RESUMEN
The Asian elephant utilizes the same sex pheromone as a number of moth species, (Z)-7-dodecen-1-yl acetate encapsulated in a serum-derived albumin. The chemical signal is emitted in the urine and received in the mucus of the trunk. The unwrapping of the package is pH mediated.
Asunto(s)
Albúminas/metabolismo , Dodecanol/análogos & derivados , Dodecanol/metabolismo , Elefantes/metabolismo , Feromonas/metabolismo , Animales , Transporte Biológico , Dodecanol/orina , Elefantes/anatomía & histología , Femenino , Concentración de Iones de Hidrógeno , Masculino , Feromonas/orinaRESUMEN
In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48 microgram/ml (0.002 mM) early in the follicular phase and to 33.0 micrograms/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals.