Is a Spider an Insect?

For some people, spiders are a phobia, while others, on the contrary, are very delighted to see these creatures. Many people also believe that spiders are insects. Next, I’ll try to explain whether that’s the case or not.

What are spiders?

Spiders are a type of arachnid. About 50.000 spider species can be found worldwide, except in Antarctica. The body of spiders is divided into two segments, the cephalothorax, and the abdomen. Spiders can have up to eight simple eyes. The eight pairs of appendages or articulated legs are connected to the cephalothorax. Cephalothorax consists of the mouth tusks, brain, stomach, and glands, which produce poison.

What are insects?

Insects are a small type of invertebrate animals that are well adapted to the environment. They are relatively small in size. Around six to ten million insect species can be found around the world. Most insects live in terrestrial environments.

The body of insects is made of three segments: the head, thorax, and abdomen. The head consists of a pair of compound eyes and a pair of antennas. Usually, two pairs of wings and three pairs of legs are connected to the chest. The body is covered with an exoskeleton, which consists of chitin.

Insects undergo a complete metamorphosis. The four stages of the life cycle are the egg, larva/nymph, pupa, and adult. The three types of insect feeding mechanisms are chewing, sucking, and spongy. Chewing insects have mouth parts such as mandibles, maxilla, and labium. Spongy insects secrete saliva on solid foods, and the solution is extracted by the mouth.

The main difference – spiders versus insects

Spiders and insects are two types of invertebrate animals that belong to the Arthropoda seam. Therefore, both spiders and insects have articulated appendages. But spiders belong to the Arachnida class, while insects belong to the insect class. Therefore, spiders and insects have distinct anatomical features in their bodies.

The main difference between spiders and insects is how the body of these two is formed. The spider’s body is divided into two segments: cephalothorax and abdomen, while the one of the insect is divided into three segments: head, thorax, and abdomen. Spiders have eight legs linked to the cephalothorax and they don’t have wings. Insects have six legs connected to the chest. Their wings are also connected to the chest.

You might also like my articles on what tarantulas eat, how to set up a tarantula’s habitat, and whether tarantulas can swim.

Spiders have tiny structures that surround the oral columns and are called palps. They use them to hold the prey. Spiders don’t have wings. The abdomen of spiders consists of a type of gland called a thread from which silk is released outward. Most spiders make a web. Spiders secrete oils to stick their bodies to the webs. The feet of spiders are sensitive to vibrations and smells. Each leg consists of six joints, with a total of 48 knees.

Spiders suffer an incomplete metamorphosis. The three stages of a spider’s life cycle are the egg, larva/nymph, and adult. Spiders only feed on liquid food. Therefore, they have their intestine in the stomach. Most spiders are predators that inject venom into their prey to paralyze it. However, there are also herbivorous spiders.

Similarities between spiders and insects

• Both spiders and insects are invertebrates that belong to the Arthropoda seam.
• Both spiders and insects are mainly terrestrial.
• They both are triploblastic, hemocelomic animals with bilateral symmetry.
• Both spiders and insects have articular legs.
• The body of spiders and insects is segmented.
• Both spiders and insects have a chitinous exoskeleton.
• Both spiders and insects have compound eyes and antennas.
• Both spiders and insects are creatures that breathe air.
• Both spiders and insects have a complete digestive system.
• Both spiders and insects have an open circulatory system.
• Both spiders and insects are cold-blooded animals.
• Spiders and insects’ excretion occurs through the Malpighian tubules.
• The nervous system of spiders and insects is composed of a brain and a ventral nerve cord.
• Both spiders and insects are unisexual animals.
• Females of both spiders and insects hatch eggs.

The difference between spiders and insects

Definition

Spiders: Spiders are eight-legged predator arachnids, consisting of two segments of the body: the cephalothorax and abdomen.

Insects: Insects are small arthropods that possess six legs and one or two pairs of wings.

Scientific classification

Spiders: Spiders belong to the Arachnida class under the Arthropoda thread.

Insects: Insects belong to the insect class under the Arthropoda seam.

Habitat

Spiders: Spiders are mainly terrestrial.

Insects: Insects are mostly terrestrial, but there are also some insects that can be aquatic and parasitic.

Division of the body

Spiders: The body of spiders is compounded from cephalothorax and abdomen.

Insects: The body of insects is divided into the head, thorax and abdomen.

Skin appendages

Spiders: Spiders have four pairs of appendages.

Insects: Insects have three pairs of appendages.

Wings

Spiders: Spiders don’t have wings.

Insects: Many insects have wings.

Mouthparts

Spiders: Spiders possess chelicerae.

Insects: Insects possess mandibles, proboscis and maxilla.

Senses

Spiders: Spiders feel through their cuticles.

Insects: Insects have a pair of antennas through which they sense.

Eyes

Spiders have one to six pairs of simple eyes.

Insects: Insects have compound eyes.

Breathing

Spiders’ breathing occurs through the trachea and lungs simultaneously.

Insects: Insects’ respiration occurs through the trachea.

The color of the blood

Spiders: Spiders have blue colored blood.

Insects: Insects have colorless blood.

Diet

Spiders: Spiders are mainly predators.

Insects: Insects feed on both plant and animal food.

Metamorphosis

Spiders: Spiders undergo an incomplete metamorphosis.

Insects: Insects undergo a complete metamorphosis.

Examples

Spiders: The jumping spider, the black widow spider, the brownish rejected spider and tarantula are examples of spiders.

Insects: Butterfly, beetle, bee, ant, fly, termites, locusts, tree bugs and lice are examples of insects.

Conclusion

Spiders and insects are two types of arthropods, containing articulated appendages. The body of spiders is divided into two segments, the Cephalothorax and abdomen. However, the body of insects is divided into three segments, the head, thorax and abdomen. Spiders have eight legs, while insects have only six legs. Insects also have wings. Most spiders are predators. Insects can feed on both plant and animal materials. Therefore, the main difference between spiders and insects is the anatomical structure of the body and diet.