Smelling wrong: hormonal contraception in lemurs alters critical female odour cues.
Animals, including humans, use olfaction to assess potential social and sexual partners. Although hormones modulate olfactory cues, we know little about whether contraception affects semiochemical signals and, ultimately, mate choice. We examined the effects of a common contraceptive, medroxyprogesterone acetate (MPA), on the olfactory cues of female ring-tailed lemurs (Lemur catta), and the behavioural response these cues generated in male conspecifics. The genital odorants of contracepted females were dramatically altered, falling well outside the range of normal female variation: MPA decreased the richness and modified the relative abundances of volatile chemicals expressed in labial secretions. Comparisons between treatment groups revealed several indicator compounds that could reliably signal female reproductive status to conspecifics. MPA also changed a female's individual chemical 'signature', while minimizing her chemical distinctiveness relative to other contracepted females. Most remarkably, MPA degraded the chemical patterns that encode honest information about genetic constitution, including individual diversity (heterozygosity) and pairwise relatedness to conspecifics. Lastly, males preferentially investigated the odorants of intact over contracepted females, clearly distinguishing those with immediate reproductive potential. By altering the olfactory cues that signal fertility, individuality, genetic quality and relatedness, contraceptives may disrupt intraspecific interactions in primates, including those relevant to kin recognition and mate choice.
Crawford
Jeremy Chase
JC
Department of Evolutionary Anthropology, Box 90383, Duke University, Durham, NC, USA.
Boulet
Marylène
M
Drea
Christine M
CM
D000819:Animal Communication; D000818:Animals; D003271:Contraceptive Agents, Female / Q000494:pharmacology*; D003463:Cues; D016002:Discriminant Analysis; D005260:Female; D005836:Genitalia, Female / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D005838:Genotype; D012739:Gonadal Steroid Hormones / Q000097:blood; D007900:Lemur / Q000502:physiology*; D008297:Male; D017258:Medroxyprogesterone Acetate / Q000494:pharmacology*; D018895:Microsatellite Repeats / Q000235:genetics; D009812:Odorants / Q000032:analysis*; D025341:Principal Component Analysis; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D055549:Volatile Organic Compounds / Q000032:analysis
D003271:Contraceptive Agents, Female; D012739:Gonadal Steroid Hormones; D055549:Volatile Organic Compounds; D017258:Medroxyprogesterone Acetate