I blogged some time ago about a Cafe Scientifique talk I gave on the topic of “Avoiding Attack” (broadly mimicry and camouflage in animals). I stole the title of the talk wholesale from the excellent book of the same name written by former colleagues Mike Speed and Tom Sherratt along with Graeme Ruxton). After giving that talk, I was asked to contribute to the Leeds Festival of Science – a great initiative where University of Leeds staff engage local people (particularly schools) with their research through on-campus and external events. As part of that event this year I took part in the “schools roadshow” where researchers go out into schools to teach about their work. I thought I would post the resources that I used here with some notes so that teachers can make use of the materials that I produced. Everything here is released on a Creative Commons license (CC-BY 4.0).
Background: There are a number of ways in which animals and plants attempt to defend themselves from predators. Sometimes they look or sound like something that they are not, such as another animal or plant that is venomous, in a process known as “mimicry”. Other times, rather than attempting to deceive a predator after being seen, the animal or plant might try to hide altogether. This second defensive strategy, known as “camouflage”, can take a number of forms. One of the most interesting forms of camouflage is “disruptive colouration” which involves breaking up the edge of an animal to make it harder to detect.
What we did: Rich Webster is a PhD student at Carleton University who applied a novel approach to the question of how disruptive colouration helps to hide animals. He used eye-tracking technology with humans as predators searching for digital moths on pictures of trees. With this approach he was able to see where people were looking and how long it really took them to find the “moth”. Importantly, he could also tell how many times they looked at the moth without actually seeing it. We were able to show that the length of time taken to find a target and the number of times that the target was missed were both significantly higher when the moth had a larger number of patches on the edge of its wings.
Importance: Mottled colouration has been observed in many species, but until now we have not had a clear description of the mechanism by which this form of defensive colouration acts. Our results provide that first insight into how and why predators sometimes fail to find prey which are camouflaged in this way.
This is part of a series of short lay summaries that describe the technical publications I have authored. This paper, entitled “Disruptive camouflage impairs object recognition”, was published in the journal Biology Letters in 2013. You can find this paper at the publisher or archived at Figshare.
Image credit: All images are by Rich Webster, and used with permission.
In September I gave a Cafe Scientifique talk at the Leeds City Museum on the evolution of mimicry and camouflage. For those of you who aren’t familiar with the concept, Cafe Scientifique offers an opportunity for scientists to give short (or long, depending on how it is run) talks on their research to a general audience and then take questions in an informal setting. I have always been a fan of this kind of outreach, and when Clare Brown, the curator of Natural History at Leeds Museum asked if I wanted to give a talk I jumped at the opportunity. I spent a bit of time pulling resources together for the talk and I thought I would post them here in case anybody else could find a use for them. I have outlined the talk I gave below:Read More »
In 2012, the US Government cancelled a $5 billion camouflage project under which it had already supplied uniforms to soldiers in Afghanistan. The pattern of camouflage, called the “universal camouflage pattern” (UCP) was supposed to allow soldiers to blend in equally well in forests, deserts, and urban environments but had been deployed but never properly tested to ensure that it provided proper protection. When this testing was finally carried out, it demonstrated that the camouflage performed poorly, and was actually putting soldiers at unnecessary risk. It got so bad that US Army soldiers were trading their uniforms with locals so that they could wear something with appropriate colouration. What this goes to show is how poorly we understand the mechanisms underlying camouflage, even while we spend enormous amounts of money attempting to exploit the phenomenon. A new paper that my colleagues (based at Carleton University) and I published today in the Royal Society journal Biology Letters adds a key piece to the camouflage puzzle by illustrating for the first time the mechanism behind “disruptive colouration“. The paper can be viewed for free at the journal homepage, as can all Biology Letters articles, until 30th November 2013 – go browse, it’s a fascinating journal with short, varied, interesting papers.