Wednesday, November 09, 2011

Saltmarsh: regeneration of an endangered habitat.

Lane Cove National Park is a narrow, irregularly-shaped ecological reserve surrounded by Sydney suburbs. It is marked in dark green in the map below. Although it extends over 10 kilometres in length, it is only 6 sq kilometres in area. It surrounds the Lane Cover River, which begins in Hornsby to the north and opens into Sydney Harbour.


Map from National Parks and Wildlife Service

Its location, topography and perimeter present major ecological impacts on the park, specifically storm-water run-off from residences and weed invasion.

A key feature of natural Sydney vegetation is that it is largely adapted to soils derived from ancient sandstone, notoriously low in nutrients--particularly phosphorus. While seeds of invasive plant species evolved in high nutrient environments are likely found in all urban Sydney bushland, they generally cannot develop to maturity where nutrient levels are poor. Where run-off occurs, however, nutrients from human activity fertilise the soil and weeds can thrive. That's why weeds are more likely to be found near suburban bushland creeks than in the bush beyond. In addition, cuttings and seeds from weeds can be washed into the area, to propagate and invade. Weeds can then out-compete native plant species and destroy habitat and food sources of native fauna.

Sugarloaf Point is a region in the park that was once a thriving saltmarsh ecosystem. In 1940, 1.2 ha of the Point (below) were mangrove swamp, and 0.2 ha were saltmarsh.


Sugarloaf Point in 1940. Image © NSW Dept of Lands 2011.

Midway through last century, the river was dredged to improve boat access, and the excavated silt deposited onto the salt marshes.

Sugarloaf Point in the 1969s, at the height of dredging operations.
Photo courtesy of National Parks and Wildlife.
Over time, bushland has regenerated on the former saltmarsh site.

Casuarinas now growing on the site where the dredged silt was dumped.

Saltmarsh ecosystems provide a crucial role in coastal estuarine systems. They provide habitat for a range of molluscs and crustaceans, and act as nurseries for species that find their way into harbours. Microbats feast nocturnally on the high insect populations they support. And marshes recycle nutrients to make them available to other species. These environments are filled with water at high tide, and completely washed out during king tides. At king tides, fish enter to feed on the abundant prey available there.


National Parks ranger, Andrew Duffy, shows plant ecology staff and students a
coastal saltmarsh at Lane Cove National Park. The bridge is part of the
Great North Walk, stretching from central Sydney to
Newcastle, 250 kilometres north.

Sarconornia quinqueflora is a key species in Australian coastal saltmarsh. 

In New South Wales, coastal saltmarsh is listed as an endangered ecological community under the Threatened Species Conservation Act 1995. Frequently associated with this saltmarsh in saline wetlands are mangrove swamps, which provide habitat to a range of endangered and threatened species of flora and fauna, including the critically endangered Beach Stone-Curlew, Esacus neglectus.


Beach Stone-Curlew. Image CC, Avicida

Mangrove swamp, Lane Cove National Park.


Given the vulnerability to disturbance and pollution in Lane Cove National Park, one might imagine that its saltmarshes don't have a hope in Hades. However, thanks to the work of the National Parks and Wildlife Service, its local ranger, Andrew Duffy, and groups like Friends of Lane Cove National Park, extraordinary saltmarsh restoration is taking place there.


Saltmarsh restoration at Lane Cove NP.


This photo shows the work done thus far on the re-creation of a saltmarsh in the park. The soil has been removed to make the site low enough to be thoroughly inundated twice a month, with the gradient calculated to keep the water at an appropriate level across the site. Volunteers have planted tubestock of the signature species, including Suaeda australis, Tecticornia arbuscula, Juncus kraussii and Isolepis nodosa (Knobby Club-Rush, one of my favourite monocots, and not just because of its common name!)

Creating physical conditions is only part of the story. There's also chemistry. The environment needs to be kept free of the pollution that encourages weeds. To this end, nutrient traps have been created to decrease harm from storm water from adjacent residential areas. Below is a gross pollutant trap, which collects leaf litter and rubbish. The content from the trap is removed and disposed of off-site.


Gross pollutant trap.


More particulate pollutants need a finer trap, so crushed sandstone storm-water treatment traps have been set up, immediately adjacent to the nearby major road.

Crushed sandstone storm-water treatment trap,
immediately adjacent to Pittwater Road.

The crushed sandstone is obtained from construction sites in the Sydney area, and makes an ideal medium to suppress weeds and provide suitable substrate for native plants. It is placed on terraces constructed across the embankment. Beneath the trap is a settlement pond, where escaped nutrients settle and are physically removed with an excavator when around five tonnes of sediment have accumulated.

One of the predictions of climate change, already observed, is rising ocean water levels which will obviously have an effect on both saltmarsh and mangrove ecological communities. To this end, thought is being given to planning the restoration of these ecosystems at slightly higher altitudes. Water levels are not the only issue these communities must contend with, however. There is a strong inverse relationship between saltmarsh diversity and temperature in Australia, which does not bode well. (See link below for more.)

Thanks to Dr Michelle Leishman of Macquarie University's Department of Biological Sciences and to NPWS Ranger, Andrew Duffy, for introducing me to his magnificent habitat and restoration work. If I were a rich woman (ya ha didle deedle, didle deedle didle deedle dum) I'd donate to this cause in a heartbeat.

Further reading:

Coastal saltmarsh in the NSW North Coast, Sydney Basin and South East Corner bioregions - endangered ecological community listing

Protecting and Restoring Coastal Saltmarsh

Coastal saltmarsh vulnerability to climate change in SE Australia

[Edit: Thanks to Doug Beckers for his correction of the ID of Sarcocornia quinqueflora!]

Monday, October 17, 2011

Some wise words from Steven Pinker.....

"I think that a failure of statistical thinking is the major intellectual shortcoming of our universities, journalism and intellectual culture. Cognitive psychology tells us that the unaided human mind is vulnerable to many fallacies and illusions because of its reliance on its memory for vivid anecdotes rather than systematic statistics. Yet pundits continue to hallucinate trends in freak events, like the Norwegian sniper (who shot all those young people on an island) and make wildly innumerate comparisons, such as between Afghanistan and Vietnam, or between today's human trafficking and the African slave trade. It's a holdover of the literary sensibilities of our science-flunking intellectual elite, who would be aghast if someone didn't know who Milton was, but cheerfully flaunt their ignorance of basic science and mathematics. I lobbied – unsuccessfully – for a course requirement at Harvard in statistical and logical reasoning."--Steven Pinker.

He is utterly correct on the failure of communication between the arts and the sciences, and as one who has been positioned pretty evenly between them, I must say that I think those in the sciences tend to be far more intellectually fluent in the arts, than vice versa.

The quote comes from an email interview by John Naughton in The Guardian about Pinker's new book, The Better Angels of Our Nature: The Decline of Violence in History and its Causes. It's on my list!


Wednesday, October 12, 2011

Parasites and art: Tommy Leung

One of my favourite blogs is Parasite of the Day, cowritten by Tommy Leung. Tommy lectures in parasitology and evolutionary biology at the University of New England (NSW, Australia). What I didn't know is that Tommy is also an artist who paints and draws various biological creatures, real and imaginary, exploring biological concepts. He's just been profiled in the Scientific American blog Symbiartic: the science of art and the art of science.


Symbiosis Tree, by Tommy Leung

I can just see some of these images on my office wall.

So, Tommy, when's the exhibition?

Sunday, October 09, 2011

Superb Lyrebird mimicry: recording!

I've previously posted about the Superb Lyrebirds (Menura novaehollandiae) in our garden, with the promise that one day I'd upload audio. Today is that day!

Since we've been living here, the lyrebirds have become increasing common and less fearful. Their increased abundance is probably due in part to cat and fox baiting in Ku-ring-gai Chase National Park which anecdotally has increased populations of a range of other native fauna, including the Short-beaked Echidna (Tachyglossus aculeatus), the endangered Southern Brown Bandicoot (Isoodon obesulus obesulus) and the Australian Brush-turkey (Alectura lathami), all of which visit our place. I suspect that the lyrebirds are particularly attracted to our garden because I do a lot of mulching, grow only native plants, and avoid the use of pesticides, so there are plenty of leaf litter invertebrates for them to feast on.

Foreground: a juvenile male.
Background: a female.

A male.

This is a recording I made this morning using my phone. Since then I've been fiddling about, converting the sound file to an .mp3, finding a host to upload it to, and sourcing a widget. I hope it plays okay on your computer. It does on mine (huzzah!).



All the sounds you can hear are the lyrebird's song, mimicking other species, with the exception of the "dock" sound, which is the call of a Striped Marsh Frog (Limnodynastes peronii) in the pond. Among the birds it's mimicking are an Eastern Whipbird (Psophodes olivaceus) and a Laughing Kookaburra (Dacelo novaeguineae). At 18 seconds is a sound in the repertoire I haven't been able to identify. It doesn't sound like a bird....

Thursday, September 22, 2011

Field Trip to Smiths Lake, Central New South Wales

Yesterday, I returned from a field trip at Smiths Lake, around 250 kilometres north of Sydney on the Central Coast. Smiths Lake is salt water, and periodically naturally opens to the sea.

View Smiths Lake Field Station in a larger map

The annual field trip is a large component of a second year ecology unit run by Macquarie University, and I was there as the plant science tutor. As well as vegetation pracs, the trip included pracs on bird communities, plant-dwelling invertebrates, benthic diatoms, fish communities and benthic invertebrates. It's the first time I've formally taught in biology, and just loved the experience. Out in the bush, there were plenty of snakes, including a Death adder, Acanthophis sp., one of the most venomous snakes in the world, but we made plenty of noise in the bush to keep them at bay. No students lost, happily.

Pelagica, one of the university's research boats. 

I didn't spend much time on our boat Pelagica, since my pracs were in the bush. But I did get to enjoy a boat trip on the final day.


My passion for terrestrial orchids grows unabated! Isn't this a cutey?

Calochilus paludosus,
Red Beardy ground orchid

A frequent visitor to the field station, a young male
Eastern Grey Kangaroo, Macropus giganteus.
This fellow was on his own, so has probably been forced out from his mob by the dominant male, and is wandering about looking for his own mob to start.

Lomandra confertifolia ssp. rubiginosa, a delicate sedge. 

An Australian Pelican, Pelicanus conspicillatus
My tent was close to this spot. Pelicans were gliding past my tent at dusk. There are hundreds of them on the lake, and given the massive numbers of fish we saw, it's hardly surprising. It's a fish smorgasbord.

A beautiful place, and a fabulous field trip! Such diversity of species. Bliss.

Saturday, September 03, 2011

Peacock Carpenter Bee

It's a few years since I last visited Muogamarra Nature Reserve, which is just north of Sydney and on the southern side of the Hawkesbury River. But today returned with some fellow biologists from Macquarie Uni. The flora was as bogglingly diverse and plentiful as ever, but today a fascinating native bee caught my eye.


This is the Peacock Carpenter Bee, also known as the Metallic Carpenter Bee, Xylocopa bombylans. Given its colouration and metallic shine, at first I thought it was a beetle, but closer examination showed its distinctly beelike nature.

The bees were busy feeding at the copious flowers of Eriostemon australasius, the Pink Wax Flower.


Eriostemon is a genus in the family Rutaceae that's recently been split by the taxonomists, with most of the species being transferred to the genus Philotheca. Only Eriostemon australasius and E.banksii remain.

The Peacock Carpenter Bee is so known because of its colouring and life-cycle. Depending on the angle of the reflected light, its colour changes from blue to green to purple. And as for their carpentry, this is what the Australian Museum has to say:
The nest of the Peacock Carpenter Bee is usually a single tunnel about 30 cm long with interconnecting passages when the wood is wide enough. The tunnels are sectioned off into brood cells, which are sealed after an egg is laid inside with a supply of nectar and pollen rolled up into a moist ball. When the eggs hatch, the larvae eat the food balls and pupate.  
Often the young bee in the bottom cell of the nest emerges from its pupa first as it was the first egg laid. It chews its way through the walls of the other cells to break free of the nest. The other pupae usually fall through the holes and gather in the bottom cell. They hatch normally and climb their way out of the nest.

Female carpenter bees sometimes cooperate during brood rearing, taking it in turns to guard the nest entrance while the main egg-laying bee goes out foraging for nectar and pollen to feed the larvae. [Source]
The bee grows to 1.8 cm in length, feeds on nectar and pollen, and is found in Eastern Australia north of Sydney.


If you're planning a trip to Sydney, I really urge you to time your visit for when Muogamarra is open to the public, a few weekends in late winter/early spring. It is a beautiful place. I've put more photos from the day, including plenty of plant shots, on Picasa, here.

Saturday, June 11, 2011

Book Review: "My Little World" by Julia Cooke

When I was a child, I was entranced by microcosms. For hours, I'd stare into my fish tank, imagining myself around an inch in height, swimming about among the fish. I constructed terrariums, seeing the  mosses and ferns as forests and jungles. My brother and I took our Matchbox cars on "safaris" in the garden. And of course, my dolls' house was a world in which I conjured epic tales of domestic drama.

In her first children's book, My Little WorldJulia Cooke (with illustrator Marjorie Crosby-Fairall), has tapped into this childhood fascination with the tiny. Shortly to gain her PhD in plant ecology, she chose for her subject matter the more diminutive flora and fauna of Australia, specifically those of Black Mountain in Canberra. 



A few weeks ago, My Growing Passion hosted a guest post by Julia, on "getting the science right". Since then, I've bought a copy of My Little World as a present for the young daughter of friends. What better gift for a child than something to help open their eyes to the natural world around them?

The book is truly a delight. The text is in verse, whimsical, inspiring and accessible. The illustrations are detailed and elegant, and, of course, technically accurate. I would have loved this book as a child. So many hidden creatures to find within, so much to awaken curiosity. So much to motivate an exploration of the garden or the local bush.

Heartily recommended!


Author: Julia Cooke
ISBN: 9781862917903
ISBN-10: 1862917906
Publisher: Scholastic
Format: Hardback Book
Pages: 24
Language: English

Buy online:
Gleebooks
Shearers

Wednesday, May 11, 2011

"I'm A Climate Scientist" ... from Hungry Beast



Bravo! A couple of familiar faces from Macquarie University here too.

[Hungry Beast is a television program from the Australian Broadcasting Corporation.]

The lyrics....

Who's a climate scientist..
I'm a climate scientist..
Not a cleo finalist
No a climate scientist
Droppin facts all over this wax
While bitches be crying about a carbon tax
Climate change is caused by people
Earth Unlike Alien Has no sequel
We gotta move fast or we'll be forsaken,
Cause we were too busy suckin dick Copenhagen: (Politician)
I said Burn! it's hot in here..
32% more carbon in the atmosphere.
Oh Eee Ohh Eee oh wee ice ice ice
Raisin' sea levels twice by twice
We're scientists, what we speak is True.
Unlike Andrew Bolt our work is Peer Reviewed... ooohhh
Who's a climate scientist..
I'm a climate scientist..
An Anglican revivalist
No a climate scientist
Feedback is like climate change on crack
The permafrosts subtracts: feedback
Methane release wack : feedback..
Write a letter then burn it: feedback
Denialists deny this in your dreams
Coz climate change means greater extremes,
Shit won't be the norm
Heatwaves bigger badder storms
The Green house effect is just a theory sucker (Alan Jones)
Yeah so is gravity float away muther f**cker
Who's a climate scientist..
I'm a climate scientist..
I'm not a climate Scientist
Who's Climate Scientists
A Penny Farthing Cyclist
No
A Lebanese typist
No
A Paleontologist
No
A Sebaceous Cyst
No! a climate scientist! Yo! PREACH~!

Tuesday, April 26, 2011

Snails and Beetles in Bali

I was gobsmacked by the diversity of terrestrial snails in Bali. Here are some I photographed.

Bali snail


Bali snail


Bali snail


Bali snail3


And some beetles I met:

Rhinoceros beetle
Rhinoceros beetle


Beetle

Invertebrate Bliss in Bali.

I recently visited Bali, with husband and daughter, to spend some time with my brother- and sister-in-law who have started up a diving school in Sanur, Joe's Gone Diving. With the rest of my in-laws visiting from the Netherlands, it was a delightful family reunion. Husband Martien got his PADI diving certificate. I'll likely do the same at some point, but for this holiday, all I wanted to do was relax!

One of the highlights was visiting the Butterfly Farm, Taman Kupu Kupu, near Tabanan. This is the largest butterfly farm in South-East Asia, and butterflies are bred for research there.

Butterflies in production
Butterflies in production


Butterfly and Martien's foot
A butterfly visits Martien's ankle


Butterfly
Sorry, I don't know the species name!


butterfly lady
Me, Crazy Butterfly Lady


Preserved specimens are for sale (only species that are common---nothing endangered!), and given the price (only $AU8 each!), how could I resist? These are next to my desk, in my study.

Butterflies on wall


The cream specimen on the top left is actually a moth, Attacus atlas, the largest moth on earth, by wing area.

In addition to butterflies, Taman Kupu Kupu have a range of other inverts on display, including this magnificent creature - an orchid mantis, Hymenopus coronatus. Extraordinary mimicry!

Hymenophus coronathus
Hymenopus coronatus




Saturday, April 23, 2011

Guest Blog by Julia Cooke, author of "My Little World".

I'm delighted to welcome guest blogger, Julia Cooke, author of My Little World, a picture book for children. Julia is on tour in the blogosphere - see here for tour dates and places!

Getting the science right in 
My Little World

My Little World is the story of a child finding a world of tiny animals and plants when they can’t see the birds and mammals that the grown-ups see on a bush walk. The main message is that you can find the most amazing things by looking carefully - and a different perspective can be useful too. But how could we encourage careful observation in a reader unless we had taken care in selecting and presenting real species?  





Full credit for the illustrations, of course, goes to award winning illustrator Marjorie Crosby-Fairall. Her use of colour to create different micro-habitats and her attention to detail is magnificent - to me the pages are bustling with life. I can’t speak for Marjorie about the production of the beautiful illustrations, so this post will focus on some of the research behind them in which I was involved.  

My Little World is set in Canberra, the bush capital, on Black Mountain (it has the iconic telecommunications tower on top). I visited the site, took photos and wrote the story around what I had seen. This research was sufficient for my English assignment (the reason I wrote the book in the first place), but when it came to producing a real book, we needed more species and full identification. As a plant ecologist, I could use my knowledge of scientific resources to contribute species lists, reference images and check details for Marjorie. It was very different research to my normal studies, and it was fun but quite a challenge!

Creating a plant list was facilitated by online records that amateurs and professionals had compiled (including from online herbaria) specifically for Black Mountain and I could identify species on the mountain myself. My Little World includes several species of eucalypt (red box, red stringy bark, inland scribbly gum, candle-bark gum) and a range of plant families including Poaceae (kangaroo and white-top wallaby grasses), Fabaceae - Mimosoideae (red stemmed and box-leaf wattles), Fabaceae - Faboideae (purple coral pea and twining glycine), Liliaceae (nodding blue lily) and ferns, a moss, a sundew and an orchid. The book is set the book in October, when many species are flowering and we used floras to check flowering times.


Scribbles on Eucalyptus haemastoma © Julia Cooke

For invertebrate species I identified the species I had seen on site and searched the online records from the Australian National Insect Collection (ANIC) for species collected on Black Mountain and Canberra. The search was a great starting point (possibly the location of CSIRO Entomology/Ecosystem Sciences at the foot of Black Mountain helped!), though not all ANIC records are available online. Other species, such as the blue-banded bee, I was introduced to at a friend’s house and was delighted to be able to include. I also wrote to more than a dozen researchers, often with suggestion of species to check details of their distribution and for reference images and sometimes for the suggestion of a snail or fungus for which readily available records and information are more limited. The generosity of the people I contacted was amazing. A range of insect orders are featured including Hemiptera, Coleoptera, Orthoptera  as well as a spider (Araneae). We chose species that are easily seen, and those that are harder to spot such as the pollen feeding katydid (Zaphrochilus australis).  

Marjorie needed good reference images for all species. The internet was a wonderful resource providing ready access to both amateur and professional pictures.  Where an image was heavily relied on, we contacted the photographer for permission to use their images or to request a higher resolution images. Again, we received very generous responses. For some species, photo references just were not available.  Line drawings and scientific descriptions were used, and in some cases we took further reference images ourselves. I photographed scribbles, the mines of the larvae of Ogmograptis spp. (which differ in morphology between Eucalyptus species), and I photographed the head and wing scales of a Meadow Argus specimen borrowed from a university colleague.  


Eye spot on wing of Junonia villida © Julia Cooke

As with the plants, we checked the phenology of the animals to ensure they could be seen in October.  The Christmas beetle (Anoplognathus montanus) which, as their name suggest, are often abundant in December, may be stretching this a little, but as there were several records of Christmas beetles on Black Mountain from October, I let it in!

Species with contrasting distributions were also selected. The meadow argus (Junonia villda) is found throughout Australia, so almost any reader in the country could see one. But then there are other species that have a much more limited distribution, such as the lemon cap orchids (Caladenia cucullata). It is the suite of species rather than an individual species that make it specific to the Canberra region. We included two endangered species, the sun moth (Synemon plana) and perunga grasshopper (Perunga ochracea), which may now be extinct on Black Mountain, but could still be found there and deserve attention.

During this process, I realised that an illustration shows more than just morphology. The illustrations depict behaviours, interactions and species co-existence - the way a bee flies, the pattern on a spider web, the way a caterpillar moves. There is a eye-patterned gum hopper (Platybrachys vidua) on one of the early pages. When I first wrote the book, the gum hopper I saw was on some grass - I spotted it because the brown animal stood out against the green leaf. The nymphs are more normally found, but better camouflaged, on eucalypt trunks, but are easily disturbed and jump away, often ending up in unlikely places. So, was it better to present typical behaviour or what I actually saw? In this case I chose to portray what I had seen (though a grass tree was substituted for some grass) and we did put a eucalypt on the page too, as a reference to their their normal habitat.

Most of the species in the book have their common name written next to them, cleverly incorporated by the designer so that they do not distract the eye from Marjorie’s illustrations.  At the back of the book I have provided notes on the focal species from each page, giving the scientific name and some brief ecological details. I hope children will ask questions about the plants, animals and fungi they see in the pictures and these names and information will provide some of the answers. I've compiled teacher’s notes too (available here) that use the book to introduce life cycles, nature diaries, phenology, scientific names, animal behaviour, animal signs, micro-habitats, camouflage, valuing invertebrates and many other issues that are scientific but accessible, important and fascinating for children.


Julia Cooke on Black Mountain
© Shannon Cornish

I hope My Little World makes a small contribution to encouraging children to delight in and appreciate nature, and in turn to conserving the natural world. It is unlikely that you would find all the species depicted in My Little World if you went for one walk on Black Mountain, but you could find them there. I’m sure I didn’t get all the details right, but I gave it my best shot and hopefully readers will appreciate that.

Cheers,
Julia.

(I'm on tour in the blogosphere - see here for tour dates and places!)

Title: My Little World
Author: Julia Cooke
Illustrator: Marjorie Crosby-Fairall
Publisher: Omnibus Books, $26.99
Publication Date: April 2011
ISBN: 9781862917903
Format: Hard cover
For ages: 4+

Sunday, March 13, 2011

This Island Earth

Often we hear of the emotional impact felt by astronauts as they look down at earth from space, comprehending on a visceral level just how isolated and vulnerable our home is. The photo of earth taken from Apollo 17 has come to symbolise that sense. This image, according to a NASA archivist, is probably the most distributed image in human history. I had a poster of it on my wall, as a teenager in the 'seventies and used to gaze at it. It seemed to put things into perspective.





As a result of yesterday's earthquake in Japan, the earth's rotation has shifted 25cm. 

The main island of Japan has moved 2.4m.

The power of the resulting tsunami streaming out across the Pacific is staggering in its intensity and range.



Image showing the intensity of the Japan tsunami, 12 March 2011.
Source: National Oceanic and Atmospheric Administration


We are a small part of a very thin and fragile biosphere, wrapped around this pulsing, shuddering behemoth.

That puts things into perspective too. 

Tuesday, February 22, 2011

Tom Paine's Ghost: Post with the Most!

A great blogging competition is afoot! Over at Tom Paine's Ghost, Kristopher Hite has announced the second annual Post with the Most event. From his blog:
A $100 cash prize will be awarded for the most powerful blog post freely available out there on the interwebs.

Post content is limited only by the bounds of imagination.
Keep in mind Tom Paine's Ghost was founded amidst a battle to defend freedom of the press and we hope to echo that theme throughout our pages.
Submissions will be selected and judged on the basis of four criteria:

1. Clarity
2. Originality
3. Integration (at least three forms of media would ideally be utilized, images, text, movies (you tube or vimeo), audio, etc.)
4. Power (the post's ability to motivate readers to action).

Last year, the wonderful Christie Wilcox of Observations of a Nerd won the award with her post, Reflections on the Gulf Oil Spill -- Conversations with my Grandpa, and you can see some other entries here.

So support good blogging, and either enter your own work or pass this on to someone you know who deserves the glory!

Sunday, January 23, 2011

Cryptostylis subulata

Native ground orchids can be contrary beasts. Since I last blogged about Cryptostylis subulata (Large Tongue Orchid) growing in our garden four years ago, there have been none in flower here... till this week:


Cryptostylis subulata
Cryptostylis subulata


This specimen is growing on the edge of a sandstone platform, the flowers hanging down over the cave beneath.

There is much that is remarkable about C. subulata. As with the other species of the genus endemic to Australia, it is exclusively pollinated by the male ichneumon wasp Lissopimpla excelsa (the dupe wasp). The orchid flower mimics a female wasp, not only through its appearance, but also by exuding a chemical counterfeit copying the pheromone of the female wasp. The male tries to mate with the flower--even to the point of ejaculation--and in doing so, transfers pollen.

This sexual deception is an extraordinary example of an exploitative symbiosis. Many plants engage in deception to trick pollinators into transferring gametes for them, and it is particularly common among orchids. There are cases of orchids emulating brood sites, food, and in at least one curious case, a marauding bee. Real bees will attack and brush against the flowers of Oncidium hyphaematicum as they wobble in the breeze, the pollen adhering to their bodies for transport to the next orchid.

Orchids also have very specific mutualistic relationships with fungi. Their seeds are minute and lack endosperm--the portion of the seed that provides food for the growing plant embryo. They are entirely dependent on fungi for energy at this stage, and later, form crucial relationships with mycorrhizal fungi for nutrients. The relationship between the evolution of pollinator deception, fungal symbionts and orchid diversity is an area of research rich with promise.


References:

A. C. Gaskett, C. G. Winnick, M. E. Herberstein (2008). "Orchid Sexual Deceit Provokes Ejaculation". The American Naturalist 171 (6)

A. C. Gaskett, M. E. Herberstein (2010). "Colour mimicry and sexual deception by Tongue orchids (Cryptostylis)". Naturwissenschaften 97: 97–102