🕷️ Are Spiders Insects?

Spiders are not insects, instead, they belong to arachnids. Spiders have two body segments, eight legs, multiple simple eyes, no antennae, and wings while insects have three body segments, six legs, one or two pairs of wings, and a pair of antennae. Therefore, spiders are not insects. Spiders are also not bugs because bugs are part of the Hemiptera order which belongs to the Insecta class. All bugs are insects and spiders are not insects. Therefore, spiders are not considered bugs.

Are spiders considered insects?

Have you ever wondered if spiders belong to animals, or insects or bugs or arachnids? Most people have the misconception that spiders are insects but actually, spiders are arachnid. Spiders are invertebrates and considered as arachnid instead of insects or bugs. Now you must be thinking what an arachnid is and how it is different from insects?

What is arachnid?

Arachnids are joint- legged invertebrates that have two body segments with eight legs. Along with these eight legs, arachnids also have two pairs of appendages that help in feeding, defense, and sensory perception. Arachnids include various species such as spiders, scorpions, ticks, mites, harvestmen, and solifuges.

How arachnids are different from insects?

Arachnids can be easily distinguished from insects by their anatomy.

  • Arachnids have two body segments: the cephalothorax (prosoma) and abdomen (opisthosoma) while the body of  insects can be divided into three segments: the head, thorax, and abdomen
  • All adult arachnids have eight legs while insects have only six legs.
  • Arachnids do not have antennae while insects have a pair of antennae
  • Arachnids have simple eyes while insects have compound eyes
  • Arachnids do not have wings while most insects have wings.
External anatomy of a female spider (Image credit: Peter coxhead )

Are spiders insects or arachnids?

The body of spiders is consists of two segments, the cephalothorax (combined head and thorax), and the abdomen. The cephalothorax part contains multiple eyes, four pairs of legs, and two pairs of appendages for feeding and defense. Spiders generally have eight simple eyes, however, it may vary with different species of spiders. Therefore, based on their external anatomy, spiders belong to arachnids.

Why are spiders not insects?

Do you still have confusion if spiders are insects or not?

Let’s go through the various differences between the spiders and the insects to clear this confusion. There are several reasons why spiders are not considered insects such as

  • Spiders have two body segments while insects have three body segments.
  • Spiders have eight legs while insects have six legs.
  • Spiders have simple eyes while insects have compound eyes.
  • Most of the insects have one or two pair wings while spiders don’t have wings.
  • Insects have antennae while spiders don’t have antennae.
  • Spiders usually have two pairs of appendages while insects have three appendages.
  • Respiration in spiders occurs through the trachea and book lungs while insects can respire only through the trachea.
  • The lifecycle of spiders includes a series of molting while insects go through complete metamorphosis.

Based on above differences, we can easily understand that spiders are not insects.

Difference between bugs, insects and arachnids (image credit: American Pest)

Are spiders bugs?

No, spiders are not bugs. In our causal conversion, we use the words ‘bugs” and ‘insects’ interchangeably. However, bugs and insects are not similar things. Technically all bugs are insects but all insects are not bugs. Bugs are part of the order Hemiptera while insects belong to Hymenoptera. Both these orders of insects (Hymenoptera) and bugs (Hemiptera) belong to class Insecta. We know that spiders belong to class arachnids. Therefore, spiders are not bugs.

Read more interesting questions about spiders:

Professor Atom

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Professor Atom is a science enthusiast and alumni of IIT Bombay. According to him, every question can be solved with curiosity and mind mapping. ( Curiosity = Asking Questions = Learning )

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