Arthropods have a great range of diversity. From arachnids that glow in the dark to insects that eat their mates, this phylum truly covers a wide array of animal behaviors and adaptations. After we look at the 4 types of arthropods, we will break down some of the most interesting families and species in this phylum. These animals truly have some unique and interesting behaviors.
Let’s get straight into it!
What is an arthropod?
Arthropods are invertebrates that have exoskeletons, aka external skeletons. They belong to the phylum Arthropoda which is the largest phylum in the animal kingdom and makes up at least 84% of all animals on the planet.
Arthropods have segmented bodies and jointed appendages. The name “arthropod” literally means “those with jointed feet”. Some examples of arthropods are insects, arachnids, myriapods, and crustaceans.
Are all insects arthropods?
Yes, all insects are arthropods though not all arthropods are insects.
Let’s have a look at the 4 types of arthropods.
4 main types of arthropods
1. Insects and springtails (Hexapoda)
Insects and springtails both are classified as hexapod invertebrates but have small differences. The defining characteristics of insects are:
- Three-part body: head, thorax, and abdomen
- Typically have wings
- Six jointed legs
Examples of insects include bees, flies, and cicadas. Springtails are similar, but do not have wings, are able to “jump” to incredible heights, and are smaller than insects.
2. Arachnids (Chelicerata)
Arachnids are similar to insect, but have a few distinct characteristics:
- Adults have eight legs (they only have six until they reach sexual maturity)
- Do not have antennae or wings
- Two-part body
Some common examples of arachnids are spiders, mites, scorpions, and ticks.
3. Crustaceans (Crustacea)
While most people think of crustaceans as water-dwelling animals, there are some crustaceans that live on the land. This subphylum is defined by the following characteristics:
- Two-parted limbs
- A bilaterally segmented symmetrical body
- Open circulatory system
Some examples of crustaceans include crabs, shrimp, woodlice, and barnacles.
4. Millipedes and centipedes (Myriapoda)
While there are distinct differences between millipedes and centipedes, the main defining characteristics of Myriapoda include:
- Two body sections (head and trunk)
- A pair of antennae
- Numerous repeating segments which include at least one pair of legs
- An upper and lower jaw.
Some examples of Myriapoda include millipedes, centipedes, and Symphyla.
14 examples of arthropods
Now that we have defined what an arthropod is and the four main types of arthropods let’s take a look at a few examples of arthropods and the different types that they fall into.
As common insects, ants are good examples of arthropods. Female worker ants don’t have wings; however, queen ants do have wings that they shed once they establish a new nest. Male ants also have wings.
There are over 12,000 different species of ants and some species have been around since the Cretaceous period. Some species of ants “war” with rival colonies. They will raid the nest of a rival colony and force the captured ants to work for the victorious colony.
2. Praying mantis
Most species of praying mantises have wings. In most cases, male mantises can fly and females cannot. There are over 2,000 different species of praying mantises, most of which live in tropical climates.
The praying mantis is carnivorous. The unique shape of the front legs of its front legs allows it to capture its prey easier. Additionally, some species practice sexual cannibalism, in which the female will consume the male during or after mating for nutrition.
Most people don’t realize it because of the grasshopper’s innate jumping ability, but most species of grasshoppers have wings. In fact, the loud noise that people associate with grasshoppers is created by the rubbing of the hind leg with the wing.
Grasshoppers are commonly green and brown and can be identified by their two large antennae. Unusually, their ears are located on their abdomen.
Many cultures eat grasshoppers on a regular basis as they are a cheap source of protein that is readily available. They can be eaten with chocolate, honey, as a powder, or simply by themselves.
The last Hexapoda on our list is one that most people are familiar with, the fly. Their unique identifying feature is that their large compound eyes that allow them to see almost 360˚at all times.
Flies live on a completely liquid diet as they lack the body parts to chew food. They convert whole food into liquid by regurgitating digestive juices to break it down. They can taste food before breaking it down through taste receptors on their feet.
Spiders are often confused as insects but are actually one of the most recognizable species of arachnids. There are over 36,000 different species of spiders that vary in color and ability. However, all adult spiders can spin silk and have eight legs.
Some species of spiders can actually spin several different types of silk for different purposes. The silk that it does produce is stronger than steel. While spiders may gross some people out, they actually help manage the insect population by killing insects like mosquitoes and flies.
Ticks also get often confused as insects, but if you look at a tick closely or even under a magnifying glass you will notice that tick resembles a spider and has eight legs. There are roughly 850 different species of ticks.
Ticks are parasites and survive from the blood of other animals. They cannot climb, but rather attach themselves by either falling off of vegetation or climbing up a host’s body. It varies by species, but some ticks can survive up to 200 days without a host.
Scorpions are another type of predatory arachnid. They are uniquely identified in the class due to their pincers and a long tail that ends with a venomous stinger. There are 1,750 known species of scorpions, but only 25 of those species are deadly to humans.
Unlike most arthropods, scorpions actually give birth to their young rather than laying eggs. Additionally, scorpions live a lot longer than most arthropods with an average lifespan of 2 to 10 years. You can easily spot a scorpion in the dark by turning on a UV light as they glow under these conditions.
Here are some common examples of scorpions in the state of Texas.
Mites are one of the smallest arthropods on our list. They can only be seen using a microscope and are only about 0.1 mm to 0.4 mm in size. If you ever get the opportunity to see a mite you will notice that it looks a lot like a spider.
Mites are everywhere and on everyone. There are mites living on your skin right now. One of the most commonly discussed mites is the dust mite. These are the source of common allergies and can be controlled using bed and pillow covers and filtration systems.
Crabs are the first water-dwelling animals on our list. Like fish, crabs have gills; however, as long as crabs gills remain damp they are able to breathe on land. There are over 4,500 different species of crab.
Crabs are recognized as decapods. They technically have ten legs, but two of the ten are their claws. Some species can actually shed and regenerate their limbs. Crabs can move in any direction but typically move sideways.
Shrimp are characterized by their compressed body, semitransparent exoskeleton, and fan-like tail. Like crabs, shrimp have ten legs. There are over 2,000 different species of shrimp.
Shrimp’s coloring is adaptable based on its habitat. You find brownish-green shrimp in muddy river beds and brightly colored shrimp in tropical locations. Most shrimp are not born with a specific gender. Environmental and other factors play a role in determining the gender at a later stage in the shrimp’s life.
Barnacles are one of the most unique and versatile crustaceans on our list. Most people recognize barnacles by their gray, volcano-shaped outer layer that are commonly found on piers and boat hulls. However, certain types of barnacles, like the rhizocephalan barnacle are actually parasites in other crustaceans.
While on the outside barnacles don’t look very much like a crustacean, inside of their outer plate barnacles look very similar to crabs. Barnacles do have tiny legs called cirri, but they don’t use them to move. They actually use their legs to collect tiny food particles from the water.
There are two different main types of lobsters: clawed and spiny. The clawed lobster has a pincer and crusher claw, while the spiny lobster does not have claws, but has a harder outer shell. There are about 90 different species of lobsters.
While lobsters turn red during the cooking process due to the expression of astaxanthin, they are typically a greenish-brown color while living. Lobsters have some unusual characteristics like peeing out of their face and having two different stomachs (one of which is located behind its eyes).
Millipedes don’t actually have 1,000 feet. It varies by species, but most millipedes have less than 100 and only two sets of feet per individual segment. They look very similar to worms only a little rounder and of course, they have feet, while worms do not.
The back of a millipede has hardened plates that will protect it from predators, while its underside is soft and vulnerable. When these decomposers feel threatened they will coil their bodies and emit either a bad-smelling or potentially acidic chemical. Millipedes have been around for a long time, so long that scientists believe they were the first animals to live on land.
Centipedes and millipedes look very similar but have a few differentiating characteristics. They only have one set of legs per segment, while millipedes have two sets. Centipedes eat insects, while millipedes eat decomposing pants. Additionally, centipedes will try to bite if they feel threatened, while millipedes coil up.
As mentioned earlier, centipedes are predators. They rely on their antennae to find a potential food source and then use their quick speed to capture and kill the prey. They are extremely fast, covering 1.3 feet per second.