The researchers at Oregon Health & Science University and the University of Auckland in New Zealand say the release of a specific proportion of two mirror images of the pheromone, frontalin, depends on whether the male elephant is mature enough and has reached a particular stage of musth, an annual period of sexual activity and increased aggression.
"This study reveals the precision and specificity of inter-animal signaling possible," co-author L.E.L. "Bets" Rasmussen, Ph.D., research professor of environmental and biomolecular systems, OHSU OGI School of Science & Engineering, said of the study published in the Dec. 22 edition of the journal Nature. "This is the first example, in mammals, of the use of this very precise signaling and ratio of enantiomers in signaling."
An enantiomer is one of a pair of chemical compounds whose molecular structures are mirror images of each other. Frontalin, a pheromone discharged during musth by male Asian elephants from a temporal gland located between the eye and ear, comes in two forms, each representing one half of the enantiomer pair and identified as either "plus" or "minus."
The OHSU and New Zealand team showed that the enantiomers of frontalin are released in the elephants in specific ratios that depend on the animal's age and stage of its musth. They also found that alterations in those ratios elicit different responses in not only female elephants, but also other male elephants near the male emitting the pheromone.
"We were certainly quite surprised" by the results, said the study's lead author, David R. Greenwood, Ph.D., associate professor in the School of Biological Sciences at the University of Auckland and scientist with the Molecular Olfaction Group at HortResearch in
Source:Oregon Health & Science University