BioBoundary Project: Paul G. Allen Family Foundation Wildlife Chemistry Laboratory
Peter Apps, PhD and Lesego Mmualefe, PhD
The BioBoundary Project's development of artificial territorial boundaries that will keep African Wild Dogs safely inside the borders of protected conservation areas is a rare example of close collaboration between field work and cutting edge chemical analysis. The field work is carried out in the BPCT study area in northern Botswana and the Tuli Block in the south east of the country, and the chemical analysis is carried out in the Paul G Allen Family Foundation Wildlife Chemistry Laboratory in Maun, Botswana.
The laboratory is staffed by semiochemical specialist Dr Peter Apps who has a doctorate in Zoology and nearly 30 years experience in analytical chemistry, and Dr Lesego Mmualefe, a specialist in sample preparation and analysis by gas chromatography - mass spectrometry, with a background in environmental analysis, who joined the BPCT team in January 2010.
The scent marks that the dogs use to demarcate their territories give off mixtures of hundreds of organic chemicals, at concentrations that reach down to below the parts per billion range. To analyse these complex mixtures the laboratory has had to develop specialized methods to collect and process samples, and the performance of the gas chromatographs and mass spectrometer, that are the heart of the analytical capability, have been enhanced by in-house modifications.
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Peter and Lesego have identified over a hundred compounds in the odours of wild dog urine and faeces, and confirmed the identities of all the major components. They have compared the chemical profiles of hundreds of urine and faeces samples from free ranging wild dogs, searching for patterns of differences in chemical composition that will point to which of the hundreds of compounds in the urine and faeces are sending the territorial "Keep Out" signal.
Comparisons between urine and faeces, and urine from different dogs have raised a host of new and exciting questions. Peter and Lesego have found striking differences between urine deposited at different places, at different times, by different packs, and by different dogs within a pack. In marks from individual dogs, major components appear and disappear over periods of one or two days, and there are one thousandfold differences in the concentration of odour chemicals in marks produced by the same dogs at different times. Even humans can smell the difference between the different scent marks. How dogs respond to these different chemical patterns will tell us whether the compounds concerned are part of the territorial signal. When the dogs scent mark, they mix urine with secretions from glands along the urinary tract, and there is an intriguing possibility that the secretions that are added depend on where the dogs are in their home ranges. Mapping chemical composition onto the locations where the samples were collected will show whether chemistry and ranging behaviour are related. Field bioassays to determine whether urine with a weak odour is semiochemically active are at the top of the field work "to do" list.
Within a pack, the urines from dominant and subdominant dogs have similar compositions, but urines from the dominant pairs of different packs differ in the presence and absence of major chemical components. This raises two critical questions; whether subdominant marks are territorially active or not, and whether the territorial signal depends on the differences between packs' scent marks, rather than on a universal "Keep Out" signal.
Working out how all this chemical complexity relates to the dogs' territoriality will need intensive field biology, and Peter will be spending a lot more time in the field, while Lesego looks after sample analysis in the laboratory.