Odor experts uncover the smelly chemistry of lemur love

April 16, 2020

Three chemicals with floral, fruity scents are likely essential ingredients in the natural cologne male ring-tailed lemurs use to attract a mate. Experts in odor communication say these chemicals could be the first fully identified sex pheromones in primates.

During the yearly breeding season, male lemurs rub glands on their wrists against their fluffy tails and then wave their tails at females, a behavior called "stink flirting." Only ring-tailed lemurs (Lemur catta) have these wrist glands and exhibit "stink flirting" behavior. The wrist glands produce a clear liquid, never before examined in detail.

"What made our study different is that we have expertise in chemistry, while most studies of animal communication are done by ecologists," said Professor Kazushige Touhara, an expert studying olfaction, the sense of smell, at the University of Tokyo and leader of the recent research study, published in Current Biology.

Recipe for lemur cologne

Researchers collected the clear liquid from males' wrist glands during both the breeding and nonbreeding seasons, then analyzed its chemical components.

The analytical technique gas chromatography-mass spectrometry can identify chemicals based on their electrical charge, molecular weight and other aspects. The research team also benefited from newer technology that can analyze small samples without complicated pretreatment.

Three odor compounds (dodecanal, 12-methyltridecanal and tetradecanal) were more abundant and one (acetamide) was less abundant in the wrist gland liquid collected during the breeding season.

Male lemurs' testosterone levels are naturally higher during the breeding season and at younger ages.

When researchers artificially increased the testosterone of a healthy, young male lemur during the nonbreeding season, the amount of the odor compounds tended to increase, similar to breeding season levels.

"This increase really supports the connection between testosterone and these odor compounds," said Project Assistant Professor Mika Shirasu, a member of the Touhara lab and co-first author of the research publication.

Females' sniff test

Researchers also saved males' breeding season wrist gland secretions to soak in cotton pads and present to females during the nonbreeding season.

"Outside of the breeding season, females had no special interest in any of the male odors we tested," said Shirasu.

To discover if any of the three odor compounds are more important for attracting females' attention, researchers presented females with cotton pads soaked in the individual odor compounds, a blend of the three compounds to mimic normal male breeding season wrist gland secretions, or a neutral control liquid.

When tested in their normal social environment, female lemurs showed no increased interest in any of the three individual male odor compounds. The more natural blend of the three compounds did capture their interest, measured as a longer time spent sniffing that cotton pad.

Although researchers can observe female lemurs' interest, the outcomes of that interest are more complicated to study.

"Curiosity does not necessarily mean sexual attraction. We cannot say for certain yet if a female spending a longer time interested in the scent means that a male will be more successful at mating," said Touhara.

Fragrance for lemurs only

It remains impossible to predict what the three likely lemur sex pheromones might mean for other primates, including humans.

"There are no humans waving tails at each other," said Touhara.

Lemurs are part of a different evolutionary lineage called the wet-nosed strepsirrhines, which have a greater sense of smell than the dry-nosed haplorhine group that includes humans and apes.

"Maybe there are no sex pheromones in humans, but there are probably odors - like parents smelling their baby's heads - that we use to affect each other's emotions," said Touhara.

Researchers cannot yet refer to the odors identified in lemurs as official sex pheromones due to the scientific definition that a pheromone must be used for communication only between members of a single species. The research team hopes that ecologists and zoologists may be able to use these new details about likely sex pheromones to increase understanding of primate behavior.

This research project was conducted over seven years, led by the University of Tokyo in collaboration with partners at Kyoto University, the Research Institute of Evolutionary Biology and the Japan Monkey Centre.
-end-
Journal Article

Mika Shirasu, Satomi Ito, Akihiro Itoigawa, Takashi Hayakawa, Kodzue Kinoshita, Isao Munechika, Hiroo Imai, and Kazushige Touhara. 16 April 2020. Key male glandular odorants attracting female ring-tailed lemurs. Current Biology. DOI: 10.1016/j.cub.2020.03.037.

Related Links

Graduate School of Agricultural and Life Sciences website: https://www.a.u-tokyo.ac.jp/english/

Touhara lab website (Japanese): http://park.itc.u-tokyo.ac.jp/biological-chemistry/index.html

Kazushige Touhara university profile page: https://www.u-tokyo.ac.jp/focus/en/people/people001152.html

Research Contact

Professor Kazushige Touhara
Laboratory of Biological Chemistry, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657
Tel: +81-03-5841-5109
E-mail: ktouhara@mail.ecc.u-tokyo.ac.jp

Press Contact

Ms. Caitlin Devor
Division for Strategic Public Relations, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-8654, JAPAN
Tel: +81-080-9707-8178
Email: press-releases.adm@gs.mail.u-tokyo.ac.jp

About the University of Tokyo

The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at http://www.u-tokyo.ac.jp/en/ or follow us on Twitter at @UTokyo_News_en.

University of Tokyo

Related Testosterone Articles from Brightsurf:

ACP issues guideline for testosterone treatment in adult men with age-related low testosterone
Physicians should prescribe testosterone for men with age-related low testosterone only to treat sexual dysfunction, the American College of Physicians (ACP) says in a new evidence-based clinical practice guideline.

Women with asthma appear more likely to have lower levels of testosterone
Women with asthma appear more likely to have lower levels of 'free' (not attached to proteins) testosterone than women who do not have asthma, according to new research published online in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

Penis development needs more than just testes and testosterone
Proper development of the fetal penis requires not just testosterone from the testes, but a second hormone produced by other tissues, including the placenta, according to a new study publishing Feb.

Testosterone treatment over 10 years can improve or reverse type 2 diabetes in men with low testosterone, and induce significant weight loss
New research presented at this year's annual meeting of the European Association for the Study of Diabetes (EASD) reveals that in men with low testosterone who have type 2 diabetes (T2D), testosterone therapy can improve their disease and reverse its progress, and can also induce significant weight loss.

Testosterone replacement therapy may slow the progression of COPD
GALVESTON, Texas -- Researchers from The University of Texas Medical Branch at Galveston found that testosterone replacement therapy may slow disease progression of chronic obstructive pulmonary disease.

Testosterone research brings new hope for cancer patients
Approximately 20 percent of cancer related deaths are attributed to the syndrome of cachexia.

Testosterone prescriptions have sharply dropped in the past few years
Testosterone use in the United States tripled between 2001 and 2011, mostly in men without a clear indication for it.

Use of prescribed testosterone therapy in US decreases in recent years
Testosterone use in the United States tripled from 2001 through 2011, mostly in men without a clear indication.

Testosterone causes men to desire luxury goods
Researchers examine testosterone's effect on men's desire for goods that are considered to have social cachet.

Men's testosterone levels largely determined by where they grow up
Men's testosterone levels are largely determined by their environment during childhood, according to new research.

Read More: Testosterone News and Testosterone Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.