Contraceptives change the olfactory communication in primates

American researchers (Crawford et al., 2010) found out that primate females tend to lose the odorous individuality in a kind of uniformation process when taking contraceptives. The study was performed in animals and this might mean that the pills have the same effect in humans.

Hormonal contraception alters the way lemurs in captivity treat each other, both from the social and the sexual perspective. This is what was revealed in a study taken at Duke University. These findings were published in an article in the Proceedings of the Royal Society B (Crawford et al., 2010).

The research is a part of a series of studies that the group led by Christine Drea has been performing using gas-chromatographic techniques to identify the chemical components of many odorous substances produced by the lemurs. These substances transmit in fact not only the state of female fertility, but also information about identity, kinship and genetic condition of the subject to avoid intra-family crosses (Charpentier et al. 2010, Drea 2007, Charpentier et al. 2008), bohužel nejsou ve zdrojovem textu uvedeny zadne prameny na ony studie).

"If all this information is subverted by hormonal contraception, this may partly explain the strange changes in aggressive behavior that were observed while studying primates in captivity treated with contraceptives, " explained Drea.

To a dozen lemur females at the Duke Lemur Center were administered doses of MPA, a popular contraceptive. The subsequent chemical analysis showed that females with contraception expressed some odors that were not present in the control group. Also relative reports among other odorous substances appeared different. Researchers have also noted that the contraception tended to make the odorous individuality of females disappear, in a sort of an uniformation process. The signals they send to members of their social group and possible partners were significantly altered.

In behavioral tests, the 13 males in the study showed a clear preference for the odor of females in the control group spending less time trying to smell those who received MPA.

"Our job is now to figure out whether these findings are also true for our species," said Christine Drea. Scientists are not sure if the olfactory comunication between humans exists or not. And if does exist, we do not know if it has some importance for searching our partners. This study might be a start to a new contribution to the solution of this problem.

Translated by Pavla Cermakova

Story source: http://lescienze.espresso.repubblica.it/

Original work:

Jeremy Chase Crawford, Marylène Boulet and Christine M. Drea (2010), Smelling wrong: hormonal contraception in lemurs alters critical female odour cues, Proceedings of the Royal Society 10.1098/rspb.2010.1203

Other sources:

Charpentier, M. J. E., Crawford, J. C., Boulet, M. & Drea, C. M. (2010): Message 'scent': lemurs detect the genetic relatedness and quality of conspecifics via olfactory cues. Anim. Behav. 80, 101-108. (doi:10.1016/j. anbehav.2010.04.005)

Drea, C. M. (2007): Sex and seasonal differences in aggression and steroid secretion in Lemur catta: are socially dominant females hormonally 'masculinized'? Horm. Behav. 51, 555-567. (doi:10.1016/j.yhbeh.2007.02.006)

Charpentier, M. J. E., Boulet, M. & Drea, C. M. (2008): Smelling right: the scent of male lemurs advertises genetic quality and relatedness. Mol. Ecol. 17, 3225-3233. (doi:10.1111/j.1365-294X.2008.03831.x)

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