While both spiders and insects have exoskeleton and both look alike, there are many features that separate spiders from insects. They both are arthropods, but belong to separate Classes. Learn the important differences between these two magnificent groups.
- Spiders are invertebrates (the creatures without vertebral column) and fall under Class arachnida.
- The first significant feature is that all spiders have eight legs.
- The body is divided into two parts: Head and Abdomen.
- The legs sprout out from the back part of the head.
- All the spiders are predators, very smart and are effective killers.
- They inject the prey with their venom which digests the insides of the prey, so that the spider can drink up the predigested protein-rich soup.
- Except a few species, most spiders hunt regardless of the time of the day, especially those web building varieties. The kill begins when the prey gets stuck to the web.
- All species of spiders are venomous, but only a few are venomous enough to kill a human.
- The venom is delivered using its pair of fangs on the head (front end).
- They can produce silk from the two gun-like shapes at the bottom of the abdomen (rear end).
- All spiders can spin a web though many would not bother to construct one.
- Spiders have hair like features on their body.
- Spiders have simple eyes, with decent amount of vision. Vision is highly developed in some species such as jumping spiders.
- They have 4 to 8 eyes depending on the species.
- Spiders depend on their sense of touch and sight for hunting and moving around.
- Defense is by either staying still and blending with the background; or shaking vigorously and becoming invisible. The funnel webs and other ground based spiders dig themselves a hole in the ground.
- Insects are also invertebrates, but belong to Class Insecta.
- The first significant feature is that insects mostly have six legs.
- The body is distinctly divided into three parts: Head, thorax and Abdomen.
- The legs sprout out from the thorax.
- Depending upon the species of insects, they eat almost anything. Carnivores, herbivores, insectivores, omnivores, piscivores (fish-eating), flower-sucking (bees and butterflies) insects are found.
- The insects come with variety of types of teeth: to crush, to bite, to pinch, to suck, to chop, to cut, etc. There are even shear and scissor-like mouth types depending on the dietary pattern.
- Insects divide themselves to be diurnal (day-timers) or nocturnal (night-shift). However, quite a few are active only during dawn and dusk.
- Not all species of insects are venomous. Only a few like the scorpions are venomous, and only a very rare few are strong enough to bring down humans.
- The venom is delivered by various means. The scorpion and bees use their club or sting in the tail (rear end).
- Their silk is the modified form of their saliva (front end).
- Not all species of insects can produce silk. A few species such as silkworm and pupating caterpillars can produce high quality silk.
- Insects, with their caterpillars as exception, do not have hairs. They have bony spikes on their bodies if required.
- Most insects have compound eyes, with decent amount of vision. A few insects have good amount of vision, whereas quite a few can see only the colors close to the ultraviolet ranges.
- Insects have compound eyes, each of which having hundreds of tiny lenses. The number eyes and the degree of vision totally depends on the species.
- Insects use different senses depending on the species – chemical communication is most common one especially in case of ants and termites, vision in case of preying mantis or katydids, smell and heat in case of mosquitoes, touch, in case of cockroaches and insects with long antennas, etc.
- Defense is by mostly by hiding behind or within the leaves. However, there are a few insects which use chemical weapons such as bombardier beetle. Curling up, standing up for a fight, freeze to blend with the background, etc are some defense strategies used.