To fly or not to fly

   One of the first, and maybe the biggest advantages invertebrates have over vertebrates, is their ability to fly. Primitive insects were the first animals on earth to fly: before dinosaurs, before birds, before bats. There are many different hypotheses about how flight evolved in insects and it remains a contentious subject. However, once insects did evolve the ability to fly, they were able to take over an environment no other animal had laid claim on. And they soon dominated it.

Some Pepsis wasps, showing off their large orange-colored wings

 Once insects were able to fly, they were able to move across large areas very quickly in search of food, new habitats, and mates. If the water dried up in a pond, they could fly to another one. If the plant they were feeding on lost most of its nutrition, they could fly off to find a new plant. Until dinosaurs, birds and bats evolved, the only other predators insects had to worry about were other insects. Many insects got very large earlier in Earth's history, with some species related to dragonflies getting as large as 6 feet in diameter, wing-tip to wing tip (Meganeura)!
    So, with all of the benefits of flying and having wings, why would a grasshopper, like the ones in the family Romaleidae (Lubber grasshoppers) have evolved to have small, nearly non-functional wings?

Brachystola sp. Lubber grasshopper found at Black Mesa, Oklahoma

   Well, its because having wings can be "expensive" for the body. Being able to fly requires large amounts of muscle tissue to be able to bend, twist, and move the wings. Especially for insects, which have a hard exoskeleton they have to pull and push like plates. This requires a lot of protein, energy to fuel the muscles, and weight.
    In many cases where the cost to the insect's body to maintain the muscles and wings is higher than the cost without them for finding food, a mate, or escaping predators, some insects have evolved to put those resources and energy to other structures as part of a "trade off". For insects such as grasshoppers, which spend most of their time munching on plants as herbivores to extract the nutrients from the grasses and other plants (think of them as the cows of the insect world of sorts), it may be better to not have wings if you aren't going to use them. Especially since grasshoppers have another formidable way to get away and disperse...they can jump really well! If investing more in their legs to jump is better than the wings, then evolution will likely push the grasshoppers to bigger legs and smaller wings. Check out how big the hind legs are on the grasshopper above!
     So, while most insects still fly and fly very well, there are a few insects that took the route less traveled and are now sticking to the ground again. If you are looking for insects, don't forget to look down as well as up!