Helping in food-deceptive orchids? A possible new mechanism maintaining polymorphism of floral signals.
Why different colour morphs have evolved in flowering plants, and how they are maintained in populations, have long intrigued ecologists. The impact of variation in floral colour and odour (the two are frequently associated) on reproductive success remains poorly understood. In European rewardless orchids, many species occasionally show rare white-flowered individuals within populations of the common-coloured morph. In a recent study, we found that in Orchis mascula the presence of rare white-flowered morphs significantly increased the reproductive success (from 6% to 27%) of purple-flowered plants, while success of the white morph remained low. This surprising result appears due solely to floral color polymorphism, which in this species is not associated with odour polymorphism. We hypothesize that colour variation plays the key role in pollinator attraction, and that white-flowered individuals may be regarded to function as "sensory traps". We also propose that the maintenance of white-flowered mutants in O. mascula may result through kin selection, in which they act as helpers increasing the reproductive success of related purple individuals.
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS, Montpellier, France.
Laurent
L
Dormont
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS, Montpellier, France.
Roxane
R
Delle-Vedove
Ecole Nationale Supérieure de Chimie de Montpellier, Laboratoire de Chimie Appliquée, Montpellier, France.
Jean-Marie
JM
Bessière
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS, Montpellier, France.
Martine Hossaert-Mc
MH
Key
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175 CNRS, Montpellier, France.
Bertrand
B
Schatz
D000818:Animals; D001947:Breeding; D035264:Flowers / Q000502:physiology; D029595:Orchidaceae / Q000235:genetics*; D054817:Pollination; D011110:Polymorphism, Genetic; D015398:Signal Transduction