‘Give us a sniff, love’: giving marsupials scents from suitors helps breeding programs



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A baby eastern barred bandicoot pokes its head out of its mother’s pouch.
M. Parrott, Zoos Victoria, Author provided

Marissa Parrott, University of Melbourne

Smell is a vital part of sexual attraction for all kinds of animals (including humans). We may be able to use smell to improve breeding programs by giving the female animal a sample sniff of potential mates and letting her choose the best one before introducing them.

Our new research found female marsupials paired with the male of their choice in captive breeding programs had a higher chance of becoming pregnant, a shorter time to pregnancy and may produce healthier young.




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Ladies’ choice

Zoos and breeding institutions traditionally pair animals based on their relatedness and pedigree so they can manage the overall genetic health of the population. It’s expensive and often not possible to transport multiple males just to give a female some options – but if she refuses her solitary suitor when he arrives, it can cause major problems.

Our research shows that presenting the female with a range of scent samples and letting her pick her favourite dramatically increased compatibility.

This simple 10-minute test more than doubled the number of pregnancies and shortened the time to becoming pregnant in a small carnivorous marsupial, the stripe-faced dunnart.

Marissa Parrott with a captive-bred mountain pygmy-possum released to the wild.
Author provided

Using the same technique in the critically endangered mountain pygmy-possum at Healesville Sanctuary, we showed that females had significantly higher breeding success with males they liked during their choice tests. We have shown a similar effect of increasing breeding success and shortening the time to pregnancy in the endangered eastern barred bandicoot at Zoos Victoria through scent and interactions.

How are female marsupials choosing mates?

Put simply, they are following their noses. We gave females a choice of male smell and allowed her to sniff out the best mate.

In the first published study of marsupial mate choice, we found female agile antechinus chose the most genetically suitable male based on his smell. Females preferred males that were genetically dissimilar to themselves (avoiding in-breeding), but not too dissimilar (avoiding genetic out-breeding).

There is a sweet spot to female choice. If you can provide a female with a suite of males, they can choose their most compatible suitor, which in turn is likely to produce the healthiest and fittest young.

Better yet, females are choosing males compared with their own genes, so each female may like a different male, which is good for managing the overall population. However, care must be taken with sisters, as they are likely to have the same choices.




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This information is particularly helpful for global programs that have endangered species spread across different institutions and zoos, such as tree kangaroos.

In the dunnarts, we found that freezing and storing the scents of males for up to 40 days did not affect a female’s choice or interest in a scent. Thus, if you have a female tree kangaroo at Melbourne Zoo and are uncertain which male should be sent from overseas, you could freeze scents from eligible bachelors and send them to her in advance for her approval. This could reduce the stress, time and cost associated with sending males between zoos, especially if the male you sent ended up being the wrong choice!

A stripe-faced dunnart in the captive breeding colony at the University of Melbourne.
M Parrott, Author provided

But why focus on females?

In marsupials, females provide the majority of the care of the young. In the extreme case of the antechinus, all males die after mating, leaving the females with all the work raising the offspring. Thus, females are generally the choosier sex, ensuring they get the maximum benefit from appropriate mate choice.

In other species, such as the critically endangered plains wanderer whose females lay eggs and leave them with stay-at-home fathers, you may expect the male bird’s choice to be more important. He is providing the care to the growing chicks and thus will want to maximise their success through choosing the best mate.

Can people learn from the marsupial approach?

Female mate choice is a perennial issue for many humans. A study that supplied 49 women with T-shirts worn by different men found the women could sniff out the men in their genetic “sweet spot” – not too similar or dissimilar – and found those scents most attractive.

We are not so different to the endangered marsupials we are working to recover. Perhaps in the future, instead of swiping right on an image, we can be sent a palette of smells to choose a potential suitor. Instead of speed dating, could we use smell dating?




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Certainly, when used in conservation breeding programs, allowing a female to choose her own mate can help find the best pairings, reduce the time to produce young and hopefully help produce the healthiest offspring to fight extinction for their species.The Conversation

Marissa Parrott, Reproductive Biologist, Wildlife Conservation & Science, Zoos Victoria, and Honorary Research Associate, BioSciences, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Why a walk in the woods really does help your body and your soul


Jeffrey Craig, Murdoch Childrens Research Institute and Susan L. Prescott, University of Western Australia

Have you ever wondered why you feel healthier and happier when you stroll through the trees or frolic by the sea? Is it just that you’re spending time away from work, de-stressing and taking in the view? Or is there more to it?

For more than 20 years, scientists have been trying to determine the mechanisms by which exposure to biodiversity improves health. Japanese scientists pioneered the search when they travelled to the island of Yakushima, famous for its biodiversity.

The Japanese already had a name for the experience of well-being in nature: shinrin-yoku or “forest bathing”.

Bathe yourself in the forests of Japan’s Yakushima island.
Alan Logan, Author provided

We do know that a diverse ecosystem supports a varied and beneficial microbial community living around and inside us.

We also know that exposure to green space, even within urban environments, increases our physical and mental well-being. But what are the mechanisms?

The forest air

The Japanese researchers suggested that we are taking in beneficial substances when we breathe forest air.

Research has identified three major inhaled factors that can make us feel healthier. These factors are beneficial bacteria, plant-derived essential oils and negatively-charged ions.

From birth to the grave, beneficial bacteria surround us; they live in the environment and, importantly, in the air we breathe. We also share almost our entire body with them. The more interaction we have with them, the happier and healthier we are.

This is in part due to our gut-dwelling bacteria, which break down the food we cannot digest and produce substances that benefit us both physically and mentally.

Plants and the bacteria living on them can produce essential oils to fight off harmful microorganisms. These are referred to collectively as phytoncides, literally, “plant-derived exterminators”.

Research on the health benefits of plant essential oils is in its infancy. But one recent study found that a phytoncide from Korean pine trees improved the health and bacterial make-up of pigs.

Notwithstanding some of the pseudoscience that gets wrapped around negative ion generating machines, there is evidence that negative air ions may influence mental outlook in beneficial ways. There are relatively higher levels of negative air ions in forested areas and close to bodies of water. This may factor into the benefits of walking in a forest or near the ocean.

But as the German writer Goethe once said:

Nature has neither kernel nor shell; she is everything at once.

Bacteria, essential oils and negative ions interact and influence each other. For example, negative ions and phytoncides may dictate the microbial make-up within a natural environment. There is evidence that this could also be taking place in the human gut.

More to be done

Nature-relatedness, or biophilia in which an individual feels connected to nature, has been linked with better health.

But we have a long way to go before we can more fully understand the mechanisms by which an innate love of nature can benefit our health. An important part of this discussion – an overlooked one in our opinion – is further understanding of an individual’s connection to nature.

Psychologists have convincingly demonstrated connections between nature relatedness and mental well-being. But how does a greater personal affinity to nature interact with dietary habits, personal microbiome, physical activity levels and many other lifestyle variables that might be intertwined with having such an affinity?

In the meantime, while scientists turn over stones and search for important mechanistic clues – including those related to biodiversity – there are many simple ways to capitalise on our biophilia.

Live in a city? The take time to walk in the city’s parks and gardens such as Melbourne’s Botanical Gardens.
Flickr/Stephen Barber, CC BY-NC-ND

Why not run in the park or by a river instead of on a treadmill, or take a walk through a park on the way to work or at lunchtime?

Critically, there is increasing evidence that we can help shape our children’s mental and physical health by exposing them to more green environments as they work, rest and play. The US-based Children and Nature Network is a great resource of research news and activities bringing children and nature together.

In the World Health Organization report Connecting Global Priorities – Biodiversity and Human Health, released in December last year, it was concluded that:

Considering ‘microbial diversity’ as an ecosystem service provider may contribute to bridging the chasm between ecology and medicine/immunology [… ] the relationships our individual bodies have with our microbiomes are a microcosm for the vital relationships our species shares with countless other organisms with which we share the planet.

It is easy to see that discussions of natural environments and human health are no mere matter of intellectual fancy.

In a paper published last month in Journal of Physiological Anthropology, we’ve called for more research into the links between biodiversity and human physical and mental well-being, particular in relation to childhood, that most formative of times.

Wouldn’t it be good if by nurturing our environment we were also nurturing our children’s future health?

The Conversation

Jeffrey Craig, Principal Research Fellow, Murdoch Childrens Research Institute and Susan L. Prescott, Professor of Paediatrics, University of Western Australia

This article was originally published on The Conversation. Read the original article.