What is the difference between arachnids and insects?

And can't arachnids and insects both be classified as "bugs" (slang term of course)?

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  • Todd
    Lv 7
    1 decade ago
    Favorite Answer

    Arachnids have two body segments, Insects have three.

    Arachnids have 12 appendages; a pair of Chelicerae, a pair of Pedipalps, and 4 pairs of legs, insects have 6 legs. (not including antennae).

    Arachnids do not have true mouth parts, instead having a labium attached to a muscular stomach and appendages modified for feeding called chelicerae. Insects have true mouth parts, that vary from chewing to sucking mouth parts.

    Arachnids have simple eyes, insects usually have a pair of compound eyes and several other simple eyes.

    Insects have antennae, arachnids do not.

    Some insects have one or two pairs of wings, no arachnids have wings.

    Arachnids mostly respire with one or more pairs of book lungs, but sometimes have an internal system of trachea, or just have trachea. Insects respire by a system of trachea connected to spiracles.

    Arachnids have a more centralized nervous system than insects do. Insects have an array of ganglia down the abdomen to control body functions.

    Arachnids have a more complex circulatory system then insects, with veins and arteries supplying hemolyph (arthropod blood) to the different sections of the body. Insects do not have veins or arteries.

    Arachnids and insects have a very different digestive systems. Arachnids have a muscled stomach used for vomiting digestive juices on food, then sucking up these juices, followed by a simple system of intestines to absorb the nutrients and store fat. Insects possess saliva glands to start the digestive process, a crop for storing food, a gizzard for grinding food, and a gastric caeca and tract for absorbing the nutrients.

  • 1 decade ago

    Defining characteristics of insects:

    - 3 pairs of legs

    - 1 pair of antennae

    - 3 body segments (head, thorax, and abdomen)

    Defining characteristics of arachnids:

    - 4 pairs of legs

    - No antennae

    - 2 body segments (cephalothorax and abdomen)

    Also important: wings are not a defining character of insects because not all insects have wings. However, if an arthropod (including insects and arachnids) has wings, it must be an insect.

    You can use the slang term liberally outside of biology, but note that there is a group of insects known as 'true bugs,' the Order Hemiptera, which includes giant water bugs, stink bugs, and cicadas, just to name a few.

  • 1 decade ago

    arachnids have 8 legs and insects have 6 legs and they both can be called bugs

  • 1 decade ago

    Insects have six legs, arachnids have eight.

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  • 1 decade ago

    Though Arachnids and insects belong to Arthropod phylum having jointed legs, the differ in their body structure, feeding habitats and behavioral pattern. Insects have exoskeleton where as arachnids don't. And also insects have mandible , where as arachnids don't..

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