Feed aggregator

Fleas get a free ride - and there's not much in it for the dog. Kristian Niemi/Flickr, CC BY-NC-ND

To call someone a “parasite” is an insult. But the word has rather a different meaning in biology.

Etymologically speaking, the earliest known record of the word parasite in the English language was in 1539, when it was defined as “a hanger-on, a toady, a person who lives on others”. The word itself was derived from the Greek parasitos, meaning “a person who eats at the table of another”.

The social use appears to precede the scientific use, which was first recorded in 1646 as “an animal or plant that lives on others”.

Parasite might trigger distant memories of school lessons about fleas and tapeworms. But is this view accurate? As with most things in life, the answer is not as straightforward as it first appears.

It’s complicated

Parasites are a group of often unrelated organisms that share a way of life. Parasitism is only one example in the spectrum of ways organisms relate to each other.

Today, ecologists use “symbiosis” to refer to any relationship between two organisms. Anton de Bary, the pioneering mycologist (a fungi specialist), defined symbiosis when he wrote in his 1879 monograph Die Erscheinung der Symbiose that “any two organisms living in close association, commonly one living in or on the body of the other, are symbiotic, as contrasted with free living”.

Symbiosis can be subdivided into four broad categories, with clear examples in each, but the boundaries between them are sometimes blurred.

Parasitism

Parasitism is a relationship in which one partner (the parasite) benefits at the expense of the other (the host). Parasites hurt their hosts in many ways, ranging from general or specialised pathology and impairment of sexual characteristics, to the modification of host behaviour. Parasites increase their own fitness by exploiting hosts for food, habitat and/or dispersal.

Less obvious but familiar examples include the cuckoo, which is a brood parasite, laying its eggs in the nests of other bird species. This relieves the parasitic parent from the investment of rearing young or building nests, enabling them to spend more time foraging and producing more offspring.

The risk of losing an egg to raiders such as small mammals is reduced by distributing the eggs among different nests – literally not putting all their eggs in one basket.

Another interesting example, a parasite for life and not just at Christmas, is mistletoe. This plant grows on a wide range of host trees and commonly stunts their growth, but can kill them with heavy infestation.

Mistletoe is not completely dependent on its host and has its own leaves that do some photosynthesis. It uses the host mainly for water and mineral nutrients.

A lion eating a wildebeest or zebra is certainly benefiting from the other organism’s loss, but lions are predators, not parasites. Well-adapted parasites have typically evolved not to kill their hosts.

What about mosquitoes, which drink human blood? Parasites usually live in a very intimate relationship with their host, depending on it for more than nutritional requirements. The host is a source of food and at the same time provides a more-or-less permanent habitat. So, a mosquito is more properly a tiny predator.

But mosquitoes also transmit disease-causing micro-organisms such as the malaria protozoan or dengue virus. These are true parasites.

Mutualism

Mutualism is a relationship in which both partners benefit from the interaction.

The classic example of mutualism is lichen, a long-term association between a fungus and a green alga (or blue-green cyanobacterium). It is this that the German mycologist Heinrich Anton de Bary described as “the living together of unlike organisms”.

The fungus benefits from the relationship because algae or cyanobacteria produce food by photosynthesis. The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment and (usually) provide an anchor to it.

A further example may be observed in a tropical aquarium. Well known to fans of the Disney film Finding Nemo, the clownfish is protected by a sea anemone, which stings the fish’s predators; in turn, the clownfish removes ectoparasites from the anemone.

Commensalism

Commensalism is a similar concept, but only one partner benefits, while the other is unaffected. The cattle egret is a classic example of a commensal.

This bird forages in fields among cows and horses, feeding on insects stirred up when the animals graze. The egret benefits from this relationship because the livestock inadvertently help it find a meal, while they are seemingly unaffected by its presence.

Another, more recently appreciated example is the colonisation of the human gut by so-called “good bacteria”, also known as probiotics, which multiply in the mammalian gut and apparently aid digestion. Whether this relationship is in fact commensal or mutual may depend on the species of bacteria involved.

Some biologists argue that any close relationship between two organisms is unlikely to be completely neutral for either party, and that relationships identified as commensal are more likely mutualistic or even parasitic in a subtle way that has not been identified.

Competition

Competition is an interaction between organisms in which the fitness of one, or potentially both, is lowered by the presence of the other. In some cases, both partners may be harmed by the relationship.

The behaviour of male red deer during the rutting season is an example of competition within a species, while trees of different species compete for light in a rainforest.

So, the next time you are tempted to call someone a parasite, think again. Your relationship with them may in fact be an example of competition, commensalism or perhaps even mutualism: you scratch my back and I’ll scratch yours.

Andrew Taylor-Robinson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

British astronaut Tim Peake says that he is concerned about the future of scientific research in Britain, following the vote to leave the European Union.

Spain’s gleaning movement has grown rapidly in response to austerity, harvesting imperfect fruit and veg - that would otherwise be wasted - for food banks. Now its own line of jams, soups and sauces is taking off too

Under a blazing Catalan sun, Abdelouahid wipes the sweat from his brow in a cabbage patch full with clouds of white butterflies. “It’s really not warm today,” he says. “It’s only hot if you stop working.”

Around him, unemployed workers and environmentalists squat in green bibs, black gloves and hats, plucking cabbages that would otherwise be threshed, to distribute at food banks around Barcelona.

Continue reading...

Public asked to take part in annual count to assess the impact of a sunless summer, cool spring and mild winter on butterfly numbers

A deadly combination of a sunless summer, cool spring and mild winter may make 2016 the worst year for butterflies since records began, experts warn.

Sir David Attenborough is urging the public to take part in the Big Butterfly Count so that scientists can discover just how disastrous the unsettled weather is proving for Britain’s 59 butterfly species.

Continue reading...

Emails show the journalist and businessman wrote to UK energy minister to tell him about a US company with ‘fascinating new technology’

An influential Conservative member of the House of Lords has been accused of lobbying the government for the benefit of the coal industry, despite previously saying he does not argue for the industry’s interests.

Viscount Matt Ridley, a journalist and businessman, benefits financially from coalmines on his estate and has used his column in the Times newspaper to downplay the seriousness of climate change.

Continue reading...

Bempton Cliffs, East Yorkshire Abundance is, however, an opportunity for egg-collecting ‘climmers’ or birds of prey

Abundance can seem a dry notion in ecology textbooks; the reality is mesmerising. The sky in front of me is thick with thousands of birds, guillemots, razorbills, kittiwakes; the sea, 100 metres below my feet, is smothered in them, the air filled with their cries.

Where the sheer chalk cliffs angle back a little to form broader ledges, northern gannets have made their home and I feast on the sight of them, the sky-blue ring around the steel-blue eye, the bill and head defined in black, like art deco, against the dusky mustard-yellow of the crown and neck.

Continue reading...

Turning leftovers into renewable power makes ecological and financial sense, says farmer, but is it the best way to recycle Britain’s huge amount of wasted food?

If electricity could be star-rated for quality, the 150 kilowatt hours going daily into the grid from Lodge Farm in north Wales would probably score five. Generated from the slurry of 300 brown Swiss and Norwegian red cattle, and topped up by chicken litter that cannot go to animal feed and by waste from the local Kellogg’s food factory, it is as good as it gets, says farmer Richard Tomlinson.

Since 2011, the gas from the organic farm’s £750,000 anaerobic co-digester (AD) has generated more than 4.5m kWh of electricity and heat for the farmhouse, an on-site engineering works and for 80-100 homes.

Continue reading...

Auction for 130MW large-scale solar in Rajasthan sees winning bids at extreme lows of (AUD) 8c/kWh (INR 4.35/kWh, USD 0.065) this week.

Coalition and Murdoch media continue attack on wind and solar, ignoring the soaring cost of gas and the actions of the energy market cartel. Meanwhile, fossil fuel generators seek to reinforce their market dominant position.

A new map of Eneropa sums up very well why campaigners for community energy are skeptical of designs to create an EU-wide renewable energy system.

Sydney-based energy data company Wattwatchers has appointed a 10-year veteran of world's biggest smart meter company as new managing director.

Qld-based Nano-Nouvelle's lithium-ion battery boosting Nanode technology to be trialled by two US battery manufacturers in new deal.

SPECIES LOSS: An analysis of global data suggests that biodiversity loss across more than half the world's surface is substantial enough to question the ability of many ecosystems to support human societies

The Threatened Species Scientific Committee is seeking comments on the assessment of Hypotaenidia sylvestris (Lord Howe woodhen). The public consultation period will be open until 2 September 2016.

Homes in Glenvill's new-build Melbourne development, YarraBend, will have rooftop solar and Tesla Powerwall battery storage as standard features. Is this the new normal for suburbs of the future?

When most Australians hear of Nauru they tend to think of immigration detention, or perhaps of the environmentally ruinous legacy of the island nation’s ill-fated phosphate mining boom.

Nauru’s troubled history has seen it fall from being one of the world’s richest nations, on a per capita basis, to a society plagued by financial mismanagement and corruption. Yet despite its tragic back story, this tiny country of just over 10,000 citizens may well be poised for a comeback.

During a recent visit to research possible sustainable development pathways, I became cautiously optimistic about the country’s trajectory. On July 9, Nauru held an election which delivered some old and new faces to its 19-member parliament, including re-elected president Baron Waqa and leading Nauruan entrepreneur Sean Oppenheimer. They now face the task of leading their battered nation’s recovery.

Environmental cleanup

Nauru’s unique geography has created threats and opportunities. Living on a raised coral atoll with a fairly high plateau, the island’s population is less vulnerable than those who live on low-lying coral atolls.

It is on this high plateau, known locally as “Topside”, where much of Nauru’s phosphate deposits formed, interspersed between calcium carbonate pinnacles.

Now, almost all of the available phosphate has been mined for use in fertiliser. The residual pinnacles have left a jagged landscape that cannot be used for agriculture or forestry.

A jagged legacy. US Department of Energy/Wikimedia Commons

Recovering from the mining boom and bust has been a slow process. In 1993, Nauru settled a landmark international legal case, in which Australia agreed to pay reparations for colonial-era mismanagement of the island’s assets. This provided substantial funds for environmental restoration through the Nauru Rehabilitation Corporation (NRC).

When the regional asylum processing centre on Nauru was reopened in 2012, it was suggested that immigration detainees might even help with the nearby Topside restoration work. This may currently seem implausible, but could be considered as a livelihood option for some who may be interested in ecological restoration skills development.

However, the only land that has thus far been rehabilitated is in an area known as “Pit 6”. Ironically, this is being developed as a local Nauruan correctional facility, with the prisoners possibly to assist with reclamation work. Thus far the NRC has not managed to achieve its reclamation objectives anywhere else.

New ideas

Despite the slow progress so far, some innovative ideas are now taking root, which could potentially offer economic and development boosts as well as helping to rehabilitate the environment.

One option is to mine the leftover limestone pinnacles, which contain several potentially useful minerals such as dolomite. The United Nations Development Program has championed these so-called “neglected development minerals” as a way of helping Pacific nations (and others) out of poverty.

Although these materials can be sourced more cheaply in China and elsewhere, Nauru could conceivably be branded as a “boutique” producer of tiles from these stones, potentially attracting consumers who are willing to pay an “origin premium” – much like Carrara marble or Vermont slate.

Sustainable growth

Ultimately, Nauru’s population is constrained by the island’s small size – just 21 square km. But there is still room to grow, as well as economic and environmental opportunities, particularly where essentials such as energy and water are concerned.

Nauru has just one brackish lake, called Buada Lagoon, and an underground lake called Moqua Well. But it has plenty of sunshine, which is being tapped for solar-powered water purification systems to deliver drinkable water.

The United Arab Emirates has also supported a pilot project to develop a solar farm on Topside. This could help wean Nauru from its reliance on diesel as a source of energy.

However, far greater investment from donors and the private sector would be required to scale up these efforts. This, in turn, could help other sectors to develop, including a modest boutique tourism sector related to the island’s location as an airline transit hub for the central Pacific.

A derelict phosphate plant. More sustainable industries are needed next time around. d-online/Flickr.com/Wikimedia Commons, CC BY Financial future

Of course, much of this depends on the international financial community maintaining its faith in Nauru after years of financial mismanagement. On this question, the signs are still mixed.

In April, Nauru was admitted to the International Monetary Fund – a mark of international confidence in its finances and a move that will ensure rigorous economic oversight. But within days of that decision Westpac severed its ties with the country, reportedly amid concerns over financial irregularity that it had been investigating over the preceding months.

In contrast, Bendigo Bank returned to Nauru in 2015 after a 15-year absence of any banking provisions in the country. The bank has registered more than 5,000 accounts since then.

Public finances are also being given some positive assurance through the recent establishment of an Intergenerational Trust Fund for the country. Seed funding has been provided by the Asian Development Bank, Australia and Taiwan. This fund has far more stringent safeguards and independent auditing requirements, in contrast to earlier sovereign wealth funds that became notorious for their mismanagement.

A critical next step will be to ensure that, this time around, unlike the previous boom, the country’s revenues from its relationship with Australia, and from its natural capital, are converted into lasting economic capital.

As the country gets ready to review its National Sustainable Development Strategy in 2017, these efforts will garner further attention. While there is no room to be sanguine about the development challenges facing Nauru, there is certainly ample reason for hope.

Nauruans are amazingly resilient people who have survived several brushes with oblivion during their history. Every year on October 26, Nauru celebrates Angam Day, which commemorates the two occasions on which the population has bounced back from near-extinction to reach 1,500, which is considered to be the threshold for their long-term survival.

With careful environmental and economic planning, Nauru has the potential to celebrate many more Angam Days to come.

Saleem will be online for an Author Q&A between 4 and 5pm on Friday, July 15, 2016. Post any questions you have in the comments below.

Professor Saleem H. Ali receives funding from from a wide variety of public and private organizations. However, this article's content has no conflict of interest with any of the funding sources that support his research.

Habitat destruction has reduced the variety of plants and animals to the point that ecological systems could become unable to function properly, with risks for agriculture and human health, say scientists

The variety of animals and plants has fallen to dangerous levels across more than half of the world’s landmass due to humanity destroying habitats to use as farmland, scientists have estimated.

The unchecked loss of biodiversity is akin to playing ecological roulette and will set back efforts to bring people out of poverty in the long term, they warned.

Continue reading...

Though it does not actually say so, the report of the Committee on Climate Change (Report, 12 July) is a salutary reminder that a capitalist economy based on infinite economic growth, as expressed in terms of consumption-led GDP, is unsustainable and, if allowed to continue in its present form, will ultimately devastate the entire planet. Moreover, unless we cease using fossil fuels for energy and replace them with renewables at the earliest possible opportunity, the voluntary agreement reached at last year’s COP 21 climate summit to limit increases in global temperatures to less than 2C will be little more than hot air.

For an energy union like the GMB with thousands of members in the gas industry, the priority must be to establish a viable, UK-based, publicly owned renewable energy industry, thus enabling a just transition for those whose jobs will cease to exist in the coming decades. For this to happen, the vested interests of the privately owned energy monopolies have to be challenged, a point eloquently made by climate activist Naomi Klein at a packed meeting during COP 21 in Paris, organised by the Trade Unions for Energy Democracy network, which GMB supports.

Continue reading...

The government has axed the Department of Energy and Climate Change (Decc) in a major departmental shake-up.

Improved materials would encourage recycling and prevent single-use containers from entering the oceans and breaking into small pieces

Plastics should be better designed to encourage recycling and prevent wasteful single-use containers finding their way into our oceans, where they break up into small pieces and are swallowed by marine animals, scientists said on Thursday.

This could be as effective as a ban on microbeads, proposed by green campaigners as a way of dealing with the rising levels of microplastic waste - tiny pieces of near-indestructible plastic materials - that are harming marine life.

Continue reading...