title: Dynamics of production of sexual forms in aphids: theoretical and experimental evidence for adaptive "coin-flipping" plasticity.
abstract: The best strategy for an organism to deal with unpredictable environmental conditions is a stochastic one, but it is not easy to distinguish it from nonadaptive randomness in phenotype production, and its convincing demonstrations are lacking. Here we describe a new method for detection of adaptive stochastic polyphenism and apply it to the following problem. In fall, each female of the bird cherry-oat aphid, Rhopalosiphum padi, faces a decision either to produce sexuals, which mate and lay cold-tolerant eggs, or to continue production of cold-sensitive parthenogenetic females, which potentially yields a higher population growth rate but is risky because a cold winter can kill all of her descendants. Using a simulation model, we show that global investment in sexual reproduction should be proportional to winter severity and that variance in the peak date of production of sexual individuals should depend on climate predictability. Both predictions are validated against standardized trap data on aphid flight accompanied by meteorological data, and the predictions support adaptive phenotypic plasticity.
authors.affiliation: Unité Mixte de Recherche Institut National de la Recherche Agronomique/Agrocampus de Rennes, Biologie des Organismes et des Populations, appliquée à la Protection des Plantes, 35042 Rennes Cedex, France. halkett@roazhon.inra.fr
authors.forename: Fabien
authors.initials: F
authors.lastname: Halkett
authors.forename: Richard
authors.initials: R
authors.lastname: Harrington
authors.forename: Maurice
authors.initials: M
authors.lastname: Hullé
authors.forename: Pavel
authors.initials: P
authors.lastname: Kindlmann
authors.forename: Frédéric
authors.initials: F
authors.lastname: Menu
authors.forename: Claude
authors.initials: C
authors.lastname: Rispe
authors.forename: Manuel
authors.initials: M
authors.lastname: Plantegenest
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001042:Aphids / Q000502:physiology*; D004777:Environment; D005260:Female; D005298:Fertility; D008297:Male; D008685:Meteorological Concepts; D008962:Models, Theoretical; D010641:Phenotype; D011157:Population Dynamics; D012621:Seasons