Richard Webster spent several months in 2013 tracking down moths for his camouflage research, proving just how frustrating – and effective – camouflage can be.So effective that his PhD thesis on disruptive camo led to an invitation to give a talk to the Department of National Defence’s Soldier Systems Unit.
An eye-tracking technology of Webster’s research offered up innovative testing that interested the military, which was engaged in measuring and evaluating their Canadian Armed Forces brand of camo known as CADPAT.
“It was stressful,” says Webster. “I was given a timeslot of 40 minutes to present all my findings and take their questions. It ended up lasting two and a half hours because they were so interested.”
Testing is a good thing.
The U.S. military is estimated to have spent $5 billion on their own “disruptive” camouflage without going through that step. They ultimately abandoned two specialized patterns for woodland and desert environments in 2004 before adopting the “Universal Camouflage Pattern.”
The Canadian Armed Forces adopted the computer-generated CADPAT in 1997 that features four different versions for different environments.
Webster’s PhD research in Carleton’s Biology Department (he is now a visiting researcher) explored whether the human eye could distinguish between two different kinds of camouflage: disruptive colouration and background matching. The eye-tracking technique he used gauged how long it took subjects to locate camouflaged moths on tree trunks. His thesis presented the hypothesis that disruptive camouflage in the animal kingdom enhances the survival rate far more than background matching.
“There’s some limitation to blending into a background because it’ll never be completely lined up and you’ll see the edge of the animal,” he said. “Disruptive camo tries to prevent the recognition of a target by masking features that are quickly identified.”
Last summer, Webster published a paper in Current Zoology to review his thesis findings and to present a new hypothesis he calls “global feature disruption.” The theory states that markings aim to camouflage revealing features of the animal as opposed to hiding random parts of its outline. Webster proposes that the distinctive features of an insect, like the wings of a moth, are disrupted to conceal their overall shape. This suggests that the moth is trying to look categorically less like a moth.
According to the article, the hypotheses on edge disruption and global feature disruption are not mutually exclusive. It suggests that animal markings could be exploiting a wider range of visual information to fool predators.
“There is a lot of new evidence to show how important global form disruption is to an animal’s survival,” said Webster.
Webster works alongside three postdoctoral students in Prof. Tom Sherratt’s lab. There’s a diverse range of ongoing projects, including UV colouration, how important insects are as predators, how animals learn to avoid something that’s distasteful, as well as Webster’s disruptive camouflage research.
During his preliminary research, Webster spent a lot of time walking around the woods of Ottawa looking for moths on trees. For three months, he and a team of research assistants traipsed in the woods many hours a day trying to find the cryptic animals that would help in his work. Now he’s developing a light to attract the moths that will add to his data instead of going out and putting their disruptive camo to the true test.
