As the title suggests… I have failed to write a new post this week. However, I was just recently published online on a very ‘Artful Scientist’ type topic. This is for EUSci, a science-themed publication on campus at University of Edinburgh. The link to my article can be found below:
Here’s the actual copy. The website is somewhat buggy in my experience.
Skin wars: Body painting fights insects and disease
In indigenous communities, body painting frequently features in important cultural ceremonies and rituals, often projects status, and serves as a symbolic, protective layer. However, scientists from Lund University in Sweden and Eotvos Lorand University in Hungary are investigating how the symbolic protection offered by body paint may, in fact, be literal.
The tradition of body-painting may have developed simultaneously on different continents. It is not known precisely when the tradition started. “Body-painting began long before humans started to wear clothes. There are archaeological finds that include markings on the walls of caves where Neanderthals lived. They suggest that they had been body-painted with earth pigments such as ochre,” says Susanne Åkesson, a professor at Lund University’s Department of Biology.
Body painting is an ancient and near-universal decorative practice. The temporary application of pigments to the skin has taken a variety of forms throughout history. From the traditional materials of many tribal cultures, who create paints from the natural pigments that surround them, to the surrealist creations of artists on the popular Netflix reality show Skin Wars, body painting is still alive and well across the world.
The places that are home to many body painting cultures are also heavily populated by bloodsucking horseflies (Tabanidae), and other insect parasites, including tsetse flies (Glossinidae) and black flies (Simuliidae). These flies are not only a painful nuisance, but also vectors for parasites and diseases such as African sleeping sickness, anthrax, and Lyme’s disease. These communities do not have universal access to protective supplies like insect netting and repellents. Moreover, they have been around since before such supplies were invented. So, they have long since developed another way to keep the bugs away. One of these techniques is the application of light-coloured stripes to naturally brown skin.
The research team had previously noted that zebras’ stripes protect against biting insects. They also discovered that white-haired horses are more protected against insect bites than dark-haired ones, which won them the IG Nobel Prize for Physics in 2016. The researchers sought to test this idea in humans and did so through a series of unique experiments.
They painted three plastic models of humans: one dark, one dark with pale stripes and one beige. They then covered the three models with a layer of insect glue to trap any incoming insects to be counted later. The dark model attracted ten times more horseflies than the striped model, and the beige model attracted twice as many as the striped one.
They also examined whether the attraction of horseflies differed between models that were lying down or standing up. The results show that only females (the bloodsuckers) were attracted to the standing models, whereas both males and females were drawn to the models lying down. This is explained by the general behaviour of these insects: “Males gravitate towards water in order to drink and land on surfaces that reflect horizontal, linear polarised light, such as signals from a water surface. Females that bite and suck blood from host animals respond to the same signals as the males, but also to light signals from in the vertical plane, such as the standing models,” concludes Åkesson.
This research illustrates an intriguing example of how local and indigenous knowledge is applied toward solving the problems of everyday life in different parts of the world. Separate from the solutions to pest insects offered by western science, these communities prevent insect bites through ways that are deeply ingrained in their culture and have minimal impact on the environment. To many indigenous communities throughout the world, body painting is more than an act of decoration; it is an act of survival.
Here’s to more original content next week!