The amazing island of New Guinea comprises only 1% of the world’s land area, but it’s home to an estimated 5% of all the planet’s plant and animal species, as many as half of which are yet to be formally described in science.
It has, for example, over 800 species of ant, around 60% of which are found nowhere else on the globe. And some of these animals resemble beasts straight from the realm of fantasy. And horror.
Take the two newest species of ant, whose appearance is so ferocious they have been named after fire-breathing dragons from Game of Thrones. Pheidole viserion and Pheidole drogon were classified using a high tech method of 3D imaging, which revealed the animals’ extraordinary exoskeletons, covered in vicious dagger-like spines.
But why have these creatures evolved such ornate body armour? The answer, according to Thomas O’Shea-Wheller, writing in The Conversation, lies in the make-up of the ant’s social structure.
The Pheidole group of ants, over 40 species of which are widely distributed across the island’s rainforests, all operate a caste system, with each type of ant assigned a different task within the colony. These are broadly divided into smaller ‘minor’ workers and larger ‘major’ workers, the latter commonly known as ‘soldier ants’ because one of their primary roles is defending the colony from predators and rival ants.
The soldier ants are several times bigger than the workers, and have huge heads, full of muscle, that make them formidable fighters. Scientists now believe that the increasing weight of their heads has forced special skeletomuscular adaptions within the body shape of these ants, and that this has been every bit as important as exoskeletal defence in driving the evolution of their dragon-like appearance.
Almost as exciting as the discovery of these spectacular species is the revolutionary method used to catalogue them, which involves scanning a mounted specimen with X-rays while rotating it 360 degrees, producing a 3D cross-section that can then be used to make a virtual model. As well as perfectly recreating their outward appearance, the technique also maps the insects’ internal structure, so scientists don’t need to dissect them to understand their physiology. It’s probable that this technique will ultimately make the old laborious method of preserving and pinning insects to sheets completely redundant.
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Ants are taking over the world. But then again, they were here first.
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