Warty hammer orchids are sexual deceivers



File 20181129 170226 u1w9ow.png?ixlib=rb 1.1

The Conversation, CC BY-SA

Ryan Phillips, La Trobe University

Orchids are famed for their beautiful and alluring flowers – and the great lengths to which people will go to experience them in the wild. Among Australian orchids, evocative names such as The Butterfly Orchid, The Queen of Sheeba, and Cleopatra’s Needles conjure up images of rare and beautiful flowers.

Yet there is a rich diversity of our orchids. Some are diminutive, warty, and unpleasant-smelling, bearing little resemblance to a typical flower.




Read more:
‘The worst kind of pain you can imagine’ – what it’s like to be stung by a stinging tree


While many orchid enthusiasts have a soft spot for these quirky members of the Australian flora, what has brought them international recognition is their flair for using some of the most bizarre reproductive strategies on Earth.



The Conversation/Ryan Phillips/Suzi Bond., CC BY

Sexual mimicry

From the very beginnings of pollination research in Australia there were signs that something unusual was going on in the Australian orchid flora.

In the 1920s Edith Coleman from Victoria made the sensational discovery that the Australian tongue and bonnet orchids (Cryptostylis) were pollinated by males of a particular species of ichneumonid wasp attempting to mate with the flower.

But this was just the beginning.

The King-in-his-carriage, Drakaea glyptodon, is the most common species of hammer orchid. Here the flower is pictured next to the female of its pollinating thynnine wasp, Zaspilothynnus trilobatus.
Rod Peakall, Author provided

We now know that while the insect species involved may vary, many of our orchid species use this strategy. Australia is the world centre for sexual deception in plants.

Perhaps the most sophisticated flower of all sexually deceptive plants is seen in the hammer orchids, a diminutive genus that only grows in southwestern Australia. Their solitary stem reaches a height of around 40cm, and each stem produces a single flower no more than 4cm in length.

Even among sexually deceptive orchids, hammer orchids stand out from the crowd. They have a single heart-shaped leaf that sits flush with the soil surface, and grow in areas of dry inhospitable sand – an unusual choice for an orchid.

The thynnine wasp Zaspilothynnus nigripes is a sexually deceived.
pollinator of the Warty hammer orchid. Here they are pictured in copula, with the
flightless female having been carried to a food source by the male.

Keith Smith, Author provided

And then there is the flower. Not only does the lip of the flower more closely resemble an insect than a petal, but it is hinged partway along. All of which starts to makes sense once you see the pollinators in action.

Like many other Australian sexually deceptive orchids, they are pollinated by thynnine wasps – a unique group in which the male picks up the flightless female and they mate in flight.

In the case of hammer orchids, the male grasps the insect-like lip and attempts to fly off with “her”. The combination of his momentum and the hinge mechanism swings him upside down and onto the orchid’s reproductive structures.

It’s not me, it’s you (you’re a flower)

So, how do you trick a wasp?

Accurate visual mimicry of the female insect does not appear to be essential, as there are some sexually deceptive orchids that are brightly coloured like a regular flower.

Instead, the key ingredient for attracting pollinators to the flower is mimicking the sex pheromone of the female insect. And boy, is this pheromone potent.

Indeed, one of the strangest fieldwork experiences I’ve had was wasps flying through my open car window while stopped at traffic lights, irresistibly drawn to make love to the hammer orchids sitting on the passenger seat!

Pollination of the Warty hammer orchid by a male of the thynnine wasp Zaspilothynnus nigripes.
Suzi Bond, Author provided

While determining the chemicals responsible for attraction of sexually deceived pollinators is a laborious process, we now know that multiple classes of chemicals are involved, several of which were new to science or had no previously known function in plants.

What’s more, we are still discovering new and unexpected cases of sexual deception in orchids that don’t conform to the insect-like appearance of many sexually deceptive orchids.

A classic example is the case of the Warty hammer orchid and the Kings spider orchid – these two species have totally different-looking flowers, yet both are pollinated by the same wasp species through sexual deception.

While the ability to attract sexually excited males without closely resembling a female insect may partly explain the evolution of sexual deception, it does not explain the benefit of evolving this strategy in the first place.

A leading hypothesis for the evolution of sexual deception is that mate-seeking males be more efficient at finding orchid flowers than food-foraging pollinators – but this remains a work in progress.

The life cycle of the Warty hammer orchid and its pollinator species,
highlighting the complex ecological requirements needed to support a population of.
the orchid.

Martin Thompson, Author provided

From a conservation point of view, pollination by sexual deception has some interesting challenges. Female animals produce sex pheromones that only attract males of their own species. This means an orchid that mimics a sex pheromone typically relies on a single pollinator species. As such, conservation of any given orchid species requires the presence of a viable population of a particular pollinator.

Further, an interesting quirk of these sexually deceptive systems is the potential for cryptic forms of the orchid: where populations of orchids that appear identical to human observers actually attract different pollinator species through shifts in pheromone chemistry. Indeed, of the ten known species of hammer orchid, three contain cryptic forms.




Read more:
Australia’s unusual species


Not only does this create a major challenge for managing rare species, it raises the possibility that – should these forms prove to be separate species – the true diversity of sexually deceptive orchids could be greatly underestimated.


Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.The Conversation

Ryan Phillips, Senior Lecturer in Ecology, Environment & Evolution, La Trobe University

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

Why battery-powered vehicles stack up better than hydrogen



File 20181114 194500 iw2c1a.jpg?ixlib=rb 1.1
A battery electric vehicle in The University of Queensland’s vehicle fleet.
CC BY-ND

Jake Whitehead, The University of Queensland; Robin Smit, The University of Queensland, and Simon Washington, The University of Queensland

Low energy efficiency is already a major problem for petrol and diesel vehicles. Typically, only 20% of the overall well-to-wheel energy is actually used to power these vehicles. The other 80% is lost through oil extraction, refinement, transport, evaporation, and engine heat. This low energy efficiency is the primary reason why fossil fuel vehicles are emissions-intensive, and relatively expensive to run.

With this in mind, we set out to understand the energy efficiency of electric and hydrogen vehicles as part of a recent paper published in the Air Quality and Climate Change Journal.

Electric vehicles stack up best

Based on a wide scan of studies globally, we found that battery electric vehicles have significantly lower energy losses compared to other vehicle technologies. Interestingly, however, the well-to-wheel losses of hydrogen fuel cell vehicles were found to be almost as high as fossil fuel vehicles.

Average well-to-wheel energy losses from different vehicle drivetrain technologies, showing typical values and ranges. Note: these figures account for production, transport and propulsion, but do not capture manufacturing energy requirements, which are currently marginally higher for electric and hydrogen fuel cell vehicles compared to fossil fuel vehicles.

At first, this significant efficiency difference may seem surprising, given the recent attention on using hydrogen for transport.




Read more:
How hydrogen power can help us cut emissions, boost exports, and even drive further between refills


While most hydrogen today (and for the foreseeable future) is produced from fossil fuels, a zero-emission pathway is possible if renewable energy is used to:

Herein lies one of the significant challenges in harnessing hydrogen for transport: there are many more steps in the energy life cycle process, compared with the simpler, direct use of electricity in battery electric vehicles.

Each step in the process incurs an energy penalty, and therefore an efficiency loss. The sum of these losses ultimately explains why hydrogen fuel cell vehicles, on average, require three to four times more energy than battery electric vehicles, per kilometre travelled.

Electricity grid impacts

The future significance of low energy efficiency is made clearer upon examination of the potential electricity grid impacts. If Australia’s existing 14 million light vehicles were electric, they would need about 37 terawatt-hours (TWh) of electricity per year — a 15% increase in national electricity generation (roughly equivalent to Australia’s existing annual renewable generation).

But if this same fleet was converted to run on hydrogen, it would need more than four times the electricity: roughly 157 TWh a year. This would entail a 63% increase in national electricity generation.

A recent Infrastructure Victoria report reached a similar conclusion. It calculated that a full transition to hydrogen in 2046 – for both light and heavy vehicles – would require 64 TWh of electricity, the equivalent of a 147% increase in Victoria’s annual electricity consumption. Battery electric vehicles, meanwhile, would require roughly one third the amount (22 TWh).




Read more:
How electric cars can help save the grid


Some may argue that energy efficiency will no longer be important in the future given some forecasts suggest Australia could reach 100% renewable energy as soon as the 2030s. While the current political climate suggests this will be challenging, even as the transition occurs, there will be competing demands for renewable energy between sectors, stressing the continuing importance of energy efficiency.




Read more:
At its current rate, Australia is on track for 50% renewable electricity in 2025


It should also be recognised that higher energy requirements translate to higher energy prices. Even if hydrogen reached price parity with petrol or diesel in the future, electric vehicles would remain 70-90% cheaper to run, because of their higher energy efficiency. This would save the average Australian household more than A$2,000 per year.

Pragmatic plan for the future

Despite the clear energy efficiency advantages of electric vehicles over hydrogen vehicles, the truth is there is no silver bullet. Both technologies face differing challenges in terms of infrastructure, consumer acceptance, grid impacts, technology maturity and reliability, and driving range (the volume needed for sufficient hydrogen compared with the battery energy density for electric vehicles).

Battery electric vehicles are not yet a suitable replacement for every vehicle on our roads. But based on the technology available today, it is clear that a significant proportion of the current fleet could transition to be battery electric, including many cars, buses, and short-haul trucks.

Such a transition represents a sensible, robust and cost-efficient approach for delivering the significant transport emission reductions required within the short time frames outlined by the Intergovernmental Panel on Climate Change’s recent report on restraining global warming to 1.5℃, while also reducing transport costs.

Together with other energy-efficient technologies, such as the direct export of renewable electricity overseas, battery electric vehicles will ensure that the renewable energy we generate over the coming decades is used to reduce the greatest amount of emissions, as quickly as possible.




Read more:
The north’s future is electrifying: powering Asia with renewables


Meanwhile, research should continue into energy efficient options for long-distance trucks, shipping and aircraft, as well as the broader role for both hydrogen and electrification in reducing emissions across other sectors of the economy.

With the Federal Senate Select Committee on Electric Vehicles set to deliver its final report on December 4, let’s hope the continuing importance of energy efficiency in transport has not been forgotten.The Conversation

Jake Whitehead, Research Fellow, The University of Queensland; Robin Smit, Adjunct professor, The University of Queensland, and Simon Washington, Professor and Head of School of Civil Engineering, The University of Queensland

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

Why daily doses of nature in the city matter for people and the planet



File 20181120 161612 jduiq9.jpg?ixlib=rb 1.1
Brisbane’s South Bank parkland isn’t exactly getting out in the wild, but experiences of urban nature are important for building people’s connection to all living things.
Anne Cleary, Author provided

Anne Cleary, Griffith University

The environmental movement is shifting away from focusing solely on raising awareness about environmental issues. Many environmental agencies and organisations now also aim to connect people with nature, and our new research suggests daily doses of urban nature may be the key to this for the majority who live in cities.

Every year in the United Kingdom the Wildlife Trusts run the 30 Days Wild campaign. This encourages people to carry out a daily “random act of wildness” for the month of June. The International Union for Conservation of Nature recently launched its #NatureForAll program, which aims to inspire a love of nature.

This shift in focus is starting to appear in environmental policy. For example, the UK’s recent 25-year environment plan identifies connecting people with the environment as one of its six key areas. Similarly, in Australia, the state of Victoria’s Biodiversity 2037 plan aims to connect all Victorians to nature as one of two overarching objectives.

The thinking behind such efforts is simple: connecting people to nature will motivate them to act in ways that protect and care for nature. Evidence does suggest that people who have a high nature connection are likely to display pro-environmental attitudes and behaviours.

Looking beyond the park

What is less clear is how to enhance an individual’s nature connection – that is feeling that they are a part of nature. Over half of all people globally, and nine out of ten people in Australia, live in urban environments. This reduces their opportunities to experience and connect with nature.

Our new study may offer some answers. A survey of Brisbane residents showed that people who experienced nature during childhood or had regular contact with nature in their home and suburb were more likely to report feeling connected with nature.

The study used a broad definition of urban nature to include all the plants and animals that live in a city. When looking to connect urban residents with local nature we need to take a broad view and look “beyond the park”. All aspects of nature in the city offer a potential opportunity for people to experience nature and develop their sense of connection to it.

Raffles Place, Singapore – all urban nature should be seen as an opportunity for nature connection.
Anne Cleary, Author provided

The study also looked at the relationship between childhood and adult nature experiences. Results suggest that people who lack childhood experience of nature can still come to have a high sense of nature connection by experiencing nature as an adult.

There have been focused efforts on connecting children to nature, such as the Forest Schools and Nature Play programs. Equal effort should be given to promoting adult nature experiences and nature connection, particularly for people who lack such experiences.

The benefits of nature experience

We still have much to discover about how an individual’s nature connection is shaped. We need a better understanding of how people from diverse cultural and social contexts experience and connect to different types of nature. That said, we are starting to understand the important role that frequent local experiences of nature may play.

In addition to boosting people’s sense of nature connection, daily doses of urban nature deliver the benefits of improved physical, mental and social wellbeing. A growing evidence base is showing that exposure to nature, particularly in urban environments, can lead to healthier and happier city dwellers.

Robert Dunn and colleagues have already advocated for the importance of urban nature experiences as a way to bolster city residents’ support for conservation. They described the “pigeon paradox” whereby experiencing urban nature, which is often of low ecological value – such as interactions with non-native species – may have wider environmental benefits through people behaving in more environmentally conscious ways. They proposed that the future of conservation depended on city residents’ ability to experience urban nature.

As new evidence emerges we need to build on this thinking. It would seem that the future of our very connection to nature, our wellbeing and conservation depend on urban people’s ability to experience urban nature.The Conversation

The pigeon paradox: interactions with urban nature – here in London’s Hyde Park – may help make city dwellers more environmentally conscious.
Anne Cleary, Author provided

Anne Cleary, Research Fellow, School of Medicine, Griffith University

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

Summer forecast: scorching heat and heightened bushfire risk


Catherine Ganter, Australian Bureau of Meteorology

Large parts of Australia are facing a hotter and drier summer than average, according to the Bureau of Meteorology’s summer outlook.

Drier than average conditions are likely for much of northern Australia. Most of the country has at least an 80% chance of experiencing warmer than average day and night-time temperatures.

The threat of bushfire will remain high, with few signs of the sustained rain needed to reduce fire risk or make a significant dent in the ongoing drought.

Expect extreme heat

Large parts of Western Australia, most of Queensland and the Top End of the Northern Territory are expected to be drier than usual. Further south, the rest of the country shows no strong push towards a wetter or drier than average summer, which is a change for parts of the southeast compared to recent months.


Bureau of Meteorology

Queensland has already seen some extraordinary record-breaking heat in recent days, with summer yet to truly begin. With the summer outlook predicting warmer days and nights, combined with recent dry conditions and our long-term trend of increasing temperatures, some extreme highs are likely this summer.


Bureau of Meteorology

All of this means above-normal bushfire potential in eastern Australia, across New South Wales, Victoria and Queensland. The bushfire outlook, also released today, notes that rain in areas of eastern Australia during spring, while welcome, was not enough to recover from the long-term dry conditions. The current wet conditions across parts of coastal New South Wales will help, but it will not take long once hot and dry conditions return for vegetation to dry out.




Read more:
Sydney storms could be making the Queensland fires worse


What about El Niño?

The Bureau is currently at El Niño ALERT, which means a roughly 70% chance of El Niño developing this season.




Read more:
Australia moves to El Niño alert and the drought is likely to continue


However, not all the ducks are lined up. While ocean temperatures have already warmed to El Niño levels, to declare a proper “event” there must also be a corresponding response in the atmosphere to reinforce the ocean – this hasn’t happened yet.

That said, climate models expect this event to arrive in the coming months. The outlook has factored in that chance, and the conditions predicted are largely consistent with what we would expect during El Niño. In summer, this includes drier weather in parts of northern Australia, and warmer summer days.

Once an El Niño is in place, weather systems across southern Australia tend to be more mobile. This can mean shorter but more intense heatwaves in Victoria and southern South Australia. However, in New South Wales and Queensland, El Niño is associated with both longer and more intense heat waves.

The exact reason why the states are affected differently is complicated, but relates to the fast-moving cold fronts and troughs that sweep through Victoria and South Australia in the summertime, creating cool changes. These weather systems don’t influence areas further north so when hot air arrives, it takes longer to clear.




Read more:
Drought, wind and heat: when fire seasons start earlier and last longer


The heavy rains seen in parts of eastern Australia in October and November have provided some welcome short-term relief to drought-stricken farmers, but longer-term rainfall relief has not arrived yet. If El Niño arrives, this widespread relief may only be on the cards in autumn.The Conversation

Catherine Ganter, Senior Climatologist, Australian Bureau of Meteorology

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