title: Cracking the olfactory code of a butterfly: the scent of ageing.
abstract: Although olfaction is a primary mode of communication, its importance in sexual selection remains understudied. Here, using the butterfly Bicyclus anynana, we address all the parameters of importance to sexual selection for a male olfactory signal. We show that variation in the male sex pheromone composition indicates male identity and male age. Courting males of different ages display small absolute (c. 200 ng) but large relative (100%) change of one specific pheromone component (hexadecanal) which, unlike the other components, showed no heritability. Females prefer to mate with mid-aged over younger males and the pheromone composition is sufficient to determine this preference. Surprisingly refined information is thus present in the male olfactory signal and is used for sexual selection. Our data also reveal that there may be no 'lek paradox' to resolve once the precise signal of importance to females is identified, as hexadecanal is, as expected, depleted in additive genetic variation.
authors.affiliation: Evolutionary Biology Group, Institute of Biology, Leiden University, 2300 RA Leiden, the Netherlands. caroline.nieberding@uclouvain.be
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Nieberding
authors.forename: Klaus
authors.initials: K
authors.lastname: Fischer
authors.forename: Marjo
authors.initials: M
authors.lastname: Saastamoinen
authors.forename: Cerisse E
authors.initials: CE
authors.lastname: Allen
authors.forename: Erika A
authors.initials: EA
authors.lastname: Wallin
authors.forename: Erik
authors.initials: E
authors.lastname: Hedenström
authors.forename: Paul M
authors.initials: PM
authors.lastname: Brakefield
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D002080:Butterflies / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D008297:Male; D052586:Mating Preference, Animal / Q000502:physiology*; D010675:Pheromones / Q000737:chemistry; D012903:Smell / Q000502:physiology
chemical_list: D010675:Pheromones