Evolution has a strange way of doing things.
So maybe the princess in the fairy tale kissed a frog instead of a grasshopper, but if she had kissed a grasshopper instead, she would have noticed something odd.
Grasshoppers, on the other hand, do not have lips. They do, however, have mouthparts that are frighteningly similar to the differences in our own teeth (depending on what those teeth are used for). Some are more like molars, designed to chew difficult plant matter so that it may be digested. Others look like incisors and are used to snare prey and rend flesh. Not all of these critters appear to eat the grass through which they crawl and leap. Some are carnivorous, while others are omnivorous.
Finding out what grasshoppers eat used to entail either seeing them in action — which is difficult when dealing with a fast-moving creature — or dissecting them to determine their stomach contents. When dealing with specimens of rare or even extinct species, dissection might be difficult. A better solution has been discovered, according to Chris Stockey of the University of Leicester in the United Kingdom, who conducted a study just published in Methods in Ecology and Evolution.
"Dental topography analysis," he explained to SYFY WIRE, "maps the 3D geometry of a food-processing item, be it a tooth or, in this case, a mandible, akin to a map." "Different forms reflect adaptations to various diets, and most creatures' relationships are the same."
By comparing the forms of grasshopper mouthparts to mammalian teeth, Stockey and his team were able to determine which species ate what by comparing what was in their mouths to mammalian teeth designed for the same purpose. Finding a match in the teeth of a known-to-eat mammal reveals the grasshopper's diet. Undulating surfaces with complex topography, such as those found on molars, suggest that the insect is interested in plants. Sharper teeth indicate a desire for flesh. These can be compared to your own molars and canines.
Although the dental topographic analysis was designed for mammals, it can be used on any mouthparts that mimic mammalian teeth and are used to analyze food before it is eaten. Using it on grasshoppers has proven certain long-held beliefs about what they eat. Before taking a closer look, the researchers had already made assumptions about what each species ate. However, they were startled to discover that of the 45 grasshopper species they analyzed, the smaller species were the ones that chased worms or other insects.
What does this suggest for the existing grasshoppers' oldest common ancestor? Unfortunately, insects do not fossilize well unless they are caught in amber, but Stockey believes that herbivorous and carnivorous insects existed in the past.
"We know the oldest grasshoppers from molecular clocks,' which are models that estimate when groups developed," he explained. "However, many of their close cousins were eating both plants and insects at the time, so I would guess they were eating both early on."
Even stranger than grasshopper mouthparts resembling mammalian teeth is the theory that grasshoppers and mammals shared a common ancestor approximately half a billion years ago. This has to have happened before the line between vertebrates and invertebrates began to blur. When the researchers looked at mouthparts, they discovered what could only be morphological changes that particular species have to make to live. When you don't have control over what you eat, you either adapt or die out.
The ability to determine what grasshoppers ate based on the shape of their mouthparts have helped to save some extremely vulnerable specimens. What you may not realize when looking at a museum display is that there are huge archives beyond the places where visitors are permitted. Behind the scenes, Darwin's complete collection is hidden. Using dental topographic analysis, all that remains of now-rare or extinct species do not have to be destroyed in order to learn what they ate and how it changed their environments.
"By using this technique to analyze their mouthparts, we can learn about their diets and, more significantly, incorporate them into bigger evaluations of how ecosystems function as a whole," Stockey explained. "In certain ways, we can resurrect them."