Enhancing Lemur Breeding in Captivity with GC-MS

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Researchers at the University of Wolverhampton have utilized gas chromatography-mass spectrometry (GC-MS) in their efforts to create new scent enrichments in their efforts to trigger mating behaviors of zoo-housed lemur species.

A recent paper (1) published in F1000Research, focuses on efforts by researchers at the University of Wolverhampton in the United Kingdom to develop novel, biologically relevant scent enrichments to trigger mating behaviors of zoo-housed lemur species, using solid-phase microextraction and gas chromatography-mass spectrometry (GC-MS) techniques.

Lemurs are prosimians (a type of primate) native to Madagascar, where they evolved in isolation. Unlike monkeys, lemurs have a moist nose and depend more heavily on their sense of smell. Physically, many have especially pointed snouts and all but the largest lemur, the Indri, have long tails (2). There are over 100 kinds of lemurs, and new species are continuing to be discovered by scientists. Lemurs are among the most threatened groups of mammals, with the International Union for the Conservation of Nature (IUCN) estimating that over 98% of lemurs face extinction in the next 20 years (2).

Utilizing GC-MS, researchers at the university’s Animal Behaviour & Wildlife Conservation Group applied established semiochemistry (utilization of a chemical that affects the behavior of an organism [3]) methods (4) to discover a pool of volatile chemical compounds distinguishing the chemical profile of anogenital odor secretions released by female lemurs during the breeding period, which suggests that there might be fertility-specific signals associated with female scents. They then tested these compounds, resulting in the triggering of sexual behaviors among unsuccessful breeding pairs of lemurs hosted in European zoos, including mating. Effects of the newly designed scent enrichments on their target species were evaluated by combining behavioral observations with fecal endocrinology.However, no statistically significant effects were found on male fecal testosterone concentration.

Four compounds (2-heptanone; 3-heptanone; 3-octanone; 4-methyl 3-hexanone) were identified that were only present in the chemical profiles of odor samples collected during the fertile window of the breeding period. The results obtained when testing bamboo or gentle lemurs (genus Hapalemur [5]) showed that the frequency of male sexual behaviors increased significantly after experiencing the scent enrichment condition as opposed to the pre-enrichment condition, as well as for a period of time after the experience. Similar findings were recorded when testing ruffed lemurs (genus Varecia [6]).

The researchers report that novel scent enrichments have the potential to impact on captive management and conservation breeding of endangered lemur species, and these results also highlight that the combination of more assessment methods (including behavioral observations and additional fecal endocrinology) can help with the evaluation of the impact of environmental enrichments (going on to admit that it often proves difficult to find statistically significant changes in fecal hormone levels due to confounding variables). However, the researchers admit that there are limitations which may have impacted the use cases. First, they focused on a relatively small sample size. Also, due to the small pool of odor samples, there are challenges involved with mixing the compounds in proportions exactly reflecting the ratios of the anogenital odor secretions released by the fertile female lemurs. Therefore, the authors plan on conducting additional investigations on the chemical profile of the female odor secretions (including non-volatile compounds) and expanding the sample size when testing compound mixtures which communicate information regarding female fertility (including several unsuccessful breeding groups housed in various institutions).

References

1. Elwell, E.; Fontani, S.; Vaglio, S. Design and Test of Novel Scent Enrichments to Enhance Breeding of Zoo-Housed Lemurs. F1000Research 2024, 13, 123. DOI: 10.12688/ f1000research.144636

2. Lemur Conservation Foundation website. https://www.lemurreserve.org/ (accessed 2024-07-08)

3. Semiochemical definition. Oxford Reference website. https://www.oxfordreference.com/display/10.1093/oi/authority.20110803100454870 (accessed 2024-07-08)

4. Walker, D.; Vaglio, S. Sampling and Analysis of Animal Scent Signals. J. Vis. Exp. 2021; 168. DOI:10.3791/60902-v

5. Bamboo lemur. Wikipedia page. https://en.wikipedia.org/wiki/Bamboo_lemur (accessed 2024-07-08)

6. Ruffed lemur. Wikipedia page. https://en.wikipedia.org/wiki/Ruffed_lemur (accessed 2024-07-08)

The bamboo lemur. © AkuAku - stock.adobe.com

The bamboo lemur. © AkuAku - stock.adobe.com

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