Losers aren't popular with the ladies

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Lose a fight and you lose the ladies. A recent study has found that female Astatotilapia burtoni literally change their feelings for males when they witness them losing a fight.

In the study, to be published in a forthcoming issue of the Proceedings of the National Academy of Sciences of the United States, the authors - Julie Desjardins, Jill Klausner and Russell Fernault of Stanford University - monitored the brain activity of the female cichlids after letting them witness a male they had selected as a potential mate spar with another male.

They found that when the preferred males lost a fight, the female brains showed heightened activity in areas associated with anxiety, whereas when the males won a fight, activity was heightened in areas associated with pleasure and reproduction.

The authors first placed gravid female cichlids in the central compartment of a tank divided into three parts by transparent barriers, before placing a male cichlid in each of the compartments on either side. 

The female was allowed to choose between the males, with the mate choice being defined by the time spent in close proximity to the male in two separate observations of 20 minutes each on consecutive days. 

After the female had chosen her potential mate, the authors placed both male fish in the same compartment and allowed them to fight, with the female fish watching from the adjacent compartment and separated by a transparent barrier. 

The female was allowed to observe her preferred male either losing or winning a fight with her non-preferred male (for about 20 minutes), after which the female was killed and her brain preserved for analysis.

The authors carried out a total of 15 trials (in which seven trials had the preferred male winning and the other eight had the preferred males losing). 

The authors monitored brain activity by measuring the expression of two immediate early genes in the brain (cellular homologue of fos and early growth response factor 1).

According to co-author Russell Fernald: "Our intuition is that this response is likely to occur under similar conditions in humans because the brain areas involved are present in all vertebrates and perform comparable functions."

"It is the same as if a woman were dating a boxer and saw her potential mate get the crap beat out of him really badly.  She may not consciously say to herself, 'Oh, I'm not attracted to this guy any more because he's a loser,' but her feelings might change anyhow", added primary author Julie Desjardins.  The human loser can take heart however, since humans have far greater cognitive abilities than fish and can reason our way past our basal urges.

For more information, see the paper: Desjardins, JK, JQ Klausner and RD Fernault (2010) Female genomic response to mate information. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1010442107