Chemical constituency and odor of semiochemicals: Studying the chemical composition and odor of volatile organic compounds of great cat marking fluid in an effort to aid tiger and lion conservation

摘要

In conjoining the disciplines of ethology and chemistry the field of Ethochemistry has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Scent-markings are comprised of semiochemicals which are the key components in biota signaling. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry and provide an insight into the animal‘s sensory perception. The overall objective of this research is to determine the chemical constituents of the African lion (Panthera leo) and Siberian tiger (Panthera tigris altaica) marking fluid scent-markings using simultaneous, state-of-the art chemical and sensory analyses. The specific objectives of this study were to: 1) develop a novel method for the simultaneous chemical and scent identification of lion and tiger marking fluid in its totality and 2) identify the characteristic odorants responsible for the overall scent of lion and tiger marking fluid. Solid-phase microextraction (SPME) for scent collection from mixed MF and urine and multidimensional gas-chromatography-mass spectrometry-olfactometry (mdGC-MS-O) for analyses were used. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior. To date, no study reported scent and composition of marking fluid (MF) from P. leo or P. tigris altaica.2,5-Dimethylpyrazine, 4-methyl phenol, and 3-methylcyclopentanone were isolated and identified as the three compounds responsible for the characteristic odor of lion MF. Twenty-eight volatile organic compounds (VOCs) emitted from lion MF were identified, adding a new list of compounds previously unidentified in lion urine. In addition, chemicals in nine new compound groups were identified: ketones, aldehydes, alcohols, amines, aromatics, sulfur containing compounds, phenyls, phenols, and acids. Eighty-nine VOCs emitted from tiger MF were identified. Additional odorants besides 2-acetyl-1-pyrroline, i.e. 3-methylbutanamine, R-3-methylcyclopentanone, propanedioic acid, urea, furfural, and 3-hydroxy-butanal were also identified as contributing to the characteristic MF odor. Simultaneous chemical and sensory analyses improved characterization of scent-markings and identified new MF compounds not previously reported in other tiger species.This research will assist animal ecologists, behaviorists, zoo keepers, and conservationists in understanding how scents from specific MF compounds impact great cat communication and improve management practices related to animal behavior in captivity and in the wild. The analytical approach for simultaneous chemical and sensory analyses can be applicable to unlock scent-marking information for other species and potentially aid conservation and management. Likewise, the analytical approach for simultaneous chemical and sensory analyses can be useful to many aspects of animal production systems, such as breeding and behavior.