All insects have six legs, but they use these three pairs of legs in various ways of getting around.
All insects have three pairs of legs which allow them to get around in various ways, including walking, running, crawling, jumping, or swimming. These movements sometimes involve all six legs, but at other times only one or two pairs are used.
If you want to know more about how various insect move, please read on.
How Do Insects Move?
Insects move using muscles much as we do. While we have tendons that connect our muscles to our bones, insects have small hooks that connect their muscles to the exoskeleton.
Most insects get around using a tripod motion, planting the first and third feet on one side first and the middle foot on the other side. As they push forward, the insect moves forward.
Different speeds, however, affect the tripod gait. If walking slowly, they may move only one leg at a time, two at a medium speed, and moving three legs at high speed.
Only insects with an exoskeleton can use the tripod gait. Caterpillars pull the hind false legs forward, in turn pushing the body forward. This gives them the appearance of bunching their bodies up in the middle.
Butterflies And Moths
In contrast to beetles, some flying insects hardly ever use their legs for locomotion. Butterflies are rarely seen walking, and many have stunted front legs, which are more for tasting than walking.
Moths vary in their ability to walk and run. One species, the mouse moth, is known for the way in which it runs about, but another, the vapourer moth, hardly uses their legs for moving.
Most insects that run and walk can also climb as their feet are equipped with sharp claws for climbing rough surfaces and adhesive pads for smooth surfaces.
While in the larval stage, many butterflies, moths, sawfly caterpillars, and some species of sawfly larvae (those resembling caterpillars), have three pairs of jointed legs just behind the head.
They also have a series of prolegs along the hind part of the body. While the number of these false legs differs, moth and butterfly caterpillars usually have five pairs, while sawfly larvae have six to eight.
These larvae crawl by extending the front of the body and the true legs, then moving each pair of prolegs forward, the hindmost ones coming last. This can make them appear to run rather than crawl.
The caterpillars of some moths only possess the two hindmost pairs of prolegs. They progress by bending the body into a vertical loop, releasing the prolegs, and then bringing them forward to a position close behind the true legs. These then release their hold so the body can be extended forward again.
Beetles – The Fastest Running Insects
Beetles use all six legs, so movement is fairly straightforward when the insect progresses slowly. The first and third feet on one side and the second foot on the other are planted on the ground so that the insect is supported like a tripod.
A backward push by these three legs then carries the insect forward while at the same time, the other three legs are moved forward and planted to repeat the motion. When the insect moves quickly, this shifting tripod pattern becomes more complicated.
The most active runners among insects include several species of beetle. Tiger beetles can cover 60cm (2ft) in one second, which would be the equivalent of a horse running at 250mph.
Stick insects are another insect where not every pair does the same job. The front legs are used as feelers to sense what is in front, the middle legs are used to steer left and right, while the hind legs provide the energy to move forward.
The jumping power of the flea could not be explained through muscle as muscles do not contract fast enough for the 13-inch jumps they can perform, almost 200 times their body length.
Fleas have a pad of extremely elastic substance called resilin inside their thorax. When the flea is about to jump, the insect gathers up its hind legs, which bend the pad, storing energy there. The sudden release of the mechanism makes the stored energy available for a short time, supplying high-speed power for the jump.
Larger jumping insects, such as locusts and large grasshoppers, do not use resilin in this way but jump using muscular action.
Many insects live in fresh water and are capable swimmers, and almost always use their legs for propulsion through the water. Big diving beetles and water boatmen swim by pushing back their hind legs simultaneously on each side like a pair of oars.
Not all aquatic insects live underwater. Many spend their time skating on the surface film. Pond skaters are probably the most well-known and widely distributed aquatic insects, and can be seen moving across the water in forward jerks, their middle legs striking backward.
The pond skater uses all three pairs of legs in different motions. The hind legs are used as rudders, the middle pair push the insect through the water, and the forelegs are used to catch prey while swimming.
Water boatmen swim on their backs using their legs as paddles. They can not only be seen swimming on their boat-shaped backs but also taking to the air as they are efficient flyers.
Whirligig beetles are another familiar sight, using their hind legs to paddle, and keeping their backs above the water level but undersides and legs below.
The most intriguing surface skimmers are beetles of the genus Stenus, which discharge a liquid from their rear to lower the surface tension of the water. The higher water tension in front draws the insect forward in a smooth and steady glide.