Flower power - all you need is a little love
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This winter the Victorian bush is once again embraced by orchid flower power, with a few of the hardier souls having already ventured out into the sunlight.
Almost a quarter of Australia’s nearly 1250 orchid species are found in just 3% of its land mass, and Victoria is a veritable Mecca of orchid diversity, representing some 370 species.
Aside from their value as highly fascinating plants, many of Victoria’s native orchids are of great conservation value, with almost 40% restricted to particular geographic locations. Some species are so rare their numbers are limited to just a handful of populations at a few sites, or in the case of the Bald-tip Beard Orchid (Calochilus richiae) just one population made up of fewer than ten individuals.
All you need is love
Across the state right now games of deception are being played out - the air is thick with wasp pheromones and the sweet smell of nectar beckons.
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This thynnine wasp has been attracted to the bird orchid, Chiloglottis valida, through its mimicry of the female wasp sex-pheromone.
Photo: mwhitehead-flickr |
From high up in the Victorian alps, down to sea level, the relatively common Large Bird Orchid (Chiloglottis valida) is attracting thynnine wasps (Neozeleboria monticola) by mimicking the sexual attractant pheromones produced by female wasps.
Intoxicated and enticed, males vie for some personal time with these larger-than-life ladies, and are conscripted as couriers of large packets of pollen, ferrying them from one plant to another and facilitating pollination.
Other species are working the culinary angle, although for these orchids it’s all about the plating up, not about the food. To satisfy the food lovers of the insect world – at least as far as their curiosity is concerned - bright colours and sweet floral scents attract wasps, bees, beetles and flies to non-existent treats.
The threatened Small Golden Moths Orchid (Diuris basaltica), a species comprised of just three populations and some 400 individuals, is thought to attract foraging halictid beetles in Melbourne’s western volcanic plains. The duped beetles mistake the orchid’s small golden-yellow flowers for nearby pollen and nectar bearing species.
Help! I need somebody
If you need somebody to love this spring, there are some deserving individuals involved in native orchid conservation and research, helping to develop our understanding of this diverse and extraordinary group of plants.
For a truly orchid-centric perspective, you can’t go past the Australasian Native Orchid Society (ANOS), a group of amateur and professional enthusiasts dedicated to the cultivation, conservation and scientific study of native orchids in the Australasian region.
The Victorian arm of ANOS have dedicated groups focusing on both terrestrial and epiphytic (growing on other plants, rather than the ground) orchids, and a conservation group that maintains sites for native orchids and carries out searches for new populations of rare and threatened species.
The group helps manage sites at Plenty Gorge and St Helena in Melbourne’s north-east, the Mornington Peninsula and western suburbs. Through ongoing monitoring, weed and other site management, they have helped protect species such as the Sunshine Diuris (Diuris fragrantissima). Once abundant in the grassy plains west of Melbourne and referred to as “snow in the paddock”, the Sunshine Diuris was thought to have disappeared, as native grasslands receded and were replaced by agriculture and industrial and residential development.
However, in 2000 a population was unexpectedly discovered in a railway yard in Melbourne’s western suburbs, and subsequent reintroductions have seen a second colony established in an area where the species once occurred.
In the academic arena, Dr Tien Huynh, lecturer and researcher at RMIT Bundoora, is involved in a number of projects examining the effects of fire on both flora and fauna around Kinglake, Wonthaggi, Portland and the Grampians.
“Victoria is one of the world’s largest hotspots for native orchid diversity and they’re embraced by the general public because of their diversity, unique floral architecture and attractiveness,” she says. “I couldn’t think of a better plant to research on.”
Dr Huynh’s work focuses on orchids and their mycorrhizal fungi (see Extending the Hyphae of Friendship) as indicators of environmental change.
“Orchids are one of the largest flowering plant families on earth so are a good representative for what happens in other plants. They (orchids and their mycorrhizal fungi) are sensitive to the environment and function as good biological indicators.”
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Glossodia major
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Diurus behia
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Diurus sulphurea
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Caladenia tentaculata
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Dr Huynh and others hope their work, encompassing the hot topics of fire frequency and season, and examining differences in orchid and fungal diversity between natural and simulated fires, will eventually aid land managers in their use of fire as a management tool within the landscape.
“There is so much we still do not know and so much to investigate and understand for applications in other plants and ecosystems, particularly vulnerable and threatened populations and environments,” says Dr Huynh.
“Fire can be a friend or foe of orchids and their mycorrhizal fungi. There are so many factors that can upset the balance. There doesn’t appear to be a universal answer for every plant.” says Dr Huynh.
Despite the King Lake area still bearing scars from the Black Saturday bushfires, both orchids and fungi have regenerated and re-established these intimate relationships with one another.
“Fires are devastating above ground but there is a lot we do not know underneath the soil,” says Dr Huynh.
“It is not enough to rely on anecdotal evidence to plan for our future, whether it be for plant conservation or land management strategies for community protection. Research will help improve our understanding of what is really happening so we can use the information for achieving the best outcome.”
Dr Huynh’s fascination with orchids is unlikely to stop with her current research into the effects of fire on ecosystems.
“I’m hoping to diversify out to medicinal potentials of orchids. For every problem we face, I think the answer is in plants and nature. Why not investigate this fascinating and diverse group that we know and understand relatively little about?”
So if you’re out and about this winter, and into spring, why not investigate the wonderful world of Victoria’s native orchids yourself?
With a keen eye and carefully placed step you just might discover a world of unique beauty within the wider wonder of our natural spaces.
Remember to take only photographs (and share them with us on our Facebook page), so that our diverse and precious orchids continue to enrich our environment and further future fascination.
Extending the hyphae of friendship
Numerous plants share symbiotic relationships with certain fungi (mycorrhizas), which act as an extension of the plant’s root system, enhancing uptake of nutrients and water. This main “body” of the fungi extends beneath the soil in great networks of growth tissue (hyphae), and also gives rise to fruiting bodies – what we recognise as mushrooms and other fungus types.
Orchid mycorrhizas represent one of several such mycorrhizal associations, and are unique in their structure and function. Fungal hyphae form coils within the cells of orchid roots or stems, providing ongoing nutrient supply to adult terrestrial orchids.
Germinating orchid seedlings, known as protocorms, are wholly dependent on their mycorrhizal fungi, as they lack root systems possessed by other species. Amazingly, these associations between orchid and mycorrhizal fungi are often species specific – with just one species of fungi forming an association with one species of orchid.
Optimal orchid enjoyment
The Australasian Native Orchid Society welcomes new members, and even for those with just a slight interest, at as low as $18 a year (if choosing to receive their bulletins by email) joining is a bargain. Membership allows you to attend monthly meetings and presentations, and participate in all ANOS activities throughout the year. For more information, visit the society's website.
Why not grow your own orchids? The Australian Orchid Nursery specialise in cool growing orchids, and sell Australian natives that you can grow in your own garden – www.australianorchids.com.au.
Check out these excellent videos of orchids in action, as these Australian species fool some male wasps. Please browse the photo album on our Celebrating Victoria's Nature Facebook page and feel free to post your own images.
 Wasp attempts to mate with hammer orchid
Male wasps tricked into mating with Australian tongue orchids
References
- Backhouse, G. and Lester, K. (2010). National Recovery Plan for the Small Golden Moths Orchid Diuris basaltica. Department of Sustainability and Environment, Melbourne.
- Brundrett M.C. (2006). Role of symbiotic relationships in Australian terrestrial orchid conservation. Australasian Plant Conservation 15, 2-7.
- McMullan-Fisher, S.J.M., May T.W., Robinson, R.M., Bell, T.L., Lebel, T., Catcheside, P. and York, A. (2010). Fungi and fire in Australian ecosystems: a review of current knowledge, management implications and research gaps and solutions. Australian Journal of Botany, 59, 70-90.
- Murphy, A.H., Webster, A., Knight, C. and Lester, K. (2008). National recovery plan for the Sunshine Diuris Dirus fragrantissima. Department of Sustainability and Environment, Melbourne.
- Webster, A., Backhouse, G. and Murphy, A.H. (2004). Action Statement No. 50: Sunshine Diuris Diuris fragrantissima. Department of Sustainability and Environment, Melbourne.
- Wright, M., Thomson, R., Smith, Z., McQualter, E. and Cross, R. (2006). Royal Botanic Gardens Melbourne contributes to Victorian orchid conservation: ex situ propagation with mycorrhizal fungi. Australasian Plant Conservation, 15, 12-13.
Related links
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