dependence determine male morph survival in the bulb mite Rhizoglyphus robini?
abstract: Alternative reproductive phenotypes (ARPs) represent discrete morphological variation within a single sex; as such ARPs are an excellent study system to investigate the maintenance of phenotypic variation. ARPs are traditionally modelled as a mixture of pure strategies or as a conditional strategy. Most male dimorphisms are controlled by a conditional strategy, where males develop into a particular phenotype as a result of their condition which allows them to reach a certain threshold. Individuals that are unable to reach the threshold of a conditional strategy are considered to 'make the best of a bad job'; however, these individuals can have their own fitness merits. Given these fitness merits, condition-dependent selection alone is not sufficient to maintain a conditionally determined male dimorphism and other mechanisms, most likely frequency-dependent selection, are required. We studied in an experiment, the male dimorphic bulb mite Rhizoglyphus robini-where males are fighters that can kill other males or benign scramblers-to assess the strength of frequency-dependent survival in a high and low-quality environment. We found that male survival was frequency-dependent in the high-quality environment but not the low-quality environment. In the high-quality environment the survival curves of the two morphs crossed but the direction of frequency-dependence was opposite to what theory predicts.
authors.affiliation: Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS, UK, jacques.deere@zoo.ox.ac.uk.
authors.forename: Jacques A
authors.initials: JA
authors.lastname: Deere
authors.forename: Isabel M
authors.initials: IM
authors.lastname: Smallegange
mesh_terms: D000818:Animals; D008297:Male; D008925:Mites / Q000033:anatomy & histology / Q000502:physiology*; D008954:Models, Biological; D010641:Phenotype; D011157:Population Dynamics; D012726:Sexual Behavior, Animal