Investigating Primate Fertility Cues Using GC–MS

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Researchers from the University of Leipzig have used gas chromatography–mass spectrometry (GC–MS) to study the fertility cues of non-human primates (1).

The use of odour cues can be seen throughout the animal kingdom and are used by animals to deliver strong messages to those around them, including the marking of territory, defensive posturing, or even to attract prey. These odour cues exist even in primates and a number of species have well developed olfactory systems. However, large knowledge gaps remain in our understanding of the chemical underpinnings of primate odour cues.

A common odour cue in primates revolves around reproduction and in particular odour-based messages that detail the fertility state of females and their reproductive quality. For example, in common marmosets (Callithrix jacchus) both males and females show scent-marking behaviour from two specialized glands and some non-specialized glands. This makes them ideal targets for olfactory studies in primates as they have a lot of complex chemical signals to investigate. A number of studies have shown that female marmosets lack visual cues to indicate reproductive readiness and yet males can detect when females are fertile, with studies determining odour cues as the source for the males (2–4). However, detailed analysis of the chemical compounds responsible has yet to be carried out.

To address this knowledge gap, researchers used behavioural bioassays and GC–MS to analyze marmoset secretion odour particles, attempting to identify fertility-related substances as well as factors that may alter or impact them.

Their findings noted that menstrual cycle states, age, and the experience of the female in offspring birthing affected the chemical profiles of marmosets, confirming previous evidence of odour cues being linked to fertility. Males would likely use these cues to optimize their mating efforts and therefore the potential for offspring. In the case of experience, or parity, as the papers terms, this refers to a high likelihood for first time marmoset mothers to lose their first litter, and thus the male preference for more experienced females. The overall chemical profile of an individual marmoset consists of a few hundred substances offering a wealth of information, but more studies are required to fully understand their roles and find their metabolic pathways.

References

1. M. Kücklich et al., Sci. Rep.9:13716 (2019).
2. L. Digby, Folia Primatol.70, 136–145 (1999).
3. T.E. Smith and D.H. Abbott, Am. J. Primatol. 46, 265–284 (1998).
4. A.F. Dixon and S.F. Lunn, Physiol. Behav.41, 577–583 (1987).