Spiders do not have a backbone. Therefore, they are considered invertebrates. They range from 6 millimeters to 10 – 12 inches, and all spiders have eight legs.
Spiders are arachnids having two body sections, the abdomen, and the cephalothorax. Spider’s head is in the front of the cephalothorax, and their mouthparts are on the either side just behind their eyes. They also have four pairs of jointed legs that extend from under their cephalothorax. These jointed legs help spiders move around quickly, catch prey, and sense vibrations in their environment, such as those made by potential victims or mates nearby.
Spiders are among the most diverse and successful animals on the planet because of their adaptability, intelligence, and ingenuity.
Spiders have an astonishing number of adaptations for catching prey. They can spin webs, produce sticky silk, design lures to attract insects by using vibrations or other stimuli such as light patterns or chemical emissions. Some spiders even create decoys to lure prey closer.
Numerous types of spiders can be found around the world. A few examples of these include American house spiders, tarantulas, and black widow spiders, to name just a few. Many people think that spiders cause painful bites, while others fear them because they look terrifying or have venom. In contrast, most spiders aren’t harmful to humans and only a few dozen species are considered poisonous. Even so, most spiders will bite if they’re handled or threatened, while some also tend to be aggressive towards others of the same species.
With all these interesting facts about spiders, some still confuse whether these little creatures are insects or not. In this article, we’ll explore some fun facts about these eight-legged creatures that live in our homes and gardens every day!
What Makes a Bug an Insect?
Insects are the most diverse group of animals, and they are among the most abundant. Their success is due partly to their complex life cycle, which varies from about one year for an aphid to more than two years for a butterfly. The developmental stage affects how insects look, behave and eat. Depending on whether they have wings or six legs, insects are classified into three groups:
1) true bugs – Hemiptera; 2) beetles – Coleoptera; 3) bees, wasps and ants – Hymenoptera.
Bugs belong to the order Hemiptera. They have a soft, flexible body cover, and they go through incomplete metamorphosis. Insects are invertebrates with a three-part body with three pairs of jointed legs, one set of antennae, and wings that may or may not be present.
True bugs or Heteroptera are insects with forewings, modified into complex cases called hemelytra. Their mouthparts form a long beak that they are using for sucking. Most of them feed on plant sap, and there may or may not be an ovisac present, depending on the species.
True bugs are found worldwide in all ecosystems, but most species live in tropical and subtropical climates. The majority of true bug species feed on plant juices, while a few sucks the blood of mammals or birds. True bugs are primarily herbivores (plant-eaters), with a few exceptions that are omnivorous (that eat both plants and animals) or carnivorous (that eat other insects
Their front pair of wings is thickened, leathery, and heavily veined. They are often brightly colored as a warning to predators that they are distasteful. True bugs cannot bite or sting. The small spines on their legs help keep them from slipping off plants while feeding.
Like the beetle, true bugs have a hard exoskeleton that they must periodically shed and replace with a new one as it becomes too small for them to grow. Then, in the final molt before adulthood, they develop wings and reproductive structures.
True bugs are highly diverse in shape, size, and color. They can be as small as 0.08 in (2 mm) like the White Apple Leafhopper or Elephant Eater, or nearly 5 in (12 cm) long like the Giant Mesquite Bug. Most are 2-6 in (5–15 cm) long, with a few exceptions that are larger than this.
Are Spiders Insects?
Spiders are arachnids and not insects, which means they have eight legs, two body segments, and no antennae or wings. Insects are invertebrates with six legs, three body segments, and one pair of antennae or wings. Spiders belong to the class Arachnida while insects belong to the class Insecta. One way to tell if a creature is an insect, is by looking at its mouthparts. Insects have mandibles that work like scissors for chewing food. Arthropods (including arachnids) don’t need to chew because their diet consists primarily of liquids. They absorb nutrients through their feet instead of using a stomach like vertebrates.
One of the main differences between insects and spiders is that they have different lifestyles and body parts. The insects’ lifestyle is through metamorphosis, which means that they change their form several times to become new creatures. They lay eggs, hatch as larvae, then turn into pupae, then finally emerge as adults. Spiders, on the other hand, usually start life as a spider and never change their form. They are spiders until they die.
Spiders and insects have different bodies. Insects have a body segmented into three parts, the abdomen, thorax, and head. On the other hand, spiders do not have these segments or ahead. Instead, they are made up of two body segments with an abdomen on the front of them, and all their legs come off from there (although some spiders have three parts). Another difference between the two is their antennae. Insects have antennae, and spiders do not.
What Characteristics Do Spiders and Insects Share?
Spiders and insects have several characteristics that they share. One of the most prominent characteristics is that they both have exoskeletons. These are on the outside of their bodies and they are using these to protect them. The exoskeleton also protects against drying out. Both insects and spiders have an open circulatory system where blood flows through pores or holes in the external body surface to exchange gases. Insects have antennae that help them sense nearby objects; spiders do not have these but rely more on their eyes. Finally, both rely on jointed appendages to move about locomotion, although insects use six legs for movement while spiders only use two different parts including what are known as book lungs which extract oxygen from air and silk glands which produce silk.
One adaptation is that insects and spiders are the way they breathe. Both organisms are transporting oxygen and carbon dioxide through the body via a circulatory system consisting of tubes called tracheae or vessels. The oxygen enters the insect’s body through spiracles, along the sides of the thorax and abdomen. The carbon dioxide leaves the body through a spiracle or a stoma on the insect’s abdomen through a tracheal opening. This opening is very similar to the gaps found in spiders that release waste.
Another adaptation used by both insects and spiders is how they excrete. Both organisms retain their nitrogenous wastes so that they may reuse the components again for metabolic processes. In insects, waste is stored as uric acid in a Malpighian tubule structure and released through an opening known as the uropodal valve into the anus. This structure is found in spiders and insects, though it is more developed in spiders than insects.
Why Are Spiders Not Insects?
There are many misconceptions about spiders, but the most common is that they’re insects.
One of the reasons people think insects and arachnids (like spiders) are related is that they look alike! If you see a picture of a spider, it might be hard to tell the difference between it and an insect.
They do not have six legs or go through metamorphosis, but they kind of look alike. They both have long bodies with multiple sets of legs, and although some spiders can be giant (some even more significant than a human hand), most are small enough to fit on the head of a pin.