Most people find spiders to be terrifying enough without having to consider the possibility that they may be able to fly. The good news is that spiders don’t have wings, and they cannot fly. Some spider species, however, can travel great distances by casting long strands of silk into the air and riding the wind until they reach their destination. Continue reading to discover why spiders don’t have wings.
Why don’t spiders have wings?
There doesn’t seem to be a good explanation for why spiders don’t have wings. In terms of evolution, they followed paths that were similar to those of winged insects and even displayed similar lifestyle and behavioural characteristics as insects. At some point during the course of evolution, something caused a split between the two, which resulted in insects developing wings and spiders developing silk. Maybe the insects developed wings so they could escape from the mouths of spiders.
Spider silk
Spider silk is a protein fibre spun by spiders using the spinnerets located at the bottom of their abdomen. Spiders use their silk to construct webs to catch their prey and even attract mates. Some species of spiders leave a continuous trail of pheromone-infused silk that spiders of the opposite sex can follow to find potential mates.
Spiders can also use their silk to suspend themselves in the air and to escape from potential predators. A single spider can produce up to seven different types of silk that all have different uses.
Not all spiders build webs. Some of them use silk to create nests or cocoons to protect their young. Egg sacs typically consist of multiple types of silk to help the eggs blend in with their surroundings and protect them from the elements. A single female spider can lay hundreds of eggs, which will hatch into spiderlings.
Some species of spiders will abandon their eggs once they have laid them, but most are maternal, so they stay and protect them. Once the eggs hatch, the spiderlings will become independent and live their lives in solitude.
Where do spiders come from?
According to National Geographic, there are over 45,000 unique species of spiders, and you can find them on every continent except Antarctica. Spiders evolved from arthropods. Arthropods were the first creatures to leave the water millions of years ago to become land dwellers. Arthropods are a larger class of animals that also includes insects, myriapods, and crustaceans. Because spiders evolved from arthropods, they can live in both land and aquatic environments.
Arthropods evolved into a wide variety of other animals, including centipedes, scorpions, mites, ticks, crabs, shrimp, and lobsters, and are classified as invertebrates. All arthropods have exoskeletons, segmented bodies and legs with jointed segments. The word “arthropod” translates to “jointed foot.”
The difference between spiders and insects
The bodies of insects are divided into three primary sections: the head, which houses the eyes, mouth, and antennae; the thorax, which houses the legs and sometimes wings; and the abdomen, which houses the reproductive organs, gut, and sometimes stingers. Spiders only have two body parts, called the cephalothorax and the abdomen. Here are some more of the differences between spiders and insects:
- Spiders have chelicerae, insects have mandibles
- Spiders have eight legs; insects have six
- Spiders don’t have wings, but many insects do
- Spiders don’t have antennae; insects do
- Spiders moult their exoskeletons, insects go through metamorphosis
Moulting
Spiders have an exoskeleton that acts as a suit of armour, protecting their internal organs. They are tough and flexible, so they can move around easily. However, for spiders to grow, they need to go through a process called moulting. During the moulting process, a spider will shed its entire exoskeleton at once.
In the days leading up to their moult, a spider will seek refuge in a burrow or some other secluded area. They will also stop eating. During the process of moulting, more than two-thirds of the blood and hemolymph from the abdomen move into the cephalothorax, which causes the back of the cephalothorax to separate from the body. The spider must then wiggle itself free.
Once the spider is free of its old exoskeleton, it will begin to pump its legs to create pressure that will cause the new exoskeleton to expand to its full size. The spider is extremely vulnerable during this stage as its new exoskeleton is very soft.
Environmental conditions can have an effect on how successfully a moult is completed. If it’s too dry, it’s possible that the spider will lose a limb or two as it tries to free itself. However, if the spider is young enough, it is possible for the limb to regrow. After a few moults, the limb will grow back completely.
How do spiders eat?
Spiders are carnivorous, which means they eat insects, including ants, bees, mosquitoes, cockroaches, centipedes, aphids, flies, beetles, and occasionally other spiders. The majority of them can only consume liquid food. When they catch their prey, they squirt digestive enzymes into it, which causes the prey’s internal organs to liquefy, allowing them to suck up the juice.
Arthropod categories
Insects form the largest portion of the arthropod family, including ants, bees, beetles, butterflies, cicadas, cockroaches, crickets, dragonflies, fleas, flies, grasshoppers, lightning bugs, mosquitos, moths, termites, and wasps.
There are over 40,000 different species of arachnids, including spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders, and vinegaroons.
There are around 13,000 species of myriapod, including millipedes, centipedes, symphyla, arthropleuridea, and Pauropoda. They have numerous body parts, which are typically carried by a pair of legs, and they don’t have wings.
