Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odour.
BACKGROUND
Among invertebrates, specific pheromones elicit inherent (fixed) behavioural responses to coordinate social behaviours such as sexual recognition and attraction. By contrast, the much more complex social odours of mammals provide a broad range of information about the individual owner and stimulate individual-specific responses that are modulated by learning. How do mammals use such odours to coordinate important social interactions such as sexual attraction while allowing for individual-specific choice? We hypothesized that male mouse urine contains a specific pheromonal component that invokes inherent sexual attraction to the scent and which also stimulates female memory and conditions sexual attraction to the airborne odours of an individual scent owner associated with this pheromone.


RESULTS
Using wild-stock house mice to ensure natural responses that generalize across individual genomes, we identify a single atypical male-specific major urinary protein (MUP) of mass 18893Da that invokes a female's inherent sexual attraction to male compared to female urinary scent. Attraction to this protein pheromone, which we named darcin, was as strong as the attraction to intact male urine. Importantly, contact with darcin also stimulated a strong learned attraction to the associated airborne urinary odour of an individual male, such that, subsequently, females were attracted to the airborne scent of that specific individual but not to that of other males.


CONCLUSIONS
This involatile protein is a mammalian male sex pheromone that stimulates a flexible response to individual-specific odours through associative learning and memory, allowing female sexual attraction to be inherent but selective towards particular males. This 'darcin effect' offers a new system to investigate the neural basis of individual-specific memories in the brain and give new insights into the regulation of behaviour in complex social mammals.See associated Commentary http://www.biomedcentral.com/1741-7007/8/71.
Mammalian Behaviour & Evolution Group, University of Liverpool, Neston CH64 7TE, UK.
Sarah A
SA
Roberts
Deborah M
DM
Simpson
Stuart D
SD
Armstrong
Amanda J
AJ
Davidson
Duncan H
DH
Robertson
Lynn
L
McLean
Robert J
RJ
Beynon
Jane L
JL
Hurst
D000818:Animals; D001245:Association Learning / Q000502:physiology*; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008568:Memory / Q000502:physiology*; D051379:Mice; D009812:Odorants; D011506:Proteins / Q000378:metabolism*; D012724:Sex Attractants / Q000652:urine*; D012726:Sexual Behavior, Animal / Q000502:physiology*; D021241:Spectrometry, Mass, Electrospray Ionization
D036341:Intercellular Signaling Peptides and Proteins; C555029:Mup20 protein, mouse; D011506:Proteins; D012724:Sex Attractants