Giant bugs have been clad in Mad Max-esque leather armor and pitted against each other in brutal brawls. Why? All in the name of science.
To be more precise, the battling bugs (video below) were part of two new studies that looked to understand what gives an individual the edge while engaging in insect-on-insect conflict, as well as the evolution of different weapon shapes.
For the first part of the research, published in the journal Functional Ecology, scientists at the University of Arizona wanted to see whether strong armor or a powerful weapon helped the insect win the fight.
"Biologists have generally assumed that the individual who inflicts more damage on their opponent will be more likely to win a given fight," John J Wiens, study author and a professor at the University of Arizona Department of Ecology and Evolutionary Biology, said in a statement. "Surprisingly, this fundamental assumption had yet to be tested in an experimental study."
Their experiments used a heavily armored species of leaf-footed bugs found in the American Southwest and Northwestern Mexico, known as giant mesquite bugs. These species gather in the desert trees during the summer and fight for access to females, using spikes to inflict damage on their competitors.
For their experiment, some of the bugs were given faux leather armor on their wings to provide extra protection against punctures from the spikes of rivals. The duels showed that individuals with this leather armor on their wings were 1.6 times more likely to win fights compared to those without extra armor, or with the same amount of armor placed on another part of the body. Crucially, this suggests that winning the fight isn't all about offensive weapons, but also defensive structures.
"This tells us that damage is important in who wins the fights," lead author and postdoctoral student Zachary Emberts adds. "This had previously been hypothesized, and it makes intuitive sense, but it had not been experimentally shown before."
Interestingly, different species of leaf-footed bugs have evolved very different types of weaponry. For the next part of the research, reported in the journal Proceedings of the Royal Society B, scientists wanted to test the idea that the evolution of different weapon shapes is linked to how much damage they can afflict.
The team looked at data on 17 different species of leaf-footed bug and found that some weapons are more effective than others at causing damage to opponents. Once again, this might sound fairly self-evident, but it’s an idea that’s never actually been tested before.
"How well the weaponry is performing - how much damage it inflicts in fights - is driving its diversification," explains Wiens.
"This finding helps answer the question, why don't all weapons evolve to look the same?" Wiens explained. "Rather than evolving towards one optimal weapon shape, there are very different shapes that perform almost as well, solving the mystery of why weapons look so different among species."