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Spiders are often mistaken for insects. Here you can find out why this is not the case, where the differences lie primarily in appearance and to which two classes arachnids and insects belong.
In a nutshell
- optical differences easily recognizable
- Tell spiders and insects apart based on the number of legs
- Assign arachnids to their own category
classification
Although spiders and insects belong to the stem group of arthropods (Arthropoda), they have their own classification: arachnids (Arachnida) and insects (Insecta). The different appearance of different anatomical parts of the body is of particular importance.
Spider (Arachnida) vs. Ant (Formicidae)
anatomy
The clearest distinguishing features between insects and spider species are in the physique or certain details of their appearance - which ultimately make them two different animal groups.
Limbs:
Insects belong to the subphylum of the six-legged family (Hexapoda) and therefore only have six legs, while spiders usually have six legs shows eight legs. In addition, the legs of the latter consist of seven joints - insect legs have only five joints per limb. Arachnids are also wingless and have no feelers. Arachnids can have other characteristics:
- usually significantly longer legs
- both front legs more flexible because they function similarly to insect feelers
- partly good jumping ability
Insect: Ribbed Curlew Beetle (Amphimallon solstitiale)
Anatomy:
The spider body is made up of two parts: the front and the back. An insect, on the other hand, always has three body sections, with the chest area clearly recognizable in addition to the front and rear parts.
Eyes:
If you look closely at the eye area, you can see some differences between spiders and insects:
- eight single eyes in arachnids - small reticulated/compound eyes in insects
- Spider with major and minor eyes - Insectas major eyes only
- Better visual quality for spiders because of separate image and motion detection (therefore usually faster escape reaction)
Giant crab spider (Sparassidae)
Notice: Did you know that there are spiders without eyes? This is the giant crab spider (Sparassidae), which was first discovered in 2012. However, the chance of encountering it in Europe is very low, as it is only native to Laos so far and lives there in complete darkness in caves.
spinnerets
Totally lacking in any insect is the ability to make silk threads/cobwebs. These produce arachnids through the so-called spinnerets, which are located on their rear end. With these they catch their prey in a completely different way than insects. Above all, arachnids target the insect for their food. They also use the spinnerets to construct the cocoons for their offspring.
poison
While the insect uses a stinger to secrete poison when attacking or to defend itself, the spider uses the so-called chelicerae to perform this function. They are also called "jaw feelers" because they are in the mouth. These are agile clawed tools that allow them to bite their prey while injecting venom into it. Anyone who keeps poisonous spiders in the house usually acquires specimens in which the poison glands have been removed. The claws are dedicated to life, because they use them to "grab" their food.
Chelicerae & Jaw Claw of a Wolf Spider (Lycosidae) vs. Stinger of a Bee (Apiformes)
Notice: Well over 80,000 different Arachnida species are known worldwide. However, more detailed information based on research is only available for about 41,000 species.
frequently asked Questions
Can spiders be combated with insecticides?If you mean chemical insecticides, these usually also work against spiders. However, you should not use these for the sake of the environment and your health. There are some home remedies that help against both types of arthropods. It is best to use fragrances that sell them. A vinegar-water mixture for spraying, for example, is ideal for this.
Are spiders as important to the ecosystem as insects?Yes, because arachnids contribute enormously to maintaining the natural balance. In addition, they are considered ideal predators of numerous insect pests, such as aphids.
Do arachnids hibernate like most insect species?As with insects, there are spider species that hibernate differently. Some are active in winter and others fall into the cold torpor in a sheltered winter quarters.