Museum of Natural History, University of Oxford Blog
Meet Erica McAlister, Senior Curator of Flies and Fleas (Diptera and Siphonaptera) at the Natural History Museum in London. In this video, Erica tells us about her work and how she became interested in insects.
Let us know what inspired your interest in insects by adding a comment below.
Around 120 years ago, William Sollas, Professor of Geology at the University of Oxford, developed a special technique for grinding down and imaging certain kinds of fossils. Sollas was based at the Museum at the time, and the process he pioneered is still used here today, as our Palaeobiology Technician Carolyn Lewis explains to mark the anniversary of Sollas’ birthday on 30 May.
Here at the Museum, I work on a collection of exceptionally well-preserved fossils from the Silurian Herefordshire Lagerstätte. They were deposited on the seabed 430 million years ago when the animals were buried by a volcanic ash flow. The fossils range in size from less than a millimetre up to a few centimetres, and represent a diverse collection of marine invertebrates that includes sponges, echinoderms, brachiopods, worms, molluscs and a wide variety of arthropods.
These Herefordshire Lagerstätte fossils are unusual in that many of them have preserved soft tissues in remarkable detail, including eyes, legs, gill filaments, and even spines and antennae only a few microns in diameter. The key to this extraordinary preservation is that as the fossils developed, calcium carbonate nodules formed around them, protecting and preserving the fossils since the Silurian Period.
Usually, only the hard parts of fossil invertebrates are preserved – the carapace of trilobites or the shells of brachiopods, for example – so the Herefordshire material provides us with a great opportunity to work out the detailed anatomy of these early sea creatures.
But the problem we face is how to extract the specimen from the rock nodule without losing the information it contains. The fossils cannot be separated from the surrounding rock by dissolution, because both fossil and nodule are made mainly of calcium carbonate, so would dissolve together. And they are too delicate to be extracted mechanically by cutting and scraping away the surrounding nodule. Even high resolution CT scans cannot, at present, adequately distinguish between the fossils and the surrounding rock material.
To get round this problem we use a method of serial grinding and photography based on the technique developed by William Sollas in the late 19th century. We grind the fossils in increments of 20 microns then photograph each newly ground surface using a camera mounted on top of a light microscope. This generates hundreds of digital images of cross sections through the specimen.
Then, using specially developed software we convert the stack of two-dimensional images into a 3D digital model that can be viewed and manipulated on screen to reveal the detailed form of the animal. These 3D models are artificially coloured to highlight different anatomical structures and can be rotated through 360o, virtually dissected on screen, and viewed stereoscopically or in anaglyph 3D.
Although our method of serial grinding is still fairly labour intensive, it is far less laborious and time-consuming than the process used by William and his daughter Igerna Sollas. Compared to the photographic methods of the early 20th century, where each photographic plate required long exposure and development times, digital photography is almost instant, enabling us to grind several specimens simultaneously.
Computer software also allows us to create 3D virtual models rather than building up physical models from layers of wax. Yet despite our modern adaptations, we are using essentially the same technique that William Sollas developed here at the Museum 120 years ago. And using this technique to study the fossils of the Silurian Herefordshire Lagerstätte has yielded a wealth of new information that opens up a unique window into the evolution and diversification of early life in our oceans.
Here at Crunchy on the Outside we love insects and we also love cartoons. What could be better, then, than cartoon insects?!
In this video Chris Jarvis shows us how to draw a mighty dung beetle called the Minotaur Beetle (Typhaeus typhoeus) complete with its own ball of dung!
Minotaur beetles grow to about 2cm in length and can be seen between September and July. They live in grassland and heathland with sandy soils. They feed on rabbit droppings and other dung (yum!) which they roll into balls and bury them in nests which can be over a metre deep underground. Male beetles may defend these nests using their long horns. The females lay their eggs in these nests. The eggs then hatch and the larvae feed on the tasty dung!
Watch the video carefully and you will see that Chris has included many of the key features of this fascinating beetle. He has deliberately left one insect feature out of his drawing. Can you spot what is missing? Here’s a clue: they help insects sense their environment.
Let us know what you think is missing by commenting below, or sending us a message using the Contact Us page. We’d also love to see you own cartoon insects!
An insect that Liam Crowley hopes will inspire others is Pseudogonalos hahnii, which is a wasp in the Trigonalidae family. He hopes to inspire others with its fascinating, “crazy and complex”, interactions.
Is there an insect that you find fascinating and inspiring? Tell us about it in the comments below.
Did you know that around 2 billion people around the world choose to eat insects as part of their regular diet? The practice of eating insects is called entomophagy (say en-toe-moe-fay-gee) and is most common in tropical areas where larger species can be found all year round. Around 1900 different species are regularly eaten, including beetles, caterpillars, bees, ants, grasshoppers and crickets. These insects are an important part of people’s diets as they are rich in protein and vital minerals and vitamins.
Across the world, 90% of people are meat-eaters. Of course, most of the meat eaten comes not from insects but from larger animals such as cows and sheep. With the world’s population set to reach 9 billion by 2050, the huge demand for animal protein is growing all the time. We are using more and more land to farm animals for food, contributing to potentially catastrophic climate change and biodiversity loss (the variety of different living things found in the environment).
Herd of cattle graze in a pasture near a village/Image credit: World Bank Photo Collection , CC BY-NC-ND 2.0
Deforestation / Image credit: World Bank Photo Collection , CC BY-NC-ND 2.0
You may think that eating insects sounds disgusting. Many of us don’t like the idea of munching on a mantis or crunching a cricket but, with rising demand for meat protein, could insects provide a solution for this global problem?
At the moment, most insects that are eaten come from the wild but there are lots of good reasons to consider farming insects.
The demand for meat and dairy products has resulted in more and more land being used for farming, leading to the destruction of many habitats. This is having a devastating effect on our planet’s biodiversity as many plant and animal species have nowhere to thrive and many are now under threat. Farming insects, however, needs much less land and water. For example, 400 square metres of land are needed to produce just 1 kilogram of beef, but 1 kilogram of crickets can be produced from just 30 square metres.
Another problem with cattle farming is the production of greenhouse gases. Cows and other large animals produce huge quantities of methane; a greenhouse gas that contributes to global warming. At the moment, livestock are responsible for more greenhouse gases than all the cars, planes and other forms of transport in the world. In contrast, most insects don’t produce methane gas as a waste product.
Of course, it’s not as simple as just switching from farming cows to farming crickets. What about the millions of farmers around the world who rely on rearing cattle for their living? What would happen to all the land that is currently being used to farm livestock? Is it ethical to kill insects for food? Read on for some suggestions about where to find out more about these issues and debates.
If you are interested in finding out more about sustainability of meat production and consumption, including the idea of eating insects, why not:
Arguments against eating insects
We would love to hear what you think on this issue. Do you think farming insects is a good idea? Would you eat a beetle burger? Do you think there are other ways to cut global consumption of meat and dairy products? Let us know you thoughts below or by using the Contact Us page.
Professor Helen Roy, President of the Royal Entomological Society, tells us about a group of insects that interest her most: ladybirds. Also known as ladybugs, ladybirds are in fact beetles. In this video, Helen shares three of her favourites.
Which ladybirds have you spotted? Can you find any of Helen’s favourites? Do you have a favourite of your own? Let us know in the comments section below, or send us a message via the Contact Us page.
Ladybird images credit: Flickr / Gilles San Martin CC BY-SA 2.0
