The latest display in our changing Presenting… series showcases some of the incredible colours seen in many insects. Zoe Simmons, collections manager in our Life Collections, explains how such wonderful hues are created.
Reflected and refracted light creates the many bright and shining colours found in some insects. The dazzling natural display shown in the specimens here is formed through a combination of embedded pigments and sculpted surfaces on each insect’s external skeleton.
Some species can be variable in colour. Here a pair of Lamprima, a genus of Stag Beetles, shows off the range of colours present in the species.
Different pigment chemicals are responsible for different colours. Carotenoids produce yellow, orange and red hues, while bilins may be green, or blue if linked with proteins. They reflect and absorb different wavelengths of light, and the wavelengths that are reflected are the ones that we see as colour. Typically humans can see wavelengths of 390-700 nanometres, with the lower wavelengths perceived as blue, and the higher ones as red.
Many of the Leaf Beetles (Chrysomelidae) exhibit metallic colours.
Many insects also have multiple thin layers over their upper surfaces to help protect them and prevent dehydration. Variations in thickness and chemical composition of these layers can interfere with the transmission of light, refracting and scattering it back.
Some of the most striking metallic colours are found in the genus Chrysina, where species can be rose, silver or gold.
The shape of the surface layer can reflect light in a multitude of directions, with micro-folds, grooves, pits, hairs and scales all helping to produce complex colours and effects.
The formation and purpose of these colours is scientifically interesting, with research having applications in areas such as nanotechnology. But these insects are also simply beautiful examples of the spectacular diversity of the natural world.
Sunset moths (Uraniidae)are so called because of the dazzling array of colours on their wings. As day-flying moths they are brightly coloured like many butterfly species.
University of Oxford PhD student Lance Millar recently ran one of our Brain Spotlight events as part of the Brain Diaries exhibition programme. Here, Lance explains his research into neurodevelopmental disorders and possible treatments.
The brain has always been a fascinating organ for me. It is the site of our intelligence, our problem-solving and social skills, and it allows us to connect our senses to the world around us.
The large, folded outer part of the human brain is called the cortex, and is responsible for decision-making, language, face recognition, and a lot of the other things that I like to think are what make us human. The word cortex comes from the Greek for husk or outer shell, which underestimates the importance of what the cortex does.
Humans can survive with damage to the cortex, but depending on the part of the cortex that is damaged, a range of disabilities can result. People who have had a stroke can lose part of their cortex, leading to limb paralysis, loss of speech, or loss of memory, depending on the site of the damage.
Cerebral cortex – Professor Michael R Peres – Wellcome Images
Some people are also born with a developmental problem in the cortex, and are said to have a neurodevelopmental disorder. Such conditions are thought to include autism, schizophrenia, ADHD, and even dyslexia – all fairly common conditions. The damage to the cortex is subtle and complex in these conditions, and scientists are still working out exactly what happens to the brain during its prenatal development.
I am studying one particular neurodevelopmental disorder caused by lack of oxygen at birth. It is known to medical specialists as neonatal hypoxia ischaemia. The image on the right shows a cross-section MRI scan of a normal newborn human brain, alongside some babies who have been damaged by oxygen deprivation. You can see that the brains are smaller, the cortex is less folded and it takes up less space inside the skull.
MRI scans of normal newborn brains alongside those of babies who have been damaged by oxygen deprivation. Image: Woodward et al., New England Journal of Medicine, 2006
Scientists still don’t know how to protect the newborn brain from these injuries. Some are caused by inflammation which is a normal response to illness, but can wreak havoc in the confined space of the skull. Some is caused by the presence of free radicals, which are thought to contribute to ageing and organ failure, as the newborn brain doesn’t have many antioxidants to fight these chemicals. It’s also possible that the electrical signals that neurons within the brain send to each other contribute to the damage when there isn’t enough oxygen to feed them.
So what can we do to treat oxygen deprivation at birth? One breakthrough treatment currently available is known known as hypothermia. In this technique, the baby is cooled to 33℃ which slows down the brain-damaging chemical reactions which in turn protects the brain. This is currently the only treatment available, but I am involved in the study of possible alternatives.
We don’t want to introduce any drugs to the baby’s system as they might be harmful to normal development. So scientists are currently working on treatments which help the baby’s natural body proteins to protect the brain. I do this by looking at neurons under the microscope, and identifying proteins expressed by these neurons using fluorescent probes known as antibodies.
An example of neurons under the microscope. Image: Lancelot Millar
These neurons are expressing neuroserpin, a natural brain protein which decreases inflammation and cell death. I’m looking at exactly where neuroserpin is expressed in the brain, how it can be upregulated in response to oxygen deprivation, and how its chemical reactions could be used to protect the brain.
Another way to help people with neurodevelopmental disorders is to better understand how the cortex connects to other parts of the brain and how it can carry out complicated decisions. There is still so much to understand about the complexity of the human brain, and what seems like fundamental research could generate the springboard for new ideas for neurodevelopmental disorder treatments.
To explore the structure of the human brain and compare it to that of other animals see the Brain Diaries Brain Explorer below.
University of Toronto research fellow Jacqueline Zimmermann recently ran one of our Brain Spotlight events as part of the Brain Diaries exhibition programme. To mark World Alzheimer’s Day today, here Jacqueline tells us about the neurophysiology of Alzheimer’s disease and the risk factors we can actively reduce to lead happier, healthier, and longer lives.
Almost all of us have in some way been affected by Alzheimer’s disease, which makes the quest for a cure that much more personal. An estimated one in nine people over the age of 65 will develop the disease, and this risk also increases with age, according to the World Alzheimer’s Report in 2015.
Jacqueline Zimmerman’s Brain Spotlight on Saturday 16 September as part of the Brain Diaries exhibition series of events.
Due to chemical toxins, and increased longevity, the incidence for Alzheimer’s disease is on the rise. But the good news is that there is a lot that you can do to reduce your risk. At the John Radcliffe Hospital in Oxford, hundreds of scientists are currently working towards identifying the cause and the solution to the disease.
At the Brain Spotlight event at the Museum I presented images of ageing brains, and explained how brains affected by Alzheimer’s have reduced volume in the temporal lobe and the hippocampus, regions critical for language and memory respectively. Diseased brains will also often show reduced frontal lobe volume, which may reflect the changes in personality and the ability to engage in planning which area associated with Alzheimer’s. The overall volume of the brain is also reduced in sufferers because cellular changes lead to the death of neurons.
Brain Atrophy in Alzheimer’s disease. Note: overall brain volume is reduced, hippocampal regions and frontal regions are particularly affected, and ventricles are enlarged. Image: http://www.lookfordiagnosis.com
Recently, a number of genes have been identified that are related to early onset Alzheimer’s, which is quite rare and much more hereditary than late-onset Alzheimer’s. At the Nuffield Department of Clinical Neurosciences, where I am a visiting researcher, we are investigating a late-onset Alzheimer’s risk gene called Apolipoprotein 4 (APOE4), looking at how it relates to subtle cognitive impairments in middle-aged people. Working with the Oxford Biobank we are trying to determine which cognitive assessments may be most effective in predicting these impairments.
Functional brain imaging using electroencephalography at Rotman Research Institute in Toronto. Image: Rotman Research Institute
Although some of us may be more susceptible to Alzheimer’s than others, there are a number of environmental factors that contribute, including air pollution or additives in our food, like nitrogen-based chemicals which are used to preserve and flavour processed foods. It is important to reduce cholesterol in the diet, eat plenty of fruits and leafy greens, and engage in frequent physical and mental exercise.
Though there is speculation about the effectiveness of ‘brain games’ and how they translate into improvements in cognition in the real world, there are certainly large benefits of keeping your brain active.
In the process of researching or conserving old pinned insects, it’s common to find a green deposit clustered around the pin. This is known as verdigris and is a natural patina created when the metal oxidizes over time. Katherine Child is Image Technician in the Museum’s Life collections and takes photos of insects for researchers, students, artists and publications. She is also an artist in her own right, so when she witnessed verdigris being removed during a conservation project, she came up with an inspired idea.
A clearwing moth before conservation, showing verdigris spreading where the metal and the insect fats, or lipids, react.
A few years ago I read a book called Colour: Travels Through the Paintbox, by Victoria Finlay, and was interested to learn that verdigris was once used as a pigment. Verdigris, which I now know translates from French as ‘Green of Greece’, is a word that’s been in my vocabulary since I was small. I loved its rich bright blue-green colour, which is often seen on old copper piping or copper statues.
Verdigris forms when copper or a copper alloy reacts with water, oxygen, carbon dioxide or sulphur.
L: Three years’ worth of verdigris, ground and ready to make into paint. R: A second attempt at mixing the paint, this time using linseed oil.
As early as 5thcentury AD, it was used in paint-making, and until the late 19th century it was the most vibrant green pigment available. But it was unstable – Leonardo da Vinci warned that it ‘vanishes into thin air if not varnished quickly.’ These days synthetic pigments provide a more constant alternative.
Despite its past uses, verdigris is a big problem in pinned insect collections. Nowadays stainless steel pins are used, but pins containing copper still remain in old collections and these react with air and insect fats. The more fatty the insect, the more verdigris tends to form and, if left, it can damage a specimen irreparably.
Comprising around five million or so insects, the Hope Entomological Collections here in the Museum take quite a bit of looking after. A few years ago a project to catalogue and conserve many of its butterfly and moth specimens was undertaken and the removal of verdigris and repining of insects was part of this.
With paint-making in mind, I asked that the beautiful, but problematic, substance be saved. About three years on I finally got around to using the pigment, which I had also been adding to while photographing the collections.
I chose a variety of differently shaped moths to paint (most of the verdigris came from moths, so moths seemed the most apt subject). To narrow my options further I went for green moths. Some of the specimens I chose had verdigris on their pin, so I was able to take pigment and use it to paint the very specimens from which it came!
Katherine tested out the newly made verdigris paint in her sketchbook.
After a first failed attempt to make watercolour paint (during which pigment and water remained stubbornly separate due to the greasy insect fats still present), I tried again, this time using linseed oil to make oil paint – and it worked! Traditionally a flat bottomed tool called a muller was used to press pigment into the water or oil. Not having one of these, I used the flat end of a pestle and a mortar which did the trick.
A Miscellany of Moths, the finished verdigris painting.
The paint went surprisingly far and, following on from the 14 green moths, I plan to use up the remainder to paint beetles.
Katherine’s Miscellany of Moths painting can be seen on display in the Museum’s Community Case until 18th October.
We’re happy to announce an exciting opportunity to coincide with our new exhibition – Settlers, opening at the Museum of Natural History in February 2018.
Settlers is the upcoming exhibition in our Contemporary Science and Society series. The latest of the series, Brain Diaries: Modern Neuroscience in Action is currently running until 1 January 2018.
The history of the people of Britain is one of movement, migration and settlement. Tracing patterns revealed by genetics, archaeology and demography, Settlers: Genetics, Geography and the peopling of Britain will tell the dynamic story of Britain’s ever-changing population.
Planning for Settlers is going well and we’re happily getting to grips with the science and archaeology, but we’d also love to have some artistic input. Can you help us?
The Museum would like to commission up to two pieces of contemporary art that explore themes such as genetics, DNA, migration, settlement and ancestry.
We’re particularly interested in work that will provoke thought and discussion and engages with 18-25 year olds, and we welcome all media, including digital and installation art.
The artwork could be displayed in the gallery itself, in the main court or even on the museum lawn.
The Museum’s centre court
If you like the sound of adding some artistic flair to Settlers, you can find out more here:. Don’t delay, though; the deadline for applications is Friday 1 September 2017.
What happens in your brain when you receive compliments? And what’s going on in your mind when you watch your football team win a match? Does the brain respond differently when recalling music, compared to listening to it? All these questions, and more, have been posed in our Big Brain Competition…
Coinciding with the Museum’s Brain Diaries exhibition, the Wellcome Centre for Integrative Neuroimaging is inviting you to ask your own question about the brain to be in with a chance to have it tested by neuroscientists using Oxford’s state-of-the art Magnetic Resonance Imaging (MRI) scanner.
The advanced MRI scanner at the John Radcliffe Hospital in Oxford is one of the strongest in the world. It allows scientists to carry out functional MRI (fMRI) scans to see the brain in action. This mind-blowing procedure can reveal how the brain changes when learning a new skill or how it compensates when someone recovers from brain damage. It can also reveal which areas are used when people speak, move or laugh, to give just a few examples.
This fMRI scan shows how blood flows to the visual cortex region at the back of the brain when viewing a visually-stimulating checkerboard patternDr Stuart Clare of the Nuffield Department of Clinical Neurosciences is asking you for questions about the brain
Functional MRI shows when a brain area is more active by detecting the changes in blood oxygen levels and blood flow that happen in response to neural activity. The technique can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.
The scientist behind the Big Brain Competition is Dr Stuart Clare, whose research involves pushing the technological boundaries of the fMRI technique to reveal new insights about how the brain functions normally and how it is affected by disease. There is still so much that the fMRI scans can bring to light, so Stuart is asking you for ideas!
Over several years of inviting people in to see the beautiful pictures that our MRI scanner can produce, I’ve been fascinated by the questions they have about the brain and whether you can see this thing or that thing in our fMRI scans. With this competition we want to give people the unique access to our scanner and the chance to try an idea out for themselves.
When coming up with an idea for investigation there are a few practical things to bear in mind. Any activity has to be something people can do when lying down in the scanner and it has to be clear when they start and stop doing the activity. But Stuart is very open to ideas for experiments that they haven’t come across before – something that scientists really don’t already know the answer to.
The animation below explains how fMRI works and what it can do. So take a look, think up an experiment of your own and enter your idea via this form. The best one will be put into action by the research team and you will be able to watch the scans take place at the John Radcliffe Hospital yourself!
More Than A Dodo 