12 May 2012

Help save the bees!

Hi all,

This isn't a proper post as I won't be writing any new articles now until early June (after my exams have finished), but I wanted to draw your attention to a petition by AVAAZ that is trying to get Bayer shareholders to vote to stop the company from producing very harmful neonicotinoid pesticides that are killing large numbers of bees globally and are significantly contributing to their catastrophic decline.

As you may or may not know, bees are crucial organisms for pollinating many species of plants and flowers and without their services very few of the planet's ecosystems will be able to survive. Bees are known to help in the production of around a third of all human food and represent an estimated US$40 billion in terms of the services that they provide to the agricultural industry. Simply put, they are irreplaceable. 

Although these pesticides aren't the only factor contributing to the decline of bees, they are a major 'player' and stopping their use is under our direct control. Please spend a few seconds to sign this petition, which is in the best interests of everyone worldwide and can have a direct result as Bayer are one of the major manufacturers of these harmful chemicals.

Thanks, 

David

1 May 2012

May hiatus

Hi all!

It's a busy period for me at the moment - I've got lots of deadlines rolling up and have exams running throughout May (thankfully my last exams ever!). This means that unfortunately, I don't have time to keep publishing posts on this blog so I will be taking a break through May in order to focus on my work. I hope you have enjoyed reading my posts thus far and I will resume regular posting after I have finished my course, so be sure to check back early in June!

David

29 April 2012

The amazing acid-proof ant

Most terrestrial insects actively avoid liquids, particularly water, because they are too small to escape from its surface if they fall in, owing to the strong hold that the liquids surface tension holds over them. Even larger insects are no different and dislike water, even though some of the bigger species may be able to paddle around to some degree and eventually escape (if they are not eaten by a bird or a fish first).

The diver ant, Camponotus schmitzi, however is a species of carpenter ant that goes against the insect social norm and actually depends on water to survive. Well, depends on acid that is; not water... The fearless ant lives in an exclusive mutualistic relationship with Nepenthes bicalcarata, a species of  carnivorous pitcher plant that lives in Borneo, where it actually dives into the plants digestive juices in order to scavenge for its prey!

A small group of diver ants waiting underneath the lip of N. bicalarata until a insect drops into the acid pool at its base. The ants will then 'liberate' the plant of its meal, eating it themselves. Although this action robs the plant of its meal initially, the ants mainly scavenge large insects and throw back what they don't eat. This also helps to remove debris from the acid pool, keeping it fresher and therefore more attractive to potential prey animals; meaning the ants also benefit the pitcher plant.

If you've never heard of pitcher plants before then you may be confused as to why they have a pool of acid in their base, but it's actually fairly simple - pitcher plants, like the more famous Venus Fly Trap, are carnivores that live by feeding off insects that they have lured into their trap. Whereas species of Venus Fly Trap clamp insects that have landed on their surface and then actively secrete acid to digest them, pitcher plants use a 'pitfall trap' mechanism. This involves a small hole in their top that their prey must climb into to reach the attractive-smelling puddle of liquid in their base. However, this liquid is actually a mixture of a powerful acid and other digestive juices and once the prey species has crawled inside, it is prevented from escaping by tough downward-pointing spines. Unfortunately, the hapless animal then faces a slow and grisly death where it is digested alive.

Nepenthes sumatrana, a species of pitcher plant that can be found throughout the Phillippines. Its bright colouration and sweet smell help to attract its prey. Some of the larger species of pitcher plant, like those found in the Amazon Rainforest, can even attract and eat mice or frogs as prey!

The observation of diver ants has found that they spend most of their time hidden under the lip of N. bicalarata and run down into the base of the plant when an insect falls into its deadly pool of acid and digestive juices. Amazingly, the ants then dive head-first into the acid and work together to pull out the now dead arthropod and begin to eat it in safety on the shore of the pool. Therefore, the ants still get a meat meal but do not have the same risk of injury that most predators face while killing their prey.

Or do they? This strange hunting method seems to have a major and very deadly risk - obviously, the pitcher plants acid should also kill the ants! Scientists are still baffled by why it doesn't and it is thought that the short exposure time of the ants to the digestive juices allows them to survive, along with some other physiological adaptation that helps provide them with some immunity to the corrosive effects of the acid.

One physiological adaptation that has been identified however, is that the ants have a fluid on their outer cuticle (layer of skin) that makes them less water-repellent and therefore, helps to negate the action of surface tension. This allows the ants to dive underwater and leave the acid pool freely and without this chemical surfactant, they would be trapped on the surface of the acid pool like other insects; eventually dying.

A unit of C. schmitzi workers dragging a dead insect (either a grasshopper or cricket) from the pitcher plant's deadly digestive juices.

What is also interesting, is that the ants appear to sprint through the acid rather than swim; using the same tripod sequence as when they move on land - they move the first and last legs on their left side along with the middle leg on their right side and then the front and last leg of their right side with the middle of their left. This simple method of swimming suggests that the ants have evolved fairly recently, since the ancient and truly aquatic insects have all developed much more complex patterns of swimming than this.

Thus, the ingenuity and unique adaptations of diver ants allow them survive in a very hostile organism that by all rights, should kill the ants; turning them into its next meal...

25 April 2012

Should wolves be re-introducted into Scotland?

Farmers have been at war with wolves for thousands of years, desperately trying to protect their livestock from being killed and eaten by the wild animals. This war has led to many familiar jobs to protect livestock, such as shepherding and even to the creation of certain breeds of dog! A fairly obvious example being German Shepherds... Since the advent of guns and their ready availability to farmers however, the war tipped in favour of humans and wolves have since been eradicated from much of their historical ranges across Europe and North America.

The United Kingdom is no different from these countries and has also eradicated the endemic populations of the grey wolf, Canis lupus, that once lived here; with the species being officially extinct in the UK in 1769. Over the past few decades  however, the interest in the re-introduction of wolves has been increasing in many countries, partly due to a better understanding of their ecological importance in pest control and partly due to the aesthetics of seeing them in the wild (many people just like knowing that they're out there). The re-introduction of grey wolves in the USA (such as in Yellowstone National Park) and in many countries throughout  Europe has been a great success and in such countries, the re-introduction of wolves has even been economically beneficial! (Despite the belief that they will cost a country money by killing farmers livestock.)

The grey wolf, Canis lupus, once roamed freely throughout much of Europe, Asia and North America until the heavy hunting by farmers and loss of their habitat due to human activity led to a huge decrease in their numbers - completely wiping them out in many areas. Thankfully, efforts have been made to restore the species and its numbers have greatly increased; with it now being classified as being of 'Least Concern' by the IUCN.

The UK's interest in re-introducing grey wolves is also increasing, particularly in releasing them back into Scotland, which still has much of their natural habitat left throughout the Scottish Highlands, so is the most suitable location for them to live in. In addition, much of the Scottish Highlands are unoccupied and are relatively unused by humans, which will help to reduce the contact between wolves and man - a factor that is essential for the re-introduction scheme to be a success; mainly due to the problems that wolves can cause farmers via eating their livestock - sheep in particular.

The Cuillin Mountains in the Scottish Highlands offer as much of an untouched environment for the re-introduction of grey wolves as now exists in the United Kingdom.

However, the re-introduction of wolves into Scotland has met with opposition and not everyone is as eager to see wolves return to the wild as conservation biologists. These people, predominantly farmers, believe that they will lose out if wolves once again roam the wilderness since the wolves will kill their livestock. Obviously, this represents a significant monetary loss for farmers who are unable to sell the sheep, for example, or use it for breeding. Farmers would have also invested a fair amount of money for the maintenance of the sheep via food costs, vets bills and its general care - money that will not be returned as the farmer cannot sell the animal! However, this has rarely been a problem in countries where grey wolves have been re-introduced and many of the governments in such countries subsidise the cost of anti-wolf devices, such as effective fencing; throat-protection (that make it harder for wolves to kill sheep) and anti-wolf collars; auditory and visual alarm systems; guard dogs; and non-lethal projectiles for farmers that help to reduce attacks. Furthermore, many governments now compensate farmers for the loss of a sheep to a wolf pack, meaning that farmers are reimbursed for the value of the sheep and the cost for maintaining it.

Large breeds of dog, such as the German Shepherd, are very effective at deterring wolves from attacking sheep and other livestock. The German Shepherd (or Alsatian) is a relatively new breed of dog, with its origins dating back to the late 1800s and itself, possesses a large amount of wolf DNA.

Thus, the presence of grey wolves in Scotland shouldn't hinder the efforts of farmers so long as we put some sort of scheme(s) in place to minimise the loss of their livestock and the related damage that it causes to them, meaning that the negative aspects of their reintroduction can be controlled for. This means that the only effects that the re-introduction of wolves will have overall, should be positive. Obviously, an endemic wolf population may well boost tourism to Scotland as many people would like to see wild wolves, helping to raise money that can boost our economy and possibly be used to aid various conservation efforts. Also, many jobs would be created (at least at first) when they are released into and established in the Scottish Highlands, both for the care of the wolves and in the scientific study of the process (such as how wolves adapt to a new environment).

However, these benefits of releasing wolves into Scotland are only secondary and the main positive influence that they would have is in helping to control the populations of the red deer, one of their main sources of prey. Since wiping out wolves from Scotland (and from the UK in general), the populations of red deer, among other prey species, have risen dramatically as they no longer have any natural predators. Their high numbers makes them very damaging to their environment due to the over-exploitation of its resources and their extensive overgrazing can destroy large areas of vegetation. This therefore, reduces the resources that are available to other woodland animals and the overall biodiversity of our woodlands has fallen in such areas; with many species of insects, birds and small mammals being unable to survive there!

The population size of the red deer, Cervus elaphus, has increased dramatically due to the eradication of grey wolves and its other natural predators from the UK. Trophy and meat hunting by humans is not extensive enough to keep their population in check by itself and as a result, their unnaturally large numbers can be very destructive to ecosystems.

As well as being detrimental for the health of ecosystems and to conservation efforts overall, this destruction of ecosystems by deer can itself damage farmers livelihoods, as red deer may eat many of the berries, apples and pears for example, that farmers sell over the summer. Furthermore, large numbers of deer can also be harmful to our health as they carry the potentially fatal Lyme disease, a blood-bourne infection that is spread from to deer to humans via ticks! Thus, in order to control the pesky red deer populations and to help ecosystems to remain balanced (there still needs to be some deer in the environment for it to remain healthy), the UK's government must periodically spend large sums of money to cull the populations of red deer once they become too large to be sustained by their environment, with the Deer Commission for Scotland aiming to maintain a population density of 6 deer per square kilometre.

Obviously, such measures are extreme and are highly unpopular as nobody wants to know about a deer massacre (however necessary). The re-introduction of wolves into Scotland however, can provide a natural alternative to this by regulating red deer populations via predation, which is both cheaper and more desirable. In addition, the abundance of red deer also means that it is unlikely that wolves will attack farmers livestock since wolves are 'creatures of habit' and have preferred species of prey. Much of the research into the behaviour of grey wolves has found that if their preferred prey (which varies between populations and packs) is present in an area, then the wolves rarely hunt other game! Obviously this has implications for farmers, meaning that re-introduced wolves may not attack their livestock at all!

However, the critics that oppose wolf re-introduction have one last argument against unleashing wolves into Scotland: wolves are highly mobile and have very expansive territorial ranges. This means that wolves are unlikely to stay solely in the areas where they've been released and could quite easily move into more heavily farmed areas than what is seen in the Scottish Highlands, where deer numbers are smaller so that the wolves would be more likely to attack livestock. Furthermore, grey wolves could quite easily spread south into England and eventually even into Wales, which are much more heavily urbanised and therefore, much less suitable for endemic wolf populations. Other than rebuilding Hadrian's Wall, it would hard to stop this migration - a fact that is of great concern to both critics and re-introduction policy makers alike; sadly, helping to make their re-introduction less likely...

Hadrian's Wall, spanning from the west to the east coast of Great Britain, was build on the order of the Roman emperor Hadrian on the border between Scotland and England in AD 122. Whereas it is disputed whether the wall was to defend the edge of the Roman Empire from the Scots or was built merely to mark the boundary of the Roman Empire, rebuilding the wall would undoubtedly help to keep wolves out of England...

Sadly, due to the problems that re-introducing wolves back into the UK would have and the long-held negative perceptions towards wolves held by farmers, their re-introduction looks unlikely at the moment even despite the many benefits that it would have. However, the will to re-introduce grey wolves is still here and maybe, after seeing how successful the new populations of wolves have been in Europe and North America, the eerie howls of wolves will one day in the future, once again drift across the Scottish Highlands...

21 April 2012

The burning weight of coins

The Royal Mint (UK) is currently planning to change the composition of '5p' and '10p' coins from the silver-based alloy cupronickel, to a new alloy that is based on steel and nickel. Changing the materials of the coins is expected to save the save the Mint an estimated £8 million (nearly US$13 million) and on a side-note, will make the coins slightly thicker and heavier.

The new 10p coins, which have dimensions more like a £1 coin than the previous styles of 10p.

However despite being good from an economic perspective, the new coins (made from steel galvanised with nickel) may cause dermatitis in members of our population with nickel allergies, which unfortunately is the most common contact allergy in the UK. Worryingly, dermatologists from St. John's Institute of Dermatology, London have said that there has been no assessment to the health risks that these new coins pose and the Central Bank of Sweden has decided that it will not be manufacturing the new coins, after a lengthy debate; with a spokesperson saying that "nickel poses unacceptable risks to health".

However, there may not be cause for alarm since the Treasury claims to have carried out a competent risk assessment over the possible health issues and a spokesman for the Royal Mint has said that "the new nickel-plated 5p and 10p coins have no additional potential to cause adverse effects on people with allergic contact dermatitis and hand dermatitis".

Thus, despite the concerns about the potential health risks that the new coins could cause, it is still unclear whether or not they will have adverse effects on some peoples' health and more research into the matter should be carried out; even if the Treasury and Royal Mint already believe the new coins to be safe and the research is just carried out to put public concerns at ease.