Elephants urine

In rabbits, the as yet unidentified maternal signal during lactation has analogous properties in guiding the reliable orientation of suckling, mainly via MOS input (Hudson and Distel, 1986 Schaal et al., unpubl.). Minor fractions may still function as flag contributors, exemplified by the attractiveness of proestrous elephant urine. Male responses show that intact urine is conspicuously more attractive in comparison with the pure insect mammal pheromone (9.) presented in water (Rasmussen et al., 1996). 

Abstract A relatively small number of mammalian pheromones has been identified, in contrast to a plethora of known insect pheromones, but two remarkable Asian elephant/insect pheromonal linkages have been elucidated, namely, (Z)-7-dodecen-1-yl acetate and frontalin. In addition, behavioral bioassays have demonstrated the presence of a chemical signal in the urine of female African elephants around the time of ovulation. Our search for possible ovulatory pheromones in the headspace over female African elephant urine has revealed for the first time the presence of a number of known insect pheromones. This search has been facilitated by the use of a powerful new analytical technique, automated solid phase dynamic extraction (SPDE)/GC-MS, as well as by novel macros for enhanced and rapid comparison of multiple mass spectral data files from Agilent ChemStation . This chapter will focus on our methodologies and results, as well as on a comparison of SPDE and the more established techniques of solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). 

Fig. 2.1 Compounds identified in female African elephant urine headspace that are known insect pheromones...

SPDE/GC-MS and Novel Macros for Analysis of Elephant Urine... 

Use of SPDE/GC-MS for Analysis of African Elephant Urine Headspace... 

Use of automated headspace SPDE/GC-MS not only enabled the identification in female African elephant urine of a number of known insect pheromones (compounds 2-6, Fig. 2.1), but also revealed the presence of the beetle biochemical precursors to frontalin (2), exo-brevicomin (3) and ent/o-brevicomin (4), thus suggesting a common biosynthetic pathway (Goodwin et al. 2006). Extensive behavioral bioassays must be performed to determine whether any of these compounds is functioning as a pheromone among African elephants. 

The macro output excerpt shown in Table 2.2 represents the same four TIC peaks from the same four elephant urine samples as in Table 2.1. Now, however, it is more clear that the first, second and fourth entries represent identical compounds, but the third entry may not be the same. The low abundance for the compound in the third entry, however, may lead to a false conclusion and thus warrant a visual inspection... 

Pheromones in urine will suffer degradation, hydrolysis, oxidation, and ultraviolet radiation effects. For example, the (Z)-7-12-acetyl derivative in elephant urine will gradually hydrolyze (Rasmussen, 1988). In this case, the lipoprotein carriers of the elephant acetate may also determine the life time of the signal besides serving to filter and select odorants, confer specificity, and play a critical role in the transport and transfer of an active ligand to the vomeronasal organ (Rasmussen and Schulte, 1998). 

CHEMICAL ANALYSIS OF PREOVULATORY FEMALE AFRICAN ELEPHANT URINE A SEARCH FOR PUTATIVE PHEROMONES... 

At this point neither the origin of compounds 1-4 in elephant urine, nor their role, if any, in chemical signaling among elephants is clear. It is noteworthy that in a previous study of the isolation of volatiles from quince fruit, high vacuum distillation/extraction followed by GC-MS yielded different results if one started with homogenized fruit at its natural pH (3.7), versus homogenate at pH 7 to which an enzyme inhibitor had been added. Specifically, the pH 3.7 sample evidenced large amounts of the theaspiranes, but the pH 7 sample showed only trace amounts (Winterhalter et al., 1987). 

Additionally, it has been demonstrated that under acidic conditions, certain monocyclic diols can be converted to the theaspiranes (3), or to the dihydroedulans (2), and that the latter (2) may be isomerized to the former (3) on strong acid treatment (Schulte-Elte et al., 1978 Winterhalter et al., 1987 Schmidt et al., 1995 Young et al., 2000). Thus it is possible that in African elephant urine at pH 3-4, we are observing products (1-4) that are formed from as yet unidentified precursors in the native pH 8 urine. If so, it is likely that the precursors are degradation products of carotenoids, as has been suggested for similar bisnoisesquiterpenes (Francke et al., 1989 Kaiser and Lamparsky, 1979). 

Elephant urine samples were provided by the following organizations Cameron Park Zoo, Indianapolis Zoo, Louisville Zoo, Nashville Zoo (R. and C. Pankow), Riddle s Elephant Sanctuary, Sedgwick County Zoo, Seneca Park Zoo, Six Flags Marine World,... 

Fig, 5. Chemical communication mediated via the flehmen response in Asian elephants. Urine and temporal gland secretions both elicit flehmen responses. Emphasis of the diagram is on sex state information. 

However, dichloromethane extracts of these urines were inactive. Conversely, wild stallions responded to the dichloromethane extracts of estrous mare urine but not to extracts of estrous elephant urine. 

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