Spiders’ eyes cast in Diamond Light

by Imran Rahman, Deputy Head of Research

There are plenty of reasons to visit Didcot. The railway station is an important junction between Oxford and the west of England, the Didcot Railway Centre houses a great collection of trains, if you like that sort of thing, and Didcot Town Football Club are currently a respectable fourth* in Division One West of the Southern League…

But if that’s not enough to tempt you, Didcot is also home to the UK’s only synchrotron – a multi-million pound facility that goes by the name of Diamond Light Source. In February, six members of the Museum’s research team visited Diamond to carry out some important experiments on spiders.

But before we get to that, what exactly is a synchrotron light source? Well, it is a type of particle accelerator which uses huge magnets to speed up tiny particles, usually electrons, until they are moving almost as quickly as the speed of light. The particles are sent flying around a ring-shaped machine hundreds of metres across – the ‘doughnut’ structure in the photo.

The Diamond Light Source synchrotron in Didcot, Oxfordshire. Particles are accelerated to close to the speed of light around the ‘doughnut’ structure. Image: Courtesy of Diamond Light Source

This beam of high-energy particles gives off large amounts of ‘light’, or electromagnetic radiation, when its direction is changed. This radiation, usually in the form of X-rays, can be funnelled down to experimental stations, known as beamlines, and used for lots of different measurements and experiments. As the UK’s national synchrotron light source, Diamond is visited by scientists from all over the world every year.

So what does a museum want with a powerful X-ray beam? One of our research fellows, Lauren Sumner-Rooney, is particularly interested in studying the eyes and brains of spiders. So the team, led by Lauren, went to Didcot to create some X-ray images of spiders from the Museum’s collections.

Ready for your X-ray close -up? A spider specimen is mounted in the I13-2 beamline at Diamond Light Source. Image: Lauren Sumner-Rooney

You may not have looked too closely at a spider’s head before, but they usually have eight eyes as well as eight legs. That said, there is actually quite a lot of variation in the number and structure of eyes between different species, and Lauren is interested in documenting this variation across selected spider families to investigate how it affects spiders’ brain structures.

Using the I13-2 beamline at Diamond, and fighting severe sleep deprivation with the aid of strategically-selected songs and snacks, the team was able to visualize details measuring less than one thousandth of a millimetre without damaging the precious specimens. They were assisted by Andrew Bodey, a senior support scientist at Diamond, and Emelie Brodrick, a PhD student at the University of Bristol.

The research team following 72 hours of very little sleep! From left to right: Ricardo Pérez-de la Fuente, Lauren Sumner-Rooney, Imran Rahman, Jack Matthews and Emelie Brodrick. Image: Emelie Brodrick

Over the course of 72 straight hours, the team scanned 116 spiders, creating about 14 terabytes of data. This will form the basis of a variety of exciting scientific research projects at the Museum over the coming years. Watch this space for the results!

*Didcot Town were fourth in the Southern League Division One West table on 8th March. The Museum accepts no responsibility for any change in their position after this date.

Top image of Pholcus moca courtesy of Smithsonian Institution.

Steven’s Christmas spiders

by Steven Williams, Oxford Brookes University research student

Described by A.G. Butler in 1873 as ‘the most gorgeously coloured spider in this genus’, Gasteracantha scintillans, with its metallic green iridescent abdomen, is the first of my Christmas Spiders.

Spiky and sparkly: Gasteracantha scintillans

The beautiful colour of the abdomen certainly has a very festive feel and it would not be out of place next to a bauble on a Christmas tree; at least not in my house. This species and the other closely-related metallic Thorn Spiders are currently only found on the Solomon Islands.

Christmas Island, in the Indian Ocean, is one of the locations where my second Christmas spider, Austracantha minax, can be found. Although not as striking as the metallic green of Gasteracantha scintillans, the layout of the abdominal spines on this spider almost give it the appearance of a star – perfect for the top of a Christmas tree, no?

Austracantha minax: starry, and found, amongst other places, on Christmas Island
Austracantha minax: starry, and found, amongst other places, on Christmas Island

The common name of ‘Christmas Spider’ is attributed to this species because in areas of Western Australia it is associated with the arrival of Christmas as the males reach maturity in mid-December and females in January.

Did you know that there is also an Eastern European folk tale of how tinsel came to be included in Christmas tree decorations? The legend tells of how spiders spun cobwebs on a poor family’s undecorated Christmas tree overnight. In the morning the webs turned to gold and silver and the family never lived in poverty again. So when you put the tinsel on the tree this year you could imagine you are a spider spinning a web!

With that spidery festive thought, have a very Merry Christmas from everyone at the Museum!