Scientists have assumed that only one form of frontalin would be made by elephants, but by merely changing the ratios of frontalin's enantiomer composition, "you're actually changing the message signals, and you end up having a signal that is essentially different," Greenwood added. "It's not just a single message."
The research team analyzed secretion samples from six male elephants and found that the pheromone is first detectable in the late teens, with the quantity secreted rising about 15-fold over a 25-year life span. Young males secreted significantly more of the "plus" frontalin than "minus," but the ratios became almost equal as the elephant matured, especially between ages 31 and 43.
Musth periods get longer as the males age, according to the study, and, importantly, the enantiomeric composition of the frontalin secreted is almost equal in the middle part of a musth episode, a period of prime signaling by male elephants. In contrast, at the end of the physiologically exhausting musth episode, the ratio becomes more varied so that at the end of musth, the ratio is askewed toward the minus enantiomer, allowing other males and females to detect the ending of musth.
The team then tested the effect the various enantiomer ratios had on the elephants. They examined ovulating or "follicular" females, and females that were either pregnant or in a non-reproductive "luteal" phase. They also tested young and old males. It found that low concentrations of frontalin, represented when the enantiomer ratio is more "plus" than "minus," was of mild interest to both young and old males, but when the ratio became balanced - equal amounts of plus and minus frontalin - males of all ages, as well as luteal-phase and pregnant females, were repulsed. Only ovulating females were attracted.
The study's results indicate that the ratio of frontalin enantiomers allows other elephants to distinguish both the maturity of male elepha
Source:Oregon Health & Science University